We describe several experimental studies of Bose-Einstein condensation in a dilute gas of sodium atoms. These include studies of static and dynamic behavior of the condensate, and of its coherence properties.

2 Regimes of 1D gases 2 2.1 Strongly versus weakly interacting regimes . . . . . . . . . . . . . . . . . . . . 4 2.2 Nearly ideal gas regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Quasi-condensate regime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3.1 Density fluctuations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.3.2 Phase fluc...

In this letter we discuss the relevance of the 3D Perfect Bose gas (PBG) condensation in extremely elongated vessels for the study of anisotropic condensate coherence and the “quasi-condensate”. To this end we analyze the case of exponentially anisotropic (van den Berg) boxes, when there are two critical densities ρc < ρm for a generalised Bose-Einstein Condensation (BEC). Here ρc is the standa...

We find that the key features of the evolution and collapse of a trapped Bose condensate with negative scattering length are predetermined by the particle flux from the non-equilibrium above-condensate cloud to the condensate and by 3-body recombination of Bose-condensed atoms. The collapse, starting once the number of Bose-condensed atoms N 0 reaches the critical value, ceases and turns to exp...

Obtaining samples that represent original fluid of reservoirs optimizes reservoirs management. The optimized management increases recovery. Also, selecting and performing proper Improved Oil Recovery (IOR) or Enhance Oil Recovery (EOR) programs depend on collecting representative samples. Achieving accurate compositions of original in-situ fluid prevents overdesigning surface facilities. Re...

The presence of exciton phonon interactions is shown to play a key role in the exciton superfluidity. We apply the Landau criterion for an exciton-phonon condensate moving uniformly at zero temperature. It turns out that there are essentially two critical velocities in the theory. Within the range of these velocities the condensate can exist only as a bright soliton. The excitation spectrum and...

The coherent and collective nature of Bose-Einstein condensate can enhance or suppress physical processes. Bosonic stimulation enhances scattering in already occupied states which leads to atom amplification, and the suppression of dissipation leads to superfluidity. In this paper, we review several experiments where suppression and enhancement have been observed and discuss the common roots of...

in this work, studies of underground gas storage (ugs) were performed on a partially depleted, naturally fractured gas reservoir through compositional simulation. reservoir dynamic model was calibrated by history matching of about 20 years of researvoir production. effects of fracture parameters, i.e. fracture shape factor, fracture permeability and porosity were studied. results showed that di...

Theoretically, a uniform, interacting, Bose gas in two dimensions is known to undergo a phase transition from a non-superfluid to a superfluid at a non-zero temperture TBKT. This Berezinski-Kosterlitz-Thouless transition occurs in a gas, a quasi-condensate without long-range order, and results in a first-order (field-field) correlation function that decays to zero at large separation only as a ...