标题： 量子超信道的公理方法 显示英文标题

标题： Axiomatic Approach to Quantum Superchannels

摘要： 量子超信道是输入和输出均为量子信道的映射。我们不是将域定义为所有线性映射的空间，而是基于量子信道张成的算子系统来引入并定义超信道。完全正映射的延拓定理使我们可以将超信道的特征化定理应用于这一较小的映射集。这些延拓方式并非唯一，表明两个不同的超信道在所有输入量子信道上表现出相同的作用，因此这个在较小域上的新定义更精确地捕捉了超信道作为量子信道之间变换的作用。这种非唯一性可能会影响特征化所需的辅助维度以及超信道的张量积。 显示英文摘要

摘要： Quantum superchannels are maps whose input and output are quantum channels. Rather than taking the domain to be the space of all linear maps we motivate and define superchannels on the operator system spanned by quantum channels. Extension theorems for completely positive maps allow us to apply the characterisation theorem for superchannels to this smaller set of maps. These extensions are non unique, showing two different superchannels act the same on all input quantum channels, and so this new definition on the smaller domain captures more precisely the action of superchannels as transformations between quantum channels. The non uniqueness can affect the auxilliary dimension needed for the characterisation as well as the tensor product of the superchannels.