RIKEN protein model reaches 12,635 atoms using quantum-classical computing A research collaboration between Cleveland Clinic, RIKEN, and IBM has reached a new benchmark in molecular modeling, simulating a protein containing 12,635 atoms, the largest ever achieved using quantum computers, the company says. The team’s success, detailed in work initially published in May 2026, combines the power of quantum and classical computing in a framework they call quantum-centric supercomputing, with calculations running on IBM Quantum Heron processors at both Cleveland Clinic and RIKEN, alongside Japan’s Fugaku and Miyabi-G supercomputers. To achieve these results, the team first scaled their method roughly 40 times while also achieving 210 times improvement in accuracy, and then advanced the work further. This achievement has earned the team a place as a finalist for the 2026 ACM Gordon Bell Prize, recognizing outstanding innovation in high-performance computing, and targets improvements in drug discovery by more accurately computing atomic energies during biological processes. The team validated the workflow on JHPC-quantum GPU supercomputer “ROQUO,” RIKEN’s newest system, eliminating the need for complex manual operations and data transfers. Quantum-Classical Methods Simulate 12,635-Atom Protein The simulation achieved a 210-fold improvement in accuracy, accomplished less than one year after the team first scaled their method roughly 40 times. This leap in precision stems from refinements to embedded wavefunction methods at Cleveland Clinic, adapted to address the specific challenges of this larger system. The researchers coupled these advancements with sample-based quantum diagonalization developed jointly by IBM and RIKEN, a technique previously highlighted on the cover of Science Advances. This combined approach, termed quantum-centric supercomputing, uses the strengths of both computational paradigms to tackle previously intractable problems in molecular modeling. RIKEN’s commitment to hybrid quantum-classical computing is underscored by its st
