Purity is a measure of how pure a quantum state is. It is often used because it is easy to compute. It is defined as tr(ρ2).

The purity is one for pure states and 1/d for maximally mixed states of dimension d.

Related to the purity is the linear entropy, which measures the mixedness of a state.

Category: Stubs Category: Entropy

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Monday, October 26, 2015 - 17:56