Quantum Breathers in a Nonlinear Lattice

TL;DR

This paper investigates quantum breather states in a one-dimensional nonlinear lattice, revealing their existence as eigenstates with particle-like properties and distinctive signatures in the dynamic structure factor.

Contribution

It demonstrates the existence of quantum breather eigenstates in a translationally invariant lattice using numerical exact diagonalization, linking quantum and classical nonlinear excitations.

Findings

Quantum breather states form particle-like bands.

Breather states show significant intensity in the dynamic structure factor.

Neighboring multi-phonon extended states are quenched.

Abstract

We study nonlinear phonon excitations in a one-dimensional quantum nonlinear lattice model using numerical exact diagonalization. We find that multi-phonon bound states exist as eigenstates which are natural counterparts of breather solutions of classical nonlinear systems. In a translationally invariant system, these quantum breather states form particle-like bands and are characterized by a finite correlation length. The dynamic structure factor has significant intensity for the breather states, with a corresponding quenching of the neighboring bands of multi-phonon extended states.