The Kohn mode for trapped Bose gases within the dielectric formalism

Abstract

The presence of undamped harmonic center of mass oscillations of a weakly interacting Bose gas in a harmonic trap is demonstrated within the dielectric formalism for a previously introduced finite temperature approximation including exchange. The consistency of the approximation with the Kohn theorem is thereby demonstrated. The Kohn modes are found explicitly, generalizing an earlier zero-temperature result found in the literature. It is shown how the Kohn mode disappears from the single-particle spectrum, while remaining in the density oscillation spectrum, when the temperature increases from below to above the condensation temperature.

6 pages revtex

References in corpus (2)

• Shifts and widths of collective excitations in trapped Bose gases by the dielectric formalism
• Collisionless modes of a trapped Bose gas

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