Information transfer on an NMR quantum information processor

Nuclear magnetic resonance (NMR) has been used to explore and demonstrate m any of the ideas behind quantum information processing (QIP). This work pro vides an illustrative example or information transfer over both quantum and classical channels using NMR techniques on the two-spin compound C-13-chlo roform. A two-qubit model of a classical channel that is a reduction oi a q uantum channel can be implemented via the correlation of a spin representin g information on a channel, with an ancilla spin representing the surroundi ng world. When information about this corellation is lost or discarded. the channel becomes classical: otherwise, it remains quantum. It is shown that , while classical information can be transmitted over either a quantum or c lassical channel, quantum information will only survive transmission over a quantum channel. (C) 2001 John Wiley & Sons, Inc. Sons, inc.