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Demonstrating that despite loss processes, Bose-Einstein condensates can be formed in steady state is a prerequisite for obtaining a coherent beam of atoms in a continuous-wave atom laser. In this paper we propose a method for loading atoms…

Quantum Physics · Physics 2009-11-06 Satyan Bhongale , Murray Holland

We investigate a temperature-based model, called extended two-temperature model (eTTM), that describes the electronic non-equilibrium and its effect on energy dissipation in metals after ultrashort laser excitation. We derive and discuss…

Materials Science · Physics 2023-08-03 Markus Uehlein , Sebastian T. Weber , Baerbel Rethfeld

We analyze the model of an atomic Bose-Einstein condensate (BEC) parametrically coupled to a molecular BEC via a photoassociation process. We show that an interplay of nonlinear inter- and intra-species interactions leads to the formation…

Condensed Matter · Physics 2021-05-26 Benedict J. Cusack , Tristram J. Alexander , Elena A. Ostrovskaya , Yuri S. Kivshar

Conventional gas-liquid phase transitions feature a coexistence line that has a monotonic and positive slope in line with our intuition that cooling always leads to condensation. Here we study the inverse phenomenon, condensation of…

Statistical Mechanics · Physics 2023-07-21 Joël A. K. L. Picard , T. Speck

A disordered version of the one dimensional asymmetric exclusion model where the particle hopping rates are quenched random variables is studied. The steady state is solved exactly by use of a matrix product. It is shown how the phenomenon…

Condensed Matter · Physics 2009-10-28 M. R. Evans

In the course of the analysis of the axiomatic principles underlying statistical physics, the assumption about the limited correctness of the postulate of equiprobability of all available microstates of a closed system was tested. Earlier,…

Statistical Mechanics · Physics 2021-08-03 Vladimir V. Savukov

Optical thermalization has been recently studied theoretically and experimentally in the 2D spatial evolution of (quasi-)monochromatic light waves propagating in multimode fibers. In this work, we investigate the spatio-temporal equilibrium…

We formulate a comprehensive theoretical description of excitation harvesting in molecular aggregates photoexcited by weak incoherent radiation. An efficient numerical scheme that respects the continuity equation for excitation fluxes is…

Chemical Physics · Physics 2021-01-01 Veljko Janković , Tomáš Mančal

We outline the general features of the conventional mean-field theory for the description of Bose-Einstein condensates at near zero temperatures. This approach, based on a phenomenological model, appears to give excellent agreement with…

Statistical Mechanics · Physics 2009-10-30 N. P. Proukakis , K. Burnett

The phase diffusion of the order parameter of trapped Bose-Einstein condensates at temperatures large compared to the mean trap frequency is determined, which gives the fundamental limit of the line-width of an atom laser. In addition a…

Condensed Matter · Physics 2009-10-31 Robert Graham

Phase transitions, where observable properties of a many-body system change discontinuously, can occur in both open and closed systems. Ultracold atoms have provided an exemplary model system to demonstrate the physics of closed-system…

The variational theory of equilibrium boson system state to have been previously developed by the author under the density matrix formalism is applicable for researching equilibrium states and thermodynamic properties of the quantum Bose…

General Physics · Physics 2014-12-19 Boris Bondarev

Bose-Einstein condensation happens as a gas of bosons is cooled below its transition temperature, and the ground state becomes macroscopically occupied. The phase transition occurs in the thermodynamic limit of many particles. However,…

Quantum Gases · Physics 2023-03-24 Fredrik Brange , Tuomas Pyhäranta , Eppu Heinonen , Kay Brandner , Christian Flindt

Exciton-polaritons in semiconductor microcavities have been used to demonstrate quantum effects such as Bose-Einstein condensation, superfluity, and quantized vortices. However, in these experiments, the polaritons have not reached thermal…

We present a simple non-equilibrium model of mass condensation with Lennard-Jones interactions between particles and the substrate. We show that when some number of particles is deposited onto the surface and the system is left to…

Statistical Mechanics · Physics 2015-09-22 Jeremi Kazimierz Ochab , Hannes Nagel , Wolfhard Janke , Bartlomiej Waclaw

Polariton condensates occur away from thermal equilibrium, in an open system where heat and particles are continually exchanged with reservoirs. These phenomena have been extensively analyzed in terms of kinetic equations. Based on the…

Quantum Physics · Physics 2024-10-08 Luisa Toledo Tude , Paul R. Eastham

Solid state quantum condensates often differ from previous examples of condensates (such as Helium, ultra-cold atomic gases, and superconductors) in that the quasiparticles condensing have relatively short lifetimes, and so as for lasers,…

Quantum Gases · Physics 2010-08-17 Jonathan Keeling , Marzena H. Szymanska , Peter B. Littlewood

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

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

We demonstrate that incoherent photon scattering by a Bose-Einstein condensate of non-ideal atomic gas is enhanced due to bosonic stimulation of spontaneous emission, similarly to coherent scattering in forward direction. Necessary initial…

Quantum Physics · Physics 2007-05-23 I. E. Mazets
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