Mixed State Entanglement Entropy in CFT

Xin Jiang; Peng Wang; Houwen Wu; Haitang Yang

Mixed State Entanglement Entropy in CFT

High Energy Physics - Theory 2025-09-19 v2

Authors: Xin Jiang , Peng Wang , Houwen Wu , Haitang Yang

Abstract

How to calculate the entanglement entropy between two subsystems for a mixed state has remained an important problem. In this paper, we provide a straightforward method, namely the subtraction approach, to solve this problem for generic covariant bipartite mixed states, where time dependence is explicitly included. We further demonstrate that the mixed state entanglement entropy $S_\text{vN}$ can be calculated in a more abstract yet powerful way. Within the context of the AdS $_3$ /CFT $_2$ and a configuration of AdS $_5$ /CFT $_4$ correspondences, we show that $S_\text{vN}$ exactly matches the corresponding entanglement wedge cross section in the AdS bulk, respectively.

Keywords

entanglement entropy quantum entanglement quantum entropy

Cite

@article{arxiv.2501.08198,
  title  = {Mixed State Entanglement Entropy in CFT},
  author = {Xin Jiang and Peng Wang and Houwen Wu and Haitang Yang},
  journal= {arXiv preprint arXiv:2501.08198},
  year   = {2025}
}

Comments

Published version in JHEP. Added clarifications and corrections. 19 pages, 9 figures

Mixed State Entanglement Entropy in CFT

Abstract

Keywords

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