Optimal mirror phase-covariant cloning

Karol Bartkiewicz, Adam Miranowicz, Şahin Kaya Özdemir
2009 Physical Review A. Atomic, Molecular, and Optical Physics  
We propose a quantum cloning machine, which clones a qubit into two clones assuming known modulus of expectation value of Pauli Z-matrix. The process is referred to as the mirror phase-covariant cloning, for which the input state is a priori less known than that for the standard phase-covariant cloning. Analytical expressions describing the cloning transformation and fidelity of the clones are found. Extremal equations for the optimal cloning are derived and analytically solved by generalizing
more » ... method of Fiurasek [Phys. Rev. A 64, 062310 (2001)]. Quantum circuits implementing the optimal cloning transformation and their physical realization in a quantum-dot system are described.
doi:10.1103/physreva.80.032306 fatcat:upkipwghz5edlayvzlfvkbe6fa