Ultracold Gases

Ultracold gases are a relatively young field in atomic and molecular physics. They became world wide known after the achievement of Bose-Einstein condensation in 1995 (see Nobel Prize in Physics in 2001). In more recent years, these systems have attracted a great deal of attention in other areas in physics, such as condensed matter physics, nuclear physics, and quantum information. This is because of the high degree of control and tunability that can be achieved experimentally. Remarkably, experimentalists can make use of Feshbach resonances to tune the interaction strength between atoms and decide whether it should be attractive or repulsive. The addition of optical potentials, like optical lattices, also allow then to play with the interaction strength and the effective dimensionality of the system. As a matter of fact, ultracold gases allow physicists to create experimental realizations of model Hamiltonians that are used in condensed matter physics to understand the properties of real materials.

At Georgetown, we are mainly interested in understanding the equilibrium and nonequilibrium properties of ultracold gases when they are loaded in optical lattices. The study of the nonequilibrium dynamics of nearly isolated quantum systems is another of the unique possibilities opened by experiments on this field. In equilibrium, we study bosons, fermions, and their mixtures, which enable the realization of many exotic quantum phases of matter. We also investigate pattern formation in mixtures of different mass atoms, with possible applications to cooling within a lattice.

Jim Freericks — strongly correlated electrons (charge and thermal transport and nonequilibrium effects), transport in multilayered nanostructures, resonant inelastic X-ray scattering, ultracold atoms in optical lattices (especially mixtures, dipolar molecules, and the Hubbard model) undergraduate understanding of quantum mechanics, student satisfaction with the major.