Optimal Purification of Single Qubits
J. I. Cirac, ARTUR K. EKERT, Chiara Macchiavello · Physical Review Letters · 1999
We introduce a new decomposition of the multiqubit states of the form ${\ensuremath{\rho}}^{\ensuremath{\bigotimes}N}$ 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.