Frequency estimation under non-Markovian spatially correlated quantum noise
Frequency estimation under non-Markovian spatially correlated quantum noise
复制标题
非马尔可夫空间相关量子噪声下的频率估计
DOI：
10.1088/1367-2630/ac92a2
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发表时间：
2022
影响因子：
3.3
通讯作者：
Viola, Lorenza
中科院分区：
文献类型：
--
作者：
Riberi, Francisco;Norris, Leigh M.;Beaudoin, Félix;Viola, Lorenza
研究了时空相关非经典噪声背景下纠缠增强的Ramsey干涉术的估计精度。我们的分析依赖于一般零均值高斯稳态退相下量子比特探针的约化密度矩阵的精确表达，该矩阵是通过累积量扩展技术建立的，并且在非马尔可夫开放动力学的背景下可能具有独立的兴趣。通过继续和扩展我们以前的工作（Beaudoin et al 2018 Phys. Rev. A 98 020102（R）），我们分析了量子位探针与其环境之间的非集体耦合机制的影响，重点关注两种限制性场景，其中耦合可能只有两个或连续的可能值。在典型的情况下，自旋玻色子退相噪声从热环境中，我们发现，它是在原则上可以抑制，平均而言，空间相关性的影响，通过随机化的位置的探针，只要足够的配置被采样的噪声相关性是负的。结果，超经典精确标度渐近恢复初始纠缠态，包括实验上可达到的单轴自旋压缩态。
We study the estimation precision attainable by entanglement-enhanced Ramsey interferometry in the presence of spatiotemporally correlated non-classical noise. Our analysis relies on an exact expression of the reduced density matrix of the qubit probes under general zero-mean Gaussian stationary dephasing, which is established through cumulant-expansion techniques and may be of independent interest in the context of non-Markovian open dynamics. By continuing and expanding our previous work (Beaudoin et al 2018 Phys. Rev. A 98 020102 (R)), we analyze the effects of a non-collective coupling regime between the qubit probes and their environment, focusing on two limiting scenarios where the couplings may take only two or a continuum of possible values. In the paradigmatic case of spin–boson dephasing noise from a thermal environment, we find that it is in principle possible to suppress, on average, the effect of spatial correlations by randomizing the location of the probes, as long as enough configurations are sampled where noise correlations are negative. As a result, superclassical precision scaling is asymptotically restored for initial entangled states, including experimentally accessible one-axis spin-squeezed states.