通过控制系统-库耦合增强量子热机的功率
Enhancing the power of a quantum heat engine via control of the system--reservoir coupling
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中文总结 AI 辅助
本研究以超冷Cs-133原子量子奥托热机为对象，通过调控耦合的超冷Rb-87原子库温度改变散射速率，实现系统-库热传递的微观控制，在固定效率下优化了热机功率输出，为纳米热流操控提供了工具。
中文摘要 AI 辅助
开放量子系统的非平衡性质由支配其与环境能量交换的微观定律决定。已有研究预测，通过控制系统-浴相互作用加快动力学，可提升量子热机的性能，但迄今为止，对热机与库之间热传递的直接微观控制仍难以实现。本研究中，我们以耦合到超冷Rb-87原子库的超冷Cs-133原子实现量子奥托热机，在实验上展示了这种控制。两者间的热交换由非弹性s波碰撞介导，其能量依赖的散射截面导致等容加热和冷却冲程中出现非对称平衡动力学。通过调节原子库的动能温度，我们改变了相关的微观散射速率，进而改变热传递规律，实现了通过控制微观多指数弛豫动力学来调控热机循环内的时间分配。这使得在固定效率下可优化功率输出。我们的结果确立了系统-库相互作用的微观控制，作为一种操控纳米尺度热流、设计量子热机有限时间性能的工具。
英文摘要
The non-equilibrium properties of open quantum systems are determined by the microscopic laws governing energy exchange with their environment. In particular, an enhancement of the performance of quantum heat engines has been predicted by speeding up the dynamics through control of the system--bath interaction. However, direct microscopic control of heat transfer between the machine and the reservoir has remained elusive so far. Here, we experimentally demonstrate such control in a quantum Otto engine realized with ultracold Cs-133 atoms coupled to an atomic reservoir of ultracold Rb-87 atoms. Heat exchange between the two is mediated by inelastic s-wave collisions whose energy-dependent scattering cross sections lead to an asymmetric equilibration dynamics in the isochoric heating and cooling strokes. By tuning the kinetic temperature of the atomic reservoir, we modify the associated microscopic scattering rates, and thereby the heat transfer law, giving control over the time allocation within the engine cycle through control over the microscopic, multi-exponential relaxation dynamics. This enables power output optimization at fixed efficiency. Our results establish microscopic control of system-reservoir interactions as a tool for manipulating heat flow at the nanoscale and engineering the finite-time performance of quantum thermal machines.
