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Decoupling with random diagonal unitaries

delete2017-07-21
delete15
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OA
AI
Y
Yoshifumi Nakata *
C
Christoph Hirche
M
Morgan, Ciara
A
Andreas Winter
DOI:10.22331/q-2017-07-21-18delete
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Abstract

Abstract

En 中文
We investigate decoupling, one of the most important primitives in quantum Shannon theory, by replacing the uniformly distributed random unitaries commonly used to achieve the protocol, with repeated applications of random unitaries diagonal in the Pauli-Z and -X bases. This strategy was recently shown to achieve an approximate unitary 2-design after a number of repetitions of the process, which implies that the strategy gradually achieves decoupling. Here, we prove that even fewer repetitions of the process achieve decoupling at the same rate as that with the uniform ones, showing that rather imprecise approximations of unitary 2-designs are sufficient for decoupling. We also briefly discuss efficient implementations of them and implications of our decoupling theorem to coherent state merging and relative thermalisation.
Keywords:
RANDOM QUANTUM CIRCUITS
STATE

Journal

Quantum cover
Quantum
IF:
5.4
Papers:
951
Citations:
1.0W

Organization

L
Leibniz University Hannover
Scholars:
1.0W
Papers: 8.5K
Citations: 1.1W
A
Autonomous University of Barcelona
Scholars:
3.7W
Papers: 2.6W
Citations: 47