Classical Commitment over Quantum Channels with Limited Entanglement Assistance

Abstract:We study classical string commitment over quantum channels with limited preshared entanglement. For noninteractive protocols, we determine the commitment capacity of a class of channels with input dimension $d$ that, at each use, sample a pair of classical random variables $(F,Z)$, apply one of the $d^2$ Heisenberg--Weyl operators indexed by $Z$ to the input, and deliver the transformed quantum system together with $F$ to the receiver. If $E$ is the available entanglement rate in bits per channel use, then the capacity is $\min\{H(Z|F),\log_2d+E\}$. This class of channels encompasses quantum erasure and depolarizing channels, as well as families of Pauli channels. Additionally, for interactive protocols, we show that the commitment rate cannot exceed $\log_2d+E$ bits per channel use, so that when $H(Z|F)\geq\log_2d+E$, interactive communication does not increase the capacity. As a consequence, for interactive protocols, we determine the capacity of the quantum erasure channel.

Quantum Physics (quant-ph); Information Theory (cs.IT)

arXiv:2608.28500 [quant-ph]

(or arXiv:2608.28500v1 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2608.28500 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

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