Macroscopic quantum coherence of chirality of a domain wall in ferromagnets

The possibility of macroscopic quantum-mechanical coherent oscillation between two chirality states of a domain wall separated by the energy barrier due to a transverse anisotropy is quantitatively discussed. The frequency of the oscillation is calculated for the case of weak transverse anisotropy. The chirality variable is shown to be canonically conjugate to the position of the domain wall. The stronger the pinning of the domain wall is, the more strongly the chirality fluctuates and the larger the frequency becomes. {} 1996 The American Physical Society.