Quantum Walk of Two Interacting Bosons

TL;DR

This paper investigates how interactions influence the quantum walk and spatial correlations of two bosons, revealing unique effects dependent on interaction strength, with experimental insights from photonic lattices and proposals for atomic lattice observations.

Contribution

It provides a detailed analysis of interaction effects on two-boson quantum walks and introduces experimental methods to observe these phenomena in photonic and atomic systems.

Findings

Interactions affect spatial correlations independently of their sign.

Experimental measurement of weak interaction effects in photonic lattices.

Proposed approach for observing strong interactions with atoms in optical lattices.

Abstract

We study the effect of interactions on the bosonic two-particle quantum walk and its corresponding spatial correlations. The combined effect of interactions and Hanbury-Brown Twiss interference results in unique spatial correlations which depend on the strength of the interaction, but not on its sign. The results are explained in light of the two-particle spectrum and the physics of attractively and repulsively bound pairs. We experimentally measure the weak interaction limit of these effects in nonlinear photonic lattices. Finally, we discuss an experimental approach to observe the strong interaction limit using single atoms in optical lattices.