局域退相干下贝尔对角态的负拟概率轨迹
Negative quasiprobability trajectories for Bell-diagonal states under local decoherence
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中文总结 AI 辅助
该研究针对局域退相干下的贝尔对角态，解析确定负拟概率分布的特性，揭示其与经典随机描述的轨迹层面差异，为量子信息动力学提供了新的独特特征。
中文摘要 AI 辅助
涨落定理（FT）将微观轨迹分布与宏观平均值关联，近期该框架已通过拟概率轨迹拓展至量子信息动力学领域。尽管信息涨落定理具有与传统热力学涨落定理相似的形式，但其涉及的拟概率的负性及统计特性仍鲜为人知。我们针对两量子比特贝尔对角态在局域退相位、退极化和振幅阻尼通道下的演化，解析确定负分布的特性。研究表明，负拟概率的出现不由初始态的纠缠或贝尔非局域性决定；相反，转移拟概率的对角干涉分解为负性提供了充分条件。更重要的是，我们证明，包含负权重的拟概率分布可违反Horváth针对所有连续凸函数的Jensen-Steffensen不等式成立的充要判据，即便涨落定理所强制的特定指数类Jensen关系及量子数据处理不等式仍然成立。这种轨迹层面与经典随机描述的对比，揭示了量子信息动力学的一个独特特征，仅考虑对应平均层面的信息不等式时无法察觉该特征。
英文摘要
The fluctuation theorem (FT) relates microscopic trajectory distributions to macroscopic averages. Using quasiprobability trajectories, this framework has recently been extended to quantum information dynamics. Despite sharing the form of conventional thermodynamic FTs, information FTs involve quasiprobabilities whose negativity and statistical properties remain poorly understood. We analytically determine the properties of negative distributions based on the two-qubit Bell-diagonal states evolving under local dephasing, depolarizing, and amplitude-damping channels. We show that the occurrence of negative quasiprobabilities is not determined by the entanglement or Bell nonlocality of the initial state. Instead, a diagonal-interference decomposition of the transition quasiprobability provides a sufficient condition for negativity. More importantly, we prove that quasiprobability distributions containing negative weights can violate Horváth's necessary and sufficient criterion for the Jensen-Steffensen inequality to hold for every continuous convex function, even though the specific exponential Jensen-like relation enforced by the FT and the quantum data-processing inequality remains valid. This trajectory-level contrast with classical stochastic descriptions reveals a distinctive feature of quantum information dynamics that is invisible when only the corresponding average-level information inequalities are considered.
