Glossary / Quantum computing
Quantum advantage
The point at which a quantum computer solves some computational problem faster than the best classical computer can.
In 2019 Google ran random circuit sampling — drawing many outputs from a randomly built circuit — on a 53-qubit superconducting chip in about 200 seconds, and claimed a supercomputer would need 10,000 years[1]. The task had been proposed in a paper the year before[2].
Classical methods have since improved and narrowed the gap considerably. Any advantage claim depends on whether the classical competitor is really the best available and on whether the answers can be verified. Advantage on a genuinely useful problem has not yet been shown.
Related terms
- Superconducting qubitA qubit made from a superconducting circuit, which has zero electrical resistance at very low temperature. Used by IBM, Google, Fujitsu and others.
- QubitThe basic unit of information in a quantum computer. Rather than being either 0 or 1, it can be in a superposition of both.
- Logical qubitA single, robust qubit made by bundling many physical qubits together and running error correction on them.