Rubio Jesús, Anders Janet, Correa Luis A
Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, United Kingdom.
Institut für Physik und Astronomie, University of Potsdam, 14476 Potsdam, Germany.
Phys Rev Lett. 2021 Nov 5;127(19):190402. doi: 10.1103/PhysRevLett.127.190402.
A paradigm shift in quantum thermometry is proposed. To date, thermometry has relied on local estimation, which is useful to reduce statistical fluctuations once the temperature is very well known. In order to estimate temperatures in cases where few measurement data or no substantial prior knowledge are available, we build instead a method for global quantum thermometry. Based on scaling arguments, a mean logarithmic error is shown here to be the correct figure of merit for thermometry. Its full minimization provides an operational and optimal rule to postprocess measurements into a temperature reading, and it establishes a global precision limit. We apply these results to the simulated outcomes of measurements on a spin gas, finding that the local approach can lead to biased temperature estimates in cases where the global estimator converges to the true temperature. The global framework thus enables a reliable approach to data analysis in thermometry experiments.
本文提出了量子测温领域的范式转变。迄今为止，测温一直依赖于局部估计，当温度已知得非常准确时，这种方法有助于减少统计波动。为了在测量数据很少或没有大量先验知识的情况下估计温度，我们转而构建了一种全局量子测温方法。基于标度论证，这里表明平均对数误差是测温的正确品质因数。其完全最小化提供了一个将测量结果后处理为温度读数的操作和最优规则，并建立了一个全局精度极限。我们将这些结果应用于自旋气体测量的模拟结果，发现当全局估计器收敛到真实温度时，局部方法可能会导致有偏差的温度估计。因此，全局框架为测温实验中的数据分析提供了一种可靠的方法。
