近日，德国乌尔姆大学的Ludovico Lami与美国路易斯安那州立大学的Mark M.Wilde合作，成功得到了玻色退相干通道的量子和私密容量的精确解。相关研究成果已于2023年4月6日在国际学术期刊《自然—光子学》上发表。

这项研究提供了所有玻色退相干通道的量子、私密、双向协助量子和秘密密钥协商容量的精确计算，并证明它们等于与均匀分布相关的通道分布的相对熵，从而解决了十多年前提出的一个问题。

据悉，嘈杂量子通道的容量能够捕捉量子通信线路上信息传输的极限速率，并且量子通道容量在确定容错量子计算平台的开销方面起着关键作用。然而，在玻色系统中，这些容量的封闭公式缺乏一类关键的非高斯通道——玻色退相干通道，用于模拟影响超导电路和光纤通信通道的噪声。

附：英文原文

Title: Exact solution for the quantum and private capacities of bosonic dephasing channels

Author: Lami, Ludovico, Wilde, Mark M.

Issue&Volume: 2023-04-06

Abstract: The capacities of noisy quantum channels capture the ultimate rates of information transmission across quantum communication lines, and the quantum capacity plays a key role in determining the overhead of fault-tolerant quantum computation platforms. Closed formulae for these capacities in bosonic systems were lacking for a key class of non-Gaussian channels, bosonic dephasing channels, which are used to model noise affecting superconducting circuits and fibre-optic communication channels. Here we provide an exact calculation of the quantum, private, two-way assisted quantum and secret-key-agreement capacities of all bosonic dephasing channels. We prove that they are equal to the relative entropy of the distribution underlying the channel with respect to the uniform distribution, solving a problem that was originally posed over a decade ago.

DOI: 10.1038/s41566-023-01190-4

Source: https://www.nature.com/articles/s41566-023-01190-4