Diffusion Dynamics in Disordered Quantum Lattices Gases

A key challenge to leveraging quantum phenomena as a foundation of next-generation technologies is understanding how the interplay of strong inter-particle interactions and disorder affects quantum behavior in materials. Strong interactions are an important ingredient to a wide range of remarkable phenomena, such as high-temperature superconductivity.

Disorder is inescapable in materials because of imperfections and contact with the environment. However, how interactions and disorder compete or cooperate to give rise to new and useful quantum states is not fully understood. This critical problem will be studied by using ultracold atoms trapped in a crystal formed from light as a model system.

Controlled and precisely known disorder will be applied by superimposing laser light consisting of randomly distributed bright and dark regions. The influence of interactions and disorder on particle-flow quantum dynamics will be studied. Knowledge gained from this work may lead to a better understanding of quantum materials and new approaches to enhance their performance.

The next generation of engineers and scientists will be trained on cutting-edge techniques in optical science, radio-frequency electronics, and advanced computer control and signaling.

This project builds on previous lattice experiments that discovered bosonic and fermionic quantum quench dynamics and localization using Rb-87 atoms and K-40 atoms. Three technical projects will be pursued. A modern computer control system robust to hardware and software obsolescence will be developed in partnership with a startup company, a high-resolution imaging system will be characterized and deployed, and a method for isolating a plane of atoms will be implemented.

Together with stimulated Raman transitions driven by tightly focused laser beams, these tools will be used to investigate diffusion dynamics in ultracold lattice gases. The impact of interactions and disorder on the diffusion constant for Rb-87 atoms will be measured for superfluid, Mott insulator, and Bose-glass states. An open-source repository of code for generating and manipulating ultracold lattice gases and to support external devices will be made available to the research community.

These studies will advance the state-of-the-art in disordered quantum gases, thus enabling new methods for attacking outstanding questions related to condensed matter physics and materials science and enhancing knowledge of strongly correlated quantum science.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.