Control of bound-pair transport by periodic driving

TL;DR

This paper demonstrates how periodic external driving can selectively control the transport of bound pairs in spin and ultracold atom systems, enabling spatial separation of paired and unpaired states.

Contribution

It reveals that periodic driving selectively renormalizes the coupling of bound pairs, allowing control over their transport relative to unpaired states in quantum systems.

Findings

Periodic driving affects bound-pair transport distinctly from unpaired states.

Control over the direction and speed of bound-pair movement is achieved.

Potential applications in experiments with ultracold fermionic atoms in optical lattices.

Abstract

We investigate the effect of periodic driving by an external field on systems with attractive pairing interactions. These include spin systems (like the ferromagnetic XXZ model) as well as ultracold fermionic atoms described by the attractive Hubbard model. We show that a well-known phenomenon seen in periodically driven systems--the renormalization of the exchange coupling strength--acts selectively on bound-pairs of spins/atoms, relative to magnon/bare atom states. Thus one can control the direction and speed of transport of bound-pair relative to magnon/unpaired atom states, and thus coherently achieve spatial separation of these components. Applications to recent experiments on transport with fermionic atoms in optical lattices which consist of mixtures of bound-pairs and bare atoms are discussed.