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IQIM Postdoctoral and Graduate Student Seminar

Friday, January 31, 2020
12:00pm to 1:00pm
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East Bridge 114
Quantum metrology with strongly interacting spin systems
Joonhee Choi, IQIM Postdoctoral Scholar, Endres Group,

Abstract: Quantum metrology makes use of coherent superpositions to detect weak signals. While in principle the sensitivity can be improved by increasing the density of sensing particles, in practice this improvement is severely hindered by interactions between them. Using a dense ensemble of interacting electronic spins in diamond, we demonstrate a novel approach to quantum metrology. It is based on a new method of robust quantum control, which allows us to simultaneously eliminate the undesired effects associated with spin-spin interactions, disorder and control imperfections. In particular, we present a new framework for the design of periodic global control pulse sequences to engineer target Hamiltonians for quantum sensing. Combined with optimal initialization and readout protocols, this allows us to break the limit for AC magnetic field sensing imposed by interactions, opening a promising avenue for the development of solid-state ensemble magnetometers with unprecedented sensitivity.

Bio: I did my Ph.D. at Harvard University in the group of Misha Lukin in physics, studying many-body quantum dynamics using interacting spin ensembles in diamond. After that, I joined Caltech last Fall as an IQIM postdoctoral scholar and work in Manuel Endres's group in physics.

For more information, please contact Marcia Brown by phone at 626-395-4013 or by email at [email protected].