Ideal superfluidity is a quantum state of matter whereby fluid motion occurs without viscousity, allowing persistent currents to flow essentially indefinitely. Superfluids can also support long-lived coherent excitations such as vortices and solitons that contain angular and linear momentum respectively. An essential element of atomic gas superfluids is the presence of a thermal fraction of the gas that fundamentally alters the superfluid motion, especially for systems far from equilibrium, or near a critical point.
Classical field methods offer a powerful theoretical approach for handling the dynamics of superfluids at high temperature. A very wide range of non-equilibrium superfluid phenomena are tractable within this framework, including the Bose-Einstein condensation transition. The interplay between thermal fluctuations, quantum viscousity, and interparticle interactions provides a rich setting for the study of emergent phenomena in dynamical superfluidity, and for the accurate modeling of current experiments.
We are currently focused on three main areas:
- Two dimensional quantum turbulence. -Quantum vortices in two dimensional superfluids offer a new window into the complex phenomena of turbulence.
- Decay of superfluid excitations. - Nonlinear excitations such as vortices and solitons offer new insights into the dissipative behavior of superfluids.
- Generalized C-field theory. -The C-field theory can be generalized to more complex systems such as spinor condensates with additional degrees of freedom.