Grainger College of Engineering, All Events

Abstract: Electrons confined to solid neon surfaces manipulated through circuit quantum electrodynamics (circuit QED) architecture represent a promising quantum computing platform with demonstrated impressive coherence times. I will present two interconnected investigations critical to advancing this technology. First, we examine how resonator and substrate surface properties influence the formation of electron-on-neon (eNe) charge states and their coupling to microwave resonators. Our experimental observations reveal that shallow-depth etching maximizes coupling strength, while comparisons of trapping statistics across devices with varied surface roughness elucidate the crucial role of fabrication-induced surface features in forming strongly coupled eNe states. These findings motivate our second investigation: characterizing the growth kinetics and film properties of neon on microchips. Using high-Tc YBCO microwave resonators, we analyze the uniformity, conformality, and solidification dynamics of both quench-condensed and liquid-grown neon thin films. Our microwave measurements between 4-30K reveal novel film thickness dynamics near neon's triple point, providing a comprehensive picture of neon deposition behavior on microwave resonators. Together, these studies address fundamental challenges in surface engineering and material growth essential for developing scalable electron-on-neon quantum computing systems. 

Bio: Kater Murch is Professor of Physics and of Electrical Engineering and Computer Sciences at UC Berkeley. Kater received his B.A. in physics from Reed College in 2002. After that, he spent a long year slacking off, working as a bee keeper, honing his guitar skills, and studying the cello before finally starting his Ph.D. work at UC Berkeley with Prof. Dan Stamper-Kurn. Kater focused his interests on general problems in quantum measurement, and performed some of the first studies of position measurement quantum backaction. For a postdoc, he joined Irfan Siddiqi's group to study superconducting quantum circuits, where he continued to study basic questions in quantum measurement and quantum noise—focusing on quantum trajectories and open quantum systems.

In 2014 Kater joined the faculty at Washington University and built a research program focusing on quantum technologies in fabricated quantum systems, open quantum systems and dissipation engineering, and quantum sensing applications. His lab utilizes superconducting circuits to explore fundamental questions in quantum information, develops novel platforms like single electrons trapped on solid neon, and applies quantum sensors to searches for dark matter. As co-director of the Center for Quantum Leaps at WashU, Kater helped establish collaborative quantum research spanning multiple schools. He also co-founded Gateway Quantum Technologies in 2023 and Facet Lab in 2025, advancing quantum technology commercialization.

Kater has received several awards including the Alfred P. Sloan Fellowship in Physics, the St. Louis Academy of Science Innovation Award, the Cottrell Scholar Award, an NSF CAREER Award, the Experimental Physics Investigator Award from the Moore Foundation, and an outstanding reviewer award from APS.

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