Adiabaticity criterion for moving vortices in dilute Bose-Einstein condensates

Area of Science:

• Atomic physics
• Quantum mechanics
• Condensed matter physics

Background:

• Bose-Einstein condensates (BECs) are quantum states of matter exhibiting unique properties.
• Vortex lines are topological defects in BECs, crucial for understanding their dynamics.
• Time-dependent Hartree-Fock-Bogoliubov-Popov (TDHFB-P) theory describes the many-body dynamics of weakly interacting quantum fluids.

Purpose of the Study:

• To derive a criterion for quasiparticle excitations to rigidly follow a moving vortex core in dilute atomic Bose-Einstein condensates.
• To investigate the validity of the adiabatic approximation in describing time-dependent vortex phenomena.
• To assess the implications of this criterion for recent experimental observations.

Main Methods:

• Utilizing time-dependent Hartree-Fock-Bogoliubov-Popov (TDHFB-P) theory.
• Analyzing the dynamics of quasiparticle excitations around a moving vortex line.
• Deriving a stringent criterion for the vortex line velocity based on adiabaticity.

Main Results:

• A specific criterion for the vortex line velocity is derived, determining if quasiparticle excitations follow the core rigidly.
• The assumption of adiabaticity in stationary self-consistent theories imposes a strict condition on vortex velocity.
• This derived condition is found to be violated in recent experiments involving vortex precession.

Conclusions:

• The study highlights the limitations of adiabatic approximations in describing dynamic vortex phenomena in BECs.
• Experimental observations of vortex precession challenge the applicability of stationary theories under certain conditions.
• A more refined theoretical framework may be needed to fully capture the dynamics of vortices in realistic BEC experiments.