Fermi-Polaron in a driven-dissipative background medium

TL;DR

This paper investigates the behavior of Fermi-polarons in open quantum systems with dissipation, analyzing spectral properties, energy, and effective mass, and revealing how dissipation influences polaron states.

Contribution

It provides an analytical and numerical study of molecular and polaron states under varying dissipation, highlighting their spectral evolution and response differences.

Findings

Spectral signals diffuse and revive with increasing dissipation.

Attractive and repulsive polarons respond differently to dissipation range.

Polaron energy, residue, and effective mass are affected by dissipation.

Abstract

The study of polaron of an open quantum system plays an important role in both verifying the effectiveness of approximate many-body theory and predicting novel quantum phenomenone in open quantum systems. In a pioneering work, Piazza et al have proposed a Fermi-polaron scheme with a lossy impurity [54], which exhibits a novel long-lived attractive polaron branch in the quantum Zeno limit. However, we would also run into a counterpart problem that an impurity scatters with an open quantum bath exciting polarons, which is what we focus in on. In this work, we conclude the molecular state under the two limits of vanishing small and infinite large dissipation intensity as well as the reason why the dissipation range leads to the decrease of the gap between the molecular state and molecule-hole continuum in the former case by means of analytically research. The spectrum functions of molecular and polaron states with different dissipation range and loss rate are investigated. We find the spectral signals of molecular and polaron states will both diffuse firstly and then revives as the dissipation is on the raise. Moreover, it is shown that the attractive and repulsive polarons show different response to the increasing dissipation range in our model. At last, we exhibit the polaron energy, residue, effective mass and two-body decay for mass balanced and imbalanced systems. Our results might be useful for future cold atom experiment on open quantum systems.