We study the response of a Bose-Einstein condensate to a periodic modulation of the depth of an optical lattice. Using Gross-Pitaevskii theory, we show that a modulation at frequency Ω drives the parametric excitation of Bogoliubov modes with frequency Ω∕2. The ensuing nonlinear dynamics leads to a rapid broadening of the momentum distribution and a consequent large increase of the condensate size after free expansion. We show that this process does not require the presence of a large condensate depletion. Our results reproduce the main features of the spectrum measured in the superfluid phase by Stöferle et al. Phys. Rev. Lett. 92 130403 (2004)].

Parametric excitation of a Bose-Einstein condensate in a one-dimensional optical lattice

Dalfovo, Franco
2005

Abstract

We study the response of a Bose-Einstein condensate to a periodic modulation of the depth of an optical lattice. Using Gross-Pitaevskii theory, we show that a modulation at frequency Ω drives the parametric excitation of Bogoliubov modes with frequency Ω∕2. The ensuing nonlinear dynamics leads to a rapid broadening of the momentum distribution and a consequent large increase of the condensate size after free expansion. We show that this process does not require the presence of a large condensate depletion. Our results reproduce the main features of the spectrum measured in the superfluid phase by Stöferle et al. Phys. Rev. Lett. 92 130403 (2004)].
6
M., Kraemer; C., Tozzo; Dalfovo, Franco
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11572/73119
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