Abstract
The development of modern atomic, molecular and optical (AMO) experiment techniques realizes the full quantum control over individual atoms, molecules and photons. With the additional versatile AMO toolbox for controlling particle interactions, interesting quantum phases of matter and their dynamics can be studied in a pristine environment.
In this seminar talk, I will first present my PhD work at University of Chicago for the first experimental realization of the quantum phase transition from an atomic Bose-Einstein condensate (BEC) to a g-wave molecular BEC near a narrow Feshbach resonance. Our work demonstrates the long-sought bosonic analogue of BEC-BCS (Bardeen-Cooper-Schrieffer) crossover in a degenerate Fermi gas. Later, we observe coherent and collective molecule formation dynamics by quenching an atomic BEC to unitary regime on the Feshbach resonance. This is the first experimental demonstration of “superchemistry” and offers a new paradigm for the control of quantum chemical reactions. Our further investigation based on a microscopic model reveals that one essential element behind the stability and dynamics in atom-molecule superfluids is the extremely narrow Feshbach resonance we use in 133Cs at 19.849 G. With additional momentum-resolved study of the non-condensed particles generated in the dynamics, a new type of universal behavior governed by the atom-molecule coupling strength manifests. This is in contrast with the previously found universal dynamics determined only by the particle density in a unitary Bose gas at a broad Feshbach resonance. I will also briefly discuss another series of my work demonstrating stimulated and coherent matter-wave generation in driven atomic condensates.
Finally I will introduce a new experimental system I constructed at Stanford University: a high-finesse multi-mode optical cavity coupled to a quantum gas of the most magnetic Dysprosium (Dy) atom. While this platform provides unique opportunities for studying novel many-body phases of matter, dynamics and feedback here at Stanford, I come up with other new research directions for my future career based on the same or variants of the Dy cavity QED experiment. These includes the exploration of ultracold photochemistry, scalable creation of holographic quantum matter and quantum enhanced Dy precision spectroscopy searching for possible variation of the fine structure constant and the associated ultralight bosonic dark matter detection.
Anyone interested is welcome to attend.