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

Quantum computers are designed to tackle problems that conventional computers cannot, but the qubits the technology relies on for certain calculations remain error-prone. — Paulina Likos, CNBC, 28 Sep. 2026

Infleqtion’s achievement of 30 logical qubits was experimentally confirmed by a signal that is approximately 1000x stronger than underlying noise, according to a press release. — Prabhat Ranjan Mishra, Interesting Engineering, 25 Sep. 2026

These qubits would make up the true fabric of our reality in the same way that screen pixels make up the physical reality of the video game characters. — Quanta Magazine, 25 Sep. 2026

The chips are coupled via a small piezoelectric disc that flexes when the qubit's electric field changes. — New Atlas, 23 Sep. 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