Physics Colloquium – Prof. Jong Yeon Lee, University of Illinois Urbana-Champaign

About this event

Beyond Quantum Memory: Designing Codes for Computation

A quantum computer must protect fragile quantum information while still allowing us to process it. Quantum error-correcting codes provide this protection by encoding information across many physical qubits. Codes that use these resources efficiently promise more compact quantum memories, but carrying this advantage into computation requires careful attention to how the stored information is manipulated. In this talk, I will discuss how the operations we want to perform can guide the design of the codes themselves. I will first describe the tradeoffs between storage efficiency, resilience to errors, and the complexity of error detection. I will then explain why efficient storage does not automatically make it easy to manipulate every encoded qubit, and how the algebraic structure of a code can help address this challenge. I will also outline how codes can be designed to work together, enabling the initialization of selected encoded qubits, the transfer of information into more robust memories, and the preparation of special quantum states needed for universal computation. The key conclusion is that we should treat the protection and manipulation of quantum information as parts of a single design problem.

Bio: Jong Yeon Lee is an assistant professor of physics at the University of Illinois Urbana-Champaign. His research lies at the intersection of quantum information science and condensed matter physics, with a focus on quantum error correction, mixed-state phases of matter, and nonequilibrium dynamics. He graduated from Caltech in 2015, receiving the Richard P. Feynman Prize, and earned his Ph.D. from Harvard University in 2020 under the supervision of Ashvin Vishwanath. He subsequently joined the Kavli Institute for Theoretical Physics as a Moore Postdoctoral Scholar. In 2026, he received a Microsoft Quantum Pioneers Program Award for his research on quantum error correction and fault-tolerant quantum computation.