The quantum origin of cosmological primordial perturbations is a cornerstone framework in the interplay between gravity and quantum physics. In this paper, we study the mutual information between two spatial regions in a radiation-dominated universe filled by a curvature perturbation field in a squeezed state. We find an enhancement with respect to the usual mutual information of the Minkowski vacuum due to momentum modes affected by particle production during inflation. This result supports our previous claim of the existence of long-range correlations between primordial black holes (PBH) at formation during the radiation era.

• Received 10 July 2020
• Accepted 22 January 2021

DOI:https://doi.org/10.1103/PhysRevD.103.043537