Suppression of Faraday waves in a Bose-Einstein condensate in the presence of an optical lattice

PABLO CAPUZZI; MARIO GATTOBIGIO; PATRIZIA VIGNOLO

PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS

AMER PHYSICAL SOC

Año: 2010 vol. 83 p. 13603 - 136036

1050-2947

   We study the formation of Faraday waves in an elongated Bose-Einstein condensate in the presence of aone-dimensional optical lattice. The waves are parametrically excited by modulating the radial confinement ofthe condensate close to a transverse breathing mode of the system. For very shallow optical lattices, phonons with a well-defined wave vector propagate along the condensate, as in the absence of the lattice, and we observe theformation of a Faraday pattern. We find that by increasing the potential depth the local sound velocity decreases,and when it equals the condensate local phase velocity, the condensate develops an incoherent superposition ofseveral modes and the parametric excitation of Faraday waves is suppressed.