Excitations and impurity dynamics in a fermionic Mott insulator with nearest-neighbor interactions

TL;DR

This paper investigates the dynamics of an impurity in a one-dimensional fermionic Mott insulator with nearest-neighbor interactions, revealing two distinct excitation types depending on interaction strengths.

Contribution

It provides an analytical and numerical study of impurity behavior in a fermionic Mott insulator, highlighting novel excitation phenomena related to interaction parameters.

Findings

Identification of two excitation types: domain wall propagation and impurity-bound excitation.

Demonstration of impurity and bath coupling depending on interaction strengths.

Observation of distinct impurity dynamics in a fermionic Mott insulator.

Abstract

We study analytically and with the numerical time-evolving block decimation method the dynamics of an impurity in a bath of spinless fermions with nearest-neighbor interactions in a one-dimensional lattice. The bath is in a Mott insulator state with alternating sites occupied and the impurity interacts with the bath by repulsive on-site interactions. We find that when the magnitudes of the on-site and nearest-neighbor interactions are close to each other, the system shows excitations of two qualitatively distinct types. For the first type, a domain wall and an anti-domain wall of density propagate in opposite directions, while the impurity stays at the initial position. For the second one, the impurity is bound to the anti-domain wall while the domain wall propagates, an excitation where the impurity and bath are closely coupled.