24.11.21 - Bassano Vacchini "Entropic bounds on information backflow"

Entropic bounds on information backflow

In has been shown that an interesting approach for the description of memory effects in the reduced quantum dynamics of an open system can be be based on the notion of information exchange between the open system itself and its environment. This exchange has typically been quantified studying the variation in time of the trace distance between distinct initial system states. We point to the fact that such an information exchange can actually be described by a large class of quantum divergences, including not only distances, but also entropic quantifiers. We consider in particular regularized versions of quantum relative entropy.  We derive general upper bounds on the revivals of quantum divergences conditioned and determined by the formation of correlations and changes in the environment. These revivals have been connected in the literature to a definition of non-Markovian dynamics. We illustrate our findings by means of examples, considering in particular the Jaynes-Cummings model and a phase covariant dynamics.

H.-P. Breuer, E.-M. Laine, J. Piilo and B. Vacchini,

Colloquium: Non-Markovian dynamics in open quantum systems,

Rev. Mod. Phys. vol. 88, 021002 (2016)

N. Megier, A. Smirne and B. Vacchini,

Entropic bounds on information backflow

Phys. Rev. Lett. vol. 127, 030401 (2021)

 Find more information here.