Non-Markovian coherent feedback control of quantum dot systems

TL;DR

This paper introduces a non-Markovian coherent feedback control method for quantum dot systems, deriving an exact Langevin equation and demonstrating decoherence suppression through feedback coupling.

Contribution

It presents a novel non-Markovian feedback scheme for quantum dots, including an exact Langevin equation and analysis of decoherence control via feedback strength.

Findings

Decoherence can be suppressed by increasing feedback coupling.

The exact non-Markovian Langevin equation is derived for quantum dot dynamics.

Green's function analysis shows effective decoherence control.

Abstract

This paper presents a non-Markovian coherent feedback scheme to control single quantum dot systems. The feedback loop is closed via a quantum tunneling junction between the natural source and drain baths of the quantum dot. The exact feedback-controlled non-Markovian Langevin equation is derived for describing the dynamics of the quantum dot. To deal with the nonlinear memory function in the Langevin equation, we analyze the Green's function-based root locus, from which we show that the decoherence of the quantum dot can be suppressed via increasing the feedback coupling strength. This effectiveness of decoherence suppression induced by non-Markovian coherent feedback is verified by an example of single quantum dot systems.