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arXiv · 2602.21549

Passive Environment-Assisted Quantum Communication

Evelyn Voss·Bikun Li·Zhaoyou Wang·Liang Jiang
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Abstract

As quantum information systems mature, efficient and coherent transfer of quantum information through noisy channels becomes increasingly important. We examine how passive environment-assisted quantum communication enhances direct quantum information transfer efficiency. A bosonic pure-loss channel, modeled as transmission through a beam splitter with a vacuum input state at the dark port, has zero quantum capacity when transmissivity is below 50%. Quantum communication through the channel can be enhanced by passive environment assistance, achieved via the selection of an appropriate input state for the ancilla port. Although ideal Gottesman-Kitaev-Preskill (GKP) states enable perfect quantum information transmission at arbitrarily small transmissivity, they are challenging to realize experimentally. We therefore explore more experimentally accessible non-Gaussian ancilla states, such as Fock, cat, and squeezed cat states, and numerically determine the optimal encoding and decoding strategies. We also construct analytical schemes that yield high-fidelity transmission and good information rates.

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Evelyn Voss, Bikun Li, Zhaoyou Wang, Liang Jiang. 2026-02-27. Passive Environment-Assisted Quantum Communication. https://arxiv.org/abs/2602.21549

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