IQUIST Seminar Series

Abstract: The transformative potential of quantum information technologies from quantum computers and secure networks to quantum-limited sensors is held back by a fundamental challenge: decoherence. Quantum states are fragile and easily disrupted by their environment, making them difficult to maintain and use in practical settings. While protecting systems from decoherence is paramount, a complementary and powerful strategy is to selectively enhance the very quantum interactions on which their functionality depends. By speeding up these key quantum processes, we can effectively outpace decoherence. This pathway also enables operation at higher temperatures and bandwidths. In this talk, we will present two advances that follow this principle. First, we introduce a new quantum emitter in diamond: the IL1 color center, which exhibits surprising natural decoupling from bulk phonons — a major source of decoherence — while simultaneously maintaining bright, fast optical emission. This unique combination of properties is promising to realize cryogen-free quantum network nodes and high-precision nanoscale sensors. Second, we present a blueprint for a high-efficiency microwave-to-optical transducer. To overcome the critical bottleneck of converting quantum information between these domains, our design employs a two-stage process via an intermediate-frequency state in the sub-THz range. This approach promises near-unity external conversion efficiency, dramatic thermal noise suppression, and removes the optical components from the dilution refrigerator, crucial advantages for connecting quantum processors over optical links. Together, these examples demonstrate how exploiting specific physical degrees of freedom that enhance the desired quantum interactions without compromising coherence can open the way to warmer, faster, and more practical quantum systems. 

Bio: Simeon obtained his B.Sc. from Ecole Polytechnique in Palaiseau (France) and his M.Sc. from the Royal Institute of Technology in Stockholm (Sweden). He did his Ph.D. studies at Northwestern University in the group of Manijeh Razeghi and completed his postdoctoral training at Purdue University under Vladimir M. Shalaev and Sasha Boltasseva. He is currently an Assistant Professor of Electrical and Computer Engineering at the University of Illinois at Urbana-Champaign. His interests include semiconductor physics, nanoscale and quantum photonics. He is a recipient of a 2023 NSF CAREER Award and is a Senior Member of Optica. 

To watch online, go to the IQUIST YouTube channel:   https://www.youtube.com/channel/UCCzAySwQXF8J4kRolUzg2ww