Speaker
Peizhi Du
(University of Science and Technology of China)
Description
Cosmological first-order phase transitions are typically associated with physics beyond the Standard Model, and thus of great theoretical and observational interest. In this talk, I will show that a broad class of non-thermal first-order phase transitions could generate distinct large-scale isocurvature in dark radiation that can be observable in the CMB. We derive constraints on $\Delta N_{\rm eff}$ from phase transitions based on CMB+BAO data, which can be much stronger than those from adiabatic initial conditions. I will also demonstrate that since perturbations of dark radiation have a non-Gaussian origin, searches for non-Gaussianity in the CMB could also place a stringent bound on $\Delta N_{\rm eff}$.
Primary authors
Matthew Buckely
(Rutgers University)
Mitchell Weikert
(Rutgers University)
Nicolas Fernandez
(Rutgers University)
Peizhi Du
(University of Science and Technology of China)
