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arXiv · 2607.24644

Quantum-Limited Symbol-Blind Channel Estimation for Coherent State Discrimination

Hongxu Chen·Renzhi Yuan·Haifeng Yao·Mugen Peng
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Abstract

Residual dispersion breaks temporal-mode matching in photon-starved coherent links. For equiprobable $M$-ary PSK coherent states in a known spectral mode, with unknown symbols and carrier phase, we establish the quantum limit for blind joint estimation of group delay and second-order dispersion: after eliminating the common phase, it is $4N_s\mathbf{C}$, set by the covariance of the centered generators alone. A multi-output quantum pulse gate with photon-number-resolving detection locally attains it and supports reception below the standard quantum limit under turbulent fading.

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Hongxu Chen, Renzhi Yuan, Haifeng Yao, Mugen Peng. 2026-07-27. Quantum-Limited Symbol-Blind Channel Estimation for Coherent State Discrimination. https://arxiv.org/abs/2607.24644

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