Constructive methods for controlling a coupled, two spin system via bounded amplitude, piecewise sinusoidal fields are provided. The fields are incident at the alrmor frequencies and take one of two phase values
@article{arxiv.quant-ph/0012019,
title = {Control of a Coupled Two Spin System Without Hard Pulses},
author = {V. Ramakrishna and R. J. Ober and K. L. Flores and H. Rabitz},
journal= {arXiv preprint arXiv:quant-ph/0012019},
year = {2007}
}