Entanglement Drives Common Noise into the Strong-Coupling Regime
Abstract
Under Gaussian collective dephasing parallel to the signal, the superdecoherence of an N-atom Greenberger--Horne--Zeilinger (GHZ) state cancels its gain in Fisher information, so GHZ frequency sensitivity is limited to an atom-number-independent floor. We demonstrate that this floor is a property of Gaussian diffusion: a single common phase kick can at most randomize the phase of an N-atom coherence, so discrete events at rate Γ cannot dephase any coherence order faster than 2Γ. At the same single-atom coherence time, finite-rate Poisson kicks with an absolutely continuous amplitude law therefore saturate the order-N decay rate and restore Heisenberg scaling. We prove that Gaussian diffusion is the worst case for GHZ and Dicke-cat probes under this calibration, that only the Brownian component of Lévy phase noise sets the asymptotic floor, and that the 1/N exponent is optimal for parallel Ramsey protocols. These results identify the counting statistics of the common noise, rather than its spectrum, as the property that bounds superdecoherence.
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BibTeX
@misc{zhou2026entanglement,
title = {{Entanglement Drives Common Noise into the Strong-Coupling Regime}},
author = {Yizhe Zhou and Xusheng Lei and Xing Heng and Zuoxian Wang and Danyue Ma},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2607.02962},
eprint = {2607.02962},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.02962},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Entanglement Drives Common Noise into the Strong-Coupling Regime
AU - Yizhe Zhou
AU - Xusheng Lei
AU - Xing Heng
AU - Zuoxian Wang
AU - Danyue Ma
PY - 2026
DA - 2026/09/12
PB - arXiv
DO - 10.48550/arxiv.2607.02962
UR - https://arxiv.org/abs/2607.02962
AB - Under Gaussian collective dephasing parallel to the signal, the superdecoherence of an N-atom Greenberger--Horne--Zeilinger (GHZ) state cancels its gain in Fisher information, so GHZ frequency sensitivity is limited to an atom-number-independent floor. We demonstrate that this floor is a property of Gaussian diffusion: a single common phase kick can at most randomize the phase of an N-atom coherence, so discrete events at rate Γ cannot dephase any coherence order faster than 2Γ. At the same single-atom coherence time, finite-rate Poisson kicks with an absolutely continuous amplitude law therefore saturate the order-N decay rate and restore Heisenberg scaling. We prove that Gaussian diffusion is the worst case for GHZ and Dicke-cat probes under this calibration, that only the Brownian component of Lévy phase noise sets the asymptotic floor, and that the 1/N exponent is optimal for parallel Ramsey protocols. These results identify the counting statistics of the common noise, rather than its spectrum, as the property that bounds superdecoherence.
ER -