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 two possible spins of the quarks correspond to the 0 and 1 states of a qubit, a unit of quantum information. —Shalma Wegsman, Quanta Magazine, 25 Nov. 2025

Quantum computers, which aim to solve much more difficult problems than traditional computers or AI, need to reach near absolute zero — or the lowest possible temperature — for the quantum bits, or qubits, to remain stable and perform calculations. —Rachyl Jones, semafor.com, 21 Nov. 2025

Symmetry as a Guide The complexity of quantum systems grows quickly as more qubits come online. —Aamir Khollam, Interesting Engineering, 20 Nov. 2025

That chip contains a special material the company says can create a new state of matter capable of producing more stable qubits. —Lisa Eadicicco, CNN Money, 12 Nov. 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 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