The developing field of ultracold atomic physics provides tantalizing opportunities for exploring physical phenomena in a regime that has heretofore been inaccessible: material systems with temperatures in the nanokelvin range (and below), with broadly and instantly tunable interactions, residing in dynamically adaptable containers, and amenable to the precise manipulation and detection tools of atomic physics. My research has focused on developing further capabilities in this field, and utilizing these advances to study many-body quantum physics, to explore the "coherent optics" and "quantum optics" of matter waves, to realize novel consequences of light-atom interactions, and to perform precision measurements of scientific and technological importance.
My present research proceeds in three directions. One focuses on creating and studying novel quantum fluids, and also in realizing model systems for the study of quantum magnetism. Here, we have developed a microscopy technique to directly image the magnetization of a spin-1 Bose gas. Using this technique, we have identified quantum phase transitions and instances of spontaneous symmetry breaking, characterized a near-quantum-limited parametric spin amplifier, uncovered dynamical signatures of long-range interactions, and observed equilibration and coarsening behavior in a ferromagnetic superfluid. We are also studying the impact of geometric frustration on orbital and spin physics of quantum systems, realized by confining cold atoms in a kagome-geometry lattice potential.
A second research direction focuses on the collective motion and spin dynamics of atoms trapped in optical resonators, using effects of cavity quantum electrodynamics (CQED) to measure quantum properties of matter-wave systems. We have contributed to the development of cavity optomechanics, making the first observations of ponderomotive squeezing and the quantization of collective motion of an atomic gas. Such advances relate to optomechanical detectors of gravity waves or other weak forces. The dynamics of atomic spins with resonators has allowed us to perform magnetic resonance imaging of a cold atomic gas with 100 nm spatial resolution.
Our third research effort is directed toward realizing atom interferometers capable of making precise measurements of scientific and/or technological importance. Here, we are studying ways to implement Sagnac interferometry in a cold-atoms-based gyroscope, making use of superfluid properties of the trapped gas.
My research agenda continues to evolve and to involve new students, postdocs, and visitors. If you are interested in our work, or interested in joining us, please contact us.
In the News
Berkeley Lab researchers have detected the smallest force ever measured – approximately 42 yoctonewtons – using a unique optical trapping system that provides ultracold atoms. A yoctonewton is one septillionth of a newton.
Berkeley Lab and UC Berkeley Researchers Record First Direct Observations of Quantum Effects in an Optomechanical System
Scientists with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley, using a unique optical trapping system that provides ensembles of ultracold atoms, have recorded the first direct observations of distinctly quantum optical effects – amplification and squeezing – in an optomechanical system.