Vortex pairing in two-dimensional Bose gases

被引：55

作者：

Foster, Christopher J. ^{[1
]}

Blakie, P. Blair ^{[2
]}

Davis, Matthew J. ^{[1
]}

机构：

[1] Univ Queensland, Sch Math & Phys, ARC Ctr Excellence Quantum Atom Opt, Brisbane, Qld 4072, Australia

[2] Univ Otago, Dept Phys, Jack Dodd Ctr Quantum Technol, Dunedin, New Zealand

来源：

PHYSICAL REVIEW A | 2010年 / 81卷 / 02期

关键词：

LONG-RANGE ORDER; DYNAMICS; DENSITY;

D O I：

10.1103/PhysRevA.81.023623

中图分类号：

O43 [光学];

学科分类号：

070207 ; 0803 ;

摘要：

Recent experiments on ultracold Bose gases in two dimensions have provided evidence for the existence of the Berezinskii-Kosterlitz- Thouless (BKT) phase via analysis of the interference between two independent systems. In this work we study the two-dimensional quantum degenerate Bose gas at finite temperature using the projected Gross-Pitaevskii equation classical field method. Although this describes the highly occupied modes of the gas below a momentum cutoff, we have developed a method to incorporate the higher momentum states in our model. We concentrate on finite-sized homogeneous systems in order to simplify the analysis of the vortex pairing. We determine the dependence of the condensate fraction on temperature and compare this to the calculated superfluid fraction. By measuring the first order correlation function we determine the boundary of the Bose-Einstein condensate and BKT phases, and find it is consistent with the superfluid fraction decreasing to zero. We reveal the characteristic unbinding of vortex pairs above the BKT transition via a coarse-graining procedure. Finally, we model the procedure used in experiments to infer system correlations [Hadzibabic et al., Nature 441, 1118 (2006)], and quantify its level of agreement with directly calculated in situ correlation functions.

引用

页数：15

共 52 条

[11] Calculation of the microcanonical temperature for the classical Bose field [J].

Davis, MJ ;

Blakie, PB .

JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL, 2005, 38 (48) :10259-10271

[12] Microcanonical temperature for a classical field: Application to Bose-Einstein condensation [J].

Davis, MJ ;

Morgan, SA .

PHYSICAL REVIEW A, 2003, 68 (05) :10

[13] Dynamics of thermal Bose fields in the classical limit [J].

Davis, MJ ;

Ballagh, RJ ;

Burnett, K .

JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS, 2001, 34 (22) :4487-4512

[14] Simulations of thermal Bose fields in the classical limit [J].

Davis, MJ ;

Morgan, SA ;

Burnett, K .

PHYSICAL REVIEW A, 2002, 66 (05) :15

[15] Simulations of bose fields at finite temperature [J].

Davis, MJ ;

Morgan, SA ;

Burnett, K .

PHYSICAL REVIEW LETTERS, 2001, 87 (16) :1-160402

[16] DILUTE BOSE-GAS IN 2 DIMENSIONS [J].

FISHER, DS ;

HOHENBERG, PC .

PHYSICAL REVIEW B, 1988, 37 (10) :4936-4943

[17]

Forster D., 1975, Hydrodynamic Fluctuations, Broken Symmetry, And Correlation Functions

[18] Coherence properties of the two-dimensional Bose-Einstein condensate [J].

Gies, C ;

Hutchinson, DAW .

PHYSICAL REVIEW A, 2004, 70 (04) :043606-1

[19] Semiclassical field method for the equilibrium Bose gas and application to thermal vortices in two dimensions [J].

Giorgetti, Luca ;

Carusotto, Iacopo ;

Castin, Yvan .

PHYSICAL REVIEW A, 2007, 76 (01)

[20] Realization of Bose-Einstein condensates in lower dimensions -: art. no. 130402 [J].

Görlitz, A ;

Vogels, JM ;

Leanhardt, AE ;

Raman, C ;

Gustavson, TL ;

Abo-Shaeer, JR ;

Chikkatur, AP ;

Gupta, S ;

Inouye, S ;

Rosenband, T ;

Ketterle, W .

PHYSICAL REVIEW LETTERS, 2001, 87 (13) :130402/1-130402/4

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