Phase winding of a condensate
= Phase winding of a condensate
{title2=$\oint d\phi=2\pi n$}
If a condensate order parameter stays nonzero along a closed loop, its phase changes by an integer multiple of $2\pi$. Broken <rotational symmetry> does not destroy this single-valuedness constraint. In an inhomogeneous ring the winding integer need not label an angular-momentum <eigenstate>.