Quantum Breathers in Electron-phonon Systems

TL;DR

This paper investigates quantum breathers in electron-phonon systems, demonstrating their existence as eigenstates, analyzing optical signatures, and introducing breather-excitons as a novel quantum nonlinear excitation.

Contribution

It provides a numerical study of quantum breathers in electron-phonon systems and introduces breather-excitons as a new quantum nonlinear excitation.

Findings

Quantum breathers can exist as eigenstates in electron-phonon systems.

Optical responses can serve as signatures of quantum breathers.

Breather-excitons are identified as bound states of breathers and excitons.

Abstract

Quantum breathers are studied numerically in several electron-phonon coupled finite chain systems, in which the coupling results in intrinsic nonlinearity but with varying degrees of nonadiabaticity. As for quantum nonlinear lattice systems, we find that quantum breathers can exist as eigenstates of the system Hamiltonians. Optical responses are calculated as signatures of these coherent nonlinear excitations. We propose a new type of quantum nonlinear excitation, breather-excitons, which are bound states of breathers and excitons, whose properties are clarified with a minimal exciton-phonon model.