Our research focuses on building exotic quantum systems with strongly interacting quantum matter and light.

Current work focuses on two primary experiments:

Rydberg-dressed cavity polaritons. In this experiment, we are integrating quantum-gas microscopy techniques for ultracold Rydberg atoms with high-finesse small-mode volume optical cavities. The competition between global cavity-mediated spin-exchange interactions and local Rydberg Ising term creates new quantum “gauged” materials, in which novel physical phenomena (topological quantum spin liquids and spin ices, string-net and gauge color condensations) are expected to emerge. This experimental program (spanning four optical tables with more than 30 ultrastable phase-coherent lasers,  3 UHV chambers, and a few thousands of optical elements) represents one of the most complex AMO efforts that cold atom physicists have embarked on. We have developed novel methods for stray field compensation and cancellation, novel thin-film deposition techniques, portable molecular optical clock, laser stabilization and control, and XHV vacuum technologies, in order to advance the frontiers of optical metrologies, quantum gases, and cavity QED to a new level. The emphasis on this project will be upon open quantum system dynamics of dipolar interacting, driven Rydberg gases in an optical cavity in the strong coupling regime. We envision that the Rydberg polariton lattice system will be a promising platform for emulating quantum systems in the quest for better understanding of strongly correlated quantum materials as well as the search for new physics in interacting spin systems.

Waveguide QED with neutral atoms. Photonic crystals represent an important class of distributed Bragg devices at the nanoscale. By trapping single atoms in these crystals, we plan to realize a “waveguide” QED system, where the intricate interplay of the atomic internal and external degrees of freedom and photonic excitations dominates over dissipative rates. Beyond the standard approach of reaching the strong coupling in the optical domain, atoms strongly coupled to waveguide can completely renormalize the passive dielectric structure, creating atom-field bound states that could mediate novel quantum Hamiltonians. In fact, with proper quantum controls, our waveguide QED platform could realize universal Hamiltonians, e.g., to create topological spin liquids for the manipulation of (Abelian and non-Abelian) anyons, and to generate dynamical gauge structures at will for exploration of the roles of quantum entanglement and information scrambling in emergent holographic quantum gravity models.

Theoretical quantum optics.
1. Quantum entanglement in topological systems
2. Quantum phase transition and quantum critical behaviors in many-body systems
3. Manipulation and control of quantum systems with driven-dissipative processes, quantum-reservoir engineering
4. Non-equilibrium quantum thermodynamics
5. Condensed matter models with waveguide and many-body QEDs.
Emergence of entanglement in low-dimensional interacting spin systems
6. Control of quantum vacuum near dielectric surfaces