  Optimal labeling schemes lead to efficient experimental protocols for quantum
information processing by nuclear magnetic resonance (NMR). A systematic
approach of finding optimal labeling schemes for a given computation is
described here. The scheme is described for both quadrupolar systems and
spin-1/2 systems. Finally, one of the optimal labeling scheme has been used to
experimentally implement a quantum full-adder in a 4-qubit system by NMR, using
the technique of transition selective pulses.
