论文标题
量子状态温度的操作定义
Operational definition of the temperature of a quantum state
论文作者
论文摘要
在热平衡处的物理系统通常定义温度。然而，人们可能会怀疑是否可以将有意义的温度归因于任意量子状态，而不是仅仅是热（Gibbs）状态。在这项工作中，我们提出了一种受热力学零核法的启发，考虑了一项操作任务的温度概念。具体而言，我们定义了两个有效温度，以量化量子系统冷却或加热热环境的能力。这样，我们可以将温度有意义的有意义的概念与任何量子密度矩阵相关联。我们为这些有效温度的单复制系统和多拷贝系统提供了一般表达，并建立了与先前讨论的文献中讨论的概念的联系。最后，我们考虑了一个更复杂的场景，在该场景中，系统和热环境之间的热量交换得到了量子参考框架的辅助。这导致了“相干量子催化”的影响，其中使用相干催化剂可以利用系统中的量子能量相干，现在导致更冷或更热的有效温度。
Temperature is usually defined for physical systems at thermal equilibrium. Nevertheless one may wonder if it would be possible to attribute a meaningful notion of temperature to an arbitrary quantum state, beyond simply the thermal (Gibbs) state. In this work, we propose such a notion of temperature considering an operational task, inspired by the Zeroth Law of thermodynamics. Specifically, we define two effective temperatures for quantifying the ability of a quantum system to cool down or heat up a thermal environment. In this way we can associate an operationally meaningful notion of temperature to any quantum density matrix. We provide general expressions for these effective temperatures, for both single- and many-copy systems, establishing connections to concepts previously discussed in the literature. Finally, we consider a more sophisticated scenario where the heat exchange between the system and the thermal environment is assisted by a quantum reference frame. This leads to an effect of "coherent quantum catalysis", where the use of a coherent catalyst allows for exploiting quantum energetic coherences in the system, now leading to much colder or hotter effective temperatures.
