Dilute Bose gas with correlated disorder: a path integral Monte Carlo study
Year: 2010
Authors: Pilati S., Giorgini S., Modugno M., Prokofev N.
Autors Affiliation: Univ Trent, INO CNR BEC Ctr, I-38123 Trento, Italy; Univ Trent, Dipartimento Fis, I-38123 Trento, Italy; Univ Florence, LENS, I-50019 Sesto Fiorentino, Italy; Univ Florence, Dipartimento Fis & Astron, I-50019 Sesto Fiorentino, Italy; Univ Massachusetts, Dept Phys, Amherst, MA 01003 USA; ETH, Inst Theoret Phys, CH-8093 Zurich, Switzerland; Univ Basque Country, Dept Theoret Phys & Hist Sci, EHU, E-48080 Bilbao, Spain; Basque Fdn Sci, IKERBASQUE, Bilbao 48011, Spain; Russell Res Ctr, Kurchatov Inst, Moscow 123182, Russia.
Abstract: We investigate the thermodynamic properties of a dilute Bose gas in a correlated random potential using exact path integral Monte Carlo methods. The study is carried out in continuous space and disorder is produced in the simulations by a three-dimensional (3D) speckle pattern with tunable intensity and correlation length. We calculate the shift of the superfluid transition temperature due to disorder and we highlight the role of quantum localization by comparing the critical chemical potential with the classical percolation threshold. The equation of state of the gas is determined in the regime of strong disorder, where superfluidity is suppressed and the normal phase exists down to very low temperatures. We find a T-2 dependence of the energy in agreement with the expected behavior in the Bose glass phase. We also discuss the major role played by the disorder correlation length and we make contact with a Hartree-Fock mean-field approach that holds if the correlation length is very large. The density profiles are analyzed as a function of temperature and interaction strength. Effects of localization and the depletion of the order parameter are emphasized in the comparison between local condensate and total density. At very low temperature, we find that the energy and the particle distribution of the gas are very well described by the T = 0 Gross-Pitaevskii theory, even in the regime of very strong disorder.
Journal/Review: NEW JOURNAL OF PHYSICS
Volume: 12 Pages from: 73003-1 to: 73003-28
More Information: We acknowledge useful discussions with B Svistunov and L P Pitaevskii. This work, as part of the European Science Foundation EUROCORES program ’EuroQUAM-FerMix’, was supported by funds from the CNR and the EC Sixth Framework Programme. NP acknowledges support from NSF grant PHY-0653183. SP and NP acknowledge support from the Army Research Office with funding from the DARPA OLE program. Calculations were performed on the HPC facility Wiglaf at the Physics Depar tment of the University of Trento and on the BEN cluster at ECT* in Trento.KeyWords: Superfluid-insulator Transition; Anderson Localization; Hard-sphere; Percolation; Liquid-he-4; Excitations; Continuum; BosonsDOI: 10.1088/1367-2630/12/7/073003Citations: 49data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-09-15References taken from IsiWeb of Knowledge: (subscribers only)