We study the stability of a Bose condensate of atomic 7 Li in a (harmonic oscillator) magnetic trap at non-zero temperatures. In analogy to the stability criterion for a neutron star, we conjecture that the gas becomes unstable if the free energy as a function of the central density of the cloud has a local extremum which conserves the number of particles. Moreover, we show that the number of c...

We have developed an evaporative cooling technique that accelerates the rotation of an ultracold 87Rb gas, confined in a static harmonic potential. As a normal gas is evaporatively spun up and cooled below quantum degeneracy, it is found to nucleate vorticity in a Bose-Einstein condensate. Measurements of the condensate's aspect ratio and surface-wave excitations are consistent with effective r...

We have observed Bose-Einstein condensation of pairs of fermionic atoms in an ultracold 6Li gas at magnetic fields above a Feshbach resonance, where no stable 6Li2 molecules would exist in vacuum. We accurately determined the position of the resonance to be 822+/-3 G. Molecular Bose-Einstein condensates were detected after a fast magnetic field ramp, which transferred pairs of atoms at close di...

We describe the properties of mixtures composed by potassium and rubidium atoms, simultaneously trapped in a magnetic potential. Potassium isotopes are cooled down to quantum degeneracy by means of sympathetic cooling with rubidium [1]. We can produce both a two-species Bose-Einstein condensate [2] mixing together Rb and K, and a degenerate system composed by a Fermi gas of K atoms and a Bose-E...

We propose an explanation of the phenomena of Bose Novae, the controlled collapse of a Bose-Einstein condensate described in the experiment of Donley et al [1], as a consequence of the squeezing and amplification of the quantum fluctuations above the condensate by the condensate dynamics. In analyzing the changing amplitude and particle contents of these excitations, our simple physical picture...

Phenomena associated with the controlled collapse of a Bose-Einstein condensate described in the experiment of Donley et al [1] are explained here as a consequence of the squeezing and amplification of quantum fluctuations above the condensate by the condensate dynamics. In analyzing the changing amplitude and particle contents of these excitations, our simple physical picture provides excellen...

We propose that the exciton condensate may form in a well-controlled way in appropriately arranged semiconductor quantum well structures. The mean-field theory of Keldysh and Kopaev, exact in both the high density and the low density limits, is solved numerically to illustrate our proposal. The electron-hole pairing gap and the excitation spectrum of the exciton condensate are obtained. The ene...

in this contribution, two approaches are followed to predict the saturated liquid density of liquefied natural gas (lng) mixtures. in one approach, 12 cubic equations of state (eoss), comprising the popular peng-robinson (pr) and redlich-kwong-soave (rks), are employed to predict the saturated liquid density of 20 lng mixtures. in the other approach, these eos are used in conjunction with a rec...