Toroidal confinement and beyond: Vorticity-defined morphologies of dipolar ^{164}Dy quantum droplets

Area of Science:

• Quantum physics
• Atomic physics
• Condensed matter physics

Background:

• Bose-Einstein condensates (BECs) are quantum states of matter.
• Dipolar Bose-Einstein condensates exhibit long-range interactions.
• Quantum droplets (QDs) are novel self-bound states in weakly interacting BECs.

Purpose of the Study:

• Investigate the formation, stability, and dynamics of 3D ring-shaped and multipole vortical quantum droplets (QDs).
• Explore QD behavior in nonrotating dipolar Bose-Einstein condensates within a toroidal trap.
• Analyze the influence of dipole-dipole interactions (DDIs) and beyond-mean-field effects on QD structures.

Main Methods:

• Utilized the extended Gross-Pitaevskii equation (eGPE) to model QD dynamics.
• Incorporated long-range dipole-dipole interactions (DDIs) and the Lee-Huang-Yang (LHY) beyond-mean-field correction.
• Analyzed stable stationary solutions for multipole QDs with varying topological charge (S).

Main Results:

• Identified stable, necklacelike multipole QDs with topological charge S up to 6 (n=2S beads).
• Observed shrinking stability regions for multipoles as S increases.
• Found that centrifugal effects destabilize ring-shaped QDs at high S, forming fragmented states.
• Characterized the dependence of chemical potential, energy, and density on particle number and S.

Conclusions:

• The Lee-Huang-Yang (LHY) correction and DDI anisotropy stabilize complex QD states.
• Nonrotating configurations support intricate multipole QD structures.
• Higher vorticity leads to destabilization and fragmentation of quantum droplets.