Optimal Purification of Single Qubits

J. I. Cirac; A. K. Ekert; C. Macchiavello

doi:10.1103/PhysRevLett.82.4344

Optimal Purification of Single Qubits

J. I. Cirac, A. K. Ekert, and C. Macchiavello

Phys. Rev. Lett. 82, 4344 – Published 24 May 1999

Abstract

We introduce a new decomposition of the multiqubit states of the form $ρ^{\otimes N}$ and employ it to construct the optimal single qubit purification procedure. The same decomposition allows us to study optimal quantum cloning and state estimation of mixed states.

Received 28 December 1998

DOI:https://doi.org/10.1103/PhysRevLett.82.4344

Authors & Affiliations

J. I. Cirac¹, A. K. Ekert², and C. Macchiavello³

¹Institut für Theoretische Physik, Universität Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
²Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
³Dipartimento di Fisica “A. Volta” and INFM–Unità di Pavia, Via Bassi 6, 27100 Pavia, Italy