Speaker
Description
Cosmological first-order phase transitions generate a stochastic background of gravitational waves (GWs), a measurement of which would signal physics beyond the Standard Model. A crucial quantity that enters the computation of the GW power spectrum is the bubble nucleation rate, which is accessible from the underlying QFT. At small coupling, the rate can be computed in perturbation theory. Alternatively, functional renormalisation group methods can be used to access the nucleation rate regardless of coupling strength. We extract the nucleation rate from the $k = 0$ quantum effective action by a suitable reconstruction of the barrier in the non-analytic convex effective potential. A benefit of this approach is that all quantum fluctuations are integrated out, and the regulator vanishes at $k = 0$. This poster charts the various techniques we have employed and some preliminary results.
| Affiliation | University of Sussex |
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| Career status | PhD student |