论文标题
优化量子$ f $ -Divergences的可回收性
Recoverability for optimized quantum $f$-divergences
论文作者
论文摘要
优化的量子$ f $ -Diverences构成了包括量子相对熵和夹心的Rényi相对准室内的一系列可区分性措施。在本文中,我们为优化的$ f $ divivergence建立了对数据处理不平等的物理有意义的改进。特别是,改进表明优化的$ f $ ddivergence及其通道加工版本之间的绝对差异是对量子通道的恢复量子状态的上限,每当将恢复通道视为旋转的PETZ恢复通道。这些结果不仅会导致对夹层rényi相对熵的数据处理不平等的物理有意义的改进,而且还对优化的$ f $ divergences的完美可逆性(即量子足够)有影响。一路走来,我们改善了以前对标准$ f $ divergence的数据处理不平等的物理有意义的改进,这是Carlen和Vershynina的最新工作[Arxiv:1710.02409,Arxiv:Arxiv:1710.08080]。最后,我们将优化的$ f $ divergence的定义,其数据处理不平等以及我们所有的可恢复性结果扩展到冯·诺伊曼(Von Neumann)代数环境,以便我们所有的结果都可以在物理环境中使用,除了限于最常见的有限量限值设置对量化信息理论的最常见的有限量化设置。
The optimized quantum $f$-divergences form a family of distinguishability measures that includes the quantum relative entropy and the sandwiched Rényi relative quasi-entropy as special cases. In this paper, we establish physically meaningful refinements of the data-processing inequality for the optimized $f$-divergence. In particular, the refinements state that the absolute difference between the optimized $f$-divergence and its channel-processed version is an upper bound on how well one can recover a quantum state acted upon by a quantum channel, whenever the recovery channel is taken to be a rotated Petz recovery channel. Not only do these results lead to physically meaningful refinements of the data-processing inequality for the sandwiched Rényi relative entropy, but they also have implications for perfect reversibility (i.e., quantum sufficiency) of the optimized $f$-divergences. Along the way, we improve upon previous physically meaningful refinements of the data-processing inequality for the standard $f$-divergence, as established in recent work of Carlen and Vershynina [arXiv:1710.02409, arXiv:1710.08080]. Finally, we extend the definition of the optimized $f$-divergence, its data-processing inequality, and all of our recoverability results to the general von Neumann algebraic setting, so that all of our results can be employed in physical settings beyond those confined to the most common finite-dimensional setting of interest in quantum information theory.