Abstract
Atom-like defects in solids are promising building blocks for quantum technologies. Among these, group-IV color centers in diamond are especially attractive because their inversion symmetry supports excellent optical coherence, while their electronic and spin properties remain highly tunable through the local solid-state environment. In this talk, I will discuss how group-IV color centers can be engineered as solid-state quantum nodes by controlling both their optical interface and their spin structure. First, I will show that a resonantly driven germanium-vacancy center can function as an atomic optical antenna that enables the detection and control of nearby dark defects. Second, I will describe ongoing work showing that large strain can reshape the spin-orbital structure of group-IV centers, partially release the electron spin from its usual locking to the defect axis and allow its quantization axis to be modified by an external magnetic field. This strain-engineered regime provides a route toward improved coherence at higher temperature, reduced sensitivity to magnetic-field alignment, enhanced optical cyclicity for spin readout, and more flexible access to nearby nuclear-spin memories. Together, these results illustrate how group-IV color centers can be transformed from passive defects into engineered quantum nodes.
Zixi Li is a PhD candidate in quantum engineering at the University of Chicago working with Prof. Alex High. Zixi received her undergraduate degree in physics from Nanjing University, where she began her research in quantum science, and she also worked as a research intern at RIKEN before starting her PhD. Her current research focuses on solid-state quantum systems based on group-IV color centers in diamond, with an emphasis on strain engineering and nanophotonic integration.