Geometrical pumping in spin coupled double quantum dots

TL;DR

This paper analytically explores non-equilibrium spin pumping in double quantum dots connected to leads, revealing a non-zero Berry-like curvature in parameter space, which is absent in single or isolated dots.

Contribution

It provides an analytical expression for the Berry-like phase in a double quantum dot system using quantum master equations, highlighting the role of spin coupling in geometric pumping.

Findings

Berry-like curvature is non-zero in the parameter space of the double quantum dots.

The curvature vanishes for single quantum dots and isolated double dots.

The study offers insights into geometric effects in quantum transport systems.

Abstract

We analytically investigate the non-equilibrium pumping for a double quantum dots system on the basis of the quantum master equation (QME), where the double quantum dots are connected to two external leads by the spin coupling. Each of leads has two tunable parameters, temperature and chemical potential. Using QME formalism, we obtain an analytical expression of the Berry-like phase for eigenstate of the QME in the parameter space. We show that the Berry-like curvature is non zero in the whole region in the parameter space. We also show that the Berry-like curvature vanishes in the case of single quantum dot and the case of isolated two dots.