Speed of sound in disordered Bose-Einstein condensates
arXiv:0908.1947 · doi:10.1103/PhysRevA.80.053620
Abstract
Disorder modifies the sound-wave excitation spectrum of Bose-Einstein condensates. We consider the classical hydrodynamic limit, where the disorder correlation length is much longer than the condensate healing length. By perturbation theory, we compute the phonon lifetime and correction to the speed of sound. This correction is found to be negative in all dimensions, with universal asymptotics for smooth correlations. Considering in detail optical speckle potentials, we find a quite rich intermediate structure. This has consequences for the average density of states, particularly in one dimension, where we find a "boson dip" next to a sharp "boson peak" as function of frequency. In one dimension, our prediction is verified in detail by a numerical integration of the Gross-Pitaevskii equation.
final, extended version with 2 new figures
References in corpus (9)
- Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
- Direct observation of Anderson localization of matter-waves in a controlled disorder
- One-dimensional Anderson localization in certain correlated random potentials
- Anderson Localization of Bogolyubov Quasiparticles in Interacting Bose-Einstein Condensates
- Bose-Einstein-condensed systems in random potentials
- Smoothing effect and delocalization of interacting Bose-Einstein condensates in random potentials
- Coherent backscattering of Bose-Einstein condensates in two-dimensional disorder potentials
- Quantum Mechanical Heat Transport in Disordered Harmonic Chains
- Anisotropic scattering of Bogoliubov excitations
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- Bogoliubov theory on the disordered lattice
- Dark soliton in a disorder potential
- Superfluid-insulator transition of two-dimensional disordered Bose gases
- The effects of disorder in dimerized quantum magnets in mean field approximations
- Thermodynamic measurement of the sound velocity of a Bose gas across the transition to Bose-Einstein condensation
- Localization landscape for interacting Bose gases in one-dimensional speckle potentials
- Quantum stochastic behaviour in cold Fermi gases: Phonon propagation
- Probing Superfluidity with Quantum Vortex Necklaces