Dynamical Density Fluctuation of Superfluids near Critical Velocities

Yusuke Kato; Shohei Watabe

doi:10.1103/physrevlett.105.035302

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arXiv · 1006.2999

Dynamical Density Fluctuation of Superfluids near Critical Velocities

Yusuke Kato·Shohei Watabe

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Abstract

We propose a stability criterion of superfluids in condensed Bose-Einstein systems, which incorporates the spectral function or the autocorrelation function of the local density. Within the Gross-Pitaevskii-Bogoliubov theory, we demonstrate the validity of our criterion for the soliton-emission instability, with use of explicit forms of zero modes of the Bogoliubov equation and a dynamical scaling near the saddle-node bifurcation. We also show that the criterion is applicable to the Landau phonon instability and the Landau roton instability within the single-mode approximation.

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Yusuke Kato, Shohei Watabe. 2010-06-15. Dynamical Density Fluctuation of Superfluids near Critical Velocities. https://doi.org/10.1103/physrevlett.105.035302

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