title: Resurgence in quasiclassical scattering.
abstract: In quasiclassical spectral theory, "resurgence" means that long periodic orbits can be expressed by short ones in such a way that the spectral determinant is real. The question has thus long been posed whether long scattering orbits can be expressed by short orbits in such a way as to make the quasiclassical scattering matrix unitary. We here find a resurgent and manifestly Hermitean expression for Wigner's R matrix, implying a unitary scattering matrix. The result is particularly important if the average resonance width is comparable with the average resonance spacing.
authors.affiliation: Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Street 38, D-01187 Dresden, Germany.
authors.forename: R E
authors.initials: RE
authors.lastname: Prange