The equation of state of the primordial plasma is reduced during each early universe phase transition. Primordial black holes, thought to form whilst the universe is radiation dominated, are exponentially sensitive to the changes in the equation of state. However, this exponential sensitivity is the same that primordial black hole formation shows to the amplitude of the primordial curvature power spectrum. Thus, using constraints on the power spectrum we are able to place constraints on primordial black hole abundances. I will show that, despite the exponential enhancement in formation rate, current constraints on the power spectrum leads to difficulties motivating primordial black holes with the standard model phase transitions. Secondly, time-permitting, I will discuss some of my more recent work. 

Biography

Xavier is a PhD student at the University of Sussex, working with Chris Byrnes. His main research interests are primordial black holes (PBHs), gravitational waves, scalar fields and phase transitions. 

Inviter: Shi Pi (皮石)