Center-of-mass-momentum-dependent interaction between ultracold atoms

TL;DR

This paper demonstrates how laser-modulated magnetic Feshbach resonances can induce center-of-mass momentum-dependent interactions in ultracold atoms, enabling new control over atomic interactions via Doppler effects.

Contribution

It introduces a novel method to realize COM-momentum-dependent interactions in ultracold gases using laser-modulated Feshbach resonances and Raman transitions.

Findings

COM-momentum dependence of scattering length demonstrated

Effective two-atom interactions can be tuned via laser parameters

Doppler effects enable new interaction control mechanisms

Abstract

We show that a type of two-body interaction, which depends on the momentum of the center of mass (COM) of these two particles, can be realized in ultracold atom gases with a laser-modulated magnetic Feshbach resonance (MFR). Here the MFR is modulated by two laser beams propagating along different directions, which can induce Raman transition between two-body bound states. The Doppler effect causes the two-atom scattering length to be strongly dependent on the COM momentum of these two atoms. As a result, the effective two-atom interaction is COM-momentum dependent, while the one-atom free Hamiltonian is still the simple kinetic energy p^2/(2m).