论文标题
在量子条件互信息及其推论的较低半内端
On lower semicontinuity of the quantum conditional mutual information and its corollaries
论文作者
论文摘要
众所周知，在本地渠道下，量子相互信息及其条件版本不会增加。本文我们表明，最近确定的量子有条件相互信息的较低的半决能力暗示（实际上，相当于）量子损失的较低的量子（条件）相互信息在本地渠道下被视为在所有状态的笛卡尔产物中被认为是复合系统的笛卡尔产物的功能，并具有所有当地通道的函数。 考虑了此属性的某些应用。量子相互信息的新连续性条件以及两分和多部分无限二维系统中的南瓜纠缠。尤其是证明，具有有限边缘熵的任何不可分解的可分离状态的多部分南瓜纠缠等于零。 建立有或没有量子侧信息的量子测量的信息获得的特殊连续性特性，可以将其视为W.R.T.的稳健性（稳定性）。测量和测量状态的扰动。
It is well known that the quantum mutual information and its conditional version do not increase under local channels. I this paper we show that the recently established lower semicontinuity of the quantum conditional mutual information implies (in fact, is equivalent to) the lower semicontinuity of the loss of the quantum (conditional) mutual information under local channels considered as a function on the Cartesian product of the set of all states of a composite system and the sets of all local channels (equipped with the strong convergence). Some applications of this property are considered. New continuity conditions for the quantum mutual information and for the squashed entanglement in both bipartite and multipartite infinite-dimensional systems are obtained. It is proved, in particular, that the multipartite squashed entanglement of any countably-non-decomposable separable state with finite marginal entropies is equal to zero. Special continuity properties of the information gain of a quantum measurement with and without quantum side information are established that can be treated as robustness (stability) of these quantities w.r.t. perturbation of the measurement and the measured state.
