Nambu-Goldstone mode in a rotating dilute Bose-Einstein condensate
- Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan and ERATO, Japan Science and Technology Corporation (JST), Saitama 332-0012 (Japan)
- Physics Department, Graduate School of Science, Tohoku University, Sendai 980-8578 (Japan)
The Nambu-Goldstone mode (NGM), associated with vortex nucleation in a harmonically confined, two-dimensional dilute Bose-Einstein condensate is studied. We argue, based on exact diagonalization calculations, that the NGM manifests in the lowest-lying envelope of the quasidegenerate spectrum that emerges as the vortex is about to enter the condensate. The quasidegenerate states constitute a series of octupole-mode branches that originate primarily from pairwise repulsive interactions between octupole excitations and are distinguished by the number of admixed quadrupolar excitations. As the vortex approaches the center of the condensate and the system's axisymmetry is restored, the NGM becomes massive due to its coupling to higher rotational bands. We clarify the mechanism of this mass acquisition by using a newly developed projection-operator method.
- OSTI ID:
- 20787138
- Journal Information:
- Physical Review. A, Vol. 73, Issue 4; Other Information: DOI: 10.1103/PhysRevA.73.043603; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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