What is quantum computing?

Classical bits are either 0 or 1, but qubits exploit superposition and entanglement, quantum effects that let many possibilities be processed together. In 2019 Google reported that its 53-qubit Sycamore chip completed a task in about 200 seconds that it estimated would take a supercomputer 10,000 years, a claim rivals disputed. In December 2024 Google’s 105-qubit Willow chip finished a benchmark in under five minutes that it said would take a top supercomputer 10 septillion years. Most quantum processors must be cooled to around 15 thousandths of a degree above absolute zero, colder than outer space. Scientists expect uses in drug design, materials science and code-breaking, which is why new quantum-resistant encryption standards are being adopted.