ULVAC Develops Dilution Refrigerator for Quantum Computers
– Supporting Japan’s First Fully Domestic Quantum Computer with Cryogenic Innovation
(2025/04/24)
ULVAC, Inc. and ULVAC CRYOGENICS INC. have successfully developed a dilution refrigerator designed for quantum computing applications. On April 4, 2025, the unit was installed at a leading quantum research institute in Japan. This achievement marks a critical milestone in the development of the country’s first fully Japan-built quantum computer―realized using only domestically developed core components. Until now, Japan has faced the long-standing challenge of building a quantum computer entirely from domestically sourced technologies. ULVAC’s cryogenic solution, now operating as a core part of this quantum system, demonstrates Japan’s growing competitiveness in the global quantum race. Localized development enables flexible scalability, secure supply chains, and lower operational risks for users. Among these elements, the dilution refrigerator―ensuring a stable cryogenic environment essential for high-precision qubit operations―plays a vital role in enabling both deployment and long-term usability.
This quantum computer will be publicly demonstrated at the Expo 2025 Osaka, Kansai, Japan during the “entangle moment – [quantum | earth | universe] × art” event, to be held from August 14-20. Visitors will be able to interact with the system via the cloud, experiencing real-time quantum operations firsthand.
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Proposal for a new quantum computer architecture that separates the memory and processor
–Paving the way to practical quantum computation with a highly memory-efficient design with excellent portability
(2025/03/04)
Takumi Kobori, a graduate student (an intern at Nippon Telegraph and Telephone Corporation at the time) and Professor Synge Todo of the Graduate School of Science at The University of Tokyo, Researchers Yasunari Suzuki and Yuuki Tokunaga of Nippon Telegraph and Telephone Corporation, Research Fellow Yosuke Ueno of the RIKEN Quantum Computer Science Institute, and Associate Professor Teruo Tanimoto of the Graduate School of Systems Information Science, Kyushu University, have proposed a new architecture for error-tolerant quantum computation that applies the basic design of conventional computers to quantum computers. This technology is expected to accelerate the early realization of useful quantum computation by enabling high portability of programs (ease of migration to other environments) and utilization of highly efficient quantum hardware.
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Bidirectional state transfer between superconducting and microwave-photon qubits by single reflection
（May 5, 2024）
Abstract
The number of superconducting qubits contained in a single quantum processor is increasing steadily. However, to realize a truly useful quantum computer, it is inevitable to increase the number of qubits much further by distributing quantum information among distant processors using flying qubits. A key element towards this goal is a deterministic quantum interaction between superconducting-atom and propagating microwave-photon qubits. Here, we confirm the bidirectional state transfer between them, which completes by simply reflecting the photon at the atom. The averaged fidelity of the photon-to-atom (atom-to-photon) state transfer reaches 0.826 (0.801), limited mainly by the lifetime of the atom qubit. The present technology would be useful for future distributed quantum computation with superconducting qubits.
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Novel Microwave Isolator Points the Way to New Radio Cameras and Quantum Computers
（July 4, 2023）
Researchers at the National Astronomical Observatory of Japan (NAOJ) invented a novel microwave isolator and demonstrated for the first time its basic principle that enables small isolators that will be essential for future quantum computers. This isolator consists of two frequency mixers, which are widely used in receivers for radio telescopes, and paves the way for the development of large-scale multi-pixel radio cameras as well.
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Research group launches Japan’s third quantum computer at Osaka University
（December 20, 2023）
Quantum computer sources majority of components from Japanese makers
Tokyo and Osaka, December 20, 2023 – A consortium of joint research partners including the Center for Quantum Information and Quantum Biology at Osaka University, RIKEN, the Advanced Semiconductor Research Center at the National Institute of Advanced Industrial Science and Technology (AIST), the Superconducting ICT Laboratory at the National Institute of Information and Communications Technology (NICT), Amazon Web Services, e trees.Japan, Inc., Fujitsu Limited, NTT Corporation (NTT), QuEL, Inc., QunaSys Inc., and Systems Engineering Consultants Co.,LTD. (SEC) today announced the successful development of Japan’s third superconducting quantum computer (1) installed at Osaka University. Starting December 22, 2023, the partners will provide users in Japan access to the newly developed computer via the cloud, enabling researchers to execute quantum algorithms (2), improve and verify the operation of software, and explore use cases remotely.
The newly developed superconducting quantum computer uses a 64 qubit chip provided by RIKEN, which leverages the same design as the chip in RIKEN’s first superconducting quantum computer, which was unveiled to users in Japan as a cloud service for non commercial use on March 27, 2023 (3).
For the new quantum computer, the research team sourced more domestically manufactured components (excluding the refrigerator). The research team confirmed that the new quantum computer, including its components, provides sufficient performance and will utilize the computer as a test bed for components made in Japan.
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“The Moonshot 6 International Symposium 2023” took place at Akasaka Intercity Conference from July 18 to July 20. During the event, PM Tsuyoshi Yamamoto presented the project report in Session 3 “Superconductivity” on July 19. The session also featured talks from two renowned researchers, Dr. Opremcak from Google Inc. and Prof. Plourde from Syracuse University, both of whom were invited from abroad.
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Small But Mighty: New Superconducting Amplifiers Deliver High Performance at Lower Power Consumption
(2023/03/20)
Researchers have devised a new concept of superconducting microwave low-noise amplifiers for use in radio wave detectors for radio astronomy observations, and successfully demonstrated a high-performance cooled amplifier with power consumption three orders of magnitude lower than that of conventional cooled semiconductor amplifiers. This result is expected to contribute to the realization of large-scale multi-element radio cameras and error-tolerant quantum computers, both of which require a large number of low-noise microwave amplifiers.
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Realization of a novel method for the detection of parasitic defects in superconducting qubits
～Paving the way for removing defects in quantum processors～
(2022/12/22)
Nippon Telegraph and Telephone Corporation (NTT, Head office: Chiyoda-ku Tokyo; President & CEO: Akira Shimada) and the National Institute of Advanced Industrial Science and Technology (AIST) have realized a novel technique for the detection of parasitic defects in superconducting qubits. Superconducting qubits are among the most promising hardware platforms for building a quantum computer, but the realization of a full-scale fault-tolerant quantum computer remains a challenging task due to limited lifetimes of the superconducting qubits. One of the major noise mechanisms limiting the qubit lifetimes is due to unwanted two-level-system (TLS) defects in superconducting qubits. Therefore, investigation and mitigation of noise contributions from TLS defects are crucial for the further improvement of superconducting quantum processors. In this work, NTT and AIST introduce a novel method of defect spectroscopy in superconducting qubits that allows one to distinguish different types of TLS defects. The reported method will become a valuable diagnostic tool for quantifying TLS defects and finding optimal techniques and materials for the fabrication of defect-free superconducting qubits. This research was reported in the American journal PRX Quantum on December 21, 2022. This work was partially supported by JST CREST (JPMJCR1774) and JST Moonshot R&D (JPMJMS2067).
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