Advanced Alicki-Fannes-Winter method for energy-constrained quantum systems and its use

Abstract

We describe an universal method for quantitative continuity analysis of entropic characteristics of energy-constrained quantum systems and channels. It gives asymptotically tight continuity bounds for basic characteristics of quantum systems of wide class (including multi-mode quantum oscillators) and channels between such systems under the energy constraint. The main application of the proposed method is the advanced version of the uniform finite-dimensional approximation theorem for basic capacities of energy-constrained quantum channels.

33 pages, Section 5 contains the answer to everyone who asked me about the possibility to improve the dimension estimates in arXiv:1707.05641, in v.3 it is shown that the proposed method gives asymptotically tight continuity bounds in more general case