Phase Co-variant Cloning: Difference between revisions

This protocol achieves the functionality of [[Quantum Cloning]] Machine (QCM). Phase-covariant cloning describes is a special [[State Dependent N-M Cloning|state-dependent cloning]] which is able to make copies of a specific class of input states which satisfy a certain condition. For qubits, a phase-covariant cloner is a machine which is able to clone equatorial states ( states whose vector lies in the equator <math>(x-y)</math> plane of the [[Bloch sphere]]).  There are different phase-covariant cloning protocols for qubits. It can be done with or without an extra [[ancilla]] state and also asymmetric or symmetric. Generally, the state-dependent cloning protocol is asymmetric, meaning that copies have different [[fidelity]] (different qualities compared to the original state) and the symmetric protocol is only a special case of the asymmetric protocol.