The generalized rotating frame

I introduce the transformation of a large spin system externally driven by several oscillating magnetic fields to the generalized rotating frame, which is a natural generalization of the standard rotating frame. This method requires that the spin system has non-equidistant energy levels, which is usually satisfied by anisotropies. Possible applications include the implementation of the Grover algorithm in molecular magnets or in large nuclear spins of semiconductors and the coherent manipulation of large single-spin states of arbitrary dimension.