AI 中文总结
本文针对强耦合非平衡器件中电流减小至零的周转效应，利用散射理论揭示其源于全反射，提出基于量子隧穿的方案可避免该效应并提升最大电流，助力挖掘相关器件潜力。
AI 中文摘要
在非平衡条件下，能量或粒子电流会流经耦合到多个热库的量子系统。尽管在弱耦合区域，随着耦合强度增强，通量会增加，但当耦合强度很大时通量会减小至零的原因仍未知。这种能量交换或输运现象的反直觉行为被称为周转效应，已在光合复合物、介观结、量子热机、化学网络等多个量子系统中被预测，且无反例，该效应因电流受限导致器件性能受约束。本文利用散射理论研究自由粒子低密度热库被量子系统通过局域势散射产生的周转效应，发现周转效应是全反射的结果，全反射阻碍热库粒子到达相互作用区域并与量子系统交换能量。此外，本文设计了一种基于量子隧穿的方案来避免周转效应并提升最大电流，该策略可用于充分挖掘基于温度或化学势梯度的器件的全部潜力。
英文摘要
Under non-equilibrium conditions, energy/particle currents flow through a quantum system coupled to multiple baths. Although the fluxes increase in the weak coupling regime as the coupling strengthens, the reason why they decrease to zero for large coupling remains unknown. This counterintuitive behavior of energy exchange or transport phenomena is called the turnover effect. It has been predicted in several quantum systems such as photosynthetic complexes, mesoscopic junctions, quantum heat machines, and chemical networks without a single counterexample, and it results in constrained performance due to limited currents. Here, we use scattering theory to study the turnover effect produced by low-zdensity reservoirs of free particles scattered by a quantum system through localized potentials. We find that the turnover effect is a consequence of total reflection that impedes the reservoir particle from reaching the interaction region and exchanging energy with the quantum system. Moreover, we design a protocol based on quantum tunneling to avoid the turnover and to increase the maximum current. This strategy could be used to unleash the full potential of devices based on temperature/chemical potential gradients.
