Breakthrough in Quantum Computing Technology
In November of last year, a research team led by Professor Ra Young-sik from the Department of Physics at KAIST developed the world’s first technology that allows clear observation and analysis of the internal operations of a light-based quantum computer during computation. This method is similar to a CT scan and is known as quantum tomography. It reconstructs the internal structure using information obtained from multiple angles without directly opening the device.
Optical-based quantum computers, which use light for calculations, have gained attention as next-generation computing technology due to their fast speed and high scalability. However, it has been very difficult to experimentally verify how these quantum computers actually perform computations. To solve this problem, the research team closely observed how light changes inside the quantum computer by dividing it into two aspects:
- how much the light signal grows and changes as intended during computation, and
- the extent of unavoidable loss and noise that mix in the actual experimental environment.
By examining these aspects separately, the team successfully verified through experiments even complex operations involving up to 16 entangled light signals simultaneously, which were previously difficult to analyze when there were only five light signals.
The research team believes this technology can be utilized to verify the reliability of large-scale quantum computers and expects it to expand into not only quantum computing but also quantum communication and quantum sensing technologies in the future.
Advancing Quantum Research and Education
Since February 2023, the KAIST Graduate School of Quantum Technology has been accelerating next-generation quantum research and the cultivation of quantum talent. It has established a joint operational system with the Electronics and Telecommunications Research Institute (ETRI) and the Korea Research Institute of Standards and Science (KRISS), and started degree programs and research. The school also operates the KAIST–MIT Quantum Information Winter School with the Massachusetts Institute of Technology (MIT), where faculty from both KAIST and MIT participate directly in lectures and discussions.
On December 3 of last year, the National Quantum Fab Research Institute was opened, and construction began on the country’s largest open quantum device-dedicated facility. This initiative marks a significant step forward in the development of quantum technologies.
Diverse Research Initiatives at KAIST
Research activities are also vigorous. Professor Ahn Jae-wook from the Department of Physics developed a technology that significantly scales up quantum computers by utilizing neutral atoms called “Rydberg atoms.” This involves freely arranging and connecting very small atoms to create large-scale quantum computers with powerful performance. It is a core technology that moves qubits, the basic units, to desired locations to dramatically expand computational scale. This research is evaluated as essential for scaling up quantum computers, which have remained theoretical, to a level where they can be practically applied.
Professor Choi Jae-yoon from the Department of Physics is a world-renowned authority in the field of quantum simulation using neutral atoms. He conducts research that freezes atoms to near absolute zero (minus 273 degrees) and traps them in an optical lattice, a laser grid, to replicate complex quantum phenomena identically as they occur in reality. This technology enables the analysis of minute physical laws that are difficult to compute with conventional computers, allowing them to be observed as if in real-time.
Professor Yoo Kyung-sik from the School of Electrical Engineering is conducting research that serves as an engineering bridge to apply quantum technology beyond the laboratory to actual devices. By precisely fabricating tiny quantum components and integrating them into a single system, he contributes to completing a practical, operational quantum system.
Professor Kim Gap-jin from the Department of Physics is a world authority in the field of spin, tiny magnets within atoms. Quantum computers process information by utilizing the direction and movement of these microscopic magnets. Professor Kim is conducting research to uncover the fundamental principles of how these magnets operate within materials. His work lays the foundation for next-generation quantum devices that operate through magnetic force rather than electricity, earning him high praise in the international academic community.
Expanding Facilities for Quantum Innovation
At the end of last year, the National Quantum Fab was also opened. The plan is for the facility to function not only as a place where researchers submit designs but also as a core hub for manufacturing various types of quantum computer components and researching new fabrication technologies. This expansion underscores the commitment of KAIST and its partners to advancing quantum technology and fostering a new era of scientific discovery.
