Sublattice dynamics and quantum state transfer of doublons in two-dimensional lattices

TL;DR

This paper investigates the dynamics of strongly-interacting fermion pairs, called doublons, in 2D lattices under periodic electric fields, revealing novel edge confinement and coexistence of topological states.

Contribution

It introduces an effective Hamiltonian for doublon dynamics in 2D lattices, uncovering unique edge confinement and coexistence of topological and Shockley-like states.

Findings

Doublons can be confined to lattice edges or specific sublattices.

Coexistence of topological and Shockley-like edge states in 2D systems.

Interaction and driving lead to surprising constraints on doublon movement.

Abstract

We study the dynamics of two strongly-interacting fermions moving in 2D lattices under the action of a periodic electric field, both with and without a magnetic flux. Due to the interaction, these particles bind together forming a doublon. We derive an effective Hamiltonian that permits us to understand the interplay between the interaction and the driving, revealing surprising effects that constrain the movement of the doublons. We show that it is possible to confine doublons to just the edges of the lattice, and also to a particular sublattice, if different sites in the unit cell have different coordination numbers. Contrary to what happens in 1D systems, here we observe the coexistence of both topological and Shockley-like edge states when the system is in a non-trivial phase.