Topological vortex formation in a Bose-Einstein condensate under gravitational field

Journal Article · Fri Oct 01 04:00:00 EDT 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.70.043605· OSTI ID:20646399

Kawaguchi, Yuki; Ohmi, Tetsuo ^[1]; Nakahara, Mikio ^[2]

---

1. Department of Physics, Kyoto University, Kyoto 606-8502 (Japan)
2. Department of Physics, Kinki University, Higashi-Osaka 577-8502 (Japan)

Topological phase imprinting is a unique technique for vortex formation in a Bose-Einstein condensate (BEC) of an alkali-metal gas, in that it does not involve rotation: the BEC is trapped in a quadrupole field with a uniform bias field which is reversed adiabatically leading to vortex formation at the center of the magnetic trap. The scenario has been experimentally verified by Leanhardt et al. employing {sup 23}Na atoms. Recently similar experiments have been conducted by Hirotani et al. in which a BEC of {sup 87}Rb atoms was used. In the latter experiments the authors found that fine-tuning of the field reverse time T{sub rev} is required to achieve stable vortex formation. Otherwise, they often observed vortex fragmentation or a condensate without a vortex. It is shown in this paper that this behavior can be attributed to the heavy mass of the Rb atom. The confining potential, which depends on the eigenvalue m{sub B} of the hyperfine spin F along the magnetic field, is now shifted by the gravitational field perpendicular to the vortex line. Then the positions of two weak-field-seeking states with m{sub B}=1 and 2 deviate from each other. This effect is more prominent for BECs with a heavy atomic mass, for which the deviation is greater and, moreover, the Thomas-Fermi radius is smaller. We found, by solving the Gross-Pitaevskii equation numerically, that two condensates interact in a very complicated way leading to fragmentation of vortices, unless T{sub rev} is properly tuned.

• OSTI ID: 20646399
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 70; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
ATOM-ATOM COLLISIONS
ATOMS
BOSE-EINSTEIN CONDENSATION
EIGENFUNCTIONS
EIGENVALUES
GRAVITATION
GRAVITATIONAL FIELDS
MAGNETIC FIELDS
POTENTIALS
QUADRUPOLES
ROTATION
RUBIDIUM 87
SODIUM 23
SPIN
THOMAS-FERMI MODEL
TOPOLOGY
TRAPPING
TRAPS
TUNING
VORTICES
WAVE EQUATIONS