Tilted washboard potential
= Tilted washboard potential
{title2=$V=-\omega\theta-\epsilon\cos\theta$}
A periodic corrugation plus a uniform tilt. For the <Adler phase equation>, $V(\theta)=-\omega\theta-\epsilon\cos\theta$ gives force $-V'=\omega-\epsilon\sin\theta$ and $V(\theta+2\pi)-V(\theta)=-2\pi\omega$. It has wells when $|\omega|<\epsilon$ and no extrema when $|\omega|>\epsilon$. It is a potential on the unwrapped phase, not a single-valued periodic potential on the circle.