Researchers at the Flatiron Institute's Center for Computational Quantum Physics (CCQ) and Boston University have solved a class of quantum physics problems previously claimed to require a quantum computer — using an ordinary laptop. The study, published in the journal Science, simulated Ising spin glasses (disordered systems of interacting magnetic particles) arranged in square, cubic, and diamond lattices involving hundreds of qubits.
The team, led by Joseph Tindall and Miles Stoudenmire, revived a 1980s algorithm and applied it to tensor networks — mathematical structures that compress the exponentially growing wave functions of quantum systems. Tindall ran the initial simulations on a personal laptop using the open-source ITensor software library, matching the accuracy of a 5,000-qubit D-Wave quantum annealer that had claimed "beyond-classical" performance in March 2025.
The result reignites the debate over where classical computing ends and true quantum advantage begins. The researchers now plan to extend the technique to more complex electron systems, calling it "one of our next big bars to clear."