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 achievement of building a quantum heat engine sets the stage to build an entire autonomous heat engine that can perform jobs like reading qubits without using microwave pulses from temperatures near absolute zero to room temperature. — Ameya Paleja, Interesting Engineering, 13 July 2026

And that can be done in parallel with the error detection and correction system that manages the logical qubit. — John Timmer, ArsTechnica, 10 July 2026

This again marked a nearly 20-fold reduction in the number of physical qubits previously estimated. — IEEE Spectrum, 7 July 2026

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 acknowledgments 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