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

To further improve stability and data integrity, the team developed a mid-circuit networking protocol, a technique designed to preserve the coherence of data qubits during network operations. —Jijo Malayil, Interesting Engineering, 12 Oct. 2025

The perfection and integration of superconducting qubits are among the state-of-the-art challenges in quantum information technology. —Zhixin Wang, The Conversation, 10 Oct. 2025

Put another way, building a functioning quantum network that can exchange many qubits securely, over long distances, could be a useful end goal completely apart from the quantum computer race. —Margo Anderson, IEEE Spectrum, 9 Oct. 2025

Modern qubit circuits have more knobs and wires and things, but that’s just how to tune the levels, how to couple or entangle them. —Ethan Siegel, Big Think, 8 Oct. 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