The '''Bell basis''' is a basis for the Hilbert space of a 2-qubit system where the basis vectors are defined in terms of the computational basis as :
:$\backslash begin\{cases\}\; |\backslash Psi^-\; \backslash rangle\; =\; \backslash frac\{1\}\{\backslash sqrt\{2\}\}(|01\backslash rangle\; -\; |10\backslash rangle)\; \backslash \backslash \; |\backslash Psi^+\; \backslash rangle\; =\; \backslash frac\{1\}\{\backslash sqrt\{2\}\}(|01\backslash rangle\; +\; |10\backslash rangle)\; \backslash \backslash \; |\backslash Phi^-\; \backslash rangle\; =\; \backslash frac\{1\}\{\backslash sqrt\{2\}\}(|00\backslash rangle\; -\; |11\backslash rangle)\; \backslash \backslash \; |\backslash Phi^+\; \backslash rangle\; =\; \backslash frac\{1\}\{\backslash sqrt\{2\}\}(|00\backslash rangle\; +\; |11\backslash rangle)\; \backslash end\{cases\}$
The quantum states represented by these vectors are called Bell states and are maximally entangled. Density matrices which are diagonal in this basis are called Bell-diagonal.
== See also ==
* Bell state
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Category:Quantum States

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Monday, October 26, 2015 - 17:56