Many body physics and the capacity of quantum channels with memory
M. B. Plenio, S. Virmani
备注：
V1: 17 sides, 5 figures. See posting by M. Hastings 0710.3324 for related results on fermionic systems. V2: 19 sides, 5 figures, extensive changes to improve readability and to correct an imprecise argument. To appear in New J. Phys. Title change due to referee request
In most studies of the capacity of quantum channels, it is assumed that the errors in each use of the channel are independent. However, recent work has begun to investigate the effects of memory or correlations in the error, and has led to suggestions that there can be interesting non-analytic behaviour in the capacity of such channels. In a previous paper we pursued this issue by connecting the study of channel capacities under correlated error to the study of critical behaviour in many-body physics. This connection enables the use of techniques from many-body physics to either completely solve or understand qualitatively a number of interesting models of correlated error with analogous behaviour to associated many-body systems. However, in order for this approach to work rigorously, there are a number of technical properties that need to be established for the lattice systems being considered. In this article we discuss these properties in detail, and establish them for some classes of many-body system.
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Capacity-time Trade-off in Highly Reliable Quantum Memory
Graduate School of China Academy of Engineering Physics（中国工程物理研究院研究生院）；Beijing Computational Science Research Center（北京计算科学研究中心）；International Research Center for Neurointelligence, University of Tokyo Institutes for Advanced Study, University of Tokyo（东京大学前沿研究系国际神经智能研究中心）
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