Tuning the dipolar interaction in quantum gases

TL;DR

This paper explores how the anisotropy of dipolar interactions in Bose-Einstein condensates can be dynamically controlled, enabling excitation of collective modes and tunability of the interaction strength and sign.

Contribution

It introduces a method for time-dependent control of dipolar anisotropy, allowing tuning of the effective interaction from positive to negative or to zero.

Findings

Dipolar interactions can excite collective modes in BECs.

The effective dipolar coupling can be tuned via rotation.

Magnetic dipole interactions are significant even in alkali gases.

Abstract

We have studied the tunability of the interaction between permanent dipoles in Bose-Einstein condensates. Based on time-dependent control of the anisotropy of the dipolar interaction, we show that even the very weak magnetic dipole coupling in alkali gases can be used to excite collective modes. Furthermore, we discuss how the effective dipolar coupling in a Bose-Einstein condensate can be tuned from positive to negative values and even switched off completely by fast rotation of the orientation of the dipoles.