A measurement scheme for purity based on two two-body gates

Abstract

A scheme for measuring the purity of a quantum system with a finite number of levels is presented. The method makes use of two square root of SWAP gates and only hinges on measurements performed on a reference system, prepared in a certain pure state and coupled with the target system. Neither tomographic methods, with the complete reconstruction of the state, nor interferometric setups is needed.

7pages, 1figure

Cited by in corpus (2)

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• Possibility of a minimal purity-measurement scheme critically depends on the parity of dimension of the quantum system