Stability and dynamics of vortex clusters in nonrotated Bose-Einstein condensates

Journal Article · Tue Aug 15 04:00:00 EDT 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.74.023603· OSTI ID:20853100

Pietilae, V; Huhtamaeki, J A. M.; Virtanen, S M. M. ^[1]; Moettoenen, M ^[1]; Isoshima, T ^[2]

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1. Laboratory of Physics, Helsinki University of Technology, P.O. Box 4100, FI-02015 TKK (Finland)
2. Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan)

We study stationary clusters of vortices and antivortices in dilute pancake-shaped Bose-Einstein condensates confined in nonrotating harmonic traps. Previous theoretical results on the stability properties of these topologically nontrivial excited states are seemingly contradicting. We clarify this situation by a systematic stability analysis. The energetic and dynamic stability of the clusters is determined from the corresponding elementary excitation spectra obtained by solving the Bogoliubov equations. Furthermore, we study the temporal evolution of the dynamically unstable clusters. The stability of the clusters and the characteristics of their destabilizing modes only depend on the effective strength of the interactions between particles and the trap anisotropy. For certain values of these parameters, there exist several dynamical instabilities, but we show that there are also regions in which some of the clusters are dynamically stable. Moreover, we observe that the dynamical instability of the clusters does not always imply their structural instability, and that for some dynamically unstable states annihilation of the vortices is followed by their regeneration, and revival of the cluster.

• OSTI ID: 20853100
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 2 Vol. 74; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
ANISOTROPY
ANNIHILATION
BOSE-EINSTEIN CONDENSATION
EXCITATION
EXCITED STATES
INSTABILITY
PHASE STABILITY
TRAPS
VORTICES