

Preprint 39/2020
Discriminating bipartite mixed states by local operations
Jin-Hua Zhang, Fu-Lin Zhang, Zhi-Xi Wang, Le-Min Lai, and Shao-Ming Fei
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Submission date: 17. Mar. 2020
Pages: 15
published in: Physical review / A, 101 (2020) 3, art-no. 032316
DOI number (of the published article): 10.1103/PhysRevA.101.032316
Bibtex
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Abstract:
Unambiguous state discrimination of two mixed bipartite states via
local operations and classical communications (LOCC) is studied
and compared with the result of a scheme realized via global
measurement. We show that the success probability of a global scheme
for mixed-state discrimination can be achieved perfectly by the local
scheme. In addition, we simulate this discrimination via a pair of
pure entangled bipartite states. This simulation is
perfect for local rather than global schemes due to the existence of
entanglement and global coherence in the pure states. We also
prove that LOCC protocol and the sequential state discrimination (SSD) can be interpreted in a unified view. We then hybridize the LOCC
protocol with three protocols (SSD, reproducing and
broadcasting) relying on classical communications.
Such hybridizations extend the gaps between the optimal success probability of global and local schemes, which can be eliminated only for the SSD rather than the other two protocols.