Successful Development of Accurate Measurement Method for Quantum State Evaluation
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- Date2021-05-25 09:33
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Successful Development of Accurate Measurement Method for Quantum State Evaluation
- The new method achieves the highest level of accuracy in quantum state estimation, and is expected to improve the reliability of quantum information technology -
A team of Korean researchers successfully developed the technology to evaluate qubit states, a basic unit of information used for quantum information science and technology, and has experimentally demonstrated it with the highest level of accuracy.
- The research team consists of Principal Researcher Sang Min Lee and Hee-Su Park (head of Quantum Technology Institute) of the Korea Research Institute of Standards and Science (KRISS), Professor Jinhyung Lee of Hanyang University, Professor Jaewan Kim of the Korea Institute for Advanced Study (KIAS), and Senior Researcher Jeongho Bang of Electronics and Telecommunications Research Institute (ETRI).
▲ Principal research scientist Sang Min Lee of the KRISS Quantum Technology Institute is conducting an experiment to accurately measure the polarization state of a single photon.
Accurate measurement of quantum states is an essential requirement for quantum information technology (such as quantum computation and quantum communication), since inaccurate measurements cause errors and reduce the reliability of the technology. Methodologies for accurately measuring quantum states have been continuously studied, and recently employ machine learning techniques, which include extensive computational loads, are used to obtain the most accurate results within limited resources.
▲ Schematic diagram of a quantum state estimation experiment using a machine learning methodology
The team of researchers from KRISS, Hanyang University, KIAS, and ETRI has developed a machine learning methodology that uses much simpler rules and significantly less computation than previous methodologies. The research team has experimentally demonstrated that the accuracy of the state estimation is less than 10-5, which is at least five times higher than the previous results. This technique can be applied to the free-space quantum key distribution system to align and compensate the reference axis in real time. The research result was published in Physical Review Letters on April 30.