Category Archives: Cross-listed

Landscape of stellar-mass black-hole spectroscopy with third-generation gravitational-wave detectors [CL]

Posted on by

http://arxiv.org/abs/2304.02283


Gravitational-wave black-hole spectroscopy provides a unique opportunity to test the strong-field regime of gravity and the nature of the final object formed in the aftermath of a merger. Here we investigate the prospects for black-hole spectroscopy with third-generation gravitational-wave detectors, in particular the Einstein Telescope in different configurations, possibly in combination with Cosmic Explorer. Using a state-of-the-art population model for stellar-origin binary black holes informed by LIGO-Virgo-KAGRA data, we compute the average number of expected events for precision black-hole spectroscopy using a Fisher-matrix analysis. We find that Einstein Telescope will measure two independent quasinormal modes within ${\cal O}(1)\%$ (resp. ${\cal O}(10)\%$) relative uncertainty for at least ${\cal O}(1)$ (resp. ${\cal O}(500)$) events per year, with similar performances in the case of a single triangular configuration or two L-shaped detectors with same arm length. A 15-km arm-length configuration would improve rates by roughly a factor of two relative to a 10-km arm-length configuration. When operating in synergy with Cosmic Explorer the rates will improve significantly, reaching few-percent accuracy for ${\cal O}(100)$ events per year.

Read this paper on arXiv…

S. Bhagwat, C. Pacilio, P. Pani, et. al.
Thu, 6 Apr 23
24/76

Comments: 13 pages, 9 figures

Peregrine: Sequential simulation-based inference for gravitational wave signals [CL]

Posted on by

http://arxiv.org/abs/2304.02035


The current and upcoming generations of gravitational wave experiments represent an exciting step forward in terms of detector sensitivity and performance. For example, key upgrades at the LIGO, Virgo and KAGRA facilities will see the next observing run (O4) probe a spatial volume around four times larger than the previous run (O3), and design implementations for e.g. the Einstein Telescope, Cosmic Explorer and LISA experiments are taking shape to explore a wider frequency range and probe cosmic distances. In this context, however, a number of very real data analysis problems face the gravitational wave community. For example, it will be crucial to develop tools and strategies to analyse (amongst other scenarios) signals that arrive coincidentally in detectors, longer signals that are in the presence of non-stationary noise or other shorter transients, as well as noisy, potentially correlated, coherent stochastic backgrounds. With these challenges in mind, we develop peregrine, a new sequential simulation-based inference approach designed to study broad classes of gravitational wave signal. In this work, we describe the method and implementation, before demonstrating its accuracy and robustness through direct comparison with established likelihood-based methods. Specifically, we show that we are able to fully reconstruct the posterior distributions for every parameter of a spinning, precessing compact binary coalescence using one of the most physically detailed and computationally expensive waveform approximants (SEOBNRv4PHM). Crucially, we are able to do this using only 2\% of the waveform evaluations that are required in e.g. nested sampling approaches. Finally, we provide some outlook as to how this level of simulation efficiency and flexibility in the statistical analysis could allow peregrine to tackle these current and future gravitational wave data analysis problems.

Read this paper on arXiv…

U. Bhardwaj, J. Alvey, B. Miller, et. al.
Thu, 6 Apr 23
27/76

Comments: 14 pages, 5 figures. Code: peregrine available at this https URL

Study of deflection angles, thin accretion structure, and the observational signatures of a static $f(R)$ black hole [CL]

Posted on by

http://arxiv.org/abs/2304.02111


In this paper, we constrain the linear dark-matter-related parameter of a static spherically symmetric f (R) black hole spacetime regarding the observed angular diameters of M87* and Sgr A* from the EHT. We then investigate the light deflection angles inferred from direct analytical calculation of null geodesics and that obtained from the Gauss-Bonnet theorem. Assuming an optically thin accretion disk for the black hole and after discussing its properties, we conceive different emission profiles and investigate the shadow cast of this black hole when it is illuminated by the disk. Furthermore, we simulate the brightness of an infalling spherical accretion in the context of the silhouette imaging of the black hole. We find that, excluding some specific cases, the specific observed brightness of the accretion disk consists of the direct emission, rather than that for the lensing and photon rings. Furthermore, it is revealed that the linear dark parameter of the black hole has considerable effects on the size of the shadow and its brightness. The discussion is done both analytically and numerically, and ray-tracing methods are employed to generate proper visualizations

Read this paper on arXiv…

M. Fathi and N. Cruz
Thu, 6 Apr 23
41/76

Comments: 28 pages, 87 figures

Testing generalized neutrino interactions with PTOLEMY [CL]

Posted on by

http://arxiv.org/abs/2304.02505


There are several unanswered questions regarding neutrinos which pave the way for physics beyond the standard model (SM) of particle physics. Generalized interactions of neutrinos provide a way to characterize these effects in a manner which is even more general than the oft-studied non-standard neutrino interactions. These interactions are described by higher dimensional operators maintaining the SM gauge symmetries. On the other hand cosmic neutrino background, although yet to be detected directly, is a robust prediction of the SM and the standard cosmology. We perform a global analysis of the relevant generalized neutrino interactions which are expressly relevant for the proposed cosmic neutrino detector PTOLEMY. The electron spectrum due to the capture of cosmic neutrinos on radioactive tritium gets modified due to the presence of these generalized interactions. We also show how the differential electron spectrum is sensitive to the finite experimental resolution, mass of the lightest neutrino eigenstate, the strength of these interactions and the ordering of neutrino mass.

Read this paper on arXiv…

I. Banerjee, U. Dey, N. Nath, et. al.
Thu, 6 Apr 23
44/76

Comments: 22 pages, 5 figures, 5 tables

Primordial Black Hole Leptogenesis in Supersymmetry [CL]

Posted on by

http://arxiv.org/abs/2304.02604


We have studied the role of Hawking evaporation of primordial black hole in the production of the supersymmetric particles like sneutrinos – the super-partner of heavy right handed neutrinos. Considering lepton number violating decays of such particles and $CP$ violating phases due to soft supersymmetry breaking terms, we have obtained the baryonic asymmetry of the universe which depends on the mass of primordial black holes. Apart from CMB and BBN constraints on such mass, we have shown more stringent upper bound on this mass from the requirement of black hole evaporation temperature to be above the temperature required for almost first order phase transition so that leptogenesis could create the observed baryonic asymmetry. We have shown how the primordial black hole mass, heavy right handed neutrino mass and soft supersymmetry breaking parameters are related from the requirement of successful leptogenesis and the allowed parameter space to avoid gravitino problem. Considering experimental constraint on branching ratio of $\mu \rightarrow e \gamma $, we have shown the connection of right handed neutrino mass scale with the lower bound of the typical mass scale of supersymmetric particles.

Read this paper on arXiv…

S. Khan and R. Adhikari
Thu, 6 Apr 23
46/76

Comments: 14 pages, 3 figures

Temperature and Strong Magnetic Field Effects in Dense Matter [CL]

Posted on by

http://arxiv.org/abs/2304.02454


We study consistently the effects of magnetic field on hot and dense matter. In particular, we look for differences that arise due to assumptions that reproduce the conditions produced in particle collisions or astrophysical scenarios, such as in the core of fully evolved neutron stars. We assume the magnetic field to be either constant or follow a profile extracted from general relativity calculations of magnetars and make use of two realistic models that can consistently describe chiral symmetry restoration and deconfinement to quark matter, {the CMF and the PNJL models}. We find that net isospin, strangeness, and {weak} chemical equilibrium with leptons can considerably change the effects of temperature and magnetic fields on particle content and deconfinement in dense matter. We finish by discussing the possibility of experimentally detecting quark deconfinement in dense and/or hot matter and the possible role played by magnetic fields.

Read this paper on arXiv…

J. Peterson, P. Costa, R. Kumar, et. al.
Thu, 6 Apr 23
47/76

Comments: N/A

Gravitational lens on an optical constant-curvature background: Its application to Weyl gravity model [CL]

Posted on by

http://arxiv.org/abs/2304.02219


We describe the gravitational lens on a constant-curvature background by using an optical constant-curvature (OCC) approach that allows to explicitly take into account a global geometry of the background space. First, light rays are curves in the space described by an optical metric. The OCC approach focuses on the case that the optical metric for the background spacetime has a constant curvature, for which the exact lens equation on an OCC background [Phys. Rev. D 105, 084022 (2022)] can be used. As a concrete example, next we discuss the gravitational lens in Mannheim-Kazanas (MK) solution, which include Rindler and de Sitter terms. By fully taking into account a background dependence of the light deflection, the deflection angle of light consistent with the OCC approach is well defined at large distance. In the OCC approach, finally, we examine the global behavior of the deflection angle and the gravitational lens observables in the Weyl gravity.

Read this paper on arXiv…

K. Takizawa and H. Asada
Thu, 6 Apr 23
52/76

Comments: 11 pages, 4 figures

Causality bounds on scalar-tensor EFTs [CL]

Posted on by

http://arxiv.org/abs/2304.01259


We compute the causality/positivity bounds on the Wilson coefficients of scalar-tensor effective field theories. Two-sided bounds are obtained by extracting IR information from UV physics via dispersion relations of scattering amplitudes, making use of the full crossing symmetry. The graviton $t$-channel pole is carefully treated in the numerical optimization, taking into account the constraints with fixed impact parameters. It is shown that the typical sizes of the Wilson coefficients can be estimated by simply inspecting the dispersion relations. We carve out sharp bounds on the leading coefficients, particularly, the scalar-Gauss-Bonnet couplings, and discuss how some bounds vary with the leading $(\partial\phi)^4$ coefficient and as well as phenomenological implications of the causality bounds.

Read this paper on arXiv…

D. Hong, Z. Wang and S. Zhou
Thu, 6 Apr 23
53/76

Comments: 72 pages, 15 figures

Gravitational Waves Produced by Domain Walls During Inflation [CL]

Posted on by

http://arxiv.org/abs/2304.02361


We study the properties of the stochastic gravitational wave background (SGWB) produced by domain walls (DWs) during inflation without forming a network. We numerically simulate the DW production caused by a second-order phase transition and calculate the SGWB spectrum using a $1000\times1000\times1000$ lattice. We show that the SGWB can be observed directly by future terrestrial and spatial gravitational wave detectors and through the B-mode spectrum in CMB. This signal can also explain the common noise process observed by pulsar timing array experiments. With numerical simulations, we derive an empirical formula for the strength and qualitative features of the SGWB spectrum. The details of the SGWB spectrum also contain information about the later evolution of the universe.

Read this paper on arXiv…

H. An and C. Yang
Thu, 6 Apr 23
68/76

Comments: 5 pages, 7 figures + appendix

Borel resummation of secular divergences in stochastic inflation [CL]

Posted on by

http://arxiv.org/abs/2304.02592


We make use of Borel resummation to extract the exact time dependence from the divergent series found in the context of stochastic inflation. Correlation functions of self-interacting scalar fields in de Sitter spacetime are known to develop secular IR divergences via loops, and the first terms of the divergent series have been consistently computed both with standard techniques for curved spacetime quantum field theory and within the framework of stochastic inflation. We show that Borel resummation can be used to interpret the divergent series and to correctly infer the time evolution of the correlation functions. In practice, we adopt a method called Borel–Pad\'{e} resummation where we approximate the Borel transformation by a Pad\'{e} approximant. We also discuss the singularity structures of Borel transformations and mention possible applications to cosmology.

Read this paper on arXiv…

M. Honda, R. Jinno, L. Pinol, et. al.
Thu, 6 Apr 23
71/76

Comments: 40 pages, 12 figures

Gravitational echoes of lepton number symmetry breaking with light and ultralight Majorons [CL]

Posted on by

http://arxiv.org/abs/2304.02399


We formulate a version of the low-scale Majoron model equipped with an inverse seesaw mechanism featuring lepton-number preserving dimension-6 operators in the scalar potential. Contrary to its dimension-4 counterpart, we find that the model can simultaneously provide light and ultralight Majorons, neutrino masses and their mixing, while featuring strong first-order cosmological phase transitions associated to the spontaneous breaking of the lepton number and the electroweak symmetries in the early Universe. We show by a detailed numerical analysis that under certain conditions on the parameter space accounted for in collider physics, the model can be probed via the primordial gravitational wave spectrum potentially observable at LISA and other planned facilities.

Read this paper on arXiv…

A. Addazi, A. Marcianò, A. Morais, et. al.
Thu, 6 Apr 23
72/76

Comments: 29 pages, 7 figures

Hybrid stars with reactive interfaces: analysis within the Nambu-Jona-Lasinio model [CL]

Posted on by

http://arxiv.org/abs/2304.01898


It has been shown recently that quark-hadron conversions at the interface of a hybrid star may have a key role on the dynamic stability of the compact object. In this work we perform a systematic study of hybrid stars with reactive interfaces using a model-agnostic piecewise-polytropic hadronic equation of state and the Nambu-Jona-Lasinio model for three-flavor quark matter. For the hadronic phase we use a soft, an intermediate and a stiff parametrization that match at $1.1 n_0$ {with predictions} based on chiral effective field theory (cEFT) interactions. In the NJL Lagrangian we include scalar, vector and ‘t Hooft interactions. The vector coupling constant $g_{v}$ is treated as a free parameter. We also consider that there is a split between the deconfinement and the chiral phase transitions which is controlled by changing the conventional value of the vacuum pressure $-\Omega_{0}$ in the NJL thermodynamic potential by $-\left(\Omega_{0}+\delta \Omega_{0}\right)$, being $\delta \Omega_{0}$ a free parameter. We analyze the mass-radius ($M$-$R$) relation in the case of rapid ($\tau \ll 1 \, \mathrm{ms}$) and slow ($\tau \gg 1 \, \mathrm{ms}$) conversions, being $\tau$ the reaction timescale. In the case of slow interface reactions we find $M$-$R$ curves with a cusp at the maximum mass point where a pure hadronic branch and a slow-stable hybrid star (SSHS) branch coincide. We find that the length of the slow-stable branch grows with the increase of the transition density and the energy density jump at the hadron-quark interface. We calculate the tidal deformabilities of SSHSs and analyse them in the light of the GW170817 event.

Read this paper on arXiv…

C. Lenzi, G. Lugones and C. Vasquez
Wed, 5 Apr 23
7/62

Comments: 12 pages, 4 figures, to be published in Physical Review D

Oscillon formation during inflationary preheating with general relativity [CL]

Posted on by

http://arxiv.org/abs/2304.01673


We study the non-perturbative evolution of inflationary fluctuations during preheating using fully non-linear general-relativistic field-theory simulations. We choose a single-field inflationary model that is consistent with observational constraints and start the simulations at the end of inflation with fluctuations both in the field and its conjugate momentum. Gravity enhances the growth of density perturbations, which then collapse and virialize, forming long-lived stable oscillon-like stars that reach compactnesses $\mathcal{C}\equiv GM/R \sim 10^{-3}-10^{-2}$. We find that $\mathcal{C}$ increases for larger field models, until it peaks due to the interplay between the overdensity growth and Hubble expansion rates. Whilst gravitational effects can play an important role in the formation of compact oscillons during preheating, the objects are unlikely to collapse into primordial black holes without an additional enhancement of the initial inflationary fluctuations.

Read this paper on arXiv…

J. Aurrekoetxea, K. Clough and F. Muia
Wed, 5 Apr 23
14/62

Comments: 7 pages. 4 figures. Comments welcome! Movie: this https URL

Nucleosynthesis and observation of the heaviest elements [CL]

Posted on by

http://arxiv.org/abs/2304.01850


The rapid neutron capture or ‘r process’ of nucleosynthesis is believed to be responsible for the production of approximately half the natural abundance of heavy elements found on the periodic table above iron (with proton number $Z=26$) and all of the heavy elements above bismuth ($Z=83$). In the course of creating the actinides and potentially superheavies, the r process must necessarily synthesize superheavy nuclei (those with extreme proton numbers, neutron numbers or both) far from isotopes accessible in the laboratory. Many questions about this process remain unanswered, such as ‘where in nature may this process occur?’ and ‘what are the heaviest species created by this process?’ In this review, we survey at a high level the nuclear properties relevant for the heaviest elements thought to be created in the r process. We provide a synopsis of the production and destruction mechanisms of these heavy species, in particular the actinides and superheavies, and discuss these heavy elements in relation to the astrophysical r process. We review the observational evidence of actinides found in the Solar system and in metal-poor stars and comment on the prospective of observing heavy-element production in explosive astrophysical events. Finally, we discuss the possibility that future observations and laboratory experiments will provide new information in understanding the production of the heaviest elements.

Read this paper on arXiv…

E. Holmbeck, T. Sprouse and M. Mumpower
Wed, 5 Apr 23
19/62

Comments: 63 pages, 17 figures

Black hole superradiant instability for massive spin-2 fields [CL]

Posted on by

http://arxiv.org/abs/2304.01265


Due to coherent superradiant amplification, massive bosonic fields can trigger an instability in spinning black holes, tapping their energy and angular momentum and forming macroscopic Bose-Einstein condensates around them. This phenomenon produces gaps in the mass-spin distribution of astrophysical black holes, a continuous gravitational-wave signal emitted by the condensate, and several environmental effects relevant for gravitational-wave astronomy and radio images of black holes. While the spectrum of superradiantly unstable mode is known in great detail for massive scalar (spin-0) and vector (spin-1) perturbations, so far only approximated results were derived for the case of massive tensor (spin-2) fields, due to the nonseparability of the field equations. Here, solving a system of ten elliptic partial differential equations, we close this program and compute the spectrum of the most unstable modes of a massive spin-2 field for generic black-hole spin and boson mass, beyond the hydrogenic approximation and including the unique dipole mode that dominates the instability in the spin-2 case. We find that the instability timescale for this mode is orders of magnitude shorter than for any other superradiant mode, yielding much stronger constraints on massive spin-2 fields. These results pave the way for phenomenological studies aimed at constraining beyond Standard Model scenarios, ultralight dark matter candidates, and extensions to General Relativity using gravitational-wave and electromagnetic observations, and have implications for the phase diagram of vacuum solutions of higher-dimensional gravity.

Read this paper on arXiv…

O. Dias, G. Lingetti, P. Pani, et. al.
Wed, 5 Apr 23
24/62

Comments: 5+1 pages, 2+1 figures

The dipolar death of massive gravity [CL]

Posted on by

http://arxiv.org/abs/2304.01252


We study extreme-mass-ratio systems in theories admitting the Schwarzschild solution and propagating a massive graviton. We show that, in addition to small corrections to the quadrupolar and higher-order modes, a dipolar mode is excited in these theories and we quantify its excitation. While LIGO-Virgo-KAGRA observations are not expected to impose meaningful constraints in the dipolar sector, future observations by the Einstein Telescope or by LISA, together with bounds from dispersion relations, can rule out theories of massive gravity admitting vacuum General Relativistic backgrounds. For the bound to be circumvented, one needs to move away from Ricci-flat solutions, and enter a territory where constraints based on wave propagation and dispersion relations are not reliable.

Read this paper on arXiv…

V. Cardoso, F. Duque, A. Maselli, et. al.
Wed, 5 Apr 23
48/62

Comments: 4 pages plus Supplemental Material

On a Super-Complete Mathematical Model of Ambipolar Processes of Cumulation and Dissipation in Self-Focusing Structures in Plasma of Planetary Atmospheres in plasma with current [CL]

Posted on by

http://arxiv.org/abs/2304.01231


4D mathematical models of structurally related (conjugated, entangled, dual) phenomena of dissipation and cumulation of electrical energy (an external source in continuous media) are discussed, accompanied by the formation of cumulative-dissipative structures and their ordering into a regular system – a dynamic dissipative “crystal” with a long-range dynamic order. The excitation of new degrees of freedom in such systems provides attractiveness or geometric self-focusing of energy-mass-momentum flows (EMMF) for the entire regular system. As a result of cumulation, EMMF structures acquire hyper-properties. The cumulation of EMMF in rendered structures is a common property of media activated to form 4D structures. The basis of such a dissipative structure is an attractor, the end result of which is a cumulative jet from an attractor with hyper-properties. Therefore, these structures are cumulative-dissipative. We discuss a method for describing these structures and prove that cumulative processes in plasmoids exist and can be described theoretically, although not with the help of full-fledged mathematical 4D models. It has been theoretically and experimentally proven that the cumulation of the electric field due to the ambipolar drift of the plasma is an inherent property of the current carrying gas-discharge plasma. The results obtained by modeling shock waves of the electric field (E/N) can be useful to explain the cumulative formation in the heliosphere, atmosphere and ionosphere of the Earth, since the Earth has a negative charge of about 500,000 C, and the Sun positively charged at the level of 1400 C. Based on the mathematical approach, a classification of shock waves and types of cumulation in 4D space-time will be carried out.

Read this paper on arXiv…

P. Vysikaylo
Wed, 5 Apr 23
52/62

Comments: 5 pages, 4 figures, this https URL

Freeze-in of WIMP dark matter [CL]

Posted on by

http://arxiv.org/abs/2304.00908


We propose a novel scenario for dark matter (DM) in which weakly interacting massive particles (WIMPs) can freeze-in due to a first-order phase transition (FOPT) in the early Universe. The FOPT dilutes the preexisting DM density to zero, and leads to a sudden change in DM mass that prevents WIMPs from re-equilibrating due to their large mass-to-temperature ratio. Following the FOPT, WIMPs are produced via a freeze-in process, even though their interactions are NOT feeble. We demonstrate this concept using a simplified model and then realize the scenario in a realistic model with a delayed electroweak phase transition. Our work extends the category of WIMP DM and opens up a new direction for the freeze-in mechanism.

Read this paper on arXiv…

X. Wong and K. Xie
Tue, 4 Apr 23
11/111

Comments: 4 pages + 3 figures + references

Primordial black hole collision with neutron stars and astrophysical black holes and the observational signatures [CL]

Posted on by

http://arxiv.org/abs/2304.00348


One of the candidates for the dark matter in the galactic halos is the low-mass Primordial Black holes (PBHs). They can gravitationally interact and collide with astrophysical objects such as neutron stars and astrophysical black holes.
The physical process such as accretion of matter and dynamical friction happens during the collision with neutron stars and gravitation wave emission during the collision with the astrophysical black holes. In this work, we investigate the rate of this collision, and the possibility of capturing PBHs within the neutron stars or the astrophysical black holes. Also, we investigate the observational consequences of this collision such as generating anomalies in the spinning period of neutron stars, formation of bond states, and detection of gravitational waves by future detectors.

Read this paper on arXiv…

S. Rahvar
Tue, 4 Apr 23
17/111

Comments: 5 pages

Polaronic Proton and Diproton Clustering in Neutron-Rich Matter [CL]

Posted on by

http://arxiv.org/abs/2304.00535


We show that strong spin-triplet neutron-proton interaction causes polaronic protons to occur in neutron matter at subnuclear densities and nonzero temperature. As the neutron density increases, proton spectra exhibit a smooth crossover from a bare impurity to a repulsive polaron branch; this branch coexists with an attractive polaron branch. With the neutron density increased further, the attractive polarons become stable with respect to deuteron formation. For two adjacent protons, we find that the polaron effects and the neutron-mediated attraction are sufficient to induce a bound diproton, which leads possibly to diproton formation in the surface region of neutron-rich nuclei in laboratories as well as in neutron stars.

Read this paper on arXiv…

H. Tajima, H. Moriya, W. Horiuchi, et. al.
Tue, 4 Apr 23
20/111

Comments: 6 pages, 4 figures (8 pages, 6 figures in the supplement)

La inserción de la Astronomía Cultural en la educación formal: fundamentos y propósitos [CL]

Posted on by

http://arxiv.org/abs/2304.01113


There are vast educational research works that highlight the serious difficulties that students present in learning astronomical subjects, as well as the prevalence of a traditional education distanced from the observational and experiential, thus accentuating the difficulties detected. We argue that progressive teaching with a topocentric and contextualized approach would favor the motivation of the students, the construction of a more real view of current science and a more active role in the learning process. Cultural Astronomy (CA) is an academic discipline that seeks to understand the multiple ways in which societies relate to celestial objects and phenomena. For this reason, we consider that it would be a powerful resource for teaching, since it provides tools for contextualization and allows working with sky experiences linked to “naked eye astronomy”, which requires little or no instruments. It should be noted that CA involves aspects of archaeoastronomy, ethnoastronomy and the history of astronomy, thus offering multiple dimensions to take into account. The present work seeks to base the incorporation of CA studies for astronomy teaching in secondary and tertiary education.

Read this paper on arXiv…

J. Bastero, F. Karaseur, S. Garofalo, et. al.
Tue, 4 Apr 23
23/111

Comments: Article in Spanish. Published version available at this http URL

Sensing Quantum Nature of Primordial Gravitational Waves Using Electromagnetic Probes [CL]

Posted on by

http://arxiv.org/abs/2110.10962


Based on optical medium analogy, we establish a formalism to describe the interaction between an electromagnetic (EM) system with gravitational waves (GWs) background. After a full discussion on the classical treatment of the EM-GW interaction and finding the EM field mode-functions in the presence of the magneto-dielectric media caused by GWs, the governing quantum interaction Hamiltonian is obtained. Investigation of the optical quadrature variance as well as the visibility of a laser field interacting with the multi-mode squeezed primordial gravitational waves imply that the inflationary primordial gravitational waves (PGWs) act as a decoherence mechanism that destroy EM coherency after a characteristic time scale, $\tau_{c}$, which depends on the inflationary parameters $(\beta,\beta_s,r)$, or equivalently, the fractional energy density of PGWs, $\Omega_{gw,0}$. The decoherency mechanism overcomes the coherent effects, such as revivals of optical squeezing, thus leaving their confirmation out of reach. Influenced by the continuum of the squeezed PGWs, the laser field suffers a line-width broadening by $\gamma= \tau_{\text{c}}^{-1}$. The most peculiar property of the EM spectrum is the apparition of side bands at $\omega\sim \omega_0\pm 1.39 \tau_c^{-1}$Hz, stemming from the squeezed nature of PGWs. The laser phase noise induced by the squeezed PGWs grows with time squarely, $\Delta\phi=(t/\tau_c)^2$, that can most possibly be sensed within a finite flight time.

Read this paper on arXiv…

F. Arani, M. Harouni, B. Lamine, et. al.
Tue, 4 Apr 23
33/111

Comments: 14 pages, 4 figures

Can supermassive black holes triggered by general QCD axion bubbles? [CL]

Posted on by

http://arxiv.org/abs/2304.00939


The supermassive black holes (SMBHs) are ubiquitous in the center of galaxies, although the origin of their massive seeds is still unknown. In this paper, we investigate the SMBHs formation from the general QCD axion bubbles. In this case, the primordial black holes (PBHs) are considered as the seeds of SMBHs, which are generated from the QCD axion bubbles due to an additional Peccei-Quinn (PQ) symmetry breaking after inflation. The QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase transition (PT). We consider the general case in which the QCD axion bubbles are formed with the bubble effective angle $\theta_{\rm eff}\in(0, \, \pi]$, leading to the minimum PBH mass $\sim\mathcal{O}(10^4-10^7)M_\odot$ with $\theta_{\rm eff}\sim\pi$ to $\pi/3$ for the axion scale $f_a\sim\mathcal{O}(10^{16})\, \rm GeV$. The PBHs at this mass region may be the seeds of SMBHs.

Read this paper on arXiv…

H. Li, Y. Peng, W. Chao, et. al.
Tue, 4 Apr 23
39/111

Comments: 7 pages, 4 figures

Modified Newtonian Dynamics as an Alternative to the Planet Nine Hypothesis [CL]

Posted on by

http://arxiv.org/abs/2304.00576


A new class of Kuiper belt objects that lie beyond Neptune with semimajor axes greater than 250 astronomical units show orbital anomalies that have been interpreted as evidence for an undiscovered ninth planet. We show that a modified gravity theory known as MOND (Modified Newtonian Dynamics) provides an alternative explanation for the anomalies using the well-established secular approximation. We predict that the major axes of the orbits will be aligned with the direction towards the galactic center and that the orbits cluster in phase space, in agreement with observations of Kuiper belt objects from the new class. Thus MOND, which can explain galactic rotation without invoking dark matter, might also be observable in the outer solar system.

Read this paper on arXiv…

K. Jones-Smith and H. Mathur
Tue, 4 Apr 23
46/111

Comments: Under review at the Astronomical Journal. Complementary to the findings of Migaszewski in arXiv:2303.13339

Solar radio emissions and ultralight dark matter [CL]

Posted on by

http://arxiv.org/abs/2304.01056


Ultralight axions and dark photons are well-motivated dark matter candidates. Inside the plasma, once the mass of ultralight dark matter candidates equals the plasma frequency, they can resonantly convert into electromagnetic waves, due to the coupling between the ultralight dark matter particles and the standard model photons. The converted electromagnetic waves are monochromatic. In this article, we review the development of using radio detectors to search for ultralight dark matter conversions in the solar corona and solar wind plasma.

Read this paper on arXiv…

H. An, S. Ge and J. Liu
Tue, 4 Apr 23
51/111

Comments: 13 pages, 3 figures. An invited review for the special issue “Solar Radio Emissions” in the journal Universe

Electrostatic Model for Antenna Signal Generation From Dust Impacts [CL]

Posted on by

http://arxiv.org/abs/2304.00452


Dust impacts on spacecraft are commonly detected by antenna instruments as transient voltage perturbations. The signal waveform is generated by the interaction between the impact-generated plasma cloud and the elements of the antenna-spacecraft system. A general electrostatic model is presented that includes the two key elements of the interaction, namely the charge recollected from the impact plasma by the spacecraft and the fraction electrons and cations that escape to infinity. The clouds of escaping electrons and cations generate induced signals, and their vastly different escape speeds are responsible for the characteristic shape of the waveforms. The induced signals are modeled numerically for the geometry of the system and the location of the impact. The model employs a Maxwell capacitance matrix to keep track of the mutual interaction between the elements of the system. A new reduced-size model spacecraft is constructed for laboratory measurements using the dust accelerator facility. The model spacecraft is equipped with four antennas: two operating in a monopole mode, and one pair configured as a dipole. Submicron-sized iron dust particles accelerated to > 20 km/s are used for test measurements, where the waveforms of each antenna are recorded. The electrostatic model provides a remarkably good fit to the data using only a handful of physical fitting parameters, such as the escape speeds of electrons and cations. The presented general model provides the framework for analyzing antenna waveforms and is applicable for a range of space missions investigating the distribution of dust particles in relevant environments.

Read this paper on arXiv…

M. Shen, Z. Sternovsky, A. Garzelli, et. al.
Tue, 4 Apr 23
60/111

Comments: Manuscript accepted online by JGR: Space Physics on 13 August 2021

Performance of the MALTA Telescope [CL]

Posted on by

http://arxiv.org/abs/2304.01104


MALTA is part of the Depleted Monolithic Active Pixel sensors designed in Tower 180nm CMOS imaging technology. A custom telescope with six MALTA planes has been developed for test beam campaigns at SPS, CERN, with the ability to host several devices under test. The telescope system has a dedicated custom readout, online monitoring integrated into DAQ with realtime hit map, time distribution and event hit multiplicity. It hosts a dedicated fully configurable trigger system enabling to trigger on coincidence between telescope planes and timing reference from a scintillator. The excellent time resolution performance allows for fast track reconstruction, due to the possibility to retain a low hit multiplicity per event which reduces the combinatorics. This paper reviews the architecture of the system and its performance during the 2021 and 2022 test beam campaign at the SPS North Area.

Read this paper on arXiv…

M. Rijnbach, G. Gustavino, P. Allport, et. al.
Tue, 4 Apr 23
85/111

Comments: N/A

Nuevas estrategias de enseñanza: unidades didácticas basadas en temas de la Astronomía Cultural [CL]

Posted on by

http://arxiv.org/abs/2304.01131


One of the main difficulties that students have in learning astronomy topics is that they fail to relate theoretical information with what they experience in the world around them. The construction by students of a conceptual framework in accordance with the astronomical scientific model demands changes in the current teaching approach. Within this framework, Cultural Astronomy (CA) is a discipline that we can use to rethink new didactic strategies. This paper presents two contextualized proposals from CA. In the first one, the teaching of space and time concepts is approached through traditional examples of orientation by the stars and the use of the calendar, using the case of historical ocean navigation without advanced instruments already highlighted in ethnoastronomical studies. In the second, these concepts are worked on from a case study, this time archaeoastronomical: the monumental horizon calendar of the Chankillo archaeological site, and then continue with the local identification of horizon markers that allow students to build their own calendars. The aim is to illustrate ways of introducing CA elements in didactic units that have as one of their main objectives that the students manage to establish correspondences between constructions of the micro to the mega-space that surrounds them.

Read this paper on arXiv…

F. Karaseur, J. Bastero, S. Garofalo, et. al.
Tue, 4 Apr 23
86/111

Comments: Article in Spanish. Published version available at this http URL

Spontaneous Human Combustion rules out all standard candidates for Dark Matter [CL]

Posted on by

http://arxiv.org/abs/2304.00319


We argue that the reported cases of Spontaneous Human Combustion (SHC) are most likely due to the impact of the human body with an extremely high energy particle like cosmic rays or Dark Matter. Normal and antimatter cosmic rays and classical weakly-interacting massive particles (WIMPs) with energies of GeV to ZeV can be easily ruled out due to their inability to dump enough energy into a small region of human tissue, leaving as the single remaining candidate massive Dark Matter particles. While primordial Black Holes would appear to be very good candidates for inducing the SHC phenomenon, we show that the estimated local Dark Matter density requires that the particles have masses of $\sim 10$\,kg, clearly ruling out this candidate. All of the other classic DM candidates — from scalar and pseudo-scalar spin 1/2 and spin 2 gauge singlets to nuclearitic strange quark “bowling balls” — can be ruled out. Axions tailored to solve the CP-problem also cannot be invoked, no matter what mass is considered. The only particles left are massive mega-axions (MaMAs), for which there are an infinite number of possible string models.

Read this paper on arXiv…

F. Hessman and J. Wheeler
Tue, 4 Apr 23
88/111

Comments: N/A

Topological densities in Einstein-scalar-Gauss-Bonnet gravity [CL]

Posted on by

http://arxiv.org/abs/2304.00322


The present work is devoted to studying the background dynamical evolution of a scalar field in Einstein-Gauss-Bonnet gravity in maximally symmetric space-time. This study is useful for giving meaning to the presence of two Gauss-Bonnet vacua, instead of using the spherically symmetric bubbles of the “true” vacuum expand in the “false” vacuum. The theory admits two possible effective cosmological constants, which lead to two maximally symmetric vacuum solutions. The first solution corresponds to the dynamics of dark energy. When there is matter, the second solution describes dark matter. In Einstein-Gauss-Bonnet gravity, we establish the expression of the topological mass spectrum which depends on the golden ratio and its inverse. In the Schwarzschild limit, the topological density corresponds to the standard model radiation energy density. We find the mass loss rate which gives the evolution of mass over time.

Read this paper on arXiv…

M. Bousder and Z. Sakhi
Tue, 4 Apr 23
96/111

Comments: 19 pages, 1 figure

A Long-Baseline Atom Interferometer at CERN: Conceptual Feasibility Study [CL]

Posted on by

http://arxiv.org/abs/2304.00614


We present results from exploratory studies, supported by the Physics Beyond Colliders (PBC) Study Group, of the suitability of a CERN site and its infrastructure for hosting a vertical atom interferometer (AI) with a baseline of about 100 m. We first review the scientific motivations for such an experiment to search for ultralight dark matter and measure gravitational waves, and then outline the general technical requirements for such an atom interferometer, using the AION-100 project as an example. We present a possible CERN site in the PX46 access shaft to the Large Hadron Collider (LHC), including the motivations for this choice and a description of its infrastructure. We then assess its compliance with the technical requirements of such an experiment and what upgrades may be needed. We analyse issues related to the proximity of the LHC machine and its ancillary hardware and present a preliminary safety analysis and the required mitigation measures and infrastructure modifications. In conclusion, we identify primary cost drivers and describe constraints on the experimental installation and operation schedules arising from LHC operation. We find no technical obstacles: the CERN site is a very promising location for an AI experiment with a vertical baseline of about 100 m.

Read this paper on arXiv…

G. Arduini, L. Badurina, K. Balazs, et. al.
Tue, 4 Apr 23
100/111

Comments: 51 pages, 39 figures, version with higher resolution figures available from this https URL

Laboratory Study of Antenna Signals Generated by Dust Impacts on Spacecraft [CL]

Posted on by

http://arxiv.org/abs/2304.00453


Space missions often carry antenna instruments that are sensitive to dust impacts, however, the understanding of signal generation mechanisms remained incomplete. A signal generation model in an analytical form is presented that provides a good agreement with laboratory measurements. The model is based on the direct and induced charging of the spacecraft from the collected and escaping fraction of free charges from the impact-generated plasma cloud. A set of laboratory experiments is performed using a 20:1 scaled-down model of the Cassini spacecraft in a dust accelerator facility. The results show that impact plasmas can be modeled as a plume of ions streaming away from the impact location and a cloud of isotropically expanding electrons. The fitting of the model to the collected antenna waveforms provides some of the key parameters of the impact plasma. The model also shows that the amplitudes of the impact signals can be significantly reduced in typical space environments due to the discharging effects in the ambient plasma.

Read this paper on arXiv…

M. Shen, Z. Sternovsky, M. Horányi, et. al.
Tue, 4 Apr 23
107/111

Comments: Manuscript accepted online by JGR: Space Physics on 05 April 2021

Energy flow in Ultra High Energy Cosmic Ray interactions as a probe of thermalization and potential solution to the Muon puzzle [CL]

Posted on by

http://arxiv.org/abs/2304.00294


Indicators that illustrate the formation of a strongly interacting thermalized matter of partons have been observed in high-multiplicity proton-proton, proton-nucleus, and nucleus-nucleus collisions at RHIC and LHC energies. Strangeness enhancement in such ultra-relativistic heavy-ion collisions is considered to be a consequence of this thermalized phase, known as quark-gluon plasma (QGP). Simultaneously, proper modeling of hadronic energy fraction in interactions of ultra-high energy cosmic rays (UHECR) has been proposed as a solution for the muon puzzle. These interactions have center-of-mass collision energies in the order of LHC or higher, indicating that the possibility of a thermalized partonic state cannot be overlooked in UHECR-air interactions. This work investigates the hadronic energy fraction and strangeness enhancement to explore QGP-like phenomena in UHECR-air interactions using various high-energy hadronic models. A thermalized system with statistical hadronization is considered through the EPOS LHC model, while PYTHIA 8, QGSJET II-04, and SYBILL 2.3d consider string fragmentation in the absence of any thermalization. We have found that EPOS LHC gives a better description of strangeness enhancement as compared to other models. We conclude that adequately treating all the relevant effects and further retuning the models is necessary to explain the observed effects.

Read this paper on arXiv…

R. Scaria, S. Deb, C. Singh, et. al.
Tue, 4 Apr 23
109/111

Comments: 7 pages and 6 figures. Submitted for publication

Variability of Antenna Signals From Dust Impacts [CL]

Posted on by

http://arxiv.org/abs/2304.00454


Electric field instruments carried by spacecraft (SC) are complementary to dedicated dust detectors by registering transient voltage perturbations caused by impact-generated plasma. The signal waveform contains information about the interaction between the impact-generated plasma cloud and the elements of SC-antenna system. The variability of antenna signals from dust impacts has not yet been systematically characterized. A set of laboratory measurements are performed to characterize signal variations in response to SC parameters (bias voltage and antenna configuration) and impactor parameters (impact speed and composition). The measurements demonstrate that dipole antenna configurations are sensitive to dust impacts and that the detected signals vary with impact location. When dust impacts occur at low speeds, the antennas typically register smaller amplitudes and less characteristic impact signal shapes. In this case, impact event identification may be more challenging due to lower signal-to-noise ratios and/or more variable waveforms shapes, indicating the compound nature of nonfully developed impact-generated plasmas. To investigate possible variations in the impacting materials, the measurements are carried out using two dust samples with different mass densities: iron and aluminum. No significant variations of the measured waveform or plasma parameters obtained from data analysis are observed between the two materials used.

Read this paper on arXiv…

M. Shen, Z. Sternovsky and D. Malaspina
Tue, 4 Apr 23
110/111

Comments: Manuscript accepted online by JGR: Space Physics on 22 March 2023

Microscopic calculation of the pinning energy of a vortex in the inner crust of a neutron star [CL]

Posted on by

http://arxiv.org/abs/2303.18151


The structure of a vortex in the inner crust of a pulsar is calculated microscopically in the Wigner-Seitz cell approximation, simulating the conditions of the inner crust of a cold, non-accreting neutron star, in which a lattice of nuclei coexists with a sea of superfluid neutrons. The calculation is based on the axially deformed Hartree-Fock-Bogolyubov framework, using effective interactions. The present work extends and improves previous studies in four ways: i) it allows for the axial deformation of protons induced by the large deformation of neutrons due to the appearance of vortices; ii) it includes the effect of Coulomb exchange; iii) considers the possible effects of the screening of the pairing interaction; and iv) it improves the numerical treatment. We also demonstrate that the binding energy of the nucleus-vortex system can be used as a proxy to the pinning energy of a vortex and discuss in which conditions this applies. From our results, we can estimate the mesoscopic pinning forces per unit length acting on vortices. We obtain values ranging between $10^{14}$ to $10^{16}$ dyn/cm, consistent with previous findings.

Read this paper on arXiv…

P. Klausner, F. Barranco, P. Pizzochero, et. al.
Mon, 3 Apr 23
7/53

Comments: Paper submitted for publication

Which Upstream Solar Wind Conditions Matter Most in Predicting Bz within Coronal Mass Ejections [CL]

Posted on by

http://arxiv.org/abs/2303.17682


Accurately predicting the z-component of the interplanetary magnetic field, particularly during the passage of an interplanetary coronal mass ejection (ICME), is a crucial objective for space weather predictions. Currently, only a handful of techniques have been proposed and they remain limited in scope and accuracy. Recently, a robust machine learning (ML) technique was developed for predicting the minimum value of Bz within ICMEs based on a set of 42 ‘features’, that is, variables calculated from measured quantities upstream of the ICME and within its sheath region. In this study, we investigate these so-called explanatory variables in more detail, focusing on those that were (1) statistically significant; and (2) most important. We find that number density and magnetic field strength accounted for a large proportion of the variability. These features capture the degree to which the ICME compresses the ambient solar wind ahead. Intuitively, this makes sense: Energy made available to CMEs as they erupt is partitioned into magnetic and kinetic energy. Thus, more powerful CMEs are launched with larger flux-rope fields (larger Bz), at greater speeds, resulting in more sheath compression (increased number density and total field strength).

Read this paper on arXiv…

P. Riley, M. Reiss and C. Mostl
Mon, 3 Apr 23
18/53

Comments: N/A

Can AI Put Gamma-Ray Astrophysicists Out of a Job? [CL]

Posted on by

http://arxiv.org/abs/2303.17853


In what will likely be a litany of generative-model-themed arXiv submissions celebrating April the 1st, we evaluate the capacity of state-of-the-art transformer models to create a paper detailing the detection of a Pulsar Wind Nebula with a non-existent Imaging Atmospheric Cherenkov Telescope (IACT) Array. We do this to evaluate the ability of such models to interpret astronomical observations and sources based on language information alone, and to assess potential means by which fraudulently generated scientific papers could be identified during peer review (given that reliable generative model watermarking has yet to be deployed for these tools). We conclude that our jobs as astronomers are safe for the time being. From this point on, prompts given to ChatGPT and Stable Diffusion are shown in orange, text generated by ChatGPT is shown in black, whereas analysis by the (human) authors is in blue.

Read this paper on arXiv…

S. Spencer, V. Joshi and A. Mitchell
Mon, 3 Apr 23
22/53

Comments: N/A

The cosmological constant is probably still zero [CL]

Posted on by

http://arxiv.org/abs/2303.17723


We consider a wide class of four-dimensional effective field theories in which gravity is coupled to multiple four-forms and their dual scalar fields, with membrane sources charged under the corresponding three-form potentials. Four-form flux, quantised in units of the membrane charges, generically generates a landscape of vacua with a range of values for the cosmological constant that is scanned through membrane nucleation. We list various ways in which the landscape can be made sufficiently dense to be compatible with observations of the current vacuum without running into the empty universe problem. Further, we establish the general criteria required to ensure the absolute stability of the Minkowski vacuum under membrane nucleation and the longevity of those vacua that are parametrically close by. This selects the current vacuum on probabilistic grounds and can even be applied in the classic model of Bousso and Polchinski, albeit with some mild violation of the membrane weak gravity conjecture. We present other models where the membrane weak gravity conjecture is not violated but where the same probabilistic methods can be used to tackle the cosmological constant problem.

Read this paper on arXiv…

Y. Liu, A. Padilla and F. Pedro
Mon, 3 Apr 23
24/53

Comments: 29 pages

Probing darK Matter Using free leptONs: PKMUON [CL]

Posted on by

http://arxiv.org/abs/2303.18117


We propose a new method to detect sub-GeV dark matter, through their scatterings from free leptons and the resulting kinematic shifts. Specially, such an experiment can detect dark matter interacting solely with muons. The experiment proposed here is to directly probe muon-philic dark matter, in a model-independent way. Its complementarity with the muon on target proposal, is similar to, e.g. XENON/PandaX and ATLAS/CMS on dark matter searches. Moreover, our proposal can work better for relatively heavy dark matter such as in the sub-GeV region. We start with a small device of a size around 0.1 to 1 meter, using atmospheric muons to set up a prototype. Within only one year of operation, the sensitivity on cross section of dark matter scattering with muons can already reach $\sigma_D\sim 10^{-19 (-20,\,-18)}\rm{cm}^{2}$ for a dark mater $\rm{M_D}=100\, (10,\,1000)$ MeV. We can then interface the device with a high intensity muon beam of $10^{12}$/bunch. Within one year, the sensitivity can reach $\sigma_D\sim 10^{-27 (-28,\,-26)}\rm{cm}^{2}$ for $\rm{M_D}=100\, (10,\,1000)$ MeV.

Read this paper on arXiv…

A. Ruzi, C. Zhou, X. Sun, et. al.
Mon, 3 Apr 23
31/53

Comments: 5 pages, 3 figures, muons enlighten darkness

SEOBNRv5PHM: Next generation of accurate and efficient multipolar precessing-spin effective-one-body waveforms for binary black holes [CL]

Posted on by

http://arxiv.org/abs/2303.18046


Spin precession is one of the key physical effects that could unveil the origin of the compact binaries detected by ground- and space-based gravitational-wave (GW) detectors, and shed light on their possible formation channels. Efficiently and accurately modeling the GW signals emitted by these systems is crucial to extract their properties. Here, we present SEOBNRv5PHM, a multipolar precessing-spin waveform model within the effective-one-body (EOB) formalism for the full signal (i.e. inspiral, merger and ringdown) of binary black holes (BBHs). In the non-precessing limit, the model reduces to SEOBNRv5HM, which is calibrated to $442$ numerical-relativity (NR) simulations, 13 waveforms from BH perturbation theory, and non-spinning energy flux from second-order gravitational self-force theory. We remark that SEOBNRv5PHM is not calibrated to precessing-spin NR waveforms from the Simulating eXtreme Spacetimes Collaboration. We validate SEOBNRv5PHM by computing the unfaithfulness against 1543 precessing-spin NR waveforms, and find that for 99.8% (84.4%) of the cases, the maximum value, in the total mass range 20-300 $M_\odot$, is below 3% (1%). These numbers reduce to 95.3% (60.8%) when using the previous version of the SEOBNR family, SEOBNRv4PHM, and to 78.2% (38.3%) when using the state-of-the-art frequency-domain multipolar precessing-spin phenomenological IMRPhenomXPHM model. Due to much better computational efficiency of SEOBNRv5PHM compared to SEOBNRv4PHM, we are also able to perform extensive Bayesian parameter estimation on synthetic signals and GW events observed by LIGO-Virgo detectors. We show that SEOBNRv5PHM can be used as a standard tool for inference analyses to extract astrophysical and cosmological information of large catalogues of BBHs.

Read this paper on arXiv…

A. Ramos-Buades, A. Buonanno, H. Estellés, et. al.
Mon, 3 Apr 23
33/53

Comments: N/A

Inflationary gravitational wave background as a tail effect [CL]

Posted on by

http://arxiv.org/abs/2303.17985


The free propagator of a massless mode in an expanding universe can be written as a sum of two terms, a lightcone and a tail part. The latter describes a subluminal (time-like) signal. We show that the inflationary gravitational wave background, influencing cosmic microwave background polarization, and routinely used for constraining inflationary models through the so-called $r$ ratio, originates exclusively from the tail part.

Read this paper on arXiv…

N. Jokela, K. Kajantie, M. Laine, et. al.
Mon, 3 Apr 23
34/53

Comments: 8 pages

Protoplanet Express, a video game based on numerical simulations [CL]

Posted on by

http://arxiv.org/abs/2303.17654


Astronomical images can be fascinating to the general public, but the interaction is typically limited to contemplation. Numerical simulations of astronomical systems do permit a closer interaction, but are generally unknown outside the research community. We are developing “Protoplanet Express”, a video game based on hydrodynamical simulations of protoplanetary discs. In the game, the player visits several discs, finds its relevant features and learns about them. Here we present the current version of the game, discuss its reception, and consider its further development.

Read this paper on arXiv…

J. Cuadra, M. Vergara, B. Escárate, et. al.
Mon, 3 Apr 23
40/53

Comments: 6 pages, 4 figures, submitted to the Proceedings of ASP 2022. Beta version of game available at this https URL

Maximal temperature of strongly-coupled dark sectors [CL]

Posted on by

http://arxiv.org/abs/2303.17973


Taking axion inflation as an example, we estimate the maximal temperature ($T_{\rm max}^{ }$) that can be reached in the post-inflationary universe, as a function of the confinement scale of a non-Abelian dark sector ($\Lambda_{\rm IR}^{ }$). Below a certain threshold $\Lambda_{\rm IR}^{ } < \Lambda_{\rm 0}^{ } \sim 2\times 10^{-8}{ } m{\rm pl}^{ }$, the system heats up to $T_{\rm max}^{ } \sim \Lambda_{\rm 0}^{ } > T_{\rm c}^{ }$, and a first-order thermal phase transition takes place. On the other hand, if $\Lambda_{\rm IR}^{ } > \Lambda_{\rm 0}^{ }$, then $T_{\rm max}^{ } \sim \Lambda_{\rm IR}^{ } < T_{\rm c}^{ }$: very high temperatures can be reached, but there is no phase transition. If the inflaton thermalizes during heating-up (which we find to be unlikely), or if the plasma includes light degrees of freedom, then heat capacity and entropy density are larger, and $T_{\rm max}^{ }$ is lowered towards $\Lambda_{\rm 0}^{ }$. The heating-up dynamics generates a gravitational wave background. Its contribution to $N^{ }{\rm eff}$ at GHz frequencies, the presence of a monotonic $\sim f{\rm 0}^3$ shape at $(10^{-4}{ } – 10^2{ })\,$Hz frequencies, and the frequency domain of peaked features that may originate via first-order phase transitions, are discussed.

Read this paper on arXiv…

H. Kolesova, M. Laine and S. Procacci
Mon, 3 Apr 23
43/53

Comments: 21 pages

Particle-In-Cell Simulations of Sunward and Anti-sunward Whistler Waves in the Solar Wind [CL]

Posted on by

http://arxiv.org/abs/2303.18214


Spacecraft observations showed that electron heat conduction in the solar wind is probably regulated by whistler waves, whose origin and efficiency in electron heat flux suppression is actively investigated. In this paper, we present Particle-In-Cell simulations of a combined whistler heat flux and temperature anisotropy instability that can operate in the solar wind. The simulations are performed in a uniform plasma and initialized with core and halo electron populations typical of the solar wind. We demonstrate that the instability produces whistler waves propagating both along (anti-sunward) and opposite (sunward) to the electron heat flux. The saturated amplitudes of both sunward and anti-sunward whistler waves are strongly correlated with their {\it initial} linear growth rates, $B_{w}/B_0\sim (\gamma/\omega_{ce})^{\nu}$, where for typical electron betas we have $0.6\lesssim \nu\lesssim 0.9$. The correlations of whistler wave amplitudes and spectral widths with plasma parameters (electron beta and temperature anisotropy) revealed in the simulations are consistent with those observed in the solar wind. The efficiency of electron heat flux suppression is positively correlated with the saturated amplitude of sunward whistler waves. The electron heat flux can be suppressed by 10–60% provided that the saturated amplitude of sunward whistler waves exceeds about 1% of background magnetic field. Other experimental applications of the presented results are discussed.

Read this paper on arXiv…

I. Kuzichev, I. Vasko, A. Artemyev, et. al.
Mon, 3 Apr 23
49/53

Comments: N/A

What can a detected photon with a given gravitational redshift tell us about the maximum density of a compact star? [CL]

Posted on by

http://arxiv.org/abs/2303.17630


Far away observers can in principle bound from below the dimensionless maximum-density parameter $\Lambda\equiv4\pi R^2\rho_{\text{max}}$ of a compact star by measuring the gravitational redshift factor $z\equiv\nu_{\text{e}}/\nu_{\infty}-1$ of photons that were emitted from the {\it surface} of the star: $\Lambda\geq{3\over2}[1-(1+z)^{-2}]$ [here $R$ is the radius of the star and ${\nu_{\text{e}},\nu_{\infty}}$ are respectively the frequency of the emitted light as measured at the location of the emission and by asymptotic observers]. However, if photons that were created somewhere {\it inside} the star can make their way out and reach the asymptotic observers, then the measured redshift parameter $z$ may not determine uniquely the surface properties of the star, thus making the above bound unreliable. In the present compact paper we prove that in these cases, in which the creation depth of a detected photon is not known to the far away observers, the empirically measured redshift parameter can still be used to set a (weaker) lower bound on the dimensionless density parameter of the observed star: $\Lambda\geq{3\over2}[1-(1+z)^{-2/3}]$.

Read this paper on arXiv…

S. Hod
Mon, 3 Apr 23
50/53

Comments: 5 pages

Electromagnetic fields in compact binaries: a post-Newtonian approach [CL]

Posted on by

http://arxiv.org/abs/2303.17536


Galactic binaries, and notably double white dwarfs systems, will be a prominent source for the future LISA and Einstein Telescope detectors. Contrarily to the black holes observed by the current LIGO-Virgo-KAGRA network, such objects bear intense magnetic fields, that are naturally expected to leave some imprints on the gravitational wave emission. The purpose of this work is thus to study those imprints within the post-Newtonian (PN) framework, particularly adapted to double white dwarfs systems. To this end, we construct an effective action that takes into account the whole electromagnetic structure of a star, and then specify it to dipolar order. With this action at hand, we compute the acceleration and Noetherian quantities for generic electric and magnetic dipoles, at a relative 2PN order. Finally, focusing on physically relevant systems, we show that the magnetic effects on the orbital frequency, energy and angular momentum is significant, confirming previous works conclusions.

Read this paper on arXiv…

Q. Henry, F. Larrouturou and C. Poncin-Lafitte
Fri, 31 Mar 23
11/70

Comments: 23 pages, no figure, supplementary material attached

Reference frames in General Relativity and the galactic rotation curves [CL]

Posted on by

http://arxiv.org/abs/2303.17516


The physical interpretation of the exact solutions of the Einstein field equations is, in general, a challenging task, part of the difficulties lying in the significance of the coordinate system. We discuss the extension of the International Astronomical Union (IAU) reference system to the exact theory. It is seen that such an extension, retaining some of its crucial properties, can be achieved in a special class of spacetimes, admitting non-shearing congruences of observers which, at infinity, have zero vorticity and acceleration. As applications, we consider the FLRW, Kerr and NUT spacetimes, the van Stockum rotating dust cylinder, spinning cosmic strings and, finally, we debunk the so-called Balasin-Grumiller (BG) model, and the claims that the galaxies’ rotation curves can be explained through gravitomagnetic effects without the need for Dark Matter. The BG spacetime is shown to be completely inappropriate as a galactic model: its dust is actually static with respect to the asymptotic inertial frame, its gravitomagnetic effects arise from unphysical singularities along the axis (a pair of NUT rods, combined with a spinning cosmic string), and the rotation curves obtained are merely down to an invalid choice of reference frame — the congruence of zero angular momentum observers, which are being dragged by the singularities.

Read this paper on arXiv…

L. Costa, J. Natário, F. Frutos-Alfaro, et. al.
Fri, 31 Mar 23
14/70

Comments: 29 pages, 10 figures

Theoretical and Experimental Constraints for the Equation of State of Dense and Hot Matter [CL]

Posted on by

http://arxiv.org/abs/2303.17021


This review aims at providing an extensive discussion of modern constraints relevant for dense and hot strongly interacting matter. It includes theoretical first-principle results from lattice and perturbative QCD, as well as chiral effective field theory results. From the experimental side, it includes heavy-ion collision and low-energy nuclear physics results, as well as observations from neutron stars and their mergers. The validity of different constraints, concerning specific conditions and ranges of applicability, is also provided.

Read this paper on arXiv…

R. Kumar, V. Dexheimer, J. Jahan, et. al.
Fri, 31 Mar 23
20/70

Comments: N/A

Stability investigations of isotropic and anisotropic exponential inflation in the Starobinsky-Bel-Robinson gravity [CL]

Posted on by

http://arxiv.org/abs/2303.17283


In this paper, we would like to examine whether a novel Starobinsky-Bel-Robinson gravity model admits exponential inflationary solutions with or without spatial anisotropies. As a result, we are able to derive exact de Sitter as well as Bianchi type I inflationary solutions to this Starobinsky-Bel-Robinson model. However, stability analysis using the dynamical system approach indicates that both of the obtained inflationary solutions turn out to be unstable. Finally, we point out that a stable de Sitter inflationary solution can be obtained by flipping the coefficient’s sign of $R^2$ term in the Starobinsky-Bel-Robinson gravity.

Read this paper on arXiv…

T. Do, D. Nguyen and T. Pham
Fri, 31 Mar 23
24/70

Comments: 25 pages, 2 figures. Comments are welcome

A search technique to observe precessing compact binary mergers in the advanced detector era [CL]

Posted on by

http://arxiv.org/abs/2303.17364


Gravitational-wave signals from compact binary coalescences are most efficiently identified through matched filter searches, which match the data against a pre-generated bank of gravitational-wave templates. Although different techniques for performing the matched filter, as well as generating the template bank, exist, currently all modelled gravitational-wave searches use templates that restrict the component spins to be aligned (or anti-aligned) with the orbital angular momentum. This means that current searches are less sensitive to gravitational-wave signals generated from binaries with generic spins (precessing), suggesting that, potentially, a significant fraction of signals may remain undetected. In this work we introduce a matched filter search that is sensitive to signals generated from precessing binaries and can realistically be used during a gravitational-wave observing run. We take advantage of the fact that a gravitational-wave signal from a precessing binary can be decomposed into a power series of five harmonics, to show that a generic-spin template bank, which is only $\sim 3\times$ larger than existing aligned-spin banks, is needed to increase our sensitive volume by $\sim 100\%$ for neutron star black hole binaries with total mass larger than $17.5\, M_{\odot}$ and in-plane spins $>0.67$. In fact, our generic spin search performs as well as existing aligned-spin searches for neutron star black hole signals with insignificant in-plane spins, but improves sensitivity by $\sim60\%$ on average across the full generic spin parameter space. We anticipate that this improved technique will identify significantly more gravitational-wave signals, and, ultimately, help shed light on the unknown spin distribution of binaries in the universe.

Read this paper on arXiv…

C. McIsaac, C. Hoy and I. Harry
Fri, 31 Mar 23
30/70

Comments: 23 pages, 12 figures. For data release, see this https URL

A Deep Learning Approach to Extracting Nuclear Matter Properties from Neutron Star Observations [CL]

Posted on by

http://arxiv.org/abs/2303.17146


Understanding the equation of state of dense QCD matter remains a major challenge in both nuclear physics and astrophysics. Neutron star observations from electromagnetic and gravitational wave spectra provide critical insights into the behavior of dense neutron-rich matter. The next generation of telescopes and gravitational wave observatories will offer even more detailed observations of neutron stars. Utilizing deep learning techniques to map neutron star mass and radius observations to the equation of state allows for its accurate and reliable determination. This work demonstrates the feasibility of using deep learning to extract the equation of state directly from neutron star observational data, and to also obtain related nuclear matter properties such as the slope, curvature, and skewness of the nuclear symmetry energy at saturation density. Most importantly, we show that this deep learning approach is able to reconstruct \textit{realistic} equations of state, and deduce \textit{realistic} nuclear matter properties. This highlights the potential of artificial neural networks in providing a reliable and efficient means to extract crucial information about the equation of state and related properties of dense neutron-rich matter in the era of multi-messenger astrophysics.

Read this paper on arXiv…

P. Krastev
Fri, 31 Mar 23
40/70

Comments: 22 pages, 12 figures, 4 tables. Invited article for Symmetry for the Special Issue “Symmetries and Ultra Dense Matter of Compact Stars”

Charged Gauss-Bonnet black holes supporting non-minimally coupled scalar clouds: Analytic treatment in the near-critical regime [CL]

Posted on by

http://arxiv.org/abs/2303.16926


Recent numerical studies have revealed the physically intriguing fact that charged black holes whose charge-to-mass ratios are larger than the critical value $(Q/M){\text{crit}}=\sqrt{2(9+\sqrt{6})}/5$ can support hairy matter configurations which are made of scalar fields with a non-minimal negative coupling to the Gauss-Bonnet invariant of the curved spacetime. Using {\it analytical} techniques, we explore the physical and mathematical properties of the composed charged-black-hole-nonminimally-coupled-linearized-massless-scalar-field configurations in the near-critical $Q/M\gtrsim (Q/M){\text{crit}}$ regime. In particular, we derive an analytical resonance formula that describes the charge-dependence of the dimensionless coupling parameter $\bar\eta_{\text{crit}}=\bar\eta_{\text{crit}}(Q/M)$ of the composed Einstein-Maxwell-nonminimally-coupled-scalar-field system along the {\it existence-line} of the theory, a critical border that separates bald Reissner-Nordstr\”om black holes from hairy charged-black-hole-scalar-field configurations. In addition, it is explicitly shown that the large-coupling $-\bar\eta_{\text{crit}}(Q/M)\gg1$ analytical results derived in the present paper for the composed Einstein-Maxwell-scalar theory agree remarkably well with direct numerical computations of the corresponding black-hole-field resonance spectrum.

Read this paper on arXiv…

S. Hod
Fri, 31 Mar 23
48/70

Comments: 8 pages

Probing into the Possible Range of the U Bosonic Coupling Constants in Neutron Stars Containing Hyperons [CL]

Posted on by

http://arxiv.org/abs/2303.17106


The range of the U bosonic coupling constants in neutron star matter is a very interesting but still unsolved problem which has multifaceted influences in nuclear physics, particle physics, astrophysics and cosmology. The combination of the theoretical numerical simulation and the recent observations provides a very good opportunity to solve this problem. In the present work, the range of the U bosonic coupling constants is inferred based on the three relations of the mass-radius, mass-frequency and mass-tidal deformability in neutron star containing hyperons using the GM1, TM1 and NL3 parameter sets under the two flavor symmetries of the SU(6) and SU(3) in the framework of the relativistic mean field theory. Combined with observations from PSRs J1614-2230, J0348+0432, J2215-5135, J0952-0607, J0740+6620, J0030-0451, J1748-2446ad, XTE J1739-285, GW170817 and GW190814 events, our numerical results show that the U bosonic coupling constants may tend to be within the range from 0 to 20 GeV$^{-2}$ in neutron star containing hyperons. Moreover, the numerical results of the three relations obtained by the SU(3) symmetry are better in accordance with observation data than those obtained by the SU(6) symmetry. The results will help us to improve the strict constraints of the equation of state for neutron stars containing hyperons.

Read this paper on arXiv…

Y. Xu, B. Diao, Y. Wang, et. al.
Fri, 31 Mar 23
54/70

Comments: 14pages,4figures

Imaging compact boson stars with hot-spots and thin accretion disks [CL]

Posted on by

http://arxiv.org/abs/2303.17296


In this work we consider the observational properties of compact boson stars with self-interactions orbited by isotropically emitting (hot-spot) sources and optically thin accretion disks. We consider two families of boson stars supported by quartic and sixth-order self-interaction potentials, and choose three samples of each of them in growing compactness; only those with large enough compactness are capable to hold light-rings, namely, null bound orbits. For the hot-spots, using inclination angles $\theta={20^\circ, 50^\circ, 80^\circ }$ we find a secondary track plunge-through image of photons crossing the interior of the boson star, which can be further decomposed into additional images if the star is compact enough. For accretion disks we find that the latter class of stars actually shows a sequence of additional secondary images in agreement with the hot-spot analysis, a feature absent in typical black hole space-times. Furthermore, we also find a shadow-like central brightness depression for some of these stars in both axial observations and at the inclination angles above. We discuss our findings in relation to the capability of boson stars to effectively act as black hole mimickers in their optical appearances as well as potential observational discriminators.

Read this paper on arXiv…

J. Rosa, C. Macedo and D. Rubiera-Garcia
Fri, 31 Mar 23
66/70

Comments: 17 pages, 16 figures

Planetary seismology as a test of modified gravity proposals [CL]

Posted on by

http://arxiv.org/abs/2303.17213


We demonstrate that it is possible to test models of gravity, such as Palatini $f(R)$ and Eddington-inspired Born-Infeld models, using seismic data from Earth. By incorporating additional limitations on Earth’s moment of inertia and mass given from observational data, the models’ parameters can be restricted to a $2\sigma$ level of accuracy. Our novel tool provides that $\beta\lesssim 10^9 \text{m}^2$ for Palatini and $\epsilon\lesssim 4\cdot 10^9 \text{m}^2$ for Eddington-inspired Born-Infeld gravity. We also discuss further enhancements to the proposed method, aimed at imposing even more stringent constraints on modified gravity proposals.

Read this paper on arXiv…

A. Kozak and A. Wojnar
Fri, 31 Mar 23
67/70

Comments: 10 pages, 3 figures

UFOs: Just Hot Air or Something Meteor? [CL]

Posted on by

http://arxiv.org/abs/2303.17103


For much of February 2023, the world was in panic as repeated balloon-like unidentified flying objects (UFOs) were reported over numerous countries by governments that often responded with military action. As a result, most of these craft either escaped or were destroyed, making any further observation of them nearly impossible. These were not the first time balloon-like objects have loomed over Earth, nor are they likely to be the last. This has prompted us to push for a better understanding of UFOs. First we demonstrate that the distribution of balloon incidents and other UFO reports are consistent with being drawn from the same geographic distribution, and further that both of these distributions are consistent with the areas of the Earth that feature the jet stream. Second we show that there are more UFO sightings during meteor showers, as we would expect if meteor showers, already a known source of extraterrestrial material, are being used to provide some manner of distraction to help alien craft enter the Earth’s atmosphere without drawing undue attention. These links between alleged balloon incidents, UFO reports, and meteor showers establish a transport pipeline for alien craft from interplanetary and possibly interstellar space to the Earth’s surface.

Read this paper on arXiv…

M. Lund
Fri, 31 Mar 23
68/70

Comments: 9 pages, 4 figures, 2 tables, submission for Saturday’s Acta Prima Aprilia

T violation and the dark sector [CL]

Posted on by

http://arxiv.org/abs/2303.16586


It is argued, as a working hypothesis, that “normal” and dark matter interactions can only be T and CP violating. One way to implement this idea is to consider that time reversal in dark matter is implemented, not by an antiunitary operator, but by a unitary operator. It is shown how this occurs naturally in the context of complex spacetime with an extended symmetry group.

Read this paper on arXiv…

R. Mendes
Thu, 30 Mar 23
9/66

Comments: 6 pages Latex

Dynamically screened strongly quantized electron transport in binary neutron-star merger [CL]

Posted on by

http://arxiv.org/abs/2303.16811


We examine electron-transport coefficients in magnetized hot and dense electron-ion plasma relevant in binary neutron star merger simulation. We calculate electrical and thermal conductivities in low density, high temperature, highly magnetized plasma of binary neutron star mergers where quantum oscillatory behavior of electrons emerge. For pronounced thermodynamic effects, we consider zeroth Landau level population of electrons for the calculation of conductivity. We solve Boltzmann equation in presence of magnetic field to obtain the dissipative components of electrical and thermal conductivities. The dissipative coefficients are formulated considering frequency dependent dynamical screening in the quantized electron-ion scattering rate. Numerical estimations show that the effect of dynamical screening of photon propagator on electrical and thermal conductivities is pronounced. We observe that dynamical screening reduces the maxima of both the electrical and thermal conductivities by factors of thirty one and twenty respectively leading to a reduction in the corresponding time scales of these coefficients. The common scaling factor between electrical and thermal conductivity is also observed to follow cubic relationship with temperature violating Wiedemann-Franz law.

Read this paper on arXiv…

S. Sarkar and S. Adhya
Thu, 30 Mar 23
10/66

Comments: Accepted in The European Physical Journal C. arXiv admin note: substantial text overlap with arXiv:2108.11878

Exact solutions and cosmological constraints in fractional cosmology [CL]

Posted on by

http://arxiv.org/abs/2303.16409


This paper investigates exact solutions of cosmological interest in fractional cosmology. Given $\mu$, the order of the fractional derivative, and $w$, the matter equation of state, we present particular exact power-law solutions. We discuss the exact general solution of the system obtained by solving a Riccati Equation, where the solution for the scale factor is a combination of power-law. Using cosmological data, we estimate the free parameters $(\alpha_0, \mu)$, where $H_{0}=100\frac{\text{km/s}}{\text{Mpc}}h$, and $\alpha_0:=t_0 H_0 = \frac{1}{6} \left(9 -2 \mu +\sqrt{8 \mu (2 \mu -9)+105}\right)(1+ 2 \epsilon_0)$, is the current age parameter. The joint analysis with data from SNe Ia + OHD leads to $h=0.684_{-0.027}^{+0.031}$, $\mu=1.840_{-0.773}^{+1.446}$ and $\epsilon_0=\left(1.213_{-1.057}^{+0.482}\right)\times 10^{-2}$, where the best-fit values are calculated at $3\sigma$ CL. On the other hand, these best-fit values lead to an age of the Universe with a value of $t_0=\alpha_0/H_0=25.62_{-4.46}^{+6.89}\;\text{Gyrs}$, a current deceleration parameter of $q_{0}=-0.37_{-0.11}^{+0.08}$, both at $3\sigma$ CL, and a current matter density parameter of $\Omega_{m,0}=0.531_{-0.260}^{+0.195}$ at $1\sigma$ CL. Finding a Universe roughly twice older as the one of $\Lambda$CDM is a distinction of Fractional Cosmology. Focusing our analysis on these results, we can conclude that the region in which $\mu>2$ is not ruled out by observations. This region of a parameter is relevant because, in the absence of matter, fractional cosmology gives a power-law solution $a(t)= \left(t/t_0\right)^{\mu-1}$, which is accelerated for $\mu>2$. We present a fractional origin model that leads to an accelerated state without appealing to $\Lambda$ or Dark Energy.

Read this paper on arXiv…

E. González, G. Leon and G. Fernandez-Anaya
Thu, 30 Mar 23
21/66

Comments: 51 pages, 10 figures

Science with the Einstein Telescope: a comparison of different designs [CL]

Posted on by

http://arxiv.org/abs/2303.15923


The Einstein Telescope (ET), the European project for a third-generation gravitational-wave detector, has a reference configuration based on a triangular shape consisting of three nested detectors with 10 km arms, where in each arm there is a xylophone' configuration made of an interferometer tuned toward high frequencies, and an interferometer tuned toward low frequencies and working at cryogenic temperature. Here, we examine the scientific perspectives under possible variations of this reference design. We perform a detailed evaluation of the science case for a single triangular geometry observatory, and we compare it with the results obtained for a network of two L-shaped detectors (either parallel or misaligned) located in Europe, considering different choices of arm-length for both the triangle and the 2L geometries. We also study how the science output changes in the absence of the low-frequency instrument, both for the triangle and the 2L configurations. We examine a broad class of simplemetrics’ that quantify the science output, related to compact binary coalescences, multi-messenger astronomy and stochastic backgrounds, and we then examine the impact of different detector designs on a more specific set of scientific objectives.

Read this paper on arXiv…

M. Branchesi, M. Maggiore, D. Alonso, et. al.
Thu, 30 Mar 23
36/66

Comments: 197 pages, 72 figures

Inferring, not just detecting: metrics for high-redshift sources observed with third-generation gravitational-wave detectors [CL]

Posted on by

http://arxiv.org/abs/2303.16323


The detection of black-hole binaries at high redshifts is a cornerstone of the science case of third-generation gravitational-wave interferometers. The star-formation rate peaks at z~2 and decreases by orders of magnitude by z~10. Any confident detection of gravitational waves from such high redshifts would imply either the presence of stars formed from pristine material originating from cosmological nucleosynthesis (the so-called population III stars), or black holes that are the direct relics of quantum fluctuations in the early Universe (the so-called primordial black holes). Crucially, detecting sources at cosmological distances does not imply inferring that sources are located there, with the latter posing more stringent requirements. To this end, we present two figures of merit, which we refer to as “z-z plot” and “inference horizon”, that quantify the largest redshift one can possibly claim a source to be beyond. We argue that such inference requirements, in addition to detection requirements, should be investigated when quantifying the scientific payoff of future gravitational-wave facilities.

Read this paper on arXiv…

M. Mancarella, F. Iacovelli and D. Gerosa
Thu, 30 Mar 23
38/66

Comments: 6 pages, 4 figures

Quantum algorithm for collisionless Boltzmann simulation of self-gravitating systems [CL]

Posted on by

http://arxiv.org/abs/2303.16490


The collisionless Boltzmann equation (CBE) is a fundamental equation that governs the dynamics of a broad range of astrophysical systems from space plasma to star clusters and galaxies. It is computationally expensive to integrate the CBE directly in a phase space, and thus the applications to realistic astrophysical problems have been limited so far. Recently, Todorova \& Steijl (2020) proposed an efficient quantum algorithm for solving the CBE with a significantly reduced computational complexity. We extend the method to perform quantum simulations that follow the evolution of self-gravitating systems. We first run a 1+1 dimensional test calculation of free streaming motion on 64$\times$64 grids using 13 simulated qubits and validate our method. We then perform simulations of Jeans collapse, and compare the result with analytic and linear theory calculations. We propose a direct method to generate initial conditions as well as a method to retrieve necessary information from a register of multiple qubits. Our simulation scheme achieves $\mathcal{O}(N_v^3)$ less computational complexity than the classical method, where $N_v$ is the number of discrete velocity grids per dimension. It will thus allow us to perform large-scale CBE simulations on future quantum computers.

Read this paper on arXiv…

S. Yamazaki, F. Uchida, K. Fujisawa, et. al.
Thu, 30 Mar 23
39/66

Comments: 10 pages, 9figures

Dynamics of Binary System around Supermassive Black Hole [CL]

Posted on by

http://arxiv.org/abs/2303.16553


We discuss motion of a binary system around a supermassive black hole. Using Fermi-Walker transport, we construct a local inertial reference frame and set up a Newtonian binary system. Assuming a circular geodesic observer around a Schwarzschild black hole, we write down the equations of motion of a binary. Introducing a small acceleration of the observer, we remove the interaction terms between the center of mass (CM) of a binary and its relative coordinates. The CM follows the observer’s orbit, but its motion deviates from an exact circular geodesic. We first solve the relative motion of a binary system, and then find the motion of the CM by the perturbation equations with the small acceleration.
We show that there appears the Kozai-Lidov (KL) oscillations when a binary is compact and the initial inclination is larger than a critical angle. In a hard binary system, KL oscillations are regular, whereas in a soft binary system, oscillations are irregular both in period and in amplitude, although stable. We find an orbital flip when the initial inclination is large. As for the motion of the CM, the radial deviations from a circular orbit become stable oscillations with very small amplitude.

Read this paper on arXiv…

K. Maeda, P. Gupta and H. Okawa
Thu, 30 Mar 23
49/66

Comments: 33 pages,12 figures, 2 tables

Scalar induced gravitational waves in modified teleparallel gravity theories [CL]

Posted on by

http://arxiv.org/abs/2303.16695


Primordial black holes (PBHs) forming out of the collapse of enhanced cosmological perturbations provide access to the early Universe through their associated observational signatures. In particular, enhanced cosmological perturbations collapsing to form PBHs are responsible for the generation of a stochastic gravitational-wave background (SGWB) induced by second-order gravitational interactions, usually called scalar induced gravitational waves (SIGWs). This SGWB is sensitive to the underlying gravitational theory; hence it can be used as a novel tool to test the standard paradigm of gravity and constrain possible deviations from general relativity. In this work, we study the aforementioned GW signal within modified teleparallel gravity theories, developing a formalism for the derivation of the GW spectral abundance within any form of gravitational action. At the end, working within viable $f(T,\phi)$ models without matter-gravity couplings, and accounting for the effect of mono-parametric $f(T)$ gravity at the level of the source and the propagation of the tensor perturbations, we show that the respective GW signal is indistinguishable from that within GR. Interestingly, we find that in order to break the degeneracy between different $f(T)$ theories through the portal of SIGWs one should necessarily consider non-minimal matter-gravity couplings at the level of the gravitational action.

Read this paper on arXiv…

C. Tzerefos, T. Papanikolaou, E. Saridakis, et. al.
Thu, 30 Mar 23
64/66

Comments: 16 pages without appendices (24 in total), 2 figures

Synchronous coordinates and gauge-invariant observables in cosmological spacetimes [CL]

Posted on by

http://arxiv.org/abs/2303.16218


We consider the relational approach to construct gauge-invariant observables in cosmological perturbation theory using synchronous coordinates. We construct dynamical synchronous coordinates as non-local scalar functionals of the metric perturbation in the fully non-linear theory in an arbitrary gauge. We show that the observables defined in this dynamical coordinate system are gauge-independent, and that the full perturbed metric has the expected form in these coordinates. Our construction generalises the familiar synchronous gauge in linearised gravity, widely used in cosmological perturbation theory, to the non-linear theory. We also work out the expressions for the gauge-invariant Einstein equations, sourced either by an ideal fluid or a scalar field up to second order in perturbation theory, and give explicit expressions for the Hubble rate — as measured by synchronous observers or by observers co-moving with the matter field — up to that order. Finally, we consider quantised linear perturbations around Minkowski and de Sitter backgrounds, and compute the two-point function of the gauge-invariant metric perturbation in synchronous coordinates, starting with two-point function in a general linear covariant gauge. Although the gauge-fixed two-point function contains gauge modes, we show that the resulting gauge-invariant two-point function only contains the physical tensor modes and it is thus positive, i.e., it has a spectral representation.

Read this paper on arXiv…

M. Fröb and W. Lima
Thu, 30 Mar 23
66/66

Comments: 52 pages. Comments are welcome

Direct searches for general dark matter-electron interactions with graphene detectors: Part I. Electronic structure calculations [CL]

Posted on by

http://arxiv.org/abs/2303.15497


We develop a formalism to describe electron ejections from graphene-like targets by dark matter (DM) scattering for general forms of scalar and spin 1/2 DM-electron interactions and compare their applicability and accuracy within the density functional theory (DFT) and tight binding (TB) approaches. This formalism allows for accurate prediction of the daily modulation signal expected from DM in upcoming direct detection experiments employing graphene sheets as the target material. A key result is that the physics of the graphene sheet and that of the DM and the ejected electron factorise, allowing for the rate of ejections from all forms of DM to be obtained with a single graphene response function. We perform a comparison between the TB and DFT approaches to modeling the initial state electronic wavefunction within this framework, with DFT emerging as the more self-consistent and reliable choice due to the challenges in the embedding of an appropriate atomic contribution into the TB approach.

Read this paper on arXiv…

R. Catena, T. Emken, M. Matas, et. al.
Wed, 29 Mar 23
6/73

Comments: 29 pages, 12 figures, 5 appendices. The TB and DFT codes can be found under this https URL and this https URL respectively

Stochastic gravitational wave background reconstruction for a non-equilateral and unequal-noise LISA constellation [CL]

Posted on by

http://arxiv.org/abs/2303.15929


We explore the impact of choosing different sets of Time-Delay Interferometry (TDI) variables for detecting and reconstructing Stochastic Gravitational Wave Background (SGWB) signals and estimating the instrumental noise in LISA. Most works in the literature build their data analysis pipelines relying on a particular set of TDI channels, the so-called AET variables, which are orthogonal under idealized conditions. By relaxing the assumption of a perfectly equilateral LISA configuration, we investigate to which degree these channels remain orthogonal and compare them to other TDI channels. We show that different sets of TDI variables are more robust under perturbations of the perfect equilateral configuration, better preserving their orthogonality and, thus, leading to a more accurate estimate of the instrumental noise. Moreover, we investigate the impact of considering the noise levels associated with each instrumental noise source to be independent of one another, generalizing the analysis from two to twelve noise parameters. We find that, in this scenario, the assumption of orthogonality is broken for all the TDI variables, leading to a misestimation of measurement error for some of the noise parameters. Remarkably, we find that for a flat power-law signal, the reconstruction of the signal parameters is nearly unaffected in these various configurations.

Read this paper on arXiv…

O. Hartwig, M. Lilley, M. Muratore, et. al.
Wed, 29 Mar 23
31/73

Comments: 31 pages, 13 figures, and supplementary material

pygwb: Python-based library for gravitational-wave background searches [CL]

Posted on by

http://arxiv.org/abs/2303.15696


The collection of gravitational waves (GWs) that are either too weak or too numerous to be individually resolved is commonly referred to as the gravitational-wave background (GWB). A confident detection and model-driven characterization of such a signal will provide invaluable information about the evolution of the Universe and the population of GW sources within it. We present a new, user-friendly Python–based package for gravitational-wave data analysis to search for an isotropic GWB in ground–based interferometer data. We employ cross-correlation spectra of GW detector pairs to construct an optimal estimator of the Gaussian and isotropic GWB, and Bayesian parameter estimation to constrain GWB models. The modularity and clarity of the code allow for both a shallow learning curve and flexibility in adjusting the analysis to one’s own needs. We describe the individual modules which make up {\tt pygwb}, following the traditional steps of stochastic analyses carried out within the LIGO, Virgo, and KAGRA Collaboration. We then describe the built-in pipeline which combines the different modules and validate it with both mock data and real GW data from the O3 Advanced LIGO and Virgo observing run. We successfully recover all mock data injections and reproduce published results.

Read this paper on arXiv…

A. Renzini, A. Romero-Rodrguez, C. Talbot, et. al.
Wed, 29 Mar 23
36/73

Comments: 32 pages, 14 figures

Scalar Love numbers and Love symmetries of 5-dimensional Myers-Perry black hole [CL]

Posted on by

http://arxiv.org/abs/2303.16036


The near-zone “Love” symmetry resolves the naturalness issue of black hole Love number vanishing with $\text{SL}\left(2,\mathbb{R}\right)$ representation theory. Here, we generalize this proposal to $5$-dimensional asymptotically flat and doubly spinning (Myers-Perry) black holes. We consider the scalar response of Myers-Perry black holes and extract its static scalar Love numbers. In agreement with the naturalness arguments, these Love numbers are, in general, non-zero and exhibit logarithmic running unless certain resonant conditions are met; these conditions include new cases with no previously known analogs. We show that there exist two near-zone truncations of the equations of motion that exhibit enhanced $\text{SL}\left(2,\mathbb{R}\right)$ Love symmetries that explain the vanishing of the static scalar Love numbers in the resonant cases. These Love symmetries can be interpreted as local $\text{SL}\left(2,\mathbb{R}\right)\times\text{SL}\left(2,\mathbb{R}\right)$ near-zone symmetries spontaneously broken down to global $\text{SL}\left(2,\mathbb{R}\right)\times U\left(1\right)$ symmetries by the periodic identification of the azimuthal angles. We also discover an infinite-dimensional extension of the Love symmetry into $\text{SL}\left(2,\mathbb{R}\right)\ltimes\hat{U}\left(1\right)_{\mathcal{V}}^2$ that contains both Love symmetries as particular subalgebras, along with a family of $\text{SL}\left(2,\mathbb{R}\right)$ subalgebras that reduce to the exact near-horizon Myers-Perry black hole isometries in the extremal limit. Finally, we show that the Love symmetries acquire a geometric interpretation as isometries of subtracted (effective) black hole geometries that preserve the internal structure of the black hole and interpret these non-extremal $\text{SL}\left(2,\mathbb{R}\right)$ structures as remnants of the enhanced isometry of the near-horizon extremal geometries.

Read this paper on arXiv…

P. Charalambous and M. Ivanov
Wed, 29 Mar 23
48/73

Comments: 45+16 pages, 3 Figures

Ultra-peripheral collisions of charged hadrons in extensive air showers [CL]

Posted on by

http://arxiv.org/abs/2303.16042


We discuss the electromagnetic collisions of high energy protons, pions and kaons with atmospheric nuclei. In particular, we use the equivalent photon approximation to estimate (i) the diffractive collisions where the projectile scatters inelastically off a nucleus, and (ii) the usual radiative processes (bremsstrahlung, pair production and photonuclear interactions) of these charged hadrons in the air. We then include the processes in the simulator AIRES and study how they affect the longitudinal development of extensive air showers. For $10^{9-11}$ GeV proton primaries we find that they introduce a very small reduction (below 1%) in the average value of both $X_{\rm max}$ and $\Delta X_{\rm max}$. At a given shower age (relative slant depth from $X_{\rm max}$), these electromagnetic processes do not change significantly the number of muons or the total energy carried by electrons and photons, increased by just 1% the muon-to-($\gamma+e$) signal at the ground level.

Read this paper on arXiv…

M. Masip, I. Rosario and S. Sciutto
Wed, 29 Mar 23
52/73

Comments: 14 pages

Direct searches for general dark matter-electron interactions with graphene detectors: Part II. Sensitivity studies [CL]

Posted on by

http://arxiv.org/abs/2303.15509


We use a formalism that describes electron ejections from graphene-like targets by dark matter (DM) scattering for general forms of scalar and spin 1/2 DM-electron interactions in combination with state-of-the-art density functional calculations to produce predictions and reach estimates for various possible carbon-based detector designs. Our results indicate the importance of a proper description of the target electronic structure. In addition, we find a strong dependence of the predicted observed signal for different DM candidate masses and interaction types on the detailed geometry and design of the detector. Combined with directional background vetoing, these dependencies will enable the identification of DM particle properties once a signal has been established.

Read this paper on arXiv…

R. Catena, T. Emken, M. Matas, et. al.
Wed, 29 Mar 23
67/73

Comments: 22 pages, 15 figures, 2 appendices. The DFT code can be found under this https URL

The radiation environment over the African continent at aviation altitudes: First results of the RPiRENA-based dosimeter [CL]

Posted on by

http://arxiv.org/abs/2303.15452


The radiation environment over the African continent, at aviation altitudes, remains mostly uncharacterized and unregulated. In this paper we present initial measurements made by a newly developed active dosimeter on-board long-haul flights between South Africa and Germany. Based on these initial tests, we believe that this low-cost and open-source dosimeter is suitable for continued operation over the Africa continent and can provide valuable long-term measurements to test dosimteric models and inform aviation policy

Read this paper on arXiv…

M. Mosotho, R. Strauss, S. S.Bottcher, et. al.
Wed, 29 Mar 23
68/73

Comments: Accepted to appear in Journal of Space Weather and Space Climate

Shadows in dyonic Kerr-Sen black holes [CL]

Posted on by

http://arxiv.org/abs/2303.14513


Black holes with dyonic charges in Einstein-Maxwell-dilaton-axion supergravity theory are revisited in the context of black hole shadows. We consider static as well as rotating (namely the dyonic Kerr-Sen) black holes. The matter stress-energy tensor components, sourced by the Maxwell, axion and dilaton fields satisfy the standard energy conditions. The analytical expressions for the horizon and the shadow radius of the static spacetimes demonstrate their dependence on $P^2+Q^2$ ($P$, $Q$ the magnetic and electric charges, respectively) and the mass parameter $M$. The shadow radius lies in the range $2M <R_{shadow}<3\sqrt{3} M$ and there is no stable photon orbit outside the horizon. Further, shadows cast by the rotating dyonic Kerr-Sen black holes are also studied and compared graphically with their Kerr-Newman and Kerr-Sen counterparts. Deviation of the shadow boundary is prominent with the variation of the magnetic charge, for the relatively slowly rotating dyonic Kerr-Sen spacetimes. We test any possible presence of a magnetic monopole charge in the backdrop of recent EHT observations for the supermassive black holes M87$^$ and Sgr A$^$. Deviation from circularity of the shadow boundary ($\Delta C$) and deviation of the average shadow radius from the Schwarzschild shadow radius (quantified as the fractional deviation parameter $\delta$) are the two observables used here. Observational bound on $\Delta C$ (available only for M87$^$) is satisfied for all theoretically allowed regions of parameter space and thus cannot constrain the parameters. The observational bound on $\delta$ available for Sgr A$^$ translates into an upper limit on any possible magnetic monopole charge linked to Sgr A$^*$ and is given as $P\lesssim 0.873\, M$. Such a constraint on $P$ is however expected to be far more stringent for other astrophysical tests.

Read this paper on arXiv…

S. Jana and S. Kar
Tue, 28 Mar 23
2/81

Comments: 23 pages, 8 figures

Relative efficiency of three mechanisms of vector fields growth in a random media [CL]

Posted on by

http://arxiv.org/abs/2303.14388


We consider a model of a random media with fixed and finite memory time with abrupt losses of memory (renovation model). Within the memory intervals we can observe either amplification or oscillation of the vector field in a given particle. The cumulative effect of amplifications in many subsequent intervals leads to amplification of the mean field and mean energy. Similarly, the cumulative effect of intermittent amplifications or oscillations also leads to amplification of the mean field and mean energy, however, at a lower rate. Finally, the random oscillations alone can resonate and yield the growth of the mean field and energy. These are the three mechanisms that we investigate and compute analytically and numerically the growth rates based on the Jacobi equation with the random curvature parameter.

Read this paper on arXiv…

E. Illarionov and D. Sokoloff
Tue, 28 Mar 23
14/81

Comments: N/A

Swampland Criteria and Constraints on Inflation in a $f(R,T)$ Gravity Theory [CL]

Posted on by

http://arxiv.org/abs/2303.14724


In this paper, we worked in the framework of an inflationary $f(R,T)$ theory, in the presence of a canonical scalar field. More specifically, the $f(R,T)=\gamma R+2\kappa\alpha T$ gravity. The values of the dimensionless parameters $\alpha$ and $\gamma$ are taken to be $\alpha \geq 0$ and $0 < \gamma \leq 1$. The motivation for that study was the striking similarities between the slow-roll parameters of the inflationary model used in this work and the ones obtained by the rescaled Einstein-Hilbert gravity inflation $f(R)=\alpha R$. We examined a variety of potentials to determine if they agree with the current Planck Constraints. In addition, we checked whether these models satisfy the Swampland Criteria and we specified the exact region of the parameter space that produces viable results for each model. As we mention in Section IV the inflationary $f(R,T)$ theory used in this work can not produce a positive $n_T$ which implies that the stochastic gravitational wave background will not be detectable.

Read this paper on arXiv…

V. Oikonomou, K. Revis, I. Papadimitriou, et. al.
Tue, 28 Mar 23
22/81

Comments: IJMPD Accepted

Applications of Gaussian Processes at Extreme Lengthscales: From Molecules to Black Holes [CL]

Posted on by

http://arxiv.org/abs/2303.14291


In many areas of the observational and experimental sciences data is scarce. Data observation in high-energy astrophysics is disrupted by celestial occlusions and limited telescope time while data derived from laboratory experiments in synthetic chemistry and materials science is time and cost-intensive to collect. On the other hand, knowledge about the data-generation mechanism is often available in the sciences, such as the measurement error of a piece of laboratory apparatus. Both characteristics, small data and knowledge of the underlying physics, make Gaussian processes (GPs) ideal candidates for fitting such datasets. GPs can make predictions with consideration of uncertainty, for example in the virtual screening of molecules and materials, and can also make inferences about incomplete data such as the latent emission signature from a black hole accretion disc. Furthermore, GPs are currently the workhorse model for Bayesian optimisation, a methodology foreseen to be a guide for laboratory experiments in scientific discovery campaigns. The first contribution of this thesis is to use GP modelling to reason about the latent emission signature from the Seyfert galaxy Markarian 335, and by extension, to reason about the applicability of various theoretical models of black hole accretion discs. The second contribution is to extend the GP framework to molecular and chemical reaction representations and to provide an open-source software library to enable the framework to be used by scientists. The third contribution is to leverage GPs to discover novel and performant photoswitch molecules. The fourth contribution is to introduce a Bayesian optimisation scheme capable of modelling aleatoric uncertainty to facilitate the identification of material compositions that possess intrinsic robustness to large scale fabrication processes.

Read this paper on arXiv…

R. Griffiths
Tue, 28 Mar 23
25/81

Comments: PhD Thesis submitted at the University of Cambridge, August 2022. The thesis is based on a number of previous works also available on arXiv (see Introduction)

Decay of ALP Condensates via Gravitation-Induced Resonance [CL]

Posted on by

http://arxiv.org/abs/2303.14800


Oscillating scalar field condensates induce small amplitude oscillations of the Hubble parameter which can induce a decay of the condensate due to a parametric resonance instability [1]. We show that this instability can lead to the decay of the coherence of the condensate of axion-like particle (ALP) fields during the radiation phase of standard cosmology for rather generic ALP parameter values, with possible implications for certain experiments aiming to search for ALP candidates. As an example, we study the application of this instability to the QCD axion. We also study the magnitude of the induced entropy fluctuations.

Read this paper on arXiv…

R. Brandenberger, V. Kamali and R. Ramos
Tue, 28 Mar 23
37/81

Comments: 9 pages, 2 figures

Inflationary Dynamics and Swampland Criteria for Modified Gauss-Bonnet Gravity Compatible with GW170817 [CL]

Posted on by

http://arxiv.org/abs/2303.14594


In this article we present an alternative formalism for the inflationary phenomenology of rescaled Einstein-Gauss-Bonnet models which are in agreement with the GW170817 event. By constraining the propagation velocity of primordial tensor perturbations, an approximate form for the time derivative of the scalar field coupled to the Gauss-Bonnet density is extracted. In turn, the overall degrees of freedom decrease and similar to the case of the canonical scalar field, only one scalar function needs to be designated, while the other is extracted from the continuity equation of the scalar field. We showcase explicitly that the slow-roll indices can be written in a closed form as functions of three dimensionless parameters, namely $x=\frac{1}{2\alpha}\bigg(\frac{\kappa\xi’}{\xi”}\bigg)^2$, $\beta=8H^2\xi”$ and $\gamma=\frac{\xi’\xi”’}{\xi”^2}$ and in turn, we prove that the Einstein-Gauss-Bonnet model can in fact produce a blue-tilted tensor spectral index if the condition $\beta\geq1$ is satisfied, which is possible only for Einstein-Gauss-Bonnet models with $\xi”(\phi_k)>0$. Afterwards, a brief comment on the running of the spectral indices is made where it is shown that $a_{\mathcal{S}}(k_)$ and $a_{\mathcal{T}}(k_)$ in the constrained case are approximately of the order $\mathcal{O}(10^{-3})$, if not smaller. Last but not least, we examine the conditions under which the Swampland criteria are satisfied. We connect the tracking condition related to scalar field theories with the present models, and we highlight the important feature of the models we propose that the tracking condition can be satisfied only if the Swampland criteria are simultaneously satisfied, however the cases with $\xi\sim1/V$ and $\xi\sim V$ are excluded, as they cannot describe the inflationary era properly.

Read this paper on arXiv…

S. Odintsov, V. Oikonomou and F. Fronimos
Tue, 28 Mar 23
41/81

Comments: PRD Accepted, abstract reduced due to arXiv limitations

Chaotic dynamics of off-equatorial orbits around Pseudo-Newtonian Schwarzschild and Kerr-like compact objects surrounded by dipolar halo [CL]

Posted on by

http://arxiv.org/abs/2303.14740


In this paper, we implement a generalized pseudo-Newtonian potential and prescribe a numerical fitting formalism, to study the off-equatorial orbits inclined at a certain angle with the equatorial plane around both Schwarzschild and Kerr-like compact object primaries surrounded by a dipolar halo of matter. The chaotic dynamics of the orbits are detailed for both non-relativistic and special-relativistic test particles. The dependence of the degree of chaos on the rotation parameter $a$ and the inclination angle $i$ is established individually using widely used indicators, such as the Poincar\’e Map and the Lyapunov Characteristic Number. We find that although the chaoticity of the orbits has a positive correlation with $i$, the growth in the chaotic behaviour is not systematic. There exists a threshold value of the inclination angle $i_{\text{c}}$, after which the degree of chaos shows a sharp increase. On the other hand, the chaoticity of the inclined orbits anti-correlates with $a$ at the lower inclination angles. At higher values of $i$, the degree of chaos is maximum for the maximally counter-rotating compact objects, though it has a weak negative, sometimes positive, correlation with $a$ at its higher values. The studies performed with several initial conditions and orbital parameters reveal the intricate nature of the system.

Read this paper on arXiv…

S. Das and S. Roychowdhury
Tue, 28 Mar 23
49/81

Comments: 17 pages, 14 figures

The astrophysical $S-$factor and reaction rate for $^{15}$N($p,γ$)$^{16}$O within the modified potential cluster model [CL]

Posted on by

http://arxiv.org/abs/2303.14680


We study a radiative $p^{15}$N capture on the ground state of $^{16}$O at stellar energies within the framework of a modified potential cluster model (MPCM) with forbidden states, including low lying resonances. The investigation of the $^{15}$N($p,\gamma $)$^{16}$O reaction includes the consideration of $^{3}S_{1}$ resonances due to $E1$ transitions and contribution of $^{3}P_{1}$ scattering wave in $p$ + $^{15}$N channel due to $^{3}P_{1}\longrightarrow $ $^{3}P_{0}$ $M1$ transition. We calculate the astrophysical low-energy $S-$factor and extrapolated $S(0)$ turned out to be within $34.7-40.4$ keV$\cdot $b. It is elucidated the important role of the asymptotic constant (AC) for the $^{15}$N($p,\gamma $)$^{16}$O process with interfering $^{3}S_{1}$(312) and $^{3}S_{1}$(962) resonances. A comparison of our calculation for $S-$factor with existing experimental and theoretical data is addressed and the reasonable agreement is found.
The reaction rate is calculated and compared with the existing rates. It has negligible dependence on the variation of AC, but shows strong impact of the interference of $^{3}S_{1}$(312) and $^{3}S_{1}$(962) resonances, especially at $T_{9}$ referring to the CNO Gamow windows. We present a stellar temperature dependence on the Gamow energy and a comparison of rates for radiative proton capture reactions for CNO cycle on nitrogen isotopes obtained in the framework of the MPCM and give temperature windows, prevalence, and significance of each process.

Read this paper on arXiv…

S. Dubovichenko, N. Burkova, R. Kezerashvili, et. al.
Tue, 28 Mar 23
55/81

Comments: 15 pages, 8 figures

Exploring QCD matter in extreme conditions with Machine Learning [CL]

Posted on by

http://arxiv.org/abs/2303.15136


In recent years, machine learning has emerged as a powerful computational tool and novel problem-solving perspective for physics, offering new avenues for studying strongly interacting QCD matter properties under extreme conditions. This review article aims to provide an overview of the current state of this intersection of fields, focusing on the application of machine learning to theoretical studies in high energy nuclear physics. It covers diverse aspects, including heavy ion collisions, lattice field theory, and neutron stars, and discuss how machine learning can be used to explore and facilitate the physics goals of understanding QCD matter. The review also provides a commonality overview from a methodology perspective, from data-driven perspective to physics-driven perspective. We conclude by discussing the challenges and future prospects of machine learning applications in high energy nuclear physics, also underscoring the importance of incorporating physics priors into the purely data-driven learning toolbox. This review highlights the critical role of machine learning as a valuable computational paradigm for advancing physics exploration in high energy nuclear physics.

Read this paper on arXiv…

K. Zhou, L. Wang, L. Pang, et. al.
Tue, 28 Mar 23
59/81

Comments: 146 pages,53 figures

First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment [CL]

Posted on by

http://arxiv.org/abs/2303.14729


We report on the first search for nuclear recoils from dark matter in the form of weakly interacting massive particles (WIMPs) with the XENONnT experiment which is based on a two-phase time projection chamber with a sensitive liquid xenon mass of $5.9$~t. During the approximately 1.1 tonne-year exposure used for this search, the intrinsic $^{85}$Kr and $^{222}$Rn concentrations in the liquid target were reduced to unprecedentedly low levels, giving an electronic recoil background rate of $(15.8\pm1.3)~\mathrm{events}/(\mathrm{t\cdot y \cdot keV})$ in the region of interest. A blind analysis of nuclear recoil events with energies between $3.3$~keV and $60.5$~keV finds no significant excess. This leads to a minimum upper limit on the spin-independent WIMP-nucleon cross section of $2.58\times 10^{-47}~\mathrm{cm}^2$ for a WIMP mass of $28~\mathrm{GeV}/c^2$ at $90\%$ confidence level. Limits for spin-dependent interactions are also provided. Both the limit and the sensitivity for the full range of WIMP masses analyzed here improve on previous results obtained with the XENON1T experiment for the same exposure.

Read this paper on arXiv…

X. Collaboration, E. Aprile, K. Abe, et. al.
Tue, 28 Mar 23
60/81

Comments: Limit points are included in the submission file

Polarized image of equatorial emission in horizonless spacetimes: naked singularities [CL]

Posted on by

http://arxiv.org/abs/2303.14756


We study the linear polarization from the accretion disk around weakly and strongly naked Janis-Newman-Winicour singularities. We consider an analytical toy model of thin magnetized fluid ring orbiting in the equatorial plane and emitting synchrotron radiation. The observable polarized images are calculated and compared to the Schwarzschild black hole for physical parameters compatible with the radio source M87. For small inclination angles the direct images of the weakly naked singularities closely mimic the Schwarzschild black hole. The deviation in the polarization properties increases if we consider larger inclination angles or higher order images as for indirect images the polarization intensity grows several times in magnitude compared to black holes. Strongly naked singularities produce significant observational signatures already in the direct images. They create a second image of the fluid ring with times larger polarization intensity and characteristic twist of the polarization direction. Due to this additional structure they can be distinguished in polarimetric experiments.

Read this paper on arXiv…

V. Deliyski, G. Gyulchev, P. Nedkova, et. al.
Tue, 28 Mar 23
65/81

Comments: 27 pages, 10 figures

Tracking the validity of the quasi-static and sub-horizon approximations in modified gravity [CL]

Posted on by

http://arxiv.org/abs/2303.14251


Within the framework of modified gravity, the quasi-static and sub-horizon approximations are widely used in analyses aiming to identify departures from the concordance model at late-times. Under these approximations, it is generally assumed that time derivatives are subdominant with respect to spatial derivatives given that the relevant physical modes are those well inside the Hubble radius. Here, in the context of the effective fluid approach applied to $f(R)$ theories, we put forward a new parameterization which allows us to obtain analytical expressions for the gravitational potentials, whence for the effective dark energy perturbations. In order to track the validity of the two aforementioned approximations, we compare our results and the standard results found in the literature against full numerical solutions for two well-known toy-models; namely, the designer ($f$DES) model and the Hu-Sawicki (HS) model. We find that: $i)$ the sub-horizon approximation can be safely applied for scales $k \gtrsim 200 H_0$, $ii)$ in this “safety region”, the quasi-static approximation is a very accurate description of the late-time dynamics even when dark energy significantly contribute to the cosmic budget, $iii)$ some relevant terms were neglected in the standard procedure yielding to inaccurate results in some of the dark energy effective fluid quantities; e.g. the sound speed. Instead, our expressions show overall agreement with respect to the full solutions. Therefore, our results indirectly indicate that the effective fluid expressions derived for more general modified gravity theories, such as Horndeski, should be revisited.

Read this paper on arXiv…

J. Orjuela-Quintana and S. Nesseris
Tue, 28 Mar 23
67/81

Comments: 27 pages, 16 figures

The Invisible Dilaton [CL]

Posted on by

http://arxiv.org/abs/2303.14469


We analyse the dynamics of a light scalar field responsible for the $\mu$ term of the Higgs potential and coupled to matter via the Higgs-portal mechanism. We find that this dilaton model is stable under radiative corrections induced by the standard model particle masses. When the background value of the scalar field is stabilised at the minimum of the scalar potential, the scalar field fluctuations only couple quadratically to the massive fields of the standard model preventing the scalar direct decay into standard model particles. Cosmologically and prior to the electroweak symmetry breaking, the scalar field rolls down along its effective potential before eventually oscillating and settling down at the electroweak minimum. These oscillations can be at the origin of dark matter due to the initial misalignment of the scalar field compared to the electroweak minimum, and we find that, when the mass of the scalar field is less than the eV scale and acts as a condensate behaving like dark matter on large scales, the scalar particles cannot thermalise with the standard model thermal bath. As matter couples in a composition-dependent manner to the oscillating scalar, this could lead to a violation of the equivalence principle aboard satellites such as the MICROSCOPE experiment and the next generation of tests of the equivalence principle. Local gravitational tests are evaded thanks to the weakness of the quadratic coupling in the dark matter halo, and we find that, around other sources, these dilaton models could be subject to a screening akin to the symmetron mechanism.

Read this paper on arXiv…

P. Brax, C. Burrage, J. Cembranos, et. al.
Tue, 28 Mar 23
74/81

Comments: 36 pages, 3 figures

Convolutional Neural Networks for the classification of glitches in gravitational-wave data streams [CL]

Posted on by

http://arxiv.org/abs/2303.13917


We investigate the use of Convolutional Neural Networks (including the modern ConvNeXt network family) to classify transient noise signals (i.e.~glitches) and gravitational waves in data from the Advanced LIGO detectors. First, we use models with a supervised learning approach, both trained from scratch using the Gravity Spy dataset and employing transfer learning by fine-tuning pre-trained models in this dataset. Second, we also explore a self-supervised approach, pre-training models with automatically generated pseudo-labels. Our findings are very close to existing results for the same dataset, reaching values for the F1 score of 97.18% (94.15%) for the best supervised (self-supervised) model. We further test the models using actual gravitational-wave signals from LIGO-Virgo’s O3 run. Although trained using data from previous runs (O1 and O2), the models show good performance, in particular when using transfer learning. We find that transfer learning improves the scores without the need for any training on real signals apart from the less than 50 chirp examples from hardware injections present in the Gravity Spy dataset. This motivates the use of transfer learning not only for glitch classification but also for signal classification.

Read this paper on arXiv…

T. Fernandes, S. Vieira, A. Onofre, et. al.
Mon, 27 Mar 23
4/59

Comments: 15 pages, 14 figures

New Resonances of Supernova Neutrinos in Twisting Magnetic Fields [CL]

Posted on by

http://arxiv.org/abs/2303.13572


We investigate the effect of resonant spin conversion of the neutrinos induced by the geometrical phase in a twisting magnetic field. We find that the geometrical phase originating from the rotation of the transverse magnetic field along the neutrino trajectory can trigger a new resonant spin conversion of Dirac neutrinos inside the supernova, even if there were no such transitions in the fixed-direction field case. We have shown that even though resonant spin conversion is too weak to affect solar neutrinos, it could have a remarkable consequence on supernova neutronization bursts where very intense magnetic fields are quite likely. We demonstrate how the flavor composition at Earth can be used as a probe to establish the presence of non-negligible magnetic moments, potentially down to $10^{-15}~\mu_B$ in upcoming neutrino experiments like the Deep Underground Neutrino Experiment (DUNE), and the Hyper-Kamiokande (HK). Possible implications are analyzed.

Read this paper on arXiv…

S. Jana and Y. Porto
Mon, 27 Mar 23
7/59

Comments: 5 pages + references, 3 figures

Reviewing the prospect of fermion triplets as dark matter and source of baryon asymmetry in non-standard cosmology [CL]

Posted on by

http://arxiv.org/abs/2303.13950


The indirect searches of Dark Matter (DM), in conjugation with the so called `missing track searches’ at the collider seems to confine fermion triplet DM mass within a narrow range around 1 TeV. The canonical picture of pure triplet fermionic DM is in tension since it is under-abundant for the said mass range. Several preceding studies have shown that the existence of an extra species over the radiation background, prior to the Big Bang Nucleosynthesis, leads to a fast expanding Universe driven by an enhanced Hubble parameter. This faster (than radiation) expansion has the potential to revive the under-abundant fermion triplet ($\mathbb{Z}_2$ odd) WIMP dark matter scenario by causing freeze-out earlier without modifying the interaction strength between DM and thermal bath. Although the CP asymmetry, produced due to the decay of $\mathbb{Z}_2$ even heavier generations of the triplet, remains unaffected by the modification of cosmology, the evolution of the same receives significant non-trivial effect. It has been observed through numerical estimations that the minimum mass of the decaying triplet, required to produce sufficient baryon asymmetry, can be lowered up to two orders (compared to the standard cosmology) in this fast expansion scenario. The non-standard parameters $n$ and $T_r$, which simultaneously control the DM relic abundance as well the frozen value of baryon asymmetry, are tightly constrained due to consecutive imposition of experimental bounds on relic density followed by observed value of baryon asymmetry of the Universe. It has been found that $n$ is strictly bounded within the interval $0.4\lesssim n \lesssim 1.6$. The upper bound is imposed by the baryon asymmetry constraint whereas the lower bound arises to satisfy the correct relic abundance of the DM. The restriction on $T_r$ is not so stringent as it can vary from sub GeV to few tens of GeV.

Read this paper on arXiv…

A. Biswas, M. Chakraborty and S. Khan
Mon, 27 Mar 23
11/59

Comments: 39 pages, 10 figures, 1 table

Constraints on $f(T)$ Cosmology with Pantheon+ [CL]

Posted on by

http://arxiv.org/abs/2303.13840


$f(T)$ cosmology has shown promise in explaining aspects of cosmic evolution. In this work, we analyze constraints on leading models of $f(T)$ gravity in the context of the recently released Pantheon+ data set, together with comparisons with previous releases. We also consider other late-time data sets including cosmic chronometers and baryonic acoustic oscillation data. Our main result is that we find that the different $f(T)$ models under investigation connect to a variety of Hubble constant, which may help alleviate the cosmic tension on this parameter.

Read this paper on arXiv…

R. Briffa, C. Escamilla-Rivera, J. Said, et. al.
Mon, 27 Mar 23
14/59

Comments: N/A

Primordial black hole dark matter from catastrogenesis with unstable pseudo-Goldstone bosons [CL]

Posted on by

http://arxiv.org/abs/2303.14107


We propose a new scenario for the formation of asteroid-mass primordial black holes (PBHs). Our mechanism is based on the annihilation of the string-wall network associated with the breaking of a $U(1)$ global symmetry into a discrete $Z_N$ symmetry. If the potential has multiple local minima ($N>1$) the network is stable, and the annihilation is guaranteed by a bias among the different vacua. The collapse of the string-wall network is accompanied by catastrogenesis, a large production of pseudo-Goldstone bosons (pGBs) — e.g. axions, ALPs, or majorons — gravitational waves, and PBHs. If pGBs rapidly decay into products that thermalize, as predicted e.g. in the high-quality QCD axion and heavy majoron models, they do not contribute to the dark matter population, but we show that PBHs can constitute 100% of the dark matter. The gravitational wave background produced by catastrogenesis with heavy unstable axions, ALPs, or majorons could be visible in future interferometers.

Read this paper on arXiv…

G. Gelmini, J. Hyman, A. Simpson, et. al.
Mon, 27 Mar 23
19/59

Comments: 24 pages, 4 figures

Multipole vector dark matter below the GeV-scale [CL]

Posted on by

http://arxiv.org/abs/2303.13643


We consider electrically neutral complex vector particles $V$ below the GeV mass scale that, from a low energy perspective, couple to the photon via higher dimensional form factor interactions. We derive ensuing astrophysical constraints by considering the anomalous energy loss from the Sun, Horizontal Branch, and Red Giant stars as well as from SN1987A that arise from vector pair-production in these environments. Under the assumption that the dark states $V$ constitute dark matter, the bounds are then complemented by direct and indirect detection as well as cosmological limits. The relic density from freeze-out and freeze-in mechanisms is also computed. On the basis of a UV-complete model that realizes the considered effective couplings, we also discuss the naturalness of the constrained parameter space, and provide an analysis of the zero mass limit of $V$.

Read this paper on arXiv…

X. Chu, J. Hisano, A. Ibarra, et. al.
Mon, 27 Mar 23
20/59

Comments: 15 pages, 3 figures

Alignment of the Alpha Magnetic Spectrometer (AMS) in space [CL]

Posted on by

http://arxiv.org/abs/2303.14072


The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector operating at an altitude of 410 km aboard the International Space Station. The AMS silicon tracker, together with the permanent magnet, measures the rigidity (momentum/charge) of cosmic rays in the range from 0.5 GV to several TV. In order to have accurate rigidity measurements, the positions of more than 2000 tracker modules have to be determined at the micron level by an alignment procedure. The tracker was first aligned using the 400 GeV/c proton test beam at CERN and then re-aligned using cosmic-ray events after being launched into space. A unique method to align the permanent magnetic spectrometer for a space experiment is presented. The developed underlying mathematical algorithm is discussed in detail.

Read this paper on arXiv…

Q. Yan and V. Choutko
Mon, 27 Mar 23
38/59

Comments: N/A

Resonant instabilities mediated by drag and electrostatic interactions in laboratory and astrophysical dusty plasmas [CL]

Posted on by

http://arxiv.org/abs/2303.13640


Dusty plasmas are known to support a diverse range of instabilities, including both generalizations of standard plasma instabilities and ones caused by effects specific to dusty systems. It has been recently demonstrated that a novel broad class of streaming instabilities, termed resonant drag instabilities (RDIs), can be attributed to a particular resonance phenomenon caused by defective eigenvalues of the linearized dust/fluid system. In this work, it is demonstrated that this resonance phenomenon is not unique to RDIs and can be used as a framework to understand a wider range of instabilities, termed resonant instabilities. Particular attention is given to the filamentary ionization instability seen in laboratory dusty plasmas and to the two-stream instability. It is shown that, due to the commonalities in underlying physics between the dust-ion-acoustic two-stream instability and the acoustic RDI, these instabilities should be relevant in strongly overlapping regimes in astrophysical dusty plasmas. It is proposed that a similar overlap in the experimental accessibility of these modes (and of the filamentary instability) allows for the possibility of experimental investigation of complex and astrophysically relevant instability dynamics.

Read this paper on arXiv…

B. Israeli, A. Bhattacharjee and H. Qin
Mon, 27 Mar 23
39/59

Comments: 18 pages, 15 figures

Inferring astrophysical neutrino sources from the Glashow resonance [CL]

Posted on by

http://arxiv.org/abs/2303.13706


We infer the ultrahigh energy neutrino source by using the Glashow resonance candidate event recently identified by the IceCube Observatory. For the calculation of the cross section for the Glashow resonance, we incorporate both the atomic Doppler broadening effect and initial state radiation $\overline{\nu}^{}{e} e^- \to W^- \gamma$, which correct the original cross section considerably. Using available experimental information, we have set a generic constraint on the $\overline{\nu}^{}{e}$ fraction of astrophysical neutrinos, which excludes the $\mu$-damped ${\rm p}\gamma$ source around $2\sigma$ confidence level. While a weak preference has been found for the pp source, next-generation measurements will be able to distinguish between ideal pp and p$\gamma$ sources with a high significance assuming an optimistic single power-law neutrino spectrum.

Read this paper on arXiv…

G. Huang, M. Lindner and N. Volmer
Mon, 27 Mar 23
42/59

Comments: 10 pages, 4 figures

Electron transport measurements in liquid xenon with Xenoscope, a large-scale DARWIN demonstrator [CL]

Posted on by

http://arxiv.org/abs/2303.13963


There is a compelling physics case for a large, xenon-based underground detector devoted to dark matter and other rare-event searches. A two-phase time projection chamber as inner detector allows for a good energy resolution, a three-dimensional position determination of the interaction site and particle discrimination. To study challenges related to the construction and operation of a multi-tonne scale detector, we have designed and constructed a vertical, full-scale demonstrator for the DARWIN experiment at the University of Zurich. Here we present first results from a several-months run with 343 kg of xenon and electron drift lifetime and transport measurements with a 53 cm tall purity monitor immersed in the cryogenic liquid. After 88 days of continuous purification, the electron lifetime reached a value of 664(23) microseconds. We measured the drift velocity of electrons for electric fields in the range (25–75) V/cm, and found values consistent with previous measurements. We also calculated the longitudinal diffusion constant of the electron cloud in the same field range, and compared with previous data, as well as with predictions from an empirical model.

Read this paper on arXiv…

L. Baudis, Y. Biondi, A. Bismark, et. al.
Mon, 27 Mar 23
48/59

Comments: N/A

Implications of Palatini gravity for inflation and beyond [CL]

Posted on by

http://arxiv.org/abs/2303.14148


We present an introduction to cosmic inflation in the framework of Palatini gravity, which provides an intriguing alternative to the conventional metric formulation of gravity. In the latter, only the metric specifies the spacetime geometry, whereas in the former, the metric and the spacetime connection are independent variables-an option that can result in a gravity theory distinct from the metric one. In scenarios where the field(s) responsible for cosmic inflation are non-minimally coupled to gravity or the gravitational sector is extended, assumptions about the underlying gravitational degrees of freedom can have substantial implications for the observational effects of inflation. We examine this explicitly by discussing various compelling scenarios, such as Higgs inflation with non-minimal coupling to gravity, Higgs inflation with non-minimal derivative coupling, $\mathcal{R}^2$ inflation, and beyond. We also comment on reheating in these models. Finally, as an application of the general results of Palatini $\mathcal{R}^2$ inflation, we review a model of successful quintessential inflation, where a single scalar field acts initially as the inflaton and then becomes dynamical dark energy, in agreement will all experimental constraints.

Read this paper on arXiv…

I. Gialamas, A. Karam, T. Pappas, et. al.
Mon, 27 Mar 23
52/59

Comments: 47 pages, 9 figures, invited review to be published in International Journal of Geometric Methods in Modern Physics

A test of Einstein's equivalence principle in ngEHT observations [CL]

Posted on by

http://arxiv.org/abs/2303.13271


We show that Event Horizon Telescope (EHT) observations allow us to test the fundamental principles of General Relativity (GR). GR is based on the universality of gravity and Einstein’s equivalence principle (EEP). However, EEP is not a basic principle of physics but an empirical fact. Non-Minimal Coupling (NMC) of electromagnetic fields violates EEP, and their effects manifest in the strong-gravity regime. Hence, EHT provides an opportunity to test NMC in the strong-gravity regime. We show that, to the leading order in the spin parameter, NMC of the electromagnetic field modifies the black hole image in two ways: First, for one polarization mode, the horizon casts a shadow of radius \emph{greater than} $\sqrt{27} GM/c^2$ on the image of the source. For the other polarization mode, it is \emph{smaller than} $\sqrt{27} GM/c^2$. Second, the brightness and the position of the lensing ring are affected by the non-minimal coupling. The lensing ring is more prominent for one polarization mode than the other. Finally, we discuss the constraints on the NMC constant from future ngEHT observations.

Read this paper on arXiv…

J. Johnson, S. Jana and S. Shankaranarayanan
Fri, 24 Mar 23
3/56

Comments: 18 pages, 4 figures

Upper limit on scalar field dark matter from LIGO-Virgo third observation run [CL]

Posted on by

http://arxiv.org/abs/2303.13088


If dark matter is a light scalar field weakly interacting with elementary particles, such a field induces oscillations of the physical constants, which results in time-varying force acting on macroscopic objects. In this paper, we report on a search for such a signal in the data of the two LIGO detectors during their third observing run (O3). We focus on the mass of the scalar field in the range of $10^{-13}-10^{-11}~{\rm eV}$ for which the signal falls within the detectors’ sensitivity band. We first formulate the cross-correlation statistics that can be readily compared with publically available data. It is found that inclusion of the anisotropies of the velocity distribution of dark matter caused by the motion of the solar system in the Milky Way Galaxy enhances the signal by a factor of $\sim 2$ except for the narrow mass range around $\simeq 3\times 10^{-13}~{\rm eV}$ for which the correlation between the interferometer at Livingston and the one at Hanford is suppressed. From the non-detection of the signal, we derive the upper limits on the coupling constants between the elementary particles and the scalar field for five representative cases. For all the cases where the weak equivalence principle is not satisfied, tests of the violation of the weak equivalence principle provide the tightest upper limit on the coupling constants. Upper limits from the fifth-force experiment are always stronger than the ones from LIGO, but the difference is less than a factor of $\sim 5$ at large-mass range. Our study demonstrates that gravitational-wave experiments are starting to bring us meaningful information about the nature of dark matter. The formulation provided in this paper may be applied to the data of upcoming experiments as well and is expected to probe much wider parameter range of the model.

Read this paper on arXiv…

K. Fukusumi, S. Morisaki and T. Suyama
Fri, 24 Mar 23
4/56

Comments: 21 pages, 5 figures

LiteBIRD and CMB-S4 Sensitivities to Reheating in Plateau Models of Inflation [CL]

Posted on by

http://arxiv.org/abs/2303.13503


We study the sensitivity of LiteBIRD and CMB-S4 to the reheating temperature and the inflaton coupling in three types of plateau-potential models of inflation, namely mutated hilltop inflation, radion gauge inflation, and $\alpha$-attractor T models. We first study the relations between model parameters and CMB observables in all models analytically. We then perform Monte Carlo Markov Chain based forecasts to quantify the information gain on the reheating temperature, the inflaton coupling, and the scale of inflation that can be achieved with LiteBIRD and CMB-S4. We compare the results of the forecasts to those obtained from a recently proposed simple analytic method. We find that both LiteBIRD and CMB-S4 can simultaneously constrain the scale of inflation and the reheating temperature in all three types of models. They can for the first time obtain both an upper and lower bound on the latter, comprising the first ever measurement. In the mutated hilltop inflation and radion gauge inflation models this can be translated into a measurement of the inflaton coupling in parts of the parameter space. Constraining this microphysical parameter will help to understand how these models of inflation may be embedded into a more fundamental theory of particle physics.

Read this paper on arXiv…

M. Drewes, L. Ming and I. Oldengott
Fri, 24 Mar 23
9/56

Comments: 46 pages plus appendices, 43 figures

On the oscillations of the inflaton field of the simplest $α$-attractor T-model [CL]

Posted on by

http://arxiv.org/abs/2303.13008


In this work, we consider homogeneous oscillations of the inflaton field after inflation. In particular, we obtain an analytical result for the (average) equation of state for the oscillating inflaton field for the simplest $\alpha$-attractor T-model. The result is useful for the study of its post-inflationary evolution. The most dramatic possibility is that during inflaton field oscillation, the (average) equation of state is that of a cosmological constant. This implies the end of slow-roll inflation in this model could be the beginning of oscillating inflation.

Read this paper on arXiv…

C. Lin
Fri, 24 Mar 23
17/56

Comments: 9 pages, 3 figures