Comment on "on a new definition of quantum entropy"

TL;DR

This paper critiques a proposed quantum entropy definition, providing a counterexample where entropy does not increase during a spontaneous process, challenging the original claim of its universal increase.

Contribution

It presents a counterexample to the claim that the new quantum entropy always increases during non-quasi-static processes, questioning its general validity.

Findings

Entropy does not always increase in spontaneous processes under the new definition

Counterexample challenges the universality of entropy increase

Questions the applicability of the proposed quantum entropy operator

Abstract

In the article, on a new definition of quantum entropy, Campisi has explained an operator for entropy based on quantum number operator. It has been claimed that the expectation values for this operator increases for every non-quasi-static time dependent perturbations. We have found an example for a case that entropy with this definition does not increase through a spontaneous process.