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

Until now, the number of qubits required to crack encryption was thought to be in the millions, and therefore out of reach. —Jim Edwards, Fortune, 31 Mar. 2026

Other milestones include higher qubit counts — which increase the potential size and complexity of problems a quantum computer can represent and help solve — and coherence times, which allow more reliable computations by reducing the impact of noise and errors. —Dylan Butts,matthew Chin, CNBC, 30 Mar. 2026

The team said the next steps include improving precision in atom placement, reducing interference further, and increasing the number of qubits on a single chip. —Neetika Walter, Interesting Engineering, 27 Mar. 2026

However, a stray thermal vibration can scramble qubit states in quantum computing or degrade the coherence in quantum sensors. —Etiido Uko march 23, New Atlas, 23 Mar. 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