Abstract
We propose a quantum cloning machine, which clones a qubit into two clones assuming known modulus of expectation value of Pauli 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 a method of Fiurášek [Phys. Rev. A 64, 062310 (2001)]. Quantum circuits implementing the optimal cloning transformation and their physical realization in a quantum-dot system are described.
- Received 31 May 2009
DOI:https://doi.org/10.1103/PhysRevA.80.032306
©2009 American Physical Society