nt - p h / 05 04 22 0 v 1 2 9 A pr 2 00 5 Network for transfer of an arbitrary n - qubit atomic state via cavity QED

I show a scheme which allows a perfect transfer of an unknown single-qubit atomic state from one atom to another by letting two atoms interact simultaneously with a cavity QED. During the interaction between atom and cavity, the cavity is only virtually excited and accordingly the scheme is insensitive to the cavity field states and cavity decay. Based on this scheme, a network for transfer of an arbitrary single-qubit atomic state between atoms is engineered. Then the scheme is generalized to perfectly transfer an arbitrary 2-qubit atomic state and accordingly a network for transfer of an arbitrary 2-qubit atomic state is designed. At last, it is proven that the schemes can be generalized to an arbitrary n(n ≥ 3)-qubit atomic state transfer case and a corresponding network is also proposed.