Speaker
Description
Using semi-analytical models, we investigate the power spectrum of gravitational waves generated by sound waves in the plasma during a first-order phase transition in new unexplored scenarios. (i) The phase transition is accompanied by a change of the equation of state from that of pure radiation. This modifies the shape of the gravitational wave power spectrum as a consequence of both sound and gravitational waves propagating across a non-conformal fluid. (ii) In addition, we investigate the novel limit where the phase transition completes with large bubbles, by which we mean that the mean bubble spacing R∗ is a non-negligible fraction of the Hubble length 1/H∗. Since the amplitude of the gravitational wave signal increases with R∗H∗, this is also the loud signal regime. In this regime the effects of gravity, hitherto neglected, become relevant. We here consider the first general relativistic corrections beyond the Universe expansion. This work improves the current estimation of the gravitational waves power spectrum from first order phase transitions and expands the possible scenarios of transitions that can be tested by gravitational wave detectors.
| Other topic / keywords: | Gravitational waves/ Phase transitions |
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