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All unital qubit channels are 4-noisy operations

  • Alexander Müller-Hermes
  • Christopher Perry
Article
  • 56 Downloads

Abstract

We show that any unital qubit channel can be implemented by letting the input system interact unitarily with a four-dimensional environment in the maximally mixed state and then tracing out the environment. We also provide an example where the dimension of such an environment has to be at least 3.

Keywords

Quantum channels Open quantum systems Noisy operations Factorizable maps Operator Schmidt rank 

Mathematics Subject Classification

81P45 46L07 46L60 

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Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.QMATH, Department of Mathematical SciencesUniversity of CopenhagenCopenhagenDenmark

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