quantum state

American  

noun

Physics.

1. the condition in which a physical system exists, usually described by a wave function or a set of quantum numbers.

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quantum state British  

noun

1. physics a state of a system characterized by a set of quantum numbers and represented by an eigenfunction. The energy of each state is precise within the limits imposed by the uncertainty principle but may be changed by applying a field of force. States that have the same energy are called degenerate See also energy level

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quantum state Scientific  

1. A description in quantum mechanics of a physical system or part of a physical system. Different quantum states for a physical system show discrete differences in the value of the variables used to define the state. For example, the spin of an isolated electron can take on one of only two values; there are no other quantum states available for the electron and no intermediate values, since spin is quantized. The quantum state is sometimes described by a set of quantum numbers that pick out the appropriate values for describing the state.

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Etymology

Origin of quantum state

First recorded in 1920–25

Example Sentences

The fidelity, or the accuracy, of a system’s quantum state.

From Barron's • May 21, 2026

Entanglement allows multiple qubits to share a single quantum state and act as one coordinated system, which is essential for powerful quantum computers.

From Science Daily • Apr. 13, 2026

A superatom consists of several natural atoms that share the same quantum state and behave collectively as one larger atom.

From Science Daily • Apr. 13, 2026

Qubits are extremely fragile, and the slightest changes in the environment can disrupt their delicate quantum state.

From Barron's • Jan. 6, 2026

Again, if we knew how the Euclidean curved space-times in the sum over histories behaved at early times, we would know the quantum state of the universe.

From "A Brief History of Time: And Other Essays" by Stephen Hawking