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Title: Quantum Advantage via Qubit Belief Propagation
Quantum technologies are maturing by the day and their near-term applications are now of great interest. Deep-space optical communication involves transmission over the pure-state classical-quantum channel. For optimal detection, a joint measurement on all output qubits is required in general. Since this is hard to realize, current (sub-optimal) schemes perform symbol-by-symbol detection followed by classical post-processing. In this paper we focus on a recently proposed belief propagation algorithm by Renes that passes qubit messages on the factor graph of a classical error-correcting code. More importantly, it only involves single-qubit Pauli measurements during the process. For an example 5-bit code, we analyze the involved density matrices and calculate the error probabilities on this channel. Then we numerically compute the optimal joint detection limit using the Yuen-Kennedy-Lax conditions and demonstrate that the calculated error probabilities for this algorithm appear to achieve this limit. This represents a first step towards achieveing quantum communication advantage. We verify our analysis using Monte-Carlo simulations in practice.  more » « less
Award ID(s):
1910571 1908730 1855879
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
2020 IEEE International Symposium on Information Theory (ISIT)
Page Range / eLocation ID:
1824 to 1829
Medium: X
Sponsoring Org:
National Science Foundation
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