Dynamics of vortex quadrupoles in nonrotating trapped Bose-Einstein condensates

Area of Science:

• Quantum physics
• Condensed matter physics
• Superfluidity

Background:

• Vortex cluster dynamics are crucial for understanding superfluid phenomena.
• Bose-Einstein condensates provide a platform for studying quantum fluid behavior.

Purpose of the Study:

• To investigate the dynamics of vortex quadrupoles in trapped two-dimensional Bose-Einstein condensates.
• To identify and characterize distinct dynamical regimes of vortex quadrupoles.

Main Methods:

• Numerical simulation of vortex quadrupole movement in 2D Bose-Einstein condensates.
• Analysis of vortex positions and trap geometry (isotropic and anisotropic).
• Identification of parameter ranges and phase diagrams for different dynamical regimes.

Main Results:

• Three distinct dynamical regimes were identified: recombination, exchange, and annihilation.
• Regime behavior is determined by vortex radial positions and trap anisotropy.
• A novel intermediate state involving connected vortex dipoles and a soliton ring mediates charge flipping and quadrupole disappearance.

Conclusions:

• The study provides a comprehensive description of vortex quadrupole dynamics in trapped Bose-Einstein condensates.
• The findings offer insights into the fundamental mechanisms governing vortex interactions and superfluid behavior.
• The results are applicable to both classical and quantum fluctuating systems in the short-time evolution.