RQC Seminar

44th RQC Seminar

• Speaker

  Prof. Xuedong Hu　
  (Department of Physics, University of Buffalo, USA)

• Date

  16:00-17:00 (JST), May 9, 2023 (Tuesday)

• Venue

  Hybrid (Zoom / Wako 2F Large Conference Room, Admin. Headquarters Bldg.)

• Title

  Spin Qubits in Semiconductors: The Past, Present, and Future

• Inquiries

  rqc_info[at]ml.riken.jp

Abstract
Research on the physical implementation of quantum computing has made dramatic progress over the past decade, spearheaded by superconducting qubits and trapped ion qubits, to the degree that small-scale quantum information processors are now within reach. Studies of semiconductor spin qubits, which have often been considered one of the most promising in the long term from the perspective of scalability, have also yielded impressive results in the past decade, demonstrating exceptional coherence properties for single spins confined in quantum dots and donors and high-fidelity single-qubit gates. Over the past year, high-fidelity single- and two-qubit gates have been demonstrated in a variety of Si nanostructures, indicating that spin qubits in Si are close to the quantum error correction threshold.

In this talk I will first introduce the basic properties of spin qubits, and discuss what makes spin qubits promising building blocks for a scalable quantum computer. I will then give a general discussion of the current status of spin qubit research, and compare semiconducting and superconducting qubits. In particular, I will identify the most important bottlenecks for spin qubits, and potential solutions to the problems. Lastly, I will discuss briefly our studies of the variable valley-orbit coupling in Si quantum dots and how it affects electron spin dynamics and coherence.