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

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

Our machine moves forward by a factor of two every logical qubit. —Andrew Edgecliffe-Johnson, semafor.com, 20 Mar. 2026

These atomic structures serve as stable quantum bits (qubits), which can store and process quantum information and couple it to light particles. —Prabhat Ranjan Mishra, Interesting Engineering, 19 Mar. 2026

Unlike classical bits, which are either on or off, qubits can exist in superpositions—effectively coexisting in multiple states simultaneously. —Chi Chen, IEEE Spectrum, 2 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