The Department of Physics welcomes Dr. Constantin Schrade for their weekly colloquia. Dr. Schrade is a Postdoctoral Research Fellow in Condensed Matter Theory at the Massachusetts Institute of Technology. His research is in the area of a particular realization of topological quantum bits based on Majorana bound states.

Abstract: Superconducting circuits are the foundation for impressive progress in quantum computing technology. However, the protection of quantum information in superconducting circuits against environmental noise remains a significant obstacle towards a large-scale quantum computer. Should we keep improving device parameters for resolving this problem, or should we opt for a fundamentally new approach that relies on the same well-developed technology but enables the robust storage of quantum information?

In this colloquium, I will present my work and vision towards the design of a protected superconducting qubit. I will introduce the concept of a “Majorana Superconducting Qubit,” which leverages topological superconductor islands as new circuit elements for reliable quantum information storage. I will then specify the requirements for initialization, read-out, and, most importantly, a universal quantum gate set. Finally, I will identify a “parity-controlled Josephson effect” as the physical foundation of my qubit design, discuss its implementation in a superconducting interference device, and present experimental results.