D. S. Petrov

Weakly Bound Dimers of Fermionic Atoms

We discuss the behavior of weakly bound bosonic dimers formed in a two-component cold Fermi gas at a large positive scattering length a for the interspecies interaction. We find the exact solution for the dimer-dimer elastic scattering and obtain a strong decrease of their collisional relaxation and decay with increasing a. The large ratio of the elastic to inelastic rate is promising for achieving Bose-Einstein condensation of the dimers and cooling the condensed gas to very low temperatures.

Regimes of quantum degeneracy in trapped 1D gases

We discuss the regimes of quantum degeneracy in a trapped 1D gas and obtain the diagram of states. Three regimes have been identified: the Bose-Einstein condensation (BEC) regimes of a true condensate and quasicondensate, and the regime of a trapped Tonks gas (gas of impenetrable bosons). The presence of a sharp crossover to the BEC regime requires extremely small interaction between particles. We discuss how to distinguish between true and quasicondensates in phase coherence experiments.

Observation of Phase Fluctuations in Elongated Bose-Einstein Condensates

The occurrence of phase fluctuations due to thermal excitations in Bose-Einstein condensates (BECs) is studied for a variety of temperatures and trap geometries. We observe the statistical nature of the appearance of phase fluctuations and characterize the dependence of their average value on temperature, number of particles, and the trapping potential. We find pronounced phase fluctuations for condensates in very elongated traps in a broad temperature range. The results are of great importance for the realization of BEC in quasi-1D geometries, for matter wave interferometry with BECs, as well as for coherence properties of guided atom laser beams.

Interatomic collisions in a tightly confined Bose gas

We discuss binary atomic collisions in a Bose gas tightly confined in one (axial) direction and identify two regimes of scattering. In the quasi-two-dimensional (quasi-2D) regime, where the confinement frequency

Three-body problem in Fermi gases with short-range interparticle interaction

{\ensuremath{\omega}}_{0}

Three-Boson Problem near a Narrow Feshbach Resonance

greatly exceeds the gas temperature

Quantum Magnetism with Multicomponent Dipolar Molecules in an Optical Lattice

T,

Scattering properties of weakly bound dimers of fermionic atoms

the scattering rates exhibit 2D features of the particle motion. At temperatures

Phase-fluctuating 3D Bose-Einstein condensates in elongated traps.

T\ensuremath{\sim}\ensuremath{\Elzxh}{\ensuremath{\omega}}_{0}

Quantum Mechanical Stabilization of a Collapsing Bose-Bose Mixture.

one has a confinement-dominated 3D regime, where the confinement can change the momentum dependence of the scattering amplitudes. We describe the collision-induced energy exchange between the axial and radial degrees of freedom and analyze recent experiments on thermalization and spin-relaxation rates in a tightly (axially) confined gas of Cs atoms.