Geometrical optimization of pumping power under adiabatic parameter driving

Abstract

Adiabatic pumping is a fundamental concept in the time-dependent transport of mesoscopic devices. To maximize pumping performance, i.e., the amount of pumping per unit time, it is necessary to carefully manage the driving speed, which should be sufficiently less than the {\it limited speed}, an upper bound of the driving speed below which non-adiabatic effects are negligible. In general, the amount of pumping increases as the contour of the driving parameter lengthens, however a long contour diminishes the pumping power because it requires more time per cycle under the limited speed constraint. We consider this trade-off carefully and show that there should exist an optimized period and contour to maximize the power of adiabatic pumping. We confirm this conclusion based on the results of charge pumping using a single-level quantum dot.