# CField Theory

Quantum many body systems relevant for ultra-cold gases have vast Hilbert spaces making exact quantum dynamics infeasible. We have developed practical methods for describing high-temperature Bose gases. These c-field methods are able to describe quantum dynamics of $10^6$ atoms at temperatures ranging from $\sim T_c$ down to well below the transition temperature. The theory allows description of Kibble-Zurek physics and rich dynamics of quantum quenches trapping vortices and other topological excitations including dark solitons.

Ultra-cold gases are, of course, rather susceptible the thermal energy, necessitating a detailed quantitative theoretical treatment of reservoir interactions. We have developed new methods for describing reservoir interactions for spinor gases and matter-waves systems confined to reduced dimension. Dissipation is crucial for understanding dynamics of vortices, solitons, and collective modes in experiments.