qu·​bit ˈkyü-bət How to pronounce qubit (audio)
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 What’s more, molecular qubits can have very long coherence times. Philip Ball, Quanta Magazine, 25 Mar. 2024 With every additional qubit, the number of states that can be represented by the qubits doubles. Daniel Lidar, Discover Magazine, 23 Nov. 2023 As for expanding the types of NP-complete problems that can be solved now, doing so comes at a cost—the number of qubits needed increases as the square of the number of qubits needed if the problem could be solved natively. John Timmer, Ars Technica, 16 Feb. 2023 This only becomes practical if the number of physical qubits needed for each logical qubit isn’t too great. Philip Ball, Quanta Magazine, 25 Mar. 2024 In the case of qubits, they can be correlated in a similar way. Quanta Magazine, 14 Mar. 2024 The photons can be used as quantum bits (qubits), the quantum equivalent of classical computing’s 0s and 1s. IEEE Spectrum, 10 Jan. 2024 Additional qubits are used to monitor the logical qubit for errors and allow for their correction. John Timmer, Ars Technica, 4 Dec. 2023 The physical qubits that make up each virtual qubit are like those oblivious quantum spies. Ben Brubaker, WIRED, 17 Mar. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'qubit.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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 acknowledgements 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

Time Traveler
The first known use of qubit was in 1994

Dictionary Entries Near qubit

Cite this Entry

“Qubit.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/qubit. Accessed 17 Jun. 2024.

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