Instability of Rotationally Tuned Dipolar Bose-Einstein Condensates

TL;DR

This paper investigates the stability of dipolar Bose-Einstein condensates under rapid rotation of dipole polarization, revealing inherent dynamical instabilities that hinder creating long-lived, rotationally tuned states.

Contribution

It provides a comprehensive analysis combining theoretical and numerical methods to demonstrate the instability of rotationally tuned dipolar BECs due to collective mode dynamics.

Findings

Condensates are inherently unstable under rapid polarization rotation.

Dynamical instability prevents the formation of stable, long-lived states.

Implications for experimental realization of rotationally tuned dipolar BECs.

Abstract

The possibility of effectively inverting the sign of the dipole-dipole interaction, by fast rotation of the dipole polarization, is examined within a harmonically trapped dipolar Bose-Einstein condensate. Our analysis is based on the stationary states in the Thomas-Fermi limit, in the corotating frame, as well as direct numerical simulations in the Thomas-Fermi regime, explicitly accounting for the rotating polarization. The condensate is found to be inherently unstable due to the dynamical instability of collective modes. This ultimately prevents the realization of robust and long-lived rotationally tuned states. Our findings have major implications for experimentally accessing this regime.