Bogoliubov sound speed in periodically modulated Bose-Einstein condensates

E. Taylor; E. Zaremba

doi:10.1103/physreva.68.053611

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arXiv · cond-mat/0308194

Bogoliubov sound speed in periodically modulated Bose-Einstein condensates

E. Taylor·E. Zaremba

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Abstract

We study the Bogoliubov excitations of a Bose-condensed gas in an optical lattice. Of primary interest is the long wavelength phonon dispersion for both current-free and current-carrying condensates. We obtain the dispersion relation by carrying out a systematic expansion of the Bogoliubov equations in powers of the phonon wave vector. Our result for the current-carrying case agrees with the one recently obtained by means of a hydrodynamic theory.

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E. Taylor, E. Zaremba. 2003-08-11. Bogoliubov sound speed in periodically modulated Bose-Einstein condensates. https://doi.org/10.1103/physreva.68.053611

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