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Ultracold Trapped Ions and Molecules for Quantum Control
Speaker Dr. Shiqian Ding, JILA, University of Colorado at Boulder
Date 25 January 2021 (Monday)
Time 10:30 - 12:00
Venue Online (Zoom)
Due to remarkable coherent control of ions’ motional and internal states, ion trap is one of the leading platforms for quantum computing. In the first part of my talk, I will discuss the nonlinear interaction of ions’ motional modes at the single-phonon level, induced by the intrinsic anharmonicity of the Coulomb interaction between the ions. I will present the applications of these nonlinear interactions for the measurement of the Wigner function, the projective measurement of phonon number, and quantum thermodynamics.
In the second part of my talk, I will describe our recent work on direct laser cooling and trapping of yttrium monoxide molecules to achieve the highest molecular phase space density in free space. We cool the molecules to 4 μK with gray molasses cooling, which is shown to be exceptionally robust against laser parameters and magnetic fields. This work paves the way for applications of ultracold molecules for quantum computing, quantum chemistry, study of strongly correlated quantum systems, and precision tests of fundamental physics.
Finally, I will outline my research proposal on spectroscopy of the thorium nuclear isomeric transition in an ion trap, and its application to build the next generation of optical clocks.

Dr. Shiqian Ding is a research associate in Prof. Jun Ye’s group at JILA, University of Colorado, Boulder. His current work focuses on direct laser cooling of molecules to μK temperatures. He completed his PhD work under the supervision of Prof. Dzmitry Matsukevich at the Centre for Quantum Technologies (CQT), National University of Singapore. At CQT, he studied quantum nonlinearity in ion traps, and quantum logic techniques for a single molecular ion.


Meeting Link: To request for meeting link, please write to phweb@ust.hk