http://arxiv.org/abs/1811.09151
Although Cosmic Microwave Background and Large Scale Structure probe the largest scales of our universe with ever increasing precision, our knowledge is still very limited for the smaller physical scales other than the bounds on Primordial Black Hole (PBH) amount. We show that the statistical properties of the small scale quantum fluctuations can be probed via the stochastic gravitational wave background, which is induced as the scalar modes re-enter the horizon. We found that even if scalar curvature fluctuations have a subdominant (or mild) non-Gaussian component, these non-Gaussian perturbations can source a dominant portion of the induced GWs. Moreover, the GWs sourced by non-Gaussian scalar fluctuations peaks at a higher frequency and this can result in distinctive observational signatures. If the induced GW background is detected, but not the signatures arising from the non-Gaussian component of the scalar fluctuations, $\zeta = \zeta_G + f_{\rm NL} \, \zeta_G^{2}$, this translates into stringent bounds on $f_{\rm NL}$ depending on the amplitude of the GW signal.
C. Unal
Mon, 26 Nov 18
58/100
Comments: 7 pages, 9 figures. Comments, suggestions and (may have unintentionally missed some) any citation requests are welcome
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