We report on the study of the momentum distribution of a one-dimensional Bose gas in an optical lattice. From the momentum distribution we extract the condensed fraction of the gas and thereby measure the depletion of the condensate and compare it with a theorical estimate. We have measured the coherence length of the gas for systems with average occupation n̄ > 1 and n̄ < 1 per lattice site. 1 T...

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 population of non-condensate states is provided by quantum depletion of a condensate caused by interatomic repulsion. Since the most reliable methods of diag...

We present experimental results on turbulence generated in thin fluid layers in the presence of a large-scale coherent flow, or a spectral condensate. It is shown that the condensate modifies the third-order velocity moment in a much wider interval of scales than the second one. The modification may include the change of sign of the third moment in the inverse cascade. This observation may help...

The problems of gas-condensate PVT-models (Pressure Volume Temperature, PVT) creation under limited input information were analyzed. Traditional fluid phase behavior characterization approach relies on the equation state (EOS) based initial composition reservoir and its future regression for critical parameters (pressure temperature), binary interaction coefficients, acentric factors residual “...

The cubic nonlinear Schrödinger equation with repulsive nonlinearity and elliptic function potential in two-dimensions models a repulsive dilute gas Bose–Einstein condensate in a lattice potential. A family of exact stationary solutions is presented and its stability is examined using analytical and numerical methods. All stable trivial-phase solutions are off-set from the zero level. Our resul...

We discuss the atom-atom scattering problem across a Feshbach resonance in a two-dimensional dilute Bose gas at zero temperature, in the limit where the s-wave scattering length exceeds the width of the vertical confinement. We determine a tunable coupling-strength parameter and by controlling it we evaluate how the condensate wave function spreads out with increasing atom-atom repulsions. We a...

Bose-Einstein condensation (BEG) of atoms with attractive mteractions i:< profoundly different from BEC of atoms with repulsive interactions. \Ye describe expenments with Bose condensates of 'Li atoms ..•...hich are weakJy attracting at uJ· tralaw temperature. We measure the distribution of condensate occupation numbers occurring in the gas using a near-resonant optical probe to image the atom ...