探测非平衡热库：频率分辨测温法与量子热流翻转
Probing Non-equilibrium baths: Frequency-Resolved Thermometry and Quantum Heat Current Turnover
AI总结：
该研究针对非平衡稳态下量子热输运的热库热态信息不足问题，提出频率选择测温协议，结合级联运动方程在自旋-玻色和两量子比特模型中揭示了热流翻转效应源于热库热态随耦合强度的演化。
AI中文摘要：
非平衡稳态（NESS）下的量子热输运存在一种特征翻转效应：随着系统-热库耦合强度增加，热流先达到最大值后下降。尽管数值精确方法可模拟这种非单调行为，但它们提供的热库热态信息有限。本文提出一种频率选择测温协议以探测维持NESS的热库，通过可调两能级探针提取频率分辨的有效温度谱，证明谱色散可作为热库非平衡态的直接见证。为验证该协议，将级联运动方程应用于自旋-玻色模型和两量子比特模型（也可使用任何精确方法），结果表明两种模型的翻转效应可通过热库热态随系统-热库耦合强度增加的演化来解释。
英文摘要：
Quantum heat transport for non-equilibrium steady state (NESS) exhibits a characteristic turnover effect, where the heat current reaches a maximum and subsequently declines as system-bath coupling increases. Although numerically exact methods can simulate this non-monotonic behavior, they offer limited information on the thermal state of the heat baths. Here, we introduce a frequency-selective thermometric protocol to probe the baths sustaining an NESS. By extracting a frequency-resolved effective temperature spectrum using a tunable two-level probe, we demonstrate that spectral dispersion serves as a direct witness for the non-equilibrium state of the heat baths. To demonstrate the protocol, we applied the hierarchical equations of motion to spin-boson and two-qubit models, though any exact method can be used. For both models, the turnover effect can be explained by how the thermal state of the heat baths evolves as the system-bath coupling strength increases.
