Dynamical thermalization and vortex formation in stirred 2D Bose-Einstein condensates

Abstract

We present a quantum mechanical treatment of the mechanical stirring of Bose-Einstein condensates using classical field techniques. In our approach the condensate and excited modes are described using a Hamiltonian classical field method in which the atom number and (rotating frame) energy are strictly conserved. We simulate a T = 0 quasi-2D condensate perturbed by a rotating anisotropic trapping potential. Vacuum fluctuations in the initial state provide an irreducible mechanism for breaking the initial symmetries of the condensate and seeding the subsequent dynamical instability. Highly turbulent motion develops and we quantify the emergence of a rotating thermal component that provides the dissipation necessary for the nucleation and motional-damping of vortices in the condensate. Vortex lattice formation is not observed, rather the vortices assemble into a spatially disordered vortex liquid state. We discuss methods we have developed to identify the condensate in the presence of an irregular distribution of vortices, determine the thermodynamic parameters of the thermal component, and extract damping rates from the classical field trajectories.

22 pages, 15 figures. v2: Minor refinements made at suggestion of referee. Discussion of other treatments revised. To appear in Phys. Rev. A

References in corpus (7)

• Bose-Einstein Condensation from a Rotating Thermal Cloud: Vortex Nucleation and Lattice Formation
• Quantum turbulence and correlations in Bose-Einstein condensate collisions
• Three-body recombination of ultracold Bose gases using the truncated Wigner method
• Superfluidity of an interacting trapped quasi-2D Bose gas
• Instabilities leading to vortex lattice formation in rotating Bose-Einstein condensates
• Two point correlations of a trapped interacting Bose gas at finite temperature
• Coherence properties of spinor condensates at finite temperatures

Cited by in corpus (4)

• Observation of vortex formation in an oscillating trapped Bose-Einstein condensate
• Commuting Heisenberg operators as the quantum response problem: Time-normal averages in the truncated Wigner representation
• Many-body physics in the classical-field description of a degenerate Bose gas
• Dynamics of quantum vortices at finite temperature