Cleveland Clinic, RIKEN, and IBM Model a 12,635-Atom Protein – the Largest Known to Be Simulated with Quantum Computers Milestone simulation of biologically meaningful molecules expands quantum-centric supercomputing’s role as a scientific tool YORKTOWN HEIGHTS, N.Y. and CLEVELAND, May 5, 2026 /PRNewswire/ — Scientists at Cleveland Clinic, RIKEN, and IBM (NYSE: IBM) have used IBM quantum computers and two of the world’s most powerful supercomputers to simulate protein complexes spanning up to 12,635 atoms. These are the largest-known simulations of biologically meaningful molecules performed with quantum hardware yet, and signal that quantum computers are maturing into useful scientific tools which can help solve fundamental problems in biology, chemistry, and life sciences. Researchers at IBM, Cleveland Clinic, and RIKEN used quantum-centric supercomputing to model the protein trypsin, a 12,635-atom protein and the largest known to be simulated with quantum computers. (Credit: IBM, Cleveland Clinic, and RIKEN) The results were achieved in part by an innovative algorithm that optimizes how quantum and classical computers can work together, a framework known as quantum-centric supercomputing. Using this approach, the team captured the behavior of two biochemically relevant proteins that are roughly 40 times larger than what this same method could initially achieve just six months ago. Additionally, the accuracy of the simulations in a key step of the workflow improved by up to 210 times over this same period. The decision to explore if quantum computers could offer value in the simulation of protein complexes was motivated by challenges faced today by researchers when studying how a drug candidate could bind to a protein. This can be one of the most difficult and expensive problems in life sciences research, and one that today’s existing computational methods have struggled to exactly solve as molecules increase in size. Doing so accurately and early in the discovery