Interacting atoms in optical lattices

This project involves a series of experiments with interacting cold atoms in far-off-resonance optical lattices. Arrays of coupled and independent one-dimensional 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 this group have explored the physics of Bose-gases in one dimension, demonstrating that these gases never thermalize. New experiments will relax the one-dimensional confinement of atoms in several ways and explore the crossover between one-dimensional and three-dimensional behavior. 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. Additionally the research will involve studies of arrays of coupled one-dimensional gases, an analog of Josephson junction arrays. Various phase transitions and dimensional crossovers will be studied with a high degree of control, allowing them to serve as models for a wide range of phenomena observed in more complicated systems.

The broader impacts of these experiments lie in the ability of cold-atom experiments to provide answers to long-open questions in nonlinear dynamics and mathematical physics. The research project will also improve the technology for creation and manipulation of Bose-Einstein Condensates with all-optical techniques. They will train undergraduate, graduate, and postdoctoral researchers in technologically important areas of physics.