Transport Dynamics of Ultracold Atoms
Abstract
We propose a program of quantum simulation to improve foundational understanding of strongly correlated materials. Specifically, we will study the conductivity of ultracold fermionic potassium in an optical lattice. The high level of control and purity in our simulator will enable its comparison to first principles calculations, with the goal of developing theoretical paradigms of many-body dynamics and transport. Unique to our study is the direct measurement of conductivity spectra, an observable closely related to optical conductivity measurements of materials. Conductivity is a standard and useful properties of materials and yet is notoriously difficult to calculate. At the microscopic level, the transport of electrons through a crystalline solid describes out-of-equilibrium dynamics of quantum degenerate particles that interact with each other and with their environment. Interacting electrons have complex wave functions because of their fermionic nature. Microscopic electron dynamics are also challenging to capture in the laboratory, because the inherent timescales for the dynamics are fast (femtosecond-scale), and inherent length scales are small (sub-nanometer). This project will address many of these challenges by using a quantum simulator built from neutral atoms. The species of atom chosen, fermionic potassium, has a quantum character similar to that of electrons. These atoms will be confined in a crystalline potential of light, which emulates the ionic crystal of electronic materials, but magnified to a micron-scale lattice constant. Since the atoms are also a hundred thousand times more massive than electrons, the dynamics of this neutral-atom simulator can be captured on a camera using fluorescence imaging. Driving this system with a weak external potential (analogous to a voltage) and measuring its response enables simulation of the conductivity of complex electronic systems. The advantage of our approach is that nearly every aspect of the neutral-atom system can be controlled, tuned, and measured precisely. The sample is pure, and the optical lattice is defect-free. This scenario is ideal to advance our first-principles understanding of complex many-body dynamics and transport. The anticipated outcomes are both an exploration of new regimes, such as a saturation of conductivity at high temperature, and also the clean observation of iconic phenomena, such as diffractive effect of crystalline order on currents.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 06, 2025
- Source ID
- FA95502410331
Entities
People
- Joseph H. Thywissen
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Toronto