Artem M. Dudarev

Compression of Atomic Phase Space Using an Asymmetric One-Way Barrier

We show how to construct asymmetric optical barriers for atoms. These barriers can be used to compress phase-space of a sample by creating a confined region in space where atoms can accumulate with heating at the single photon recoil level. We illustrate our method with a simple two-level model and then show how it can be applied to more realistic multilevel atoms.

FM spectroscopy in recoil-induced resonances

We report on an experimental study of recoil-induced resonances as a method of velocimetry for cold atomic samples. We present a refined experimental method that greatly improves the sensitivity of the measurement over previous experiments. Using frequency-modulation (FM) spectroscopy techniques we achieve a sensitivity that approaches the shot noise limit. In addition, we present a novel approach to deriving the line shape of the observed signal, based on the concept of quantum transport and tunnelling in motional Bloch bands.

Statistical mechanics of an optical phase space compressor

We describe the statistical mechanics of a new method to produce very cold atoms or molecules. The method results from trapping a gas in a potential well, and sweeping through the well a semi-permeable barrier, one that allows particles to leave but not to return. If the sweep is sufficiently slow, all the particles trapped in the well compress into a very cold gas. We derive analytical expressions for the velocity distribution of particles in the cold gas, compare these results with numerical simulations, and discuss limitations on reduction in energy due to imperfections of the barrier.

The dynamical generation of two-dimensional matter-wave discrete solitons

We suggest a method to experimentally obtain two-dimensional matter-wave discrete solitons with a self-repulsive Bose–Einstein condensate in optical lattices. At the edge of the Brillouin zone, a wavepacket effective mass is negative, which could be treated as an inversion of the nonlinearity sign. Above critical nonlinearity this makes the wavepackets collapse partially into localized modes with a chemical potential located in the gap between the first and the second bands. This critical nonlinearity is also associated with the smallest nonlinearity for which the discrete solitons are possible in the gap. Extensive numerical simulations for square and asymmetric honeycomb lattices in the continuous model illustrate every stage of the process.