About the event
The Department of Physics and Astronomy invites all to a colloquium featuring Dr. Yong Chen, Department of Physics and Astronomy Purdue University. Dr. Chen will present his talk, “Spin‐helical particles: an enabling platform for quantum matter and quantum technologies.”
Meet for refreshments before the lecture at 3:45 – 4:10 p.m. in the foyer on floor G above the lecture hall.
Abstract: Spin is one of the most fundamental quantum properties of particles. In this talk I will describe our experimental studies of spin‐helical” particles (analogous to neutrinos with spin locked to the momentum, but for electrons and atoms) as a powerful platform to realize novel quantum matter and enable new applications in quantum technologies ‐‐‐ such as quantum information, quantum energy, quantum chemistry and quantum simulation. For example the spin‐helical electrons on the surface of “topological insulators” (TI) enabled observation of a “topological spin battery”  that opens a unique possibility to electrically induce and readout a nuclear and electronic spin polarization, and observation of unusual behaviors in Josephson junctions and SQUIDs made of our TIs  that may be relevant for the study of “topological superconductor” and “majorana fermions”. I will then focus on discussing spin‐helical bosons in a Bose‐Einstein condensate (BEC) of laser‐cooled atoms with “synthetic” spin orbit coupling and gauge fields, where we can dynamically control the Hamiltonian and perform various quantum transport, interferometry, chemistry, and even “collider” experiments. We demonstrate a new “interferometric” approach for quantum control of chemical reactions by preparing reactants in spin superpositions . The system could also be used as a quantum simulator to study phenomena ranging from spin decoherence in interacting systems  to novel quantum matter in extra “synthetic” dimensions or curved spaces not easily realized in electronic materials .
Refs:  J. Tian et al., “On the understanding of current‐induced spin polarization of three‐dimensional topological insulators”, Nature Comm. 10, 1461 (2019);  M.Kayyalha et al., “Highly skewed current‐phase relation in superconductor‐topological insulatorsuperconductor Josephson junctions”, arXiv:1812.00499;  D.Blasing et al. “Observation of Quantum Interference and Coherent Control in a Photo‐Chemical Reaction”, PRL 121, 073202 (2018);  C. Li et al.”Spin Current Generation and Relaxation in a Quenched Spin‐Orbit Coupled Bose‐Einstein Condensate”, Nature Comm. 10, 375 (2019);  C.Li et al., “A Bose‐Einstein Condensate on a Synthetic Hall Cylinder”, arXiv:1809.02122