Delocalized Qubits as a Computational Basis in the System of Interacting   Spins
  It is suggested to map the qubits into solid state NMR spin system collective states instead of the states of the individual spin. Such an approach introduces the stable computational basis without any additional actions and allows to obtain the universal set of quantum gates, which operation time is determined only by a RF pulse duration. 
Alexander R. Kessel and Vladimir L. Ermakov