Taking accurate measurements of the temperature of quantum systems is a challenging task. The mathematical peculiarities of quantum information make it virtually impossible to measure with infinite precision. In the present paper, we introduce a generalize thermal state, which is conditioned on the pointer states of the available measurement apparatus. We show that this conditional thermal state outperforms the Gibbs state in quantum thermometry. The origin for the enhanced precision can be sought in its asymmetry quantified by the Wigner–Yanase–Dyson skew information. This additional resource is further clarified in a fully resource-theoretic analysis, and we show that there is a Gibbs-preserving map to convert a target state into the conditional thermal state. We relate the quantum J-divergence between the conditional thermal state and the same target state to quantum heat.

中文翻译：

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条件量子测温——通过减少测量来提高精度


准确测量量子系统的温度是一项具有挑战性的任务。量子信息的数学特性使其几乎不可能以无限精度进行测量。在本文中，我们介绍了一种广义热状态，它以可用测量设备的指针状态为条件。我们证明这种条件热态在量子测温中优于吉布斯态。精度提高的根源可以通过 Wigner-Yanase-Dyson 偏斜信息量化的不对称性来寻找。这种额外的资源在完全资源理论分析中得到了进一步阐明，并且我们表明存在吉布斯保留图将目标状态转换为条件热状态。我们将条件热态和相同目标态之间的量子 J 散度与量子热联系起来。