Glossary / Quantum computing
Superconducting qubit
A qubit made from a superconducting circuit, which has zero electrical resistance at very low temperature. Used by IBM, Google, Fujitsu and others.
In 1999 Yasunobu Nakamura, Yuri Pashkin and Jaw-Shen Tsai at NEC first created and controlled a quantum superposition in a tiny superconducting circuit[1]. The state lasted only nanoseconds, but because such circuits can be made with the same microfabrication as chips, the approach became one of today's main lines.
They must be cooled to about 0.01 kelvin in large refrigerators. Operations are fast but coherence is short, and each qubit connects easily only to its neighbours — properties that shape how error correction is designed.
Related terms
- QubitThe basic unit of information in a quantum computer. Rather than being either 0 or 1, it can be in a superposition of both.
- Trapped ionUsing atomic ions, suspended in a vacuum by electric fields and manipulated with lasers, as qubits. Used by Quantinuum and others.
- Quantum advantageThe point at which a quantum computer solves some computational problem faster than the best classical computer can.