Induced two-body scattering resonances from a square-well potential with oscillating depth

TL;DR

This paper introduces a novel mechanism for resonantly enhancing ultracold atom interactions using an oscillating magnetic field, enabling control over scattering properties without magnetic Feshbach resonances.

Contribution

It proposes a new method to induce two-body scattering resonances via oscillating potential depth, with universal control over resonance parameters through oscillation amplitude.

Findings

Resonance in the real part of the scattering length near the Bohr frequency

Control of resonance parameters by oscillation amplitude

Universal functions of dimensionless parameters for shallow bound states

Abstract

In systems of ultracold atoms, pairwise interactions can be resonantly enhanced by a new mechanism which does not rely upon a magnetic Feshbach resonance. In this mechanism, interactions are controlled by tuning the frequency of an oscillating parallel component of the magnetic field close to the Bohr frequency for the transition to a two-atom bound state. The real part of the s-wave scattering length $a$ has a resonance as a function of the oscillation frequency near the Bohr frequency. The resonance parameters can be controlled by varying the amplitude of the oscillating field. The amplitude also controls the imaginary part of $a$ which arises predominantly because the oscillating field converts atom pairs into molecules. For the case of a shallow bound state in the scattering channel, the dimensionless resonance parameters are universal functions of the dimensionless oscillation amplitude.