Scheme for the implementation of a universal quantum cloning machine via cavity-assisted atomic collisions in cavity QED

摘要

We propose a scheme to implement the $1\to2$ universal quantum cloningmachine of Buzek et.al [Phys. Rev.A 54, 1844(1996)] in the context of cavityQED. The scheme requires cavity-assisted collision processes between atoms,which cross through nonresonant cavity fields in the vacuum states. The cavityfields are only virtually excited to face the decoherence problem. That's whythe requirements on the cavity quality factor can be loosened.