Non-Gaussian Stochastic Gravitational Wave Background from Phase Transitions

by Soubhik Kumar (UC Berkeley)

Monday 7 Feb 2022, 17:00 → 18:00 Europe/Berlin

Cosmological phase transitions in the primordial universe can produce an anisotropic stochastic gravitational wave background (GWB), similar to the CMB. For adiabatic perturbations, the fluctuations in GWB follow those in the CMB, but if primordial fluctuations carry an isocurvature component, this need no longer be true. I will describe a scenario in which primordial isocurvature fluctuations can survive in GWB and exhibit significant non-Gaussianity (NG) in contrast to an approximately Gaussian CMB. While it may be somewhat challenging to probe GWB NG at LISA, future proposals such as DECIGO and BBO can be powerful probes of NG, complimentary to CMB and LSS.