More about a bosonic string with a topological term

Smooth flux-sheets with topological winding modes

“…The total surface integral of the intrinsic curvature in the action induces topological fluctuations [18] with subsequent modifications of the boundary conditions [17] by virtue of the Gauss-Bonnet theorem. The coupling of the PK string action to the boundary curvatures [17] could displace the energy spectrum to detectable levels over hadronic diameters R < 0.5 fm.…”