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In this work, we describe the dynamics of a Bose-Einstein condensate interacting with a degenerate Fermi gas, at zero temperature. First, we analyze the mean-field approximation of the many-body Schr\"odinger dynamics and prove emergence of…

Mathematical Physics · Physics 2025-07-04 Esteban Cárdenas , Joseph K. Miller , Nataša Pavlović

In this work, improvements are introduced to the current models of the ideal Fermi gas and the ideal Bose gas by incorporating the quantum nature of phase space, which is directly linked to the uncertainty principle. These improved models…

Phase correlations, density fluctuations and three-body loss rates are relevant for many experiments in quasi one-dimensional geometries. Extended mean-field theory is used to evaluate correlation functions up to third order for a quasi…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 M. Eckart , R. Walser , W. P. Schleich

We present a general framework in which we can accurately describe the non-equilibrium dynamics of trapped atomic gases. This is achieved by deriving a single Fokker-Planck equation for the gas. In this way we are able to discuss not only…

Statistical Mechanics · Physics 2007-05-23 H. T. C. Stoof

Open quantum systems theory is central to describing the dynamics and equilibration of dilute-gas Bose-Einstein condensates (BECs). We present an analysis of the linearized stochastic projected Gross-Pitaevskii equation (SPGPE) describing…

Quantum Gases · Physics 2025-09-11 Nils A. Krause , Ashton S. Bradley

The mean field approximation is numerically validated in the bosonic case by considering the time evolution of quantum states and their associated reduced density matrices by many-body Schr\"odinger dynamics. The model phase-space is…

Mathematical Physics · Physics 2015-08-04 Boris Pawilowski

We study an ultracold gas of neutral atoms subject to the periodic optical potential generated by a high-$Q$ cavity mode. In the limit of very low temperatures, cavity field and atomic dynamics require a quantum description. Starting from a…

Quantum Physics · Physics 2008-02-15 Christoph Maschler , Igor B. Mekhov , Helmut Ritsch

We use the quantum kinetic theory to calculate the steady state and the fluctuations of a trapped Bose-Einstein condensate at finite temperature. The system is divided in a condensate and a non-condensate part. A quantum mechanical…

Statistical Mechanics · Physics 2009-10-30 D. Jaksch , C. W. Gardiner , K. M. Gheri , P. Zoller

Sympathetic cooling of an atomic Fermi gas by a Bose gas is studied by solution of the coupled quantum Boltzmann equations for the confined gas mixture. Results for equilibrium temperatures and relaxation dynamics are presented, and some…

Quantum Physics · Physics 2009-10-31 W. Geist , L. You , T. A. B. Kennedy

Stochastic field equations represent a powerful tool to describe the thermal state of a trapped Bose gas. Often, such approaches are confronted with the old problem of an ultraviolet catastrophe, which demands a cutoff at high energies. In…

Statistical Mechanics · Physics 2015-05-20 S. Heller , W. T. Strunz

We investigate the real-time evolution of lattice bosons in two spatial dimensions whose dynamics is governed by a Markovian quantum master equation. We employ the Wigner-Weyl phase space quantization and derive the functional integral for…

Quantum Gases · Physics 2016-12-19 Florian Hebenstreit

We calculate analytically the quantum and thermal fluctuations corrections of a dilute quasi-two-dimensional Bose-condensed dipolar gas. We show that these fluctuations may change their character from repulsion to attraction in the…

Quantum Gases · Physics 2019-09-18 Abdelaali Boudjemaa

A model for studying atomtronic devices and circuits based on finite temperature Bose-condensed gases is presented. The approach involves numerically solving equations of motion for atomic populations and coherences, derived using the…

Atomic Physics · Physics 2016-08-29 Weng W. Chow , Cameron J. E. Straatsma , Dana Z. Anderson

We analyze the equilibrium properties of a weakly interacting, trapped quasi-one-dimensional Bose gas at finite temperatures and compare different theoretical approaches. We focus in particular on two stochastic theories: a…

Quantum Gases · Physics 2015-03-17 S. P. Cockburn , A. Negretti , N. P. Proukakis , C. Henkel

We study thermodynamic properties of weakly interacting Bose gases above the transition temperature of Bose-Einstein condensation in the framework of a thermodynamic perturbation theory. Cases of local and non-local interactions between…

Quantum Gases · Physics 2021-02-05 M. S. Bulakhov , A. S. Peletminskii , Yu. V. Slyusarenko , A. G. Sotnikov

We investigate the number fluctuations in small cells of quantum gases pointing out important deviations from the thermodynamic limit fixed by the isothermal compressibility. Both quantum and thermal fluctuations in weakly as well as highly…

Quantum Gases · Physics 2011-09-30 M. Klawunn , A. Recati , L. P. Pitaevskii , S. Stringari

The mean-field Gross-Pitaevskii equation with repulsive interactions exhibits frictionless flow when stirred by an obstacle below a critical velocity. Here we go beyond the mean-field approximation to examine the influence of quantum…

Quantum Gases · Physics 2021-05-06 Chao Feng , Matthew J. Davis

We present a new exact method to numerically compute the thermodynamical properties of an interacting Bose gas in the canonical ensemble. As in our previous paper (Phys. Rev. A, 63 023606 (2001)), we write the density operator $\rho$ as an…

Soft Condensed Matter · Physics 2009-11-07 Iacopo Carusotto , Yvan Castin

This study utilizes the Cornwall-Jackiw-Tomboulis effective action approach combined with variational perturbation theory to investigate the relative shift in the transition temperature of a homogeneous, repulsive, weakly interacting Bose…

Quantum Gases · Physics 2026-05-12 Nguyen Van Thu , Pham Duy Thanh , Lo Thi Thuy

The burgeoning field of Bose-Einstein condensation in dilute alkali and hydrogen gases has stimulated a great deal of research into the statistical physics of weakly interacting quantum degenerate systems. The recent experiments offer the…

Condensed Matter · Physics 2009-10-31 J. E. Williams , M. J. Holland