In October 2019 Google AI's team, led by John Martinis, publishes in Nature "Quantum supremacy using a programmable superconducting processor": the 53-qubit Sycamore processor performs in 200 seconds a random circuit sampling task that Google claims would take 10,000 years on the fastest classical supercomputer — the first experimental demonstration of quantum supremacy. The result is controversial: IBM argued optimized classical simulation could do it in 2.5 days, and in 2022 Chinese researchers classically simulated it in hours. The task has no known practical application. Despite controversy, Sycamore marks a historic inflection point, demonstrating tens-of-qubit quantum processors are buildable and operable, inaugurating the NISQ (Noisy Intermediate-Scale Quantum) era.