Interacting Atoms in an Optical Lattice

This project involves a series of experiments with interacting cold atoms in far-off-resonance optical lattices. Arrays of coupled and independent one-dimensional (1D) gases of bosons will be prepared and studied to help resolve some outstanding mysteries of quantum statistical mechanics and quantum phase transitions. Prior experiments by the group have explored the physics of Bose-gases in one dimension, demonstrating that these gases never thermalize. In order to explore the crossover between one-dimensional and three-dimensional behavior, new experiments will relax the conditions that make 1D atomic gases not thermalize, and will apply new tools to measuring the onset of thermalization. In particular, a low energy 1D atom collider will be developed. These experiments will address a long open theoretical question of the existence of a threshold for chaos in a many-body quantum system, as there is in classical mechanics. This project may clarify how irreversibility of macroscopic behavior arises from the reversible behavior of individual atoms. In addition, 1D gas momentum distributions will be measured for the first time, and two-dimensional (2D) gases with variable interactions will be studied.

The broader impact of this work lies in the ability of cold-atom experiments to provide answers to long-open questions in nonlinear dynamics and mathematical physics. These experiments will train undergraduate, graduate, and postdoctoral researchers in this technologically-important area of physics.