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We present a new method of calculating the distribution function and fluctuations for a Bose-Einstein condensate (BEC) of N interacting atoms. The present formulation combines our previous master equation and canonical ensemble…

Statistical Mechanics · Physics 2009-11-11 Anatoly A. Svidzinsky , Marlan O. Scully

We present a study of the effects of temperature upon the excitation frequencies of a Bose-Einstein condensate formed within a dilute gas with a weak attractive effective interaction between the atoms. We use the self-consistent…

Condensed Matter · Physics 2009-10-31 M. J. Davis , D. A. W. Hutchinson , E. Zaremba

This article gives a rigorous analysis of the fluctuations of the Bose-Einstein condensate for a system of non-interacting bosons in an arbitrary potential, assuming that the system is governed by the canonical ensemble. As a result of the…

Probability · Mathematics 2014-03-05 Sourav Chatterjee , Persi Diaconis

We optimize the classical field approximation of the version described in J. Phys. B 40, R1 (2007) for the oscillations of a Bose gas trapped in a harmonic potential at nonzero temperatures, as experimentally investigated by Jin et al.…

Quantum Gases · Physics 2010-03-31 Tomasz Karpiuk , Miroslaw Brewczyk , Mariusz Gajda , Kazimierz Rzazewski

We present a theory for the linear dynamics of a weakly interacting Bose gas confined inside a harmonic trap at finite temperature. The theory treats the motions of the condensate and of the non-condensate on an equal footing within a…

Statistical Mechanics · Physics 2007-05-23 Xia-Ji Liu , Hui Hu , A. Minguzzi , M. P. Tosi

Experimentally the temperature in a Bose--Einstein condensate is always deduced resorting to the comparison between the Maxwell--Boltzmann velocity distribution function and the density profile in momentum space. Though a successful method…

Statistical Mechanics · Physics 2008-09-10 Abel Camacho , Luis F. Barragan , Alfredo Macias

The surface mode spectrum is computed self-consistently for dilute Bose-Einstein condensates, providing the temperature dependence of the surface mode induced vortex nucleation frequency. Both the thermodynamic critical frequency for vortex…

Soft Condensed Matter · Physics 2008-07-10 T. P. Simula , S. M. M. Virtanen , M. M. Salomaa

By including the contribution of the thermal cloud to the Lagrangian of the condensate of a Bose gas, we extend the time-dependent variational method at zero temperature to study temperature-dependent low collective excitation modes. A…

Condensed Matter · Physics 2009-10-31 Hualin Shi , Wei-Mou Zheng

The dynamics of Bose-Einstein condensate (BEC) is studied at nonzero temperatures using our variational time-dependent-HFB formalism. We have shown that this approach is an efficient tool to study the expansion and collective excitations of…

Quantum Gases · Physics 2013-08-29 Abdelâali Boudjemâa

We calculate the breathing mode frequency $\omega$ in a one-dimensional Bose gas confined to a harmonic trap of frequency $\omega_z$. We predict Exciting temporal oscillations of the density distribution is a high-precision method for…

Quantum Gases · Physics 2015-08-12 A. Iu. Gudyma , G. E. Astrakharchik , Mikhail B. Zvonarev

We quantify the effect of phase fluctuations on atom chip interferometry of Bose-Einstein condensates. At very low temperatures, we observe small phase fluctuations, created by mean-field depletion, and a resonant production of vortices…

Other Condensed Matter · Physics 2015-05-13 R. G. Scott , D. A. W. Hutchinson , T. E. Judd , T. M. Fromhold

We develop a method for investigating nonequilibrium dynamics of an ultracold system that is initially at thermal equilibrium. Our procedure is based on the classical fields approximation with appropriately prepared initial state. As an…

Quantum Gases · Physics 2015-05-20 Emilia Witkowska , Tomasz Świsłocki , Michał Matuszewski

We study the effects of quantum and thermal fluctuations on Bose-Bose mixtures at finite temperature employing the time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory. The theory governs selfconsistently the motion of the condensates, the…

Quantum Gases · Physics 2018-04-05 Abdelaali Boudjemaa

The correlation function of the quantum fluctuations due to collective excitations is calculated and used to investigate the phase diffusion of a Bose-Einstein condensate close to zero temperature. It is shown that the phase diffusion time…

Soft Condensed Matter · Physics 2015-06-24 Hongwei Xiong , Shujuan Liu , Guoxiang Huang

A self-consistent field model for a mixture of Bose and Fermi particles is formulated. There is explored in detail the case of a delta-like interaction, for which the thermodynamic functions are obtained, and Bose-Einstein condensation of…

Quantum Gases · Physics 2017-10-31 Yu. M. Poluektov , A. A. Soroka

The mode structure of a Bose-Einstein condensate non-adiabatically loaded into a one-dimensional optical lattice is studied by analyzing the visibility of the interference pattern as well as the radial profile of the condensate after a…

Soft Condensed Matter · Physics 2009-11-07 O. Morsch , J. H. Müller , D. Ciampini , M. Cristiani , P. B. Blakie , C. J. Williams , P. S. Julienne , E. Arimondo

We investigate the effect of non-zero temperature to the condensate fraction of a homogeneous dilute weakly interacting Bose gas in very low-temperature region. Within inproved Hartree-Fock approximation, the Cornwall-Jackiw-Tomboulis…

Quantum Gases · Physics 2023-12-15 Nguyen Van Thu , Pham Duy Thanh

We determine the leading shift of the Bose-Einstein condensation temperature for an ultracold dilute atomic gas in a harmonic trap due to weak disorder by treating both a Gaussian and a Lorentzian spatial correlation for the quenched…

Disordered Systems and Neural Networks · Physics 2009-11-11 Matthias Timmer , Axel Pelster , Robert Graham

We study the dynamics of vortices in finite temperature atomic Bose-Einstein condensates, focussing on decay rates, precession frequencies and core brightness, motivated by a recent experiment (Freilich et al. Science 329, 1182 (2010)) in…

Quantum Gases · Physics 2013-01-30 A. J. Allen , E. Zaremba , C. F. Barenghi , N. P. Proukakis

We derive the finite temperature oscillation modes of a harmonically confined Bose-Einstein condensed gas undergoing rigid body rotation supported by a vortex lattice in the condensate. The hydrodynamic modes separate into two classes…

Soft Condensed Matter · Physics 2009-11-10 Armen Sedrakian , Ira Wasserman