Quantum Optics Seminar by Yong P. Chen

Quantum synthesis and quantum transport in an optically dressed atomic BEC

In this talk, I will describe our recent experiments (at Purdue) in a Bose-Einstein condensate (BEC) of ultracold (87Rb) atoms subject to optically-generated “synthetic” spin-orbit coupling (SOC), a powerful platform for making and manipulating quantum matter where we have focused on quantum transport and quantum chemistry. We have demonstrated a new approach of quantum control of (photo) chemical reactions (photoassociation of molecules from atoms) --- a “quantum chemistry interferometry” --- by preparing reactants in (spin) quantum superposition states and interfering multiple reaction pathways [1]. By performing a “quantum quench” in a SOC BEC, we induce head-on collisions between two spinor BECs and study spin transport and how it is affected by SOC, revealing rich phenomena arising from the interplay between quantum interference and many-body interactions [2]. We have further realized a (bosonic) topological state with band crossings protected by nonsymmorphic symmetry [3], by creating a “synthetic” cylinder with combined physical and synthetic dimensions and also a synthetic radial magnetic flux, where the BEC acquires an emergent crystalline order and exhibits quantum transport (Bloch oscillations) mimicking motion on a Mobius strip in energy-momentum space (band structure).  Our experimental system can be a rich playground to study physics of interests to AMO physics, quantum chemistry, condensed matter physics, and even high energy physics and cosmology.  In the end of the talk I will describe some new research directions related to light-matter interactions in a new Villum program on hybrid quantum materials and devices that I am starting at Aarhus University this coming year. 

Refs:[1] D. Blasing et al., “Observation of Quantum Interference and Coherent Control in a Photo-Chemical Reaction”, Phys. Rev. Lett. 121, 073202 (2018)

[2] C. Li et al., “Spin Current Generation and Relaxation in a Quenched Spin-Orbit Coupled Bose-Einstein Condensate”, Nature Communications 10, 375 (2019)

[3] C. Li et al., “A Bose-Einstein Condensate on a Synthetic Hall Cylinder”, arXiv: 1809.02122