# Does light from steady sources bear any observable imprint of the dispersive intergalactic medium? [IMA]

There has recently been some interest in the prospect of detecting ionized intergalactic baryons by examining the properties of incoherent light from background cosmological sources, namely quasars. Although the paper by \cite{lieu13} proposed a way forward, it was refuted by the later theoretical work of \cite{hir14} and observational study of \cite{hal16}. In this paper we investigated in detail the manner in which incoherent radiation passes through a dispersive medium both from the frameworks of classical and quantum electrodynamics, which led us to conclude that the premise of \cite{lieu13} would only work if the pulses involved are genuinely classical ones involving many photons per pulse, but unfortunately each photon must not be treated as a pulse that is susceptible to dispersive broadening. We are nevertheless able to change the tone of the paper at this juncture, by pointing out that because current technology allows one to measure the phase of individual modes of radio waves from a distant source, the most reliable way of obtaining irrefutable evidence of dispersion, namely via the detection of its unique signature of a quadratic spectral phase, may well be already accessible. We demonstrate how this technique is only applied to measure the column density of the ionized intergalactic medium.

R. Lieu and L. Duan
Fri, 1 Dec 17
47/68

Comments: 21 pages, 67 equations, ApJ in press

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# Quantum chaos of dark matter in the Solar System [CL]

We perform time-dependent analysis of quantum dynamics of dark matter particles in the Solar System. It is shown that this problem has similarities with a microwave ionization of Rydberg atoms studied previously experimentally and analytically. On this basis it is shown that the quantum effects for chaotic dark matter dynamics become significant for dark matter mass ratio to electron mass being smaller than $2 \times 10^{-15}$. Below this border multiphoton diffusion over Rydberg states of dark matter atom becomes exponentially localized in analogy with the Anderson localization in disordered solids. The life time of dark matter in the Solar System is determined in dependence on mass ratio in the localized phase and a few photon ionization regime. Various implications of these quantum results are discussed for the capture of dark matter from Galaxy and its steady-state density distribution.

D. Shepelyansky
Thu, 23 Nov 17
48/52

# Quantum chaos of dark matter in the Solar System [CL]

We perform time-dependent analysis of quantum dynamics of dark matter particles in the Solar System. It is shown that this problem has similarities with a microwave ionization of Rydberg atoms studied previously experimentally and analytically. On this basis it is shown that the quantum effects for chaotic dark matter dynamics become significant for dark matter mass ratio to electron mass being smaller than $2 \times 10^{-15}$. Below this border multiphoton diffusion over Rydberg states of dark matter atom becomes exponentially localized in analogy with the Anderson localization in disordered solids. The life time of dark matter in the Solar System is determined in dependence on mass ratio in the localized phase and a few photon ionization regime. Various implications of these quantum results are discussed for the capture of dark matter from Galaxy and its steady-state density distribution.

D. Shepelyansky
Thu, 23 Nov 17
25/52

# Quantum to classical transition in the Hořava-Lifshitz quantum cosmology [CL]

A quasi-Gaussian quantum superposition of Ho\v{r}ava-Lifshitz (HL) stationary states is built in order to describe the transition of the quantum cosmological problem to the related classical dynamics. The obtained HL phase-space superposed Wigner function and its associated Wigner currents describe the conditions for the matching between classical and quantum phase-space trajectories. The matching quantum superposition parameter is associated to the total energy of the classical trajectory which, at the same time, drives the engendered Wigner function to the classical stationary regime. Through the analysis of the Wigner flows, the quantum fluctuations that distort the classical regime can be quantified as a measure of (non)classicality. Finally, the modifications to the Wigner currents due to the inclusion of perturbative potentials are computed in the HL quantum cosmological context. In particular, the inclusion of a cosmological constant provides complementary information that allows for connecting the age of the Universe with the overall stiff matter density profile.

A. Bernardini, P. Leal and O. Bertolami
Wed, 8 Nov 17
57/84

# Recent progress on the description of relativistic spin: vector model of spinning particle and rotating body with gravimagnetic moment in General Relativity [CL]

We review the recent results on development of vector models of spin and apply them to study the influence of spin-field interaction on the trajectory and precession of a spinning particle in external gravitational and electromagnetic fields. The formalism is developed starting from the Lagrangian variational problem, which implies both equations of motion and constraints which should be presented in a model of spinning particle. We present a detailed analysis of the resulting theory and show that it has reasonable properties on both classical and quantum level. We describe a number of applications and show how the vector model clarifies some issues presented in theoretical description of a relativistic spin: A) One-particle relativistic quantum mechanics with positive energies and its relation with the Dirac equation and with relativistic {\it Zitterbewegung}; B) Spin-induced non commutativity and the problem of covariant formalism; C) Three-dimensional acceleration consistent with coordinate-independence of the speed of light in general relativity and rainbow geometry seen by spinning particle; D) Paradoxical behavior of the Mathisson-Papapetrou-Tulczyjew-Dixon equations of a rotating body in ultra relativistic limit, and equations with improved behavior.

A. Deriglazov and W. Ramirez
Mon, 23 Oct 17
52/52

Comments: Invited review article for the Journal “Advances in Mathematical Physics”. Based on the recent works: arXiv:1312.6247, arXiv:1406.6715, arXiv:1409.4756, arXiv:1509.05357, arXiv:1511.00645, arXiv:1609.00043. 61 pages, 3 figures

# Matter-wave coherence limit owing to cosmic gravitational wave background [CL]

We study matter-wave interferometry in the presence of a stochastic background of gravitational waves. It is shown that if the background has a scale-invariant spectrum over a wide bandwidth (which is expected in a class of inflationary models of Big Bang cosmology), then separated-path interference cannot be observed for a lump of matter of size above a limit which is very insensitive to the strength and bandwidth of the fluctuations, unless the interferometer is servo-controlled or otherwise protected. For ordinary solid matter this limit is of order 1–10 mm. A servo-controlled or cross-correlated device would also exhibit limits to the observation of macroscopic interference, which we estimate for ordinary matter moving at speeds small compared to c.

A. Steane
Tue, 17 Oct 17
44/163