What it is
Certified randomness lets a user obtain random bits from an untrusted remote device and prove they contain genuine entropy, something classical computation alone cannot deliver. The team ran the protocol on the 56-qubit Quantinuum H2-1 trapped-ion computer accessed over the internet: a client sends quantum challenge circuits built from a small seed, the untrusted server executes them, and the client verifies the returned results. Leveraging the classical hardness of random circuit sampling and 1.1 x 10^18 floating-point operations per second of sustained classical verification, they certified 71,313 bits of entropy against a restricted class of near-term adversaries.
Why it matters
Most quantum-advantage demonstrations produce outputs that are hard to simulate but have no direct use and cannot be independently confirmed. This turns the classical hardness of random circuit sampling into an end-to-end application whose result is both useful and checkable. Certified randomness underpins cryptographic key generation, lotteries, and any setting where the freshness of random bits must be provable rather than trusted.
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Filed undercertified randomness, trapped ions, quantum advantage, cryptography, random circuit sampling