PIRSA:20040094

On Gauss-Bonnet gravity in four dimensions

Kubiznak, D. (2020). On Gauss-Bonnet gravity in four dimensions. Perimeter Institute. https://pirsa.org/20040094

Kubiznak, David. On Gauss-Bonnet gravity in four dimensions. Perimeter Institute, Apr. 30, 2020, https://pirsa.org/20040094 

          @misc{ pirsa_PIRSA:20040094,
            doi = {10.48660/20040094},
            url = {https://pirsa.org/20040094},
            author = {Kubiznak, David},
            keywords = {Strong Gravity},
            language = {en},
            title = {On Gauss-Bonnet gravity in four dimensions},
            publisher = {Perimeter Institute},
            year = {2020},
            month = {apr},
            note = {PIRSA:20040094 see, \url{https://pirsa.org}}
          }

David Kubiznak

Charles University

Talk number
PIRSA:20040094
Collection
Talk Type
Subject
Abstract

We comment on the recently introduced Gauss-Bonnet gravity in four dimensions. We argue that it does not make sense to consider this theory to be defined by a set of D->4 solutions of the higher-dimensional Gauss-Bonnet gravity. We show that a well-defined D->4 limit of Gauss-Bonnet Gravity is obtained generalizing a method employed by Mann and Ross to obtain a limit of the Einstein gravity in D=2 dimensions. This is a scalar-tensor theory of the Horndeski type obtained by dimensional reduction methods. By considering simple spacetimes beyond spherical symmetry (Taub-NUT spaces) we show that the naive limit of the higher-dimensional theory to four dimensions is not well defined and contrast the resultant metrics with the actual solutions of the new theory. Theory and solutions in lower dimensions will also be briefly discussed.