In Situ Thermometry of a Cold Fermi Gas via Dephasing Impurities.
In Situ Thermometry of a Cold Fermi Gas via Dephasing Impurities.
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DOI：
10.1103/physrevlett.125.080402
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发表时间：
2020-04
影响因子：
8.6
通讯作者：
M. Mitchison;Thomás Fogarty;G. Guarnieri;S. Campbell;T. Busch;J. Goold
中科院分区：
文献类型：
--
作者：
M. Mitchison;Thomás Fogarty;G. Guarnieri;S. Campbell;T. Busch;J. Goold
对量子科学来说，低温的精确测量是一项具有挑战性的、重要的、基础的任务。特别是，由于其量子模拟的潜力，原位测温对于冷原子系统是非常可取的。在这里，我们证明了非相互作用费米气体的温度可以通过浸入其中的杂质的非平衡动力学来精确推断，使用干涉测量协议和既定的实验方法。采用量子参数估计理论的工具，我们证明了我们所提出的方案在现有实验中的简并费米气体的相关温度范围内达到了最佳精度。我们还发现了由杂质-气体耦合控制的测量时间和温度测量精度之间的一个有趣的权衡，弱耦合导致最大的灵敏度。这可以解释为与安德森正交突变相关的缓慢退相干的结果，安德森正交突变在其与浸入杂质的局部相互作用后主导了气体动力学。
The precise measurement of low temperatures is a challenging, important, and fundamental task for quantum science. In particular, in situ thermometry is highly desirable for cold atomic systems due to their potential for quantum simulation. Here, we demonstrate that the temperature of a noninteracting Fermi gas can be accurately inferred from the nonequilibrium dynamics of impurities immersed within it, using an interferometric protocol and established experimental methods. Adopting tools from the theory of quantum parameter estimation, we show that our proposed scheme achieves optimal precision in the relevant temperature regime for degenerate Fermi gases in current experiments. We also discover an intriguing trade-off between measurement time and thermometric precision that is controlled by the impurity-gas coupling, with weak coupling leading to the greatest sensitivities. This is explained as a consequence of the slow decoherence associated with the onset of the Anderson orthogonality catastrophe, which dominates the gas dynamics following its local interaction with the immersed impurity.