You are a leading researcher in the field of superconducting quantum computing in South Korea. Can you tell me about your research journey so far?
I studied physics – working on Josephson devices based on high-temperature superconductors - at Seoul National University, where I completed my bachelor's, master's, and doctorate courses. During my degree, I had the opportunity to visit the Forschungszentrum Jülich in Germany with the support of DAAD, the German Academic Exchange Service. Afterwards, I studied the development of quantum voltage standard devices as a postdoctoral researcher at NIST Boulder in the United States. In 2005, I returned to South Korea and conducted research on precise measurements using superconducting quantum devices at the Korea Research Institute of Standards and Science (KRISS), focusing on quantum computing research with superconducting qubits for over 10 years. I moved to Sungkyunkwan University in 2020. Over the past 30 years I have been able to work on a wide variety of superconducting devices and superconducting properties, and this experience is the basis for my research on superconducting quantum computers.
What are the role and vision of the Quantum Information Research Support Center at Sungkyunkwan University?
The Quantum Information Research Support Center (QCenter) opened in 2020 as a large-scale government project (all government projects share a budget of about $45 million over 5 years). Quantum information technology is developing very rapidly: systematic education and research support have not yet been established, but the government has been actively increasing R&D investments and so there was a crucial need for further initiatives to support these investments. The QCenter’s main missions are to train the future workforce in this area, to support the use of a quantum computing cloud, and to create an infrastructure including fabrication and testbed facilities for quantum device production. Presently I am the director of the QCenter.
Could you tell me about your group's research on government projects? How do you contribute to government R&D projects?
Apart from my role in the QCenter, I am also in charge of the government's quantum computing technology development project. The idea is to develop the technology for a 5-qubit quantum computer based on superconductivity. The team includes researchers from various universities and government research institutes who conduct research on quantum computers from device design production to measurement and algorithms, and is organized in the form of consortia. This project was the seed for the current 50-qubit scale superconducting quantum computing system project by the government, hosted by KRISS.
You are an experienced Zurich Instruments user: how did the instruments help with your experiments?
The Zurich Instruments Quantum Computing Control System (QCCS) made it possible to set up and start the measurement of qubits very quickly. The QCCS solution also made it more efficient and easier to configure complex measurement settings as the number of qubits increased. In particular, the generation of precise high frequency signals using double superheterodyne frequency conversion significantly reduced the calibration burden in the qubit readout and control measurement setup for which up-down conversion is required.
What is the direction of research and development in quantum computing in South Korea?
Currently, quantum computer development is actively led by the South Korean government. As in other countries, this field is developing so fast that a problem is the lack of specialized R&D workforce that can keep up with the speed of the developments. Although there are not many Korean researchers yet in this area of study, there are a few who carry out very high-quality and competitive research. In this sense, I think Korea's contribution to the field of quantum information processing has a bright future.
I think the government's role in supporting quantum computing research, including superconducting qubits, should be to scale up and expand its base. However, large-scale R&D projects are rare and it isn’t easy to build expensive equipment, especially in universities with limited project budgets. Many leading researchers, including those at the Quantum Information Research Support Center, are considering different ways to make research projects more affordable.
What are your hobbies?
I used to enjoy playing classical guitar and listening to music, but these days I'm too busy to find time for any of this. However, I still have two guitars in my office.