English

A Sharp Fannes-type Inequality for the von Neumann Entropy

Quantum Physics 2009-11-13 v1

Abstract

We derive an inequality relating the entropy difference between two quantum states to their trace norm distance, sharpening a well-known inequality due to M. Fannes. In our inequality, equality can be attained for every prescribed value of the trace norm distance.

Keywords

Cite

@article{arxiv.quant-ph/0610146,
  title  = {A Sharp Fannes-type Inequality for the von Neumann Entropy},
  author = {Koenraad M. R. Audenaert},
  journal= {arXiv preprint arXiv:quant-ph/0610146},
  year   = {2009}
}

Comments

5 pages, 3 figures

R2 v1 2026-07-22T19:57:32.579Z