Yuki Yokokura (RIKEN iTHEMS, Waco, Japan)

Semi-classical Spacetime Region with Maximum Entropy

We consider a spherical static spacetime region without a trapped surface, and study the entropy of any semi-classical interior degrees of freedom taking into account the full self-gravity in the semi-classical Einstein equation. We find a universal entropy bound, which reduces to Bekenstein’s bound in a special case. Then, the saturating spacetime with positive pressures is determined uniquely as a dense configuration without horizon or singularity, and the maximum entropy agrees with the Bekenstein-Hawking entropy exactly. [arXiv: 2207.14274, 2303.xxxxx]