光子驱动量子点制冷机

Quantum dot refrigerator driven by photon

提出了由两个二能级量子点、一个光子库与两个导体端构成的光子驱动量子点制冷机模型.基于主方程,导出了制冷机的制冷率和制冷系数的表达式,获得了制冷机处于紧耦合时所满足的条件.接着,数值模拟出该制冷机处于紧耦合和一般情况下制冷率与制冷系数之间的性能特征图,确定了制冷机性能的优化范围.最后,以最大制冷率、最大制冷率下的制冷系数、最大制冷系数和最大制冷系数下的制冷率作为优化目标,分析了光子库温度、跃迁系数和温比对制冷机性能的影响.

A model of quantum dot refrigerator driven by photon,which consists of two two-level quantum dots,a photon reservoir and two leads,is proposed in this paper.Comparing with previous studies,we consider the transitions of electrons between different energy levels in a single quantum dot,which is more practical.Based on the theory of master equation and the assumption of weak coupling,we derive the expression of the cooling rate and the coefficient of performance of the refrigerator and obtain the condition of the tight coupling of the refrigerator operation.Next,we plot numerically the performance characteristic curves between the cooling rate and the coefficient of performance in the case of the tight coupling and in the general case.We find that the curves between the cooling rate and the coefficient of performance are opened loops for tight coupling,but they are closed loops in the general case.And we gain the conclusions that the refrigerator can be reversible under the condition of the tight coupling,while it can be irreversible in the general case.Then the optimally operating range of the refrigerator is determined.Finally,the effect of the temperature of the photon reservoir,transition coefficient,and temperature ratio on the performance of refrigerator under the conditions of the maximum cooling rate are studied,and also the coefficient of performance under the maximum cooling rate,the maximum coefficient of performanceand the cooling rate under the maximum coefficient of performanceare analyzed in detail.