We study the motion of a heavy tracer particle weakly coupled to a dense, weakly interacting Bose gas exhibiting Bose-Einstein condensation. In the so-called mean-field limit, the dynamics of this system approaches one determined by nonlinear Hamiltonian evolution equations. We prove that if the initial speed of the tracer particle is above the speed of sound in the Bose gas, and for a suitable...

We derive the Joule expansion of an isolated perfect gas from the principles of quantum mechanics. Contrary to most studies of irreversible processes which consider composite systems, the interesting and ignored degrees of freedom are here described by operators acting in the same many-body Hilbert space. Moreover, the expansion of the gas into the entire accessible volume is obtained for pure ...

A granular clock is observed in a vertically vibrated compartmentalized granular gas composed of two types of grains with the same size. The dynamics of the clock is studied in terms of an unstable evaporation or condensation model for the granular gas. In this model, the temperatures of the two types of grains are considered to be different, and they are functions of the composition of the gas...

Exhaust gases from an internal combustion engine, alternatively powered by gasoline or by liquefied petroleum gas, were analysed for polynuclear aromatic hydrocarbons. The engine operated a lift truck for the handling of warehouse goods. A combined condensation-filtration apparatus was constructed for sampling of the exhausts. The basic steps of the analytical procedure are summarized here. Sev...

A Hartree-Fock mean-field theory of a weakly interacting Bose-gas in a quenched white noise disorder potential is presented. A direct continuous transition from the normal gas to a localized Bose-glass phase is found which has localized short-lived excitations with a gapless density of states and vanishing superfluid density. The critical temperature of this transition is as for an ideal gas un...

We propose two interferometric schemes to experimentally detect in real space the onset of pair condensation in a two-spin-component Fermi gas. Two atomic wave packets are coherently extracted from the gas at different positions and are mixed by a matter-wave beam splitter: we show that the spatial long-range order of the atomic pairs in the gas reflects in the atom counting statistics in the b...

We have measured the critical atom number in a harmonically trapped two-dimensional (2D) Bose gas of rubidium atoms at different temperatures. We found this number to be about five times higher than predicted by the semi-classical theory of Bose-Einstein condensation (BEC) in the ideal gas. This demonstrates that the conventional BEC picture is inapplicable in an interacting 2D atomic gas, in s...

Using real-time simultaneous gas- and particle-phase data, the condensation of naphthalene ?-caryophyllene oxidation products on a molecular level is discussed.

Bose–Einstein condensation is the anomalous accumulation of particles in the ground state of a system of bosons, when compared with the population in a system of particles obeying classical statistics. I use undergraduate-level statistical mechanics and a symbolic algebra computer program to study the occupation numbers of the energy levels of a finite number of noninteracting particles confine...

We report on the achieving of Bose-Einstein condensation of a dilute atomic gas based on trapping atoms in tightly confining CO2-laser dipole potentials. Quantum degeneracy of rubidium atoms is reached by direct evaporative cooling in both crossed and single beam trapping geometries. At the heart of these alloptical condensation experiments is the ability to obtain high initial atomic densities...