论文标题
通过多体弱值评估物理和配置空间中的量子热化
Assessing Quantum Thermalization in Physical and Configuration Spaces via Many-Body Weak Values
论文作者
论文摘要
我们在Schroedinger方程描述的孤立量子系统中探索了时间的箭头的起源。我们提供了来自配置空间中弱值的解释，这些解释被理解为经过明确定义的协议在实验室中获得的操作属性。我们表明，满足本征态热假设的量子系统可以同时提供热量的集合期望值和动量的非热量弱值，这均来自相同的操作概率分布。动量的弱价值可能逃离特征态热假设的原因是因为它们仅与能量表示中密度矩阵的非对抗元素有关。但是，对于难以区分的粒子，无法在配置空间中定义操作属性。因此，我们声明Schroedinger方程所描述的孤立量子系统中时间的箭头的起源来自处理通过平均（取出）一些配置空间自由度获得的属性。然后，我们认为在配置空间中定义的属性中没有发生热化，并且我们的参数与捍卫热化是物理空间中定义的属性中的真实现象兼容。所有这些结论在实验室中都可以通过多体弱价值来检验。
We explore the origin of the arrow of time in an isolated quantum system described by the Schroedinger equation. We provide an explanation from weak values in the configuration space, which are understood as operational properties obtained in the laboratory following a well-defined protocol. We show that quantum systems satisfying the eigenstate thermalization hypothesis can simultaneously provide thermalized ensemble expectation values and nonthermalized weak values of the momentum, both from the same operational probability distribution. The reason why weak values of the momentum may escape from the eigenstate thermalization hypothesis is because they are linked only to off-diagonal elements of the density matrix in the energy representation. For indistinguishable particles, however, operational properties can not be defined in the configuration space. Therefore, we state that the origin of the arrow of time in isolated quantum systems described by the Schroedinger equation comes from dealing with properties obtained by averaging (tracing out) some degrees of freedom of the configuration space. We then argue that thermalization does not occur in the properties defined in the configuration space, and our argument is compatible with defending that thermalization is a real phenomenon in the properties defined in the physical space. All of these conclusions are testable in the laboratory through many-body weak values.
