Large and ultra-flat optical traps for uniform quantum gases

Abstract

Abstract Ultracold atomic gases with uniform density can be created by flat-bottom optical traps. These gases provide an ideal platform to study many-body physics in a system that allows for simple connections with theoretical models and emulation of numerous effects from a wide range of fields of physics. In Earth-bound laboratories the trap sizes, number of species and states, as well as the range of physical effects are largely restricted by the adopted levitation technique. Homogeneous ultracold gases in microgravity simulators and space however offer an interesting perspective which is actively being pursued. To effectively make use of a gravity-compensated laboratory, realizing box potentials with large spatial extent enables access to previously inaccessible length scales and reduce finite-size and boundary effects. We present an approach based on two identical orthogonally aligned acousto-optic deflector setups to generate large time-averaged optical potentials with trapping volumes up to three orders of magnitude larger than conventional setups. These potentials follow power-law scalings with exponents of up to 152. We characterize the system and validate its performance through simulations of the mean-field ground state of a quantum gas, including dynamical excitations arising from the realistic time-dependent painting potentials. The implementation of this setup may open new directions at the interface with condensed matter, few-body Efimov physics or the exploration of critical, non-equilibrium phenomena.