Entropy Obstruction to Closed Semiclassical Bounces
Abstract
We prove a finite-Ghslash singularity theorem for semiclassical spacetimes with compact Cauchy slices. Let a compact Cauchy slice be divided by a compact surface into regions B and C. Suppose that B is conditionally hyperentropic, Hmax,genε(BC|C)>0, that the future-inward null boundary from the dividing surface toward B is a discrete max lightsheet, and that C is robustly quantum trapped. Assuming discrete max-focusing and a regular semiclassical endpoint for a closing lightsheet, the future Cauchy development of B contains an incomplete null generator. This parallels entropy singularity theorems in which hyperentropy is combined with the existence of an inward lightsheet, while robust quantum trapping supplies the additional finite-Ghslash local obstruction needed here. In a closed Friedmann universe, the theorem excludes a controlled semiclassical bounce when a contracting hemisphere lies on such a lightsheet and contains more independent information than its boundary can support.
Related
- The generalized entropy in holographic semiclassical de Sitter spacetime
- Unifying energy-entropy bounds in semiclassical gravity
- Obstruction to local entropy laws on arbitrary black-hole cuts in five-dimensional Einstein--Gauss--Bonnet gravity
- On the Increase of Boltzmann Entropy in Closed Macroscopic Quantum Systems
- Exploring the robustness of permutation entropy analysis to differentiate between closed-eyes and open-eyes resting states
BibTeX
@misc{kumar2026entropy,
title = {{Entropy Obstruction to Closed Semiclassical Bounces}},
author = {Naman Kumar},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.09196},
eprint = {2609.09196},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.09196},
}
RIS
TY - UNPB
TI - Entropy Obstruction to Closed Semiclassical Bounces
AU - Naman Kumar
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.09196
UR - https://arxiv.org/abs/2609.09196
AB - We prove a finite-Ghslash singularity theorem for semiclassical spacetimes with compact Cauchy slices. Let a compact Cauchy slice be divided by a compact surface into regions B and C. Suppose that B is conditionally hyperentropic, H_max,gen^ε(BC|C)>0, that the future-inward null boundary from the dividing surface toward B is a discrete max lightsheet, and that C is robustly quantum trapped. Assuming discrete max-focusing and a regular semiclassical endpoint for a closing lightsheet, the future Cauchy development of B contains an incomplete null generator. This parallels entropy singularity theorems in which hyperentropy is combined with the existence of an inward lightsheet, while robust quantum trapping supplies the additional finite-Ghslash local obstruction needed here. In a closed Friedmann universe, the theorem excludes a controlled semiclassical bounce when a contracting hemisphere lies on such a lightsheet and contains more independent information than its boundary can support.
ER -