Hidehiro Yonezawa
Optical Quantum Control Research Team Team Leader
Outline
Our team is investigating high-performance measurement and estimation techniques, quantum control techniques, and related quantum optical technology. In quantum systems, quantum states suffer from external disturbances or measurements. Thus, the control technology of quantum systems is of paramount importance. For controlling quantum systems, high-quality quantum estimation is a prerequisite, followed by the realisation of coherent control and measurement-based control. Coherent control is a control technique that excludes quantum measurements, resulting in simpler and wider bandwidth systems. Measurement-based control, on the other hand, is a control technique based on measurements, which utilises the effects of measurements and enables more complex processing compared to coherent control. Through these investigations, our team aims to realise and improve optical quantum computers and related quantum information technologies.
Representative Research Results
・S Yokoyama, et. al., “Feasibility study of a coherent feedback squeezer,” Phys. Rev. A 101, 033802 (2020)
・S Yokoyama, et. al., “Characterization of entangling properties of quantum measurement via two-mode quantum detector tomography using coherent state probes,” Opt. Express 27, 34416 (2019)
・W. Asavanant, et. al., “Generation of time-domain-multiplexed two-dimensional cluster state,” Science 366, 373 (2019).
・S. Yokoyama, et. al., “Ultra-large-scale continuous-variable cluster states multiplexed in the time domain,” Nature Photon. 7, 982 (2013)
・H. Yonezawa, et.al., “Quantum-Enhanced Optical-Phase Tracking,” Science 337, 1514 (2012).
Estimation of quantum state of light