Green Computing Systems Research OrganizationWaseda University

Development of new quantum computing hardware based on nanofiber cavity QED

• AOKI, Takao Professor, Faculty of Science and Engineering

• AOKI, Takao Professor, Faculty of Science and Engineering, School of Advanced Science and Engineering
• FUKUHARA, Takeshi Professor (non-tenure-track), Faculty of Science and Engineering, Graduate School of Advanced Science and Engineering
• HARADA, Kenichi Researcher (Associate Professor), Green Computing Systems Research Organization
• KASAHARA, Hironori Professor, Faculty of Science and Engineering, School of Fundamental Science and Engineering
• KIMURA, Keiji Professor, Faculty of Science and Engineering, School of Fundamental Science and Engineering
• TAKAHATA, Mitsuyoshi Researcher (Assistant Professor), Green Computing Systems Research Organization
• TOGAWA, Nozomu Professor, Faculty of Science and Engineering, School of Fundamental Science and Engineering
• YUASA, Kazuya Professor, Faculty of Science and Engineering, School of Advanced Science and Engineering

• GOBAN, Akihisa Guest Researcher (Guest Associate Professor), Green Computing Systems Research Organization
• INOUE, Ryotaro Guest Researcher (Guest Associate Professor), Green Computing Systems Research Organization
• KOMAGATA, Kenichi Nicolas Guest Junior Researcher (Guest Assistant Professor), Green Computing Systems Research Organization
• KONISHI, Hideki Guest Researcher (Guest Assistant Professor), Green Computing Systems Research Organization
• OZAWA, Hideki Guest Junior Researcher (Guest Assistant Professor), Green Computing Systems Research Organization

• HIROSE, Masashi
• HISAI, Yusuke
• KATO, Shinya

To realize an fault-tolerant universal quantum computer, which is anticipated to bring about a revolution in information technologies, hardware that is capable of quantum error correction and scaling the number of physical qubits to the order of 10⁶ to 10⁸ is required. However, as existing hardware including superconducting circuits have significant technical challenges to increasing qubits, it is necessary to develop a novel hardware that is advantageous for this purpose. In addition, it is also anticipated regardless of the hardware, it is going to be extremely difficult to increase the number of physical qubits to the order of 10⁶ to 10⁸ in a single unit, and therefore it is necessary to develop an hardware capable of scalable distributed quantum computing. Furthermore, for efficient application of quantum error correction, the hardware should have an any-to-any connection in which any pair of qubits can be coupled with each other.
A cavity quantum electrodynamics (cavity QED) system consists of light confined in an optical cavity and the atoms that interact with it. As the quantum natures of light and atoms manifest themselves in a pure form, it has played a great role in the progress of the basic researches on quantum physics. Furthermore, a cavity QED system has been regarded as a promising platform for the implementation of quantum computers from the early days of quantum information science. However, in order to implement a quantum computer, the development of an optical cavity equipped with good connectivity to optical fibers, capability of coupling to a large number of individually addressable atoms, and low loss was needed.
Given this background, the Aoki Research Group at the Department of Applied Physics, Waseda University has developed a nanofiber cavity as a cavity suitable for building a quantum computer based on cavity QED, and has created a cavity QED system using this cavity named the “nanofiber cavity QED system.” We will develop quantum computer hardware based on nanofiber cavity QED. This system is an atom-photon hybrid system in which both atoms and photons can be used as qubits with any-to-any coupling. Furthermore, with this system, large-scale distributed quantum computing via optical fiber connection is possible, and it can be integrated with a quantum communication network.
Under national government’s research programs centered around the Moonshot Research and Development Program under the initiative of the Cabinet Office, our research group will promote research and development through intensive joint research by Waseda University and Nanofiber Quantum Technologies, Inc. (NanoQT).

Aoki Research Group