Helical symmetry of a potential
= Helical symmetry of a potential
A potential $V(r,\phi,z)=f(r,\phi-kz)$ is invariant under the screw transformation $(\phi,z)\mapsto(\phi+ks,z+s)$. The <Noether conserved quantity for a mechanical point symmetry> is
$$
p_z+kp_\phi,
$$
a linear combination of axial <linear momentum> and axial <angular momentum>.