高阶噪声统计在集体退相干下恢复海森堡标度
Entanglement Drives Common Noise into the Strong-Coupling Regime
- School of Instrumentation and Optoelectronic Engineering, Beihang University（北京航空航天大学仪器科学与光电工程学院）
- Institute of Large-Scale Scientific Facility, Beihang University（北京航空航天大学大型科学装置研究院）
- Hangzhou Innovation Institute, Beihang University（北京航空航天大学杭州创新研究院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
研究纠缠探针在噪声计量学中的情况，指出仅用两点关联函数表征退相干不足。通过分析不同噪声源，揭示高阶统计对纠缠增强标度的影响，证明高斯下限是最坏情况，找到控制噪声量子计量的新途径。
AI中文摘要：
噪声计量理论通过两点关联函数表征退相干。对于纠缠探针这不足，两个单原子\(T_2\)相同但高阶统计不同的集体浴产生相反的纠缠增强标度。在高斯马尔可夫集体退相干下，GHZ探针达到与原子数无关的灵敏度下限。对于完全马尔可夫复合泊松浴，Dicke相干按特定速率衰减，GHZ探针在集体有限速率噪声主导时恢复海森堡标度。高斯下限是最坏情况，任意Lévy相位噪声下渐近纠缠探针灵敏度由扩散分量决定。逆界表明无输入态、辅助或测量能改进GHZ标度。机制是纯指数和CP可分的，不同于其他途径。耗散类似物限制Dicke超辐射爆发。普通噪声的全计数统计成为噪声量子计量的控制轴。
英文摘要：
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.
