Cross-Entropy Benchmarking Verifier

Random circuit sampling only proves "quantum supremacy" if you can statistically certify that the samples really came from the hard-to-simulate quantum distribution and not from a classical shortcut. This simulator reproduces that certificate: linear cross-entropy benchmarking (XEB). A Porter–Thomas-distributed target distribution stands in for a genuinely scrambled random circuit's output, and two independent sample streams draw bitstrings from it live — an "honest" noisy quantum sampler whose fidelity you control, and a classical "spoofing" adversary whose sophistication you control. Both streams feed the exact linear-XEB estimator used on real hardware, and you watch the two running averages diverge in real time: the honest stream climbs toward the true fidelity while a naive classical guesser is pinned near zero, exactly the gap that makes XEB a working supremacy test.