表征开放量子系统中多电流的量子精度增强
Characterizing quantum precision enhancement for multiple currents in open quantum systems
- School of Physics, Trinity College Dublin（都柏林三一学院物理学院）
- Departamento de Física—CIOyN, Universidad de Murcia（穆尔西亚大学物理系—CIOyN）
- Department of Physics, King’s College London（伦敦国王学院物理系）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文推导了多电流动力学不确定性关系（MKUR），通过对比经典模拟器，证明量子相干演化可降低联合电流涨落，从而超越经典精度极限，并用二能级系统和三能级热机模型加以验证。
AI中文摘要：
动力学不确定性关系（KUR）以动力学活动性（即单位时间内的平均跃迁次数）为约束，限制了经典非平衡系统中单个电流的涨落。本文推导了多电流动力学不确定性关系（MKUR），确立了非平衡稳态下经典随机过程中多个电流的精度极限。随后，我们将该理论应用于识别量子器件，通过将量子系统与具有相同稳态平均电流的经典模拟器进行比较，发现其相关电流涨落超越了经典极限。由此，对模拟器MKUR的违反具有明确的物理意义，即量子相干演化将联合电流涨落降低到具有相同能级结构和非相干资源的经典马尔可夫系统所不可能达到的水平。由于MKUR包含了电流之间的相关性，其违反能够在单电流KUR满足的参数区间内精确指出非经典涨落。我们通过两个例子阐明了这些界限在表征联合电流精度方面的必要性和互补作用：一个相干驱动的二能级系统，以及一个受寄生环境耦合影响的三能级热机的实验动机模型。
英文摘要：
The kinetic uncertainty relation (KUR) constrains fluctuations of individual currents in classical nonequilibrium systems in terms of the dynamical activity, which quantifies the average number of transitions per unit of time. Here, we derive a multi-current KUR (MKUR) establishing the precision limit for multiple currents generated in classical stochastic processes in the nonequilibrium steady state. We then apply our theory to identify quantum devices whose correlated current fluctuations surpass this classical limit by comparing the quantum system to a classical emulator with the same average currents in the steady state. In this way, violations of the emulator's MKUR have a clear physical meaning, i.e., that the quantum-coherent evolution reduces joint current fluctuations below what is possible for a classical Markovian system with the same energy-level structure and incoherent resources. Since the MKUR incorporates correlations between currents, its violation pinpoints nonclassical fluctuations in parameter regimes where the single-current KUR is satisfied. We illustrate the essential and complementary role of these bounds for characterizing joint current precision with two examples: a coherently driven two-level system and an experimentally motivated model of a three-level heat engine subject to parasitic environmental couplings.
