Researchers model 12,635‑atom protein with quantum computers in record-setting simulation

In a sign that quantum computing is edging into real-world laboratory work, researchers at Cleveland Clinic, RIKEN and IBM have used IBM quantum processors alongside two of the world’s most powerful supercomputers to simulate protein complexes spanning up to 12,635 atoms.

The team described the result, disclosed on May 5, 2026, as the largest known simulation of biologically meaningful molecules performed with quantum hardware to date, reported in a preprint study. The advance hinges on an algorithm that improves how quantum and classical machines divide the workload — a framework the group refers to as quantum‑centric supercomputing.

Using this approach, the scientists modeled two biochemically relevant proteins that are roughly 40 times larger than what their method handled six months earlier, while improving accuracy in a key step of the workflow by up to 210 times over the same period. The work targets a longstanding bottleneck in drug research: predicting how a candidate compound will bind to a protein.

As molecules grow larger, today’s classical methods often struggle to capture the underlying quantum mechanics with high fidelity. The researchers say earlier, more accurate insight could shorten drug development timelines that now frequently extend beyond a decade.

“This work marks an important advance and underscores quantum computing’s emerging role on systems of relevance to drug discovery,” said Kenneth Merz, Ph.D., lead author of the study and a staff scientist in Cleveland Clinic’s Computational Life Sciences Department.

“By crossing the 12,000‑atom barrier, we have significantly expanded the scale of biologically meaningful molecular simulations possible with quantum computing.” IBM Research Director and IBM Fellow Jay Gambetta said the results show quantum computers “are producing results that matter to science,” adding that the molecules simulated are the kind biologists and chemists work with in practice.

The research builds on prior milestones by the same institutions, including work featured in Science Advances that introduced techniques to model electronic states in molecules, first shown on iron sulfides, and a subsequent demonstration on the 303‑atom benchmark molecule Trp‑cage — cited as the first known full quantum‑centric simulation of a chain comprising 20 amino acids.

In the latest experiments, classical supercomputers decomposed protein‑ligand complexes into computable fragments, while IBM’s 156‑qubit IBM Quantum Heron processors calculated the quantum‑mechanical behavior of those pieces.

The quantum hardware ran at Cleveland Clinic in the United States and at RIKEN in Japan, working in tandem with the Fugaku supercomputer at RIKEN and Miyabi‑G, operated by the University of Tokyo and the University of Tsukuba. The team frames the result as evidence that quantum‑centric supercomputing is becoming a practical scientific instrument.

The next steps, according to the preprint, involve scaling the approach to more complex systems and integrating it further into computational pipelines used in biology and chemistry.