the isospin transition matrix elements in partially twisted heavy baryon . Nucleons (deltas) are represented by single (double) lines, while mesons are represented by dashed lines. The cross is the hairpin interaction, and the wiggly line shows the insertion of the isospin raising operator. []{data-label="f:Nvecff"}](Nvecff.eps){width="35.00000%"}

Dynamical effects due to twisted boundary conditions arise from the propagation of the light Goldstone modes to the boundary. The sensitivity of these modes to the boundary conditions must be taken into account and can be done so in a model-independent way using baryon  in finite volume. The modification to the effective theory is straightforward. In effect, we replace the integrals over loop momenta with sums over the allowed[^5] modes $\bm{k} = 2 \pi \bm{n}/ L$. The twisting is already taken into account in the effective theory by the $U(1)$ gauge covariant derivative $\Dt_\mu$ above. The Poisson re-summation formula then allows us to cast these sums into the infinite volume result plus the finite volume modification.

There are, however, further contributions from using the partially twisted chiral theory in a box.[^6] Diagrams that ordinarily vanish in infinite volume can now make contributions in a finite volume. This is the case for the diagrams depicted in 