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arXiv · 2607.15405

Boosting State Discrimination in Quantum Brownian Motion Channel via Memory-Induced Coherence Preservation

João C. P. Porto·Pedro R. Dieguez·Carlos H. S. Vieira·Irismar G. da Paz·Giandomenico Palumbo·Lucas S. Marinho
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Abstract

Preserving quantum resources in dissipative environments is a fundamental challenge in quantum information processing. While environmental interactions usually degrade quantum resources, we theoretically show that in a Quantum Brownian Motion (QBM) channel, continuous-variable state discrimination can be improved by increasing, rather than minimizing, the initial thermal noise. Specifically, without suppressing the inherent environmental dissipation, when combined with squeezing, this initial noise induces a coherence preservation mechanism driven by the transient non-thermalization of the probe with the bath. This preservation translates into a pronounced reduction in error probabilities for state discrimination between orthogonal squeezing directions. Furthermore, we also show that quadrature homodyne detection achieves near-optimal performance, approaching the Helstrom limit. These results highlight the advantage of exploiting thermal-squeezed states, offering a robust physical architecture for quantum communication in high-temperature environments.

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João C. P. Porto, Pedro R. Dieguez, Carlos H. S. Vieira, Irismar G. da Paz, Giandomenico Palumbo, Lucas S. Marinho. 2026-07-16. Boosting State Discrimination in Quantum Brownian Motion Channel via Memory-Induced Coherence Preservation. https://arxiv.org/abs/2607.15405

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