Neutron-antineutron oscillations in an applied magnetic field

The phenomenology of neutron-antineutron ($n-\overline{n}$) oscillations in the presence of an applied external magnetic field is developed. Conditions are derived for optimizing the growth of $\overline{n}$ probability in a neutron beam. For the case of a space-varying field (precession around a field axis), no "long-time" or "high-field" solutions exist. For the case of a time-varying field, long-time solutions exist but with a quadratic growth coefficient about $\frac{1}{3}$ that of the degaussed (zero-field) solution. No high-field solutions were found to be better than the zero-field solutions. However, it may be experimentally advantageous to apply a driving field instead of degaussing to the levels required for the zero-field case.