  We consider the energy averaged two-point correlator of spectral determinants
and calculate contributions beyond the diagonal approximation using
semiclassical methods. Evaluating the contributions originating from
pseudo-orbit correlations in the same way as in [S. Heusler {\textit {et al.}}\
2007 Phys. Rev. Lett. {\textbf{98}}, 044103] we find a discrepancy between the
semiclassical and the random matrix theory result. A complementary analysis
based on a field-theoretical approach shows that the additional terms occurring
in semiclassics are cancelled in field theory by so-called curvature effects.
We give the semiclassical interpretation of the curvature effects in terms of
contributions from multiple transversals of periodic orbits around shorter
periodic orbits and discuss the consistency of our results with previous
approaches.
