Development of
Large-scale Fault-tolerant Universal
Optical Quantum Computers

Conventional computers express information in terms of 0s and 1s, but a quantum computer can hold both 0s and 1s, and by taking advantage of this property, can perform many different calculations instantaneously. It has been thought,however, to be difficult to use the quantum computer as a general-purpose computer due to issues such as the accuracy of the calculations and due to the limitation of its applicable field.

In this project, we are challenging the issue of generalization of quantum computers by using optical quantum technology.

The quantum computers currently available are designed using electrical signals, but we are utilizing optical signals instead of electrical signals: the optical quantum computer. Light has a higher clock frequency and can perform calculations faster than electric signals.

3D model of
the quantum entanglement

List of R & D issues

Research and Development Subjects01
Research and development on time-domain multiplexed general-purpose optical quantum computer

We will study and develop a hybrid error correction method with continuous quantity error correction using a state called GKP qubit, which is expected to be a low threshold for error tolerance.

Research and Development Subjects02
Research and development on superconducting photon number discriminator

We will develop a superconducter photon number discriminator that can discriminate more than 60 photons with an operating bandwidth of 1 GHz and a quantum efficiency of more than 99%.

Research and Development Subjects03
Research and development on waveguide optical parametric amplifiers and optical quantum waveguide circuits

We aim to realize waveguide optical parametric amplifiers and optical quantum waveguide circuit devices in order to realize quantum teleportation chips that can operate satisfactorily even in conditions exceeding the error tolerance threshold.

Research and Development Subjects04
Research and development on social implementation of optical quantum computers

The main objective of this project is to build a man-machine interface that includes the development of compilers and assemblers, and to realize an actual machine that can be operated as a cloud computer.

Project Structure

Development of Large-scale Fault-tolerant Universal Optical Quantum Computers

Project Manager
Furusawa Akira Professor, Graduate School of Engineering, The University of Tokyo
1961 Born in Saitama Prefecture
1984 graduated from the University of Tokyo with a bachelor's degree in applied physics
1986 master's degree in applied physics the graduate school of the University of Tokyo, and joined Nikon Corporation. After working as a researcher at the University of Tokyo's Research Center for Advanced Science and Technology, a visiting researcher at the California Institute of Technology
Associate professor at the Graduate School of Engineering of the University of Tokyo,
2007 professor at the Graduate School of Engineering of the University of Tokyo
Publications of textbooks such as "Quantum Teleportation", "What is Quantum Entanglement?”

Moonshot target 6

Realization of an error-tolerant general-purpose quantum computer that will dramatically advance the economy, industry, and security by 2050

As the progress of conventional computers is reaching limits, quantum computers are attracting attention for their ability to respond to the explosive growth in demand for various information processing. In order to solve diverse, complex, and large-scale real-world problems at high speed using a quantum computer, the key is to realize an error-tolerant general-purpose quantum computer that can perform accurate calculations while correcting quantum errors. In this program, we will promote research and development in hardware, software, networks, and related fields. In our "Research and Development of an Error-Tolerant Large-Scale General-Purpose Optical Quantum Computer," we will develop our original quantum look-up table method to realize large-scale error-tolerant quantum operations. We aim then to realize a large-scale optical quantum computer characterized by room-temperature operation by 2050.

News & Press release


If you have any questions about the Moonshot Research and Development Program, the content of each project, or this project, please contact the appropriate department.

  • The Moonshot Research and Development Program
  • Japan Science and Technology Agency
  • The University of Tokyo
  • Institute of Engineering Innovation,School of Engineering, the University of Tokyo
  • RIKEN Center for Quantum Computing