English

One-half reflected entropy is not a lower bound for entanglement of purification

Quantum Physics 2024-02-23 v2 High Energy Physics - Theory

Abstract

In recent work, Akers et al. proved that the entanglement of purification Ep(A:B)E_p(A:B) is bounded below by half of the qq-R\'enyi reflected entropy SR(q)(A:B)S_R^{(q)}(A:B) for all q2q\geq2, showing that Ep(A:B)=12SR(q)(A:B)E_p(A:B) = \frac{1}{2} S_R^{(q)}(A:B) for a class of random tensor network states. Naturally, the authors raise the question of whether a similar bound holds at q=1q = 1. Our work answers that question in the negative by finding explicit counter-examples, which we arrive at through numerical optimization. Nevertheless, this result does not preclude the possibility that restricted sets of states, such as CFT states with semi-classical gravity duals, could obey the bound in question.

Keywords

Cite

@article{arxiv.2309.02506,
  title  = {One-half reflected entropy is not a lower bound for entanglement of purification},
  author = {Josiah Couch and Phuc Nguyen and Sarah Racz and Georgios Stratis and Yuxuan Zhang},
  journal= {arXiv preprint arXiv:2309.02506},
  year   = {2024}
}