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

Unlike digital computers that use 0s and 1s, quantum computers use qubits, which operate under the principles of quantum mechanics to process information at much higher speeds. —Gordon G. Chang, Newsweek, 11 Dec. 2024

If the physical qubits are too failure-prone, error correction is counterproductive — adding more physical qubits will make the logical qubits worse, not better. —Ben Brubaker, Quanta Magazine, 9 Dec. 2024

Instead of bits, which represent either 1 or 0, quantum computing uses qubits, a unit that can exist in multiple states at the same time, such as 1, 0, and anything in between. —Emma Roth, The Verge, 9 Dec. 2024

With each new discovery in quantum error correction and scaling new qubit modalities, the predictions for Q-day or Y2Q get closer. —Denis Mandich, Forbes, 21 Oct. 2024

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