Superconducting Quantum Simulation Research Team

Principal Investigator

PI Name Jaw Shen Tsai
Degree Ph.D.
Title Team Leader
Brief Resume
1983Ph.D., State University of New York at Stony Brook, USA
1983Research Scientist, Microelectronics Research Laboratories, NEC
2000Fellow, American Physical Society, USA
2001Fellow, Nano Electronics Research Laboratories, NEC
2001Team Leader, Macroscopic Quantum Coherence Team, RIKEN
2012Group Director, Single Quantum Dynamics Research Group, RIKEN
2012Team Leader, Macroscopic Quantum Coherence Research Team, Quantum Information Electronics Division, RIKEN Center for Emergent Matter Science
2014Team Leader, Superconducting Quantum Simulation Research Team, Quantum Information Electronics Division, RIKEN Center for Emergent Matter Science (-present)
2015Professor, Tokyo University of Science (-present)


We are studying macroscopic quantum coherence that occurs in small Josephson junction circuits. In the system, charge and phase degrees of freedoms co-exist, and their coherent control can be exploited as quantum bit (qubit), the basic component of the quantum computer. Superconducting qubit possesses high degree of freedoms in the circuit design and ability to local control as well as readout quantum states. Utilizing these properties, the development of small scale quantum simulation circuit and quantum annealing circuit are targeted.

Research Fields

Physics, Engineering


Josephson effect
Quantum coherence
Artificial atoms


On-demand Single-Photon Source with Superconducting Artificial Atoms (Qubit)

An on-demand single-photon source is a key element in a series of prospective quantum technologies and applications. Here we demonstrate the operation of a tuneable on-demand microwave photon source based on a fully controllable superconducting artificial atom strongly coupled to an open-ended transmission line. The atom emits a photon upon excitation by a short microwave p-pulse applied through a control line. The intrinsically limited device efficiency is estimated to be in the range 65–80% in a wide frequency range from 7.75 to 10.5 GHz continuously tuned by an external magnetic field. The actual demonstrated efficiency is also affected by the excited state preparation, which is about 90% in our experiments. The single-photon generation from the single-photon source is additionally confirmed by anti-bunching in the second-order correlation function. The source may have important applications in quantum communication, quantum information processing and sensing.

Microphotograph of the single-photon source and its equivalent circuit.
Z. H. Peng, et al., Nature Communications 7, 12588 (2016)


Jaw Shen Tsai

Team Leader tsai[at] R

Yu Zhou

Visiting Scientist

Zhihui Peng

Visiting Scientist

Simon Devitt

Visiting Scientist

Oleg Astafiev

Visiting Scientist