Superfluidity versus Bose-Einstein condensation in a Bose gas with disorder

We investigate the phenomenon of Bose-Einstein condensation and superfluidity in a Bose gas at zero temperature with disorder. By using the diffusion Monte Carlo method, we calculate the superfluid and the condensate fraction of the system as a function of density and strength of disorder. In the regime of weak disorder we find agreement with the analytical results obtained within the Bogoliubov model. For strong disorder the system enters an unusual regime where the superfluid fraction is smaller than the condensate fraction.

[1]  Ceperley,et al.  Effect of disorder on the critical temperature of a dilute hard-sphere Gas , 2000, Physical Review Letters.

[2]  Schober,et al.  Dynamics of liquid 4He in vycor , 1999, Physical review letters.

[3]  S. Giorgini,et al.  Ground state of a homogeneous Bose gas: A diffusion Monte Carlo calculation , 1999, cond-mat/9902185.

[4]  F. Dalfovo,et al.  Theory of Bose-Einstein condensation in trapped gases , 1998, cond-mat/9806038.

[5]  Zhang,et al.  Quantum simulations of the superfluid-insulator transition for two-dimensional, disordered, hard-core bosons. , 1994, Physical Review Letters.

[6]  Giorgini,et al.  Effects of disorder in a dilute Bose gas. , 1994, Physical review. B, Condensed matter.

[7]  Boronat,et al.  Monte Carlo analysis of an interatomic potential for He. , 1993, Physical review. B, Condensed matter.

[8]  M. S. Singh,et al.  Disordered bosons: Condensate and excitations. , 1993, Physical review. B, Condensed matter.

[9]  Huang,et al.  Hard-sphere Bose gas in random external potentials. , 1992, Physical review letters.

[10]  J. Reppy.  Superfluid helium in porous media , 1992 .

[11]  N. Trivedi,et al.  Superfluid-insulator transition in disordered boson systems , 1991, Physical review letters.

[12]  R. Scalettar,et al.  Localization in interacting, disordered, Bose systems. , 1991, Physical review letters.

[13]  Vaidman,et al.  Properties of a quantum system during the time interval between two measurements. , 1990, Physical review. A, Atomic, molecular, and optical physics.

[14]  Fisher,et al.  Boson localization and the superfluid-insulator transition. , 1989, Physical review. B, Condensed matter.

[15]  Pollock,et al.  Path-integral computation of superfluid densities. , 1987, Physical review. B, Condensed matter.

[16]  Lee,et al.  Strongly disordered superfluids: Quantum fluctuations and critical behavior. , 1986, Physical review. B, Condensed matter.