We propose a quantum cloning machine, which clones a qubit into two clones assuming known modulus of expectation value of Pauli σz 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.
|Original language||English (US)|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - Sep 3 2009|
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics