Theory of elementary excitations in unstable Bose-Einstein condensates

U. Leonhardt, T. Kiss, P. Ohberg

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

Like classical fluids, quantum gases may suffer from hydrodynamic instabilities. Our paper develops a quantum version of the classical stability analysis in fluids, the Bogoliubov theory of elementary excitations in unstable Bose-Einstein condensates. In unstable condensates the excitation modes have complex frequencies. We derive the normalization conditions for unstable modes such that they can serve in a mode decomposition of the noncondensed component. Furthermore, we develop approximative techniques to determine the spectrum and the mode functions. Finally, we apply our theory to sonic horizons - sonic black and white holes. For sonic white holes the spectrum of unstable modes turns out to be intrinsically discrete, whereas black holes may be stable.
LanguageEnglish
JournalPhysical Review A
Volume67
Issue number3
DOIs
Publication statusPublished - 2003

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elementary excitations
Bose-Einstein condensates
Bogoliubov theory
fluids
horizon
condensates
hydrodynamics
decomposition
gases
excitation

Keywords

  • soft condensed matter
  • bose-einstein
  • fluids
  • physics

Cite this

Leonhardt, U. ; Kiss, T. ; Ohberg, P. / Theory of elementary excitations in unstable Bose-Einstein condensates. In: Physical Review A. 2003 ; Vol. 67, No. 3.
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Theory of elementary excitations in unstable Bose-Einstein condensates. / Leonhardt, U.; Kiss, T.; Ohberg, P.

In: Physical Review A, Vol. 67, No. 3, 2003.

Research output: Contribution to journalArticle

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T1 - Theory of elementary excitations in unstable Bose-Einstein condensates

AU - Leonhardt, U.

AU - Kiss, T.

AU - Ohberg, P.

PY - 2003

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N2 - Like classical fluids, quantum gases may suffer from hydrodynamic instabilities. Our paper develops a quantum version of the classical stability analysis in fluids, the Bogoliubov theory of elementary excitations in unstable Bose-Einstein condensates. In unstable condensates the excitation modes have complex frequencies. We derive the normalization conditions for unstable modes such that they can serve in a mode decomposition of the noncondensed component. Furthermore, we develop approximative techniques to determine the spectrum and the mode functions. Finally, we apply our theory to sonic horizons - sonic black and white holes. For sonic white holes the spectrum of unstable modes turns out to be intrinsically discrete, whereas black holes may be stable.

AB - Like classical fluids, quantum gases may suffer from hydrodynamic instabilities. Our paper develops a quantum version of the classical stability analysis in fluids, the Bogoliubov theory of elementary excitations in unstable Bose-Einstein condensates. In unstable condensates the excitation modes have complex frequencies. We derive the normalization conditions for unstable modes such that they can serve in a mode decomposition of the noncondensed component. Furthermore, we develop approximative techniques to determine the spectrum and the mode functions. Finally, we apply our theory to sonic horizons - sonic black and white holes. For sonic white holes the spectrum of unstable modes turns out to be intrinsically discrete, whereas black holes may be stable.

KW - soft condensed matter

KW - bose-einstein

KW - fluids

KW - physics

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JF - Physical Review A - Atomic, Molecular, and Optical Physics

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