[Nov. 22] Physics Special Seminar - Dr. Kyung Hoon Lee (BLEXIMO Corp.)

물리학과 특별세미나 개최 안내

물리학과에서는 특별세미나를 아래와 같이 개최하오니 관심있는 분들의 많은 참석을 바랍니다.

1. 연사: 이경훈 박사
2. 일시: 2022. 11. 22(화), 오후 4시
3. 장소: 공학3동 302호 (세미나실)

4. 제목: Quantum materials-based quantum computing

                  : vdW 2D materials and extending coherence in superconducting qubits

Scalability is the biggest challenge for superconducting quantum computers. Despite major advances in our understanding and control of superconducting qubits, the problem of error rates has been limiting the realization of scalable and fault-tolerant quantum computers. The main culprit for high error rates is short coherence, which limits how long a qubit can store information. Five orders of improvements in coherence have been achieved over the past two decades by focusing on qubit design optimization such as transmon qubits (T1, T2 ~ 100 μs)  vs charge qubit (1 ns) in conventional superconducting films (Nb, Al). Nonetheless, the computational power is still limited by the decoherence that results from materials defects, spins of molecular adsorbates, oxidation, fabrication-induced impurities/damages, and materials properties-associated nonequilibrium excitations. Thus, solving decoherence issues is largely a materials engineering challenge such that innovation in quantum materials is critically needed for the future of practical quantum computers. 2D materials hold promises to address these challenges thanks to their atomically perfect interfaces and an unprecedented designability in material properties. In the first part of my talk, I will talk about vdW 2D materials with a special focus on twisted bilayer graphene and visualization of moiré lattices and superstructures with ultrahigh-resolution microwave impedance microscopy (uMIM) towards designer quantum materials. In the second part of my talk, I will discuss materials challenges and opportunities to improve the coherence of superconducting circuits with introducing our efforts toward mitigating nonequilibrium quasiparticle poisoning effects. Finally, the talk will describe new approaches to quantum materials-based next-generation quantum computing.