Spiky CMB distortions from primordial bubbles

Abstract

Primordial bubbles that possibly nucleate through quantum tunneling during inflation in a multidimensional potential might have left some relic detectable at the present time. These bubbles turn into black holes during the radiation era, which may account for the LIGO black holes, supermassive black holes, and may play an important role in dark matter. Typically, these black holes are surrounded by an energy deficit in the form of a spherical sound wave packet propagating outwards. In this work we study how this perturbation of the cosmic plasma dissipates before the time of recombination, leading to spectral distortions in CMB. We find that there may exist some rare regions on the last scattering surface containing huge black holes, which have produced potentially detectable point-like signals of µ-type distortions.

Angular correlation as a novel probe of supermassive primordial black holes

“…(2.3) and the distribution of φ becomes Gaussian with its mean being φ ini . Roughly speaking, a PBH of mass M PBH is formed (after inflation) in the Hubble #1 As an alternative scenario, nucleation of bubbles by quantum tunneling during inflation has been studied in [21][22][23]. We do not consider this class of models in our paper.…”

Press-Schechter primordial black hole mass functions and their observational constraints

“…Wherever a phase transition occurs, an expanding bubble of true-vacuum will emerge, which will accelerate propelled by the energy difference between the true and false vacua, expanding causally (and relativistically) throughout the Universe (Garriga et al 2016;Deng et al 2018;Jinno et al 2019). Then, the places where PBHs are most likely to form are the regions where the walls of said bubbles collide (Hawking et al 1982;Moss 1994;Khlopov et al 1998;Deng & Vilenkin 2017;Lewicki & Vaskonen 2019;Deng 2020a;Kusenko et al 2020;Deng 2020b), as illustrated in Fig. 2.…”