Phonon-enhanced relaxation and excitation in the Holstein-Hubbard model

TL;DR

This paper investigates how phonons influence electron relaxation and excitation in the Hubbard-Holstein model through nonequilibrium simulations, revealing phonon-assisted decay and enhanced doublon production after interaction quenches.

Contribution

It introduces a generalized Lang-Firsov scheme for time-dependent interactions and applies it to study nonequilibrium dynamics in the Hubbard-Holstein model, highlighting phonon effects.

Findings

Phonon-assisted decay of excess doublons observed.

Persistent phonon oscillations after electron-phonon coupling quenches.

Enhanced doublon production due to phonon interactions.

Abstract

We study quenches of the interaction and electron-phonon coupling parameter in the Hubbard-Holstein model, using nonequilibrium dynamical mean field theory. The calculations are based on a generalized Lang-Firsov scheme for time-dependent interactions or externally driven phonons, and an approximate strong-coupling impurity solver. The interaction quench calculations reveal the phonon-assisted decay of excess doublons, while the quenches of the electron-phonon coupling lead to persistent oscillations of the phonons and to a phonon-enhanced doublon production.