GoKawiilScientists used a new error correction strategy to encode 70 logical qubits and tackle a problem considered classically intractable.
The quantum computation was completed in about 15 minutes, while leading classical computing methods would require an impractical amount of time to perform the same task.
IBM and researchers at the University of Chicago have announced a quantum computing demonstration that meets key criteria for quantum advantage. The experiment performed a calculation beyond the practical reach of leading classical simulation techniques while also providing evidence that the quantum computer produced a reliable result.
In a new paper, "Sampling hard circuits with verifiably high fidelity," the researchers describe how they achieved both goals using a newly designed form of encoded quantum circuit. The work represents one of the largest demonstrations of logical quantum computing reported so far.
The circuits and experimental results have also been made publicly available through the Quantum Advantage Tracker.
Why Quantum Results Are So Difficult to Verify
Researchers have long used a benchmark called random circuit sampling (RCS) to explore whether quantum computers can outperform conventional machines.
In simplified terms, RCS challenges a quantum computer to generate patterns that become so complicated that a classical computer cannot efficiently reproduce them. That makes the benchmark useful for testing the limits of classical simulation.
But it also creates a major problem. Once the quantum calculation becomes too difficult for a classical computer to reproduce, verifying that the quantum machine actually produced the correct result becomes increasingly difficult as well. Eventually, checking the answer can itself become infeasible unless researchers make strong assumptions about how the quantum computer behaves internally.
The IBM and University of Chicago team approached this verification problem by developing a more structured alternative to RCS.
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