FARADAY WAVES IN ELONGATED BOSE-EINSTEIN CONDENSATES IN AN OPTICAL LATTICE

PABLO CAPUZZI; MARIO GATTOBIGIO; PATRIZIA VIGNOLO

Niza

Workshop; Fifth International Workshop on "Theory of Quantum Gases and Quantum Coherence"; 2010

Universidad de Niza-Sophia Antipolis

We study the formation of Faraday waves in elongated Bose-Einstein condensates subject to 1D optical lattices. By applying a temporal modulation of the transverse confining potential we may excite counter-propagating phonons on top of the optical lattice which in turn form the Faraday wave. We find that the efficiency of this nucleation process strongly depends on the depth of the lattice potential; for moderate lattice depths the wavelength of the Faraday pattern can be associated to the corresponding wavevector of the sound propagation at half the frequency of the temporal modulation, while for stronger potentials the transverse modulation seems to be ineffective to excite the pattern. The dynamics of the condensate is described by means of the Non-Polynomial Schroedinger equation  and compared to the hydrodynamic collective modes of the elongated condensate subject to the optical lattice.