quantum bit

American  

noun

Computers.

1. the fundamental unit of information in a quantum computer, capable of existing in two states, 0 or 1, simultaneously or at a different time.

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quantum bit Scientific  

1. The smallest unit of information in a quantum computer. Unlike bits in classical systems, which are in one of two possible states labelled 1 and 0, a quantum bit exists in a superposition of these two states, settling on one or the other only when a measurement of the state is made.

2. Also called qubit

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Etymology

Origin of quantum bit

First recorded in 1990–95

Example Sentences

See Examples For:

quantum bit

A familiar example is a quantum bit, or qubit, which can exist in a combination of both 0 and 1 at the same time.

From Science Daily ● Jun. 15, 2026

By harnessing that odd behavior, scientists can instead build a quantum bit, or qubit, which stores a combination of 1 and 0.

From New York Times ● Oct. 23, 2019

But superposition means that a quantum bit, or qubit, isn’t confined to being just 0 or 1.

From Washington Post ● Oct. 23, 2019

Quantum computers work in a fundamentally different way from classical machines: a classical bit is either a 1 or a 0, but a quantum bit, or qubit, can exist in multiple states at once.

From Nature ● Oct. 22, 2019

But a quantum bit, or ‘qubit’, can assume both states and an infinite number of states inbetween.

From Scientific American ● Aug. 1, 2013