A Korean research team that studies quantim computers has published research results that can be used to verify the states and processes of the quantum computing unit, qubit.
Professor Cho Yong-uk’s team at the Korea Institute of Science and Technology (KIST) said that it has found that the geometric phase occurs in the process of measureing the states of qubit, the basic unit of quantum computers. The team worked in cooperation with Professor Kim Yoon-ho’s team at POSTECH.
Cho said, "These results will be directly applied to the verification of the quantum states and processes." "The geometric phase is well known to help maintain the quantum nature of qubit, and it will contribute to the study of quantum information processing in the field of quantum computing in the future," he added.
Unlike conventional computers, quantum computers can handle many computations at once and finish calculations that the supercomputer would take 150 years in a matter of minutes.
When qubit is manipulated, it returns to the original starting position after a certain exercise and the phenomenon of remembering such process occurs. This is called the geometric phase phenomenon, in which quantum states and processes are remembered in the form of phase.
Although the geometric phase was generally thought to only occur in the adiabatic process in which the quantum state changes slowly, there was a theory that it could also occur in the quantum measurement process, in which the state changes immediately. The mechanism was not clarified until KIST researchers of this study experimentally identified the mechanism of the generation of the geometric phase occurring in the quantum measurement process of qubit, the basic unit of quantum information.
According to the principle of quantum mechanics, measurements are accompanied by a reaction, which is called a measurement reaction. That is, the quantum information is changed by the quantum measurement. The researchers identified two important concepts for understanding quantum physics, which are geometric topology and measurement response, for the first time in the world. In particular, this study was conducted using a qubit-based quantum circuit and shows the advancement of qubit control and measurement technology of Korean researchers.