Topological phases for bound states moving in a finite volume

We show that bound states moving in a finite periodic volume have an energy correction which is topological in origin and universal in character. The topological volume corrections contain information about the number and mass of the constituents of the bound states. These results have broad applications to lattice calculations involving nucleons, nuclei, hadronic molecules, and cold atoms. We illustrate and verify the analytical results with several numerical lattice calculations.

Figure 1

Lattice results and continuum extrapolation with error estimates for the fermion-dimer scattering length (top) and effective range parameter (bottom). For comparison we show the continuum results obtained via the Skorniakov-Ter-Martirosian equation.