Journal of Modern Optics

Fidelity for Mixed Quantum States

Richard Jozsa

Published Dec 1, 1994• 1,898 citations

Abstract

We propose a definition of fidelity for mixed quantum states in terms of Uhlmann's ‘transition probability’ formula F(ϱ1, ϱ2) = {trace [(√ϱ1ϱ2 × √ϱ1)1/2]}2 and give new elementary proofs of its essential properties.

DOI: 10.1080/09500349414552171

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