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

Central to this capability of quantum computers are quantum bits or qubits that can exist in states of 0, 1 or a combination of both, known as a superposition. —Ameya Paleja, Interesting Engineering, 12 May 2026

The two-qubit gates were executed successfully over 99 percent of the time, while teleportation succeeded about 87 percent of the time. —ArsTechnica, 8 May 2026

Adding qubits together increases the number of states exponentially. —Gary Skuse, The Conversation, 28 Apr. 2026

Ours is an economy built from entangled qubits, or quantum bits — the foundation of technologies that have changed how the world sends, stores, protects and processes the information encoding nearly every inch of our lives. —David Awschalom, Chicago Tribune, 26 Apr. 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