Decoherence of an impurity in a one-dimensional fermionic bath with mass imbalance

TL;DR

This paper investigates how an impurity's decoherence and energy dissipation are affected by mass imbalance in a one-dimensional fermionic system, revealing that decoherence peaks with a light impurity and heavy bath, while energy dissipation peaks at equal masses.

Contribution

It introduces a mass imbalance parameter in a 1D fermionic bath model and analyzes its effects on decoherence and dissipation using numerical and analytical methods.

Findings

Fastest decoherence occurs for a light impurity in a heavy bath.

Maximum energy dissipation occurs when impurity and bath masses are equal.

A simple model explains decoherence in the heavy bath limit.

Abstract

We study the transport, decoherence and dissipation of an impurity interacting with a bath of free fermions in a one-dimensional lattice. Numerical simulations are made with the time-evolving block decimation method. We introduce a mass imbalance between the impurity and bath particles and find that the fastest decoherence occurs for a light impurity in a bath of heavy particles. By contrast, the fastest dissipation of energy occurs when the masses are equal. We present a simple model for decoherence in the heavy bath limit, and a linear density response description of the interaction which predicts maximum dissipation for equal masses.