Four-Dimensonal Gauss-Bonnet Gravity Without Gauss-Bonnet Coupling to Matter - Spherically Symmetric Solutions, Domain Walls and Spacetime Singularities

Eduardo Guendelman, Emil Nissimov, Svetlana Pacheva

Research output: Working paper/PreprintPreprint

Abstract

We discuss a new extended gravity model in ordinary D = 4 spacetime dimensions, where an additional term in the action involving Gauss-Bonnet
topological density is included without the need to couple it to matter fields
unlike the case of ordinary D = 4 Gauss-Bonnet gravity models. Avoiding
the Gauss-Bonnet density becoming a total derivative is achieved by employing
the formalism of metric-independent non-Riemannian spacetime volume-forms.
The non-Riemannian volume element triggers dynamically the Gauss-Bonnet
scalar to become an arbitrary integration constant on-shell. We describe in some
detail the class of static spherically symmetric solutions of the above modified
D = 4 Gauss-Bonnet gravity including solutions with deformed (anti)-de Sitter geometries, black holes, domain walls and Kantowski-Sachs-type universes.
Some solutions exhibit physical spacetime singular surfaces not hidden behind
horizons and bordering whole forbidden regions of space. Singularities can be
avoided by pairwise matching of two solutions along appropriate domain walls.
For a broad class of solutions the corresponding matter source is shown to be a
special form of nonlinear electrodynamics whose Lagrangian L(F2) is a nonanalytic function of F2 (the square of Maxwell tensor Fµν ), i.e., L(F2) is not
of Born-Infeld type
Original languageEnglish GB
StatePublished - 2018

Publication series

NamearXiv preprint

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