Anomalous density for Bose gases at finite temperature

Boudjemâa, Abdelâali; Benarous, M.

doi:10.1103/physreva.84.043633

Cited by 37 publications

(109 citation statements)

References 77 publications

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“…This pairing phase is similar to the BCS phase in superconductors at low temperature proposed by Evans and Imry [22] a long time ago. In addition, it has been argued that the anomalous density accompanies in an analogous manner the condensate: they both arise from the gauge symmetry breaking [23,24]. If the condensate density is nonzero, the anomalous average is also finite.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…First of all, the anomalous phase is usually of the order of or even larger than the noncondensed density [23][24][25][26][27][28][29][30]. So, the exclusion of such a quantity is indeed an unjustified approximation and may render the system unstable [23,24]. Moreover, the absence of the anomalous density prevents the occurrence of the superfluidity in Bose gases [21,24,28,29], which is natural since both quantities arise from atomic correlations.…”

Section: Introductionmentioning

confidence: 99%

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Collective modes of a one-dimensional trapped Bose gas in the presence of the anomalous density

Boudjemâa

2016

Phys. Rev. A

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We study the collective modes of a one-dimensional (1D) harmonically trapped Bose-Einstein condensate (BEC) in the presence of the anomalous density using the time-dependent-Hartree-FockBogoliubov (TDHFB) theory. Within the hydrodynamic equations, we derive analytical expressions for the mode frequencies and the density fluctuations of the anomalous density which constitutes the minority component at very low temperature and feels an effective external potential exerted by the majority component i.e. the condensate. On the other hand, we numerically examine the temperature dependence of the breathing mode oscillations of the condensate at finite temperature in the weak-coupling regime. At zero temperature, we compare our predictions with available experimental data, theoretical treatments and Monte carlo simulations in all interaction regimes and the remaining hindrances are emphasized. We show that the anomalous correlations have a non-negligible role on the collective modes at both zero and finite temperatures.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Collective modes of a one-dimensional trapped Bose gas in the presence of the anomalous density

Boudjemâa

2016

Phys. Rev. A

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“…In order to apprehend better this coupling and to understand the role of the anomalous density, we extended the formalism to the non-local case [4,5], thus obtaining an intrinsic dynamics of the thermal cloud and the anomalous average which has never been written down before (an exception is perhaps the paper of Chernyak et al [6] which discusses a somewhat similar set of equations using the generalized coherent state representation). We focused in these last two papers on the anomalous density owing to its importance to account for many-body effects.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper, we would like to go beyond the approximations discussed in [4,5] by explicitely taking into account the high lying modes. This will obviously lead to self-consistent equations exhibiting UV divergences that have to be regularized.…”

Section: Introductionmentioning

confidence: 99%

Anomalous effects in a trapped Bose-Einstein condensate

Benarous

2013

Eur. Phys. J. D

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We study the anomalous density in an ultra-cold trapped bose gas in a variational framework, for both zero and finite temperature. We show that it is finite in 1D, while it is logarithmically and linearly divergent in 2D and 3D. The renormalization that we adopt is more reliable and compatible with the variational scheme. The main outcome is that the anomalous and non condensate densities are of the same order of magnitude and should therefore be treated on an equal footing.

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Superfluidity and Bose–Einstein Condensation in a Dipolar Bose Gas with Weak Disorder

Boudjemâa

2015

J Low Temp Phys

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We investigate the properties of a three-dimensional homogeneous dipolar Bose gas in a weak random potential with a Gaussian correlation function at finite temperature. Using the Bogoliubov theory (beyond the mean field), we calculate the superfluid and the condensate fractions in terms of the interaction strength on the one hand and in terms of the width and the strength of the disorder on the other. The influence of the disordered potential on the second-order correlation function, the ground state energy, and the chemical potential is also analyzed. We find that for fixed strength and correlation length of the disorder potential, the dipole-dipole interaction leads to modify both the condensate and the superfluid fractions. We show that for a strong disorder strength the condensed fraction becomes larger than the superfluid fraction. We discuss the effect of the trapping potential on a disordered dipolar Bose in the regime of large number of particles.

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Anomalous density for Bose gases at finite temperature

Cited by 37 publications

References 77 publications

Collective modes of a one-dimensional trapped Bose gas in the presence of the anomalous density

Collective modes of a one-dimensional trapped Bose gas in the presence of the anomalous density

Anomalous effects in a trapped Bose-Einstein condensate

Superfluidity and Bose–Einstein Condensation in a Dipolar Bose Gas with Weak Disorder

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