Tunable Field-Linked $s$-wave Interactions in Dipolar Fermi Mixtures

TL;DR

This paper demonstrates tunable $s$-wave interactions in dipolar fermionic spin mixtures using microwave fields, enabling stable, strongly-interacting quantum gases with potential for new quantum phases.

Contribution

It introduces a universal description of tunable $s$-wave resonances in dipolar fermions without sacrificing microwave shielding, advancing control over quantum many-body systems.

Findings

Universal $s$-wave resonance accessible without compromising shielding

Development of a universal model for $s$-wave interactions and tetratomic states

Potential for stable, strongly-interacting dipolar fermion mixtures

Abstract

Spin mixtures of degenerate fermions are a cornerstone of quantum many-body physics, enabling superfluidity, polarons, and rich spin dynamics through $s$-wave scattering resonances. Combining them with strong, long-range dipolar interactions provides highly flexible control schemes promising even more exotic quantum phases. Recently, microwave shielding gave access to spin-polarized degenerate samples of dipolar fermionic molecules, where tunable $p$-wave interactions were enabled by field-linked resonances available only by compromising the shielding. Here, we study the scattering properties of a fermionic dipolar spin mixture and show that a universal $s$-wave resonance is readily accessible without compromising the shielding. We develop a universal description of the tunable $s$-wave interaction and weakly bound tetratomic states based on the microwave-field parameters. The $s$-wave resonance paves the way to stable, controllable and strongly-interacting dipolar spin mixtures of deeply degenerate fermions and supports favorable conditions to reach this regime via evaporative cooling.