qubit

noun

qu·​bit ˈkyü-bət 

plural qubits

: a unit of computing information that is represented by a state of an atom or elementary particle (such as the spin) and can store multiple values at once due to the principles of quantum mechanics

And the most basic truth of quantum mechanics dictates that you cannot measure a qubit without destroying the superposition. The register that said 1 and 0 will randomly collapse into 1 or 0.

—George Johnson

compare bit entry 3 sense 1

Examples of qubit in a Sentence

Recent Examples on the Web

The company is pursuing a hybrid analog-digital approach to quantum computing, with a roadmap aiming for systems with up to 10,000 physical qubits and 100 logical qubits within the next few years. —John Prisco, Forbes.com, 4 Aug. 2025

However, while qubits are commonly associated with quantum computing, in this case the antiproton qubit will be used to test for differences between ordinary matter and antimatter. —Keith Cooper, Space.com, 24 July 2025

The merged company expects to build systems with 256 qubits by 2026, over 10,000 by 2027 and 2 million by 2030. —Samantha Subin, CNBC, 9 June 2025

Probably the biggest challenge is still keeping qubits in a stable state. —Bernard Marr, Forbes.com, 23 July 2025

Word History

Etymology

qu- (in quantum entry 2) + bit entry 4, probably formed with punning allusion to cubit

Note: According to the American physicist Benjamin Schumacher, in the acknowledgements to a paper ("Quantum coding," Physical Review A, vol. 51, issue 4 [April, 1995], p. 2747), "The term 'qubit' was coined in jest during one of the author's many intriguing and valuable conversations with W. K. Wootters, and became the initial impetus for this work."

First Known Use

1994, in the meaning defined above

Rhymes for qubit

• cubit