JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, cilt.83, sa.1-3, ss.395-398, 1990 (SCI-Expanded)
We exhibit a novel solution of the strong CP problem, which does not involve any massless particles. The low energy effective Lagrangian of our model involves a discrete spacetime independent axion field which can be thought of as a parameter labeling a dense set of $\theta$ vacua. In the full theory this parameter is seen to be dynamical, and the model seeks the state of lowest energy, which has $\theta_{eff} = 0$. The processes which mediate transitions between $\theta$ vacua involve heavy degrees of freedom and are very slow. Consequently, we do not know whether our model can solve the strong CP problem in a universe which has been cool for only a finite time. We present several speculations about the cosmological evolution of our model.