Momentum-dependent pseudo-spin dimers of coherently coupled bosons in optical lattices

TL;DR

This paper investigates how coherent coupling and lattice effects create momentum-dependent internal structures in bosonic dimers, revealing novel bound state behaviors and potential observable phenomena in optical lattices.

Contribution

It introduces a new understanding of momentum-dependent pseudo-spin structures in coherently coupled bosons within optical lattices, highlighting their complex bound and scattering states.

Findings

Bound states depend on center of mass momentum.

Presence of effective momentum-dependent magnetic field.

Bosonic states can exhibit mixed attractive and repulsive properties.

Abstract

We study the two-body bound and scattering states of two particles in a one dimensional optical lattice in the presence of a coherent coupling between two internal atomic levels. Due to the interplay between periodic potential, interactions and coherent coupling, the internal structure of the bound states depends on their center of mass momentum. This phenomenon corresponds to an effective momentum-dependent magnetic field for the dimer pseudo-spin, which could be observed in a chirping of the precession frequency during Bloch oscillations. The essence of this effect can be easily interpreted in terms of an effective bound state Hamiltonian. Moreover for indistinguishable bosons, the two-body eigenstates can present simultaneously attractive and repulsive bound-state nature or even bound and scattering properties.