A quantum computer (QC) is a machine that uses special quantum-mechanical phenomena, such as superposition and entanglement, to quickly solve problems that would normally require repeated substitutions over a very long period of time, mainly through a process of drastically increasing probabilistic prediction. The unit of information on a classical computer is called a “bit”, whereas it is called a “qubit” on a quantum computer. The special properties of quantum particles are hard to see in the macroscopic world but become more evident in the microscopic world; protons, electrons, and atoms all show these properties. POSTECH was selected for the first time in the quantum computing field of the Engineering Research Center (ERC), the largest research project of the National Research Foundation of Korea (NRF). The Scalable Quantum Computer Technology Platform Center opened in June 2019 consisting of researchers from EEE, PHYS, ME, and CSE. The center aims to develop technology to manipulate and observe qubits in extremely low-temperature superconducting environments where quantum phenomena are well-observed and construct a functional quantum computer in POSTECH. The quantum computer will be accessible via the internet and serve as a platform that researchers all over the world can utilize in their research. This project aims to contribute to a better future for humanity.

Why I started researching QCs
As the amount of data continued to expand exponentially in the information age, current semiconductor technologies started to show its limitations; futuristic computers with a new paradigm became a major topic in scientific research. As many global IT companies began to jump on this bandwagon, quantum technologies that had been steadily advancing for the past 40 years gained an unprecedented boost. Now, QCs are not that far off from being just a “dream computer”. As the number of qubits increases, the implementation of an integrated system that allows user-defined programs to individually control these qubits using ultra-fine electric signals becomes more and more important. If the foundation of QCs was in the domain of physics, research on implementing a scalable QC is in the realm of engineering, and we have to overcome a lot of engineering/technical barriers. My field of research is semiconductor circuit design, and I started working on QCs because I believed my research would become an increasingly important part of the system integration of QCs.

What is unique about our QC
There are a variety of ways to implement qubits, and among them, superconducting qubits have the most advantage in terms of scalability. Global IT companies such as IBM and Google are also focusing their research on superconducting qubits, and currently possess QCs that have around 50 superconducting qubits inside. However, for a QC to replace modern supercomputers, at least 1000 qubits need to work together simultaneously. Currently, it is physically impractical to implement a QC with 1000 qubits as the machine itself would become way too large. To solve this problem, new technologies that can upscale QCs without increasing their physical size are needed. Developing this technology is our center’s current objective, and you can say that worldwide research on this area has just started.

What it means to have a fully domestic QC
Of the three major quantum technologies (quantum communication, quantum sensors, and QC), the implementation of a QC is the most challenging as it requires a large number of qubits, but it is also considered to be the ultimate technology to solve a multitude of difficult problems. However, our country is a latecomer in the field of quantum computing. Various problems such as drug development, future prediction, Artificial Intelligence, and genetic analysis can be solved using QCs. The quantum software algorithms needed can be researched individually; however, building the actual hardware that can run these algorithms can only be achieved through collective research; this can determine the competitiveness of a nation’s science and technology. If we can build a fully functional QC, domestic researchers will then be able to use the hardware to verify their research, and ultimately, this achievement will become the center of an expanding base of quantum computing and engineering researchers in Korea.

Advice to Postechians interested in QCs
Nowadays, a variety of fields such as electrical engineering, material science, computers, mathematics, industrial engineering are involved in QCs, not just physics. You may not have a talent in every single field, and that is absolutely normal. Find hints about your aptitude from childhood pastimes that you were especially interested in, and you will find the right field for you. I hope you can become an outstanding researcher in that field and contribute to the development of QCs. Sometimes there may be friends that you do not like, but I am positive that there will be some kind of goodness in them. Try to have a more generous and open mind, so that you can become a scientist who can work with various researchers in diverse fields in the future.
There exists a term called “quantum supremacy”. This term denotes that QCs can solve certain problems that classical computers could not and can be considered a milestone in the history of computers. Google actually published a paper announcing the achievement of “quantum supremacy” in 2019. This result is limited to one problem, and many of the barriers to commercialization of scalable QCs still remain to be overcome. However, it is now certain that what was previously predicted to happen vaguely in the next 50 years or so might arrive much earlier. It is very difficult to predict the future. It is hard to predict how much QCs will improve in the next ten years, but at least then, what position this technology will take in the history of computers will become much clearer.