QLunch: Quasi-factorization of the quantum relative entropy

Speaker: Angela Capel from Universidad Autónoma de Madrid

Title: Quasi-factorization of the quantum relative entropy

Abstract:
The existence of a positive log-Sobolev constant implies a bound on the mixing time of a quantum dissipative evolution under the Markov approximation. For classical spin systems, such constant was proven to exist, under the assumption of a mixing condition in the Gibbs measure associated to their dynamics, via a quasi-factorization of the entropy in terms of some conditional entropies.

In this talk, we analyze analogous quasi-factorization results in the quantum case. For that, we define the quantum conditional relative entropy and prove several quasi-factorization results for it. As an illustration of their potential, we use one of them to obtain a positive log-Sobolev constant for the heat-bath dynamics with product fixed point. 

This is joint work with Angelo Lucia (U. Copenhagen) and David Pérez-García (U. Complutense de Madrid).