Publications [#352262] of Henry Pfister

Papers Published

1. Rengaswamy, N; Seshadreesan, KP; Guha, S; Pfister, HD, Quantum Advantage via Qubit Belief Propagation, Ieee International Symposium on Information Theory Proceedings, vol. 2020-June (June, 2020), pp. 1824-1829, ISBN 9781728164328 [doi]
   (last updated on 2023/06/01)

   Abstract:
   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.