nLab Bell state



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In quantum physics, what are called Bell states or EPR states or EPR pairs are certain quantum states exhibiting maximal quantum entanglement.

In qbit-based quantum computation, the elementary Bell state is usually prepared via the following small quantum circuit consisting of a Hadamard gate followed by a quantum CNOT gate:

quantum probability theoryobservables and states


The terminology “EPR state” is in honor of Einstein, Podoldsky & Rosen 1935 and “Bell state” is in honor of Bell 1964.

Textbook accounts:

In string diagram-calculus (finite quantum mechanics in terms of dagger-compact categories):

See also:

Last revised on October 26, 2022 at 08:53:01. See the history of this page for a list of all contributions to it.