Condensed Fraction of an Atomic Bose Gas Induced by Critical Correlations

Smith, Robert P.; Tammuz, Naaman; Campbell, Robert L.; Holzmann, Markus; Hadzibabic, Zoran

doi:10.1103/physrevlett.107.190403

Cited by 30 publications

(29 citation statements)

References 38 publications

(52 reference statements)

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“…Deviations from the mean-field prediction and effects due to critical correlations have been measured in Refs. [13,14]. A major breakthrough has been achieved recently with the realization of Bose-Einstein condensation in quasiuniform trapping potentials [15].…”

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confidence: 99%

Critical Temperature of Interacting Bose Gases in Periodic Potentials

et al. 2014

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The superfluid transition of a repulsive Bose gas in the presence of a sinusoidal potential which represents a simple-cubic optical lattice is investigated using quantum Monte Carlo simulations. At the average filling of one particle per well the critical temperature has a nonmonotonic dependence on the interaction strength, with an initial sharp increase and a rapid suppression at strong interactions in the vicinity of the Mott transition. In an optical lattice the positive shift of the transition is strongly enhanced compared to the homogenous gas. By varying the lattice filling we find a crossover from a regime where the optical lattice has the dominant effect to a regime where interactions dominate and the presence of the lattice potential becomes almost irrelevant. The combined effect of interparticle interactions and external potentials plays a fundamental role in determining the quantum-coherence properties of several many-body systems, including He in Vycor or on substrates, paired electrons in superconductors and in Josephson junction arrays, neutrons in the crust of neutron stars [1], and ultracold atoms in optical potentials. However, even the (apparently) simple problem of calculating the superfluid transition temperature T c of a dilute homogeneous Bose gas has challenged theoreticians for decades [2]. Many techniques have been employed, obtaining contradicting results, differing even in the functional dependence of T c on the interaction parameter (the two-body scattering length a) and in the sign of the shift with respect to the ideal gas transition temperature T 0 c (for a review see Ref.[3]). In the weakly interacting limit, the shift of the critical temperature 4,5], where n is the density and the coefficient c ¼ 1.29ð5Þ was determined using Monte Carlo simulations of a classical-field model defined on a discrete lattice [6,7]. Continuous-space quantum Monte Carlo simulations of Bose gases with short-range repulsive interactions have shown that this linear form is valid only in the regime n 1=3 a ≲ 0.01, while at stronger interaction T c reaches a maximum where ΔT c =T 0 c ≃ 6.5% and then decreases for n 1=3 a ≳ 0.2 [8]. This suppression of T c occurs in a regime where universality in terms of the scattering length is lost and other details of the interaction potential become relevant [8][9][10]. In recent years ultracold atomic gases have emerged as the ideal experimental test bed for many-body theories [11]. However, the direct measurement of interactions effects on T c has been hindered by the presence of the harmonic trap. In the presence of confinement the main interactions effect can be predicted by mean-field theory and is due to the broadening of the density profile [12], leading to a suppression of T c . Deviations from the mean-field prediction and effects due to critical correlations have been measured in Refs. [13,14]. A major breakthrough has been achieved recently with the realization of Bose-Einstein condensation in quasiuniform trapping potentials [15]. This setup allows a more ...

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Critical Temperature of Interacting Bose Gases in Periodic Potentials

et al. 2014

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“…Several studies on the homogeneous Bose gases found that repulsive interactions decrease the critical temperature [23][24][25], but most studies pointed to an increase of the critical temperature [26][27][28][29][30][31][32][33][34]. The critical temperature of a trapped Bose gas has also been studied experimentally [35][36][37].…”

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confidence: 99%

Effect of impurities on the transition temperature of a dilute dipolar trapped Bose gas

Yavari

Afsaneh

2013

Phys. Rev. A

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By using a two-fluid model the effect of impurities on the transition temperature of a dipolar trapped Bose gas is investigated. By treating Gaussian spatial correlation for impurities from the interaction modified spectra of the system, the formula for the shift of the transition temperature is derived. The shift of the transition temperature contains essentially three contributions due to contact, dipole-dipole, and impurity interactions. Applying our results to dipolar Bose gases shows that the shift of the transition temperature due to impurities could be measured for an isotropic trap (dipole-dipole contribution is zero) and the Feshbach resonance technique (contact potential contribution is negligible).

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“…(34), the first term provides the condensate fraction in the thermodynamic limit. The second term, which is vanishes for T > 1, provides a consistent way for treating the interaction effect [36][37][38][39].…”

Section: µ0(t =0)mentioning

confidence: 99%

Semiclassical Hartree-Fock theory of a rotating Bose-Einstein condensation

2017

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In this paper, we investigate the thermodynamic behavior of a rotating Bose-Einstein condensation with non-zero interatomic interactions theoretically. The analysis relies on a semiclassical Hartree-Fock approximation where an integral is performed over the phase space and function of the grand canonical ensemble is derived. Subsequently, we use this result to derive several thermodynamic quantities including the condensate fraction, critical temperature, entropy and heat capacity. Thereby, we investigate the effect of the rotation rate and interactions parameter on the thermodynamic behavior. The role of finite size is discussed. Our approach can be extended to consider the rotating condensate in optical potential.

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Condensed Fraction of an Atomic Bose Gas Induced by Critical Correlations

Cited by 30 publications

References 38 publications

Critical Temperature of Interacting Bose Gases in Periodic Potentials

Critical Temperature of Interacting Bose Gases in Periodic Potentials

Effect of impurities on the transition temperature of a dilute dipolar trapped Bose gas

Semiclassical Hartree-Fock theory of a rotating Bose-Einstein condensation

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