Decoherence processes of a quantum two-level system coupled to a fermionic environment

TL;DR

This paper investigates how a localized spin's quantum coherence decays when interacting with conduction electrons in metals and semiconductors, deriving master equations to quantify decoherence rates.

Contribution

It introduces a method to derive master equations for spin decoherence in fermionic environments, highlighting differences between metallic and semiconducting cases.

Findings

Decoherence occurs faster in metals than in semiconductors.

Master equations are derived using linked-cluster-expansion techniques.

The study provides quantitative insights into environment-induced decoherence.

Abstract

We study decoherence processes of an S = 1/2 localized spin coupled to conduction band electrons in a metal or a semiconductor via an Ising-like interaction. We derive master equations for the density matrix of the localized spin, by tracing out all degrees of freedom in the conduction electron system based on the linked-cluster-expansion technique. It is found that the decoherence occurs more rapidly for the metallic case than for semiconducting case.