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Infinite dimensional generalizations of Choi’s Theorem
In this paper we give a simple sequence of necessary and sufficient finite dimensional conditions for a positive map between certain subspaces of bounded linear operators on separable Hilbert spaces to be completely positive. These criterions are natural generalization of Choi’s characterization for...
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Published in: | Special matrices 2019-01, Vol.7 (1), p.67-77 |
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Main Author: | |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | In this paper we give a simple sequence of necessary and sufficient finite dimensional conditions for a positive map between certain subspaces of bounded linear operators on separable Hilbert spaces to be completely positive. These criterions are natural generalization of Choi’s characterization for completely positive maps between pairs of linear operators on finite dimensional Hilbert spaces. We apply our conditions to a completely positive map between two trace class operators on separable Hilbert spaces. A completely positive map
is called a quantum channel, if it is trace preserving, and
is called a quantum subchannel if it decreases the trace of a positive operator.We give simple neccesary and sufficient condtions for
to be a quantum subchannel.We show that
is a quantum subchannel if and only if it hasHellwig-Kraus representation. The last result extends the classical results of Kraus and the recent result of Holevo for characterization of a quantum channel. |
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ISSN: | 2300-7451 2300-7451 |
DOI: | 10.1515/spma-2019-0006 |