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

Imec just demonstrated that silicon qubits can be easily scaled and do not require an evolution in quantum computing technology to be rolled out. —Ameya Paleja, Interesting Engineering, 26 May 2026

Other companies, including a number funded in the same announcement, are using technologies that host qubits in very different hardware or no hardware at all. —ArsTechnica, 25 May 2026

Recent advances have resulted in lower error rates as more qubits are added. —Aldo Svaldi, Mercury News, 19 May 2026

The technique, which works by bouncing signals onto qubits and effectively listening for their echoes, runs 13,000 times faster on Willow than an equivalent algorithm would on the best classical supercomputer. —Zeeya Merali, Scientific American, 19 May 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