Determine the negative-mode spectrum of the complex Gauss–Bonnet wormholes

Determine the fluctuation spectrum of the complex wormhole solutions supported by a massless scalar linearly coupled to the four-dimensional Gauss–Bonnet invariant, and establish the number and nature of their negative modes.

Background

The paper establishes the existence of a complex branch of O(4)-symmetric wormholes, proves that the branch satisfies the Kontsevich–Segal–Witten criterion, and identifies an algebraic branch point at which the branch terminates.

It does not analyze perturbations around these saddles. The unresolved fluctuation problem is important for determining their semiclassical character and whether they can contribute consistently to a gravitational path integral.