Tuning long-range fermion-mediated interactions in cold-atom quantum simulators

TL;DR

This paper presents methods to tune and control long-range fermion-mediated interactions in cold-atom quantum simulators, enabling exploration of new quantum phases and regimes previously inaccessible.

Contribution

It introduces experimental tuning knobs, such as optical lattices and anisotropic traps, to modify interaction range and shape in cold-atom systems.

Findings

Ability to interpolate between power-law and exponential decay interactions

Introduction of an effective cutoff for interaction range

Access to frustrated regimes with topological and chiral phases

Abstract

Engineering long-range interactions in cold-atom quantum simulators can lead to exotic quantum many-body behavior. Fermionic atoms in ultracold atomic mixtures can act as mediators, giving rise to long-range RKKY-type interactions characterized by the dimensionality and density of the fermionic gas. Here, we propose several tuning knobs, accessible in current experimental platforms, that allow to further control the range and shape of the mediated interactions, extending the existing quantum simulation toolbox. In particular, we include an additional optical lattice for the fermionic mediator, as well as anisotropic traps to change its dimensionality in a continuous manner. This allows us to interpolate between power-law and exponential decays, introducing an effective cutoff for the interaction range, as well as to tune the relative interaction strengths at different distances. Finally, we show how our approach allows to investigate frustrated regimes that were not previously accessible, where symmetry-protected topological phases as well as chiral spin liquids emerge.