1996/03/18 by S. Stringari · 1 citation
Physics and Astronomy · #cond-mat
paper · pdf · doi:10.1103/physrevlett.77.2360
uuencoded file including 12 pages REVTEX and 1 figure
arxiv created 1996/03/18 · arxiv updated 2009/11/30
By taking the hydrodynamic limit we derive, at T=0, an explicit solution of the linearized time dependent Gross-Pitaevskii equation for the order parameter of a Bose gas confined in a harmonic trap and interacting with repulsive forces. The dispersion law ω=ω0(2n2+2nℓ+3n+ℓ)1/2 for the elementary excitations is obtained, to be compared with the prediction ω=ω0(2n+ℓ) of the noninteracting harmonic oscillator model. Here n is the number of radial nodes and ℓ is the orbital angular momentum. The effects of the kinetic energy pressure, neglected in the hydrodynamic approximation, are estimated using a sum rule approach. Results are also presented for deformed traps and attractive forces.