Quantinuum and RIKEN have announced that a full scientific workflow, studying biomolecular reactions, has been executed across RIKEN’s supercomputer Fugaku and Quantimuun’s trapped-ion computer Reimei.
The Reimei system was integrated with Fugaku in February 2025, as part of a national project commissioned by Japan’s New Energy and Industrial Technology Development Organization (NEDO), the national research and development entity under the Ministry of Economy, Trade and Industry.
Quantum Biology
In this first foray into hybrid HPC-quantum computation, the research explored chemical reactions that occur inside biomolecules such as proteins. Reactions of this type are found throughout biology, from enzyme functions to drug interactions.
Simulating such reactions accurately is extremely challenging. The region where the chemical reaction occurs—the “active site”—requires very high precision, because subtle electronic effects determine the outcome. At the same time, this active site is embedded within a much larger molecular environment that must also be represented, though typically at a lower level of detail. To address this complexity, computational chemistry has long relied on layered approaches, in which different parts of a system are treated with different methods.
The Project
The purpose of this project was to demonstrate a fully functional hybrid system working as an end-to-end platform for real scientific applications. Fugaku handled geometry optimization and baseline electronic structure calculations, while Reimei was used to enhance the treatment of the most difficult electronic interactions in the active site, which are known to challenge conventional approximate methods. The entire process was coordinated through Quantinuum’s workflow system Tierkreis, which allows jobs to move between machines.
Read the scientific paper here.
