I theoretically investigate the coefficient of performance (COP) of a mesoscopic thermo-electric refrigerator realized by using a tunnel junction. I analyze the influence of charge and heat current fluctuations on the COP out of equilibrium regime. I calculate the average COP by using full counting statistics and found that it depends on time t. The deviation from the macroscopic COP value is expressed with the Skellam distribution. The average COP possesses either a minimum or a maximum depend on the DOS of the tunnel junction. My result properly provides a finite result, even in the limit of t → 0, which is beyond the Gauss approximation valid in the linear response regime. I also numerically evaluate the time dependent COP in the parameter regime, where the Gauss approximation is not applicable.
三重大学大学院 工学研究科 博士前期課程 物理工学専攻