Abstract: First-Principles Theory for Excited-States Kinetics and Optical Readout of Quantum Defects
Stable, scalable, and reliable quantum information science (QIS) is poised to revolutionize human well-being through quantum computation, communication and sensing. In this talk, I will show our recent development on first-principles computational platforms to study quantum kinetics and optical readout as critical processes in QIS and spintronics in solid-state materials, by combining first-principles many-body theory and open quantum dynamics.
First, we will show how we reliably predict energetics, electronic and optical properties of spin defects in solids from first-principles many-body perturbation theory, which can accurately describe highly anisotropic dielectric screening and strong many-body interactions in two-dimensional systems. In particular, we will show how we predict spin-dependent optical contrast for quantum information readout of spin qubits by computing radiative and phonon-assisted nonradiative as well as spin-orbit induced intersystem crossing rates from first-principles. We then solve master equation for excited-state populations for different spin states under magnetic field. This provides theoretically predicted optically-detected magnetic resonance (ODMR) contrast, commonly used for spin state initialization and readout.
Next, we will introduce our recently developed real-time density-matrix dynamics approach with first-principles electron-electron, electron-phonon, electron-impurity scatterings and self-consistent spin-orbit coupling, which can accurately predict spin and carrier lifetime and pump-probe Kerr-rotation signatures for general solids. As an example, we will show distinct dependence on electron-phonon couplings in spin and carrier in halide perovskites, and effect of g factor variation on spin dephasing under magnetic field. Our theoretical and computational development is critical for designing new materials promising in quantum-information science and spintronics applications.
Bio:
Yuan Ping received her B.Sc. degree from University of Science and Technology of China in 2007, Ph.D. from UC Davis in 2013, and materials postdoctoral fellow at Caltech in 2016. From then she is an assistant professor in chemistry and affiliated professor in physics at UC Santa Cruz, and promoted to be associate professor with tenure in 2022. She moved to University of Wisconsin-Madison as associate professor in Materials Science and Engineering in July 2023. Her research group focuses on developing and employing first-principles many-body theory and quantum dynamics for materials applications. Ping is a recipient of Alfred Sloan Research Fellow (2022), NSF CAREER Award (2022), Air Force YIP award (2021), and ACS COMP OpenEye Award (2021). She leads the DOE Computational Chemical Science center (ADEPTs) and a co-thrust lead of EFRC center (CHOISE) on spin phenomena.
