English

A New Proof of the QNEC

High Energy Physics - Theory 2025-10-06 v2 General Relativity and Quantum Cosmology Mathematical Physics math.MP Operator Algebras Quantum Physics

Abstract

We give a simplified proof of the quantum null energy condition (QNEC). Our proof is based on an explicit formula for the shape derivative of the relative entropy, with respect to an entangling cut. It allows bypassing the analytic continuation arguments of a previous proof by Ceyhan and Faulkner and can be used e.g., for defining entropy current fluctuations.

Keywords

Cite

@article{arxiv.2503.04651,
  title  = {A New Proof of the QNEC},
  author = {Stefan Hollands and Roberto Longo},
  journal= {arXiv preprint arXiv:2503.04651},
  year   = {2025}
}

Comments

24 pages, 1 figure; v2: domain assumptions on quantum state relaxed, version accepted for publication