A universal set of qubit quantum channels

作者：Braun Daniel^*; Giraud Olivier; Nechita Ion; Pellegrini Clement; Znidaric Marko

来源：Journal of Physics A-Mathematical and Theoretical, 2014, 47(13): 135302.

DOI：10.1088/1751-8113/47/13/135302

• quantum channel
• qubit channel
• universal set of channels

We investigate the set of quantum channels acting on a single qubit. We provide an alternative, compact generalization of the Fujiwara-Algoet conditions for complete positivity to non-unital qubit channels, which we then use to characterize the possible geometric forms of the pure output of the channel. We provide universal sets of quantum channels for all unital qubit channels as well as for all extremal (not necessarily unital) qubit channels, in the sense that all qubit channels in these sets can be obtained by concatenation of channels in the corresponding universal set. We also show that our universal sets are essentially minimal.

• 出版日期2014-4-4