Probing the sign of on-site Hubbard interaction by two-particle quantum walks

TL;DR

This paper proposes a method using two-particle quantum walks to determine whether the on-site Hubbard interaction between bosons is attractive or repulsive, based on analyzing quantum correlation dynamics.

Contribution

It introduces a novel probing scheme that leverages quantum walk properties to distinguish the sign of on-site interactions in a Hubbard model.

Findings

Sign of interaction affects quantum correlation dynamics.

Discrimination requires initial superposition of localized states.

Features are linked to the Hubbard Hamiltonian's band structure.

Abstract

We consider two identical bosons propagating on a one-dimensional lattice and address the prob- lem of discriminating whether their mutual on-site interaction is attractive or repulsive. We suggest a probing scheme based on the properties of the corresponding two-particle quantum walks, and show that the sign of the interaction introduces specific and detectable features in the dynamics of quantum correlations, thus permitting to discriminate between the two cases. We also discuss how these features are connected to the band-structure of the Hubbard Hamiltonian, and prove that discrimination may be obtained only when the two walkers are initially prepared in a superposition of localized states.