New software tries to combine quantum computing and supercomputing

A project led by RIKEN is developing system software to tightly integrate quantum computers with supercomputers. The goal is to show that hybrid quantum and high-performance computing workflows can outperform supercomputers alone for selected problems.

The effort brings together researchers involved in Japan’s Fugaku supercomputer. It uses both ion-trap and superconducting quantum systems to keep the software compatible as quantum hardware scales.

The five-year project began in November 2023. Partners include the University of Tokyo, Osaka University, and SoftBank Corporation. The work focuses on testing practical hybrid use cases under supercomputer-level control.

The project is led by researchers from the Quantum High-Performance Computing Collaboration Platform Division at the RIKEN Center for Computational Science in Kobe. The leadership team includes contributors to the development of Fugaku, one of the world’s fastest supercomputers.

Quantum computers and supercomputers are designed for different tasks. Supercomputers handle large-scale simulations and massive datasets reliably. Quantum computers are suited to specific calculations that involve many possible combinations.

As problem complexity increases, conventional systems face rapid growth in possible outcomes. Quantum computers are designed to handle these cases more efficiently. This makes them useful for areas such as materials development, drug discovery, artificial intelligence, and optimization.

Current quantum computers remain limited in size and stability. They require conventional computers to control operations and manage communication. As quantum systems scale to thousands of qubits, supercomputer-level resources are expected to become essential.

The project has deployed two quantum systems. Reimei is an ion-trap quantum computer developed by Quantinuum and installed at RIKEN’s Wako campus in February 2025. The second system is a superconducting machine from IBM, known as IBM Quantum System Two, installed at RIKEN’s Kobe campus in June.

Both systems are being tested by multiple user groups. The work evaluates how tightly integrated quantum and supercomputer resources can be programmed together.

The project aims to demonstrate that coordinated quantum and supercomputer computing can deliver practical benefits today, rather than only in future systems.