Is there a novel Einstein-Gauss-Bonnet theory in four dimensions?

Sisman, Tahsin Cagri
Tekin, Bayram
No! We show that the field equations of Einstein-Gauss-Bonnet theory defined in generic D>4 dimensions split into two parts one of which always remains higher dimensional, and hence the theory does not have a non-trivial limit to D=4. Therefore, the recently introduced four-dimensional, novel, Einstein-Gauss-Bonnet theory does not admit an intrinsically four-dimensional definition, in terms of metric only, as such it does not exist in four dimensions. The solutions (the spacetime, the metric) always remain D>4 dimensional. As there is no canonical choice of 4 spacetime dimensions out of D dimensions for generic metrics, the theory is not well defined in four dimensions.

Citation Formats
M. GÜRSES, T. C. Sisman, and B. Tekin, “Is there a novel Einstein-Gauss-Bonnet theory in four dimensions?,” EUROPEAN PHYSICAL JOURNAL C, vol. 80, no. 7, pp. 0–0, 2020, Accessed: 00, 2020. [Online]. Available: