Einstein-Gauss-Bonnet Gravity in Four-Dimensional Spacetime

In this Letter we present a general covariant modified theory of gravity in D=4 spacetime dimensions which propagates only the massless graviton and bypasses Lovelock's theorem. The theory we present is formulated in D>4 dimensions and its action consists of the Einstein-Hilbert term with a cosmological constant, and the Gauss-Bonnet term multiplied by a factor 1/(D-4). The four-dimensional theory is defined as the limit D→4. In this singular limit the Gauss-Bonnet invariant gives rise to nontrivial contributions to gravitational dynamics, while preserving the number of graviton degrees of freedom and being free from Ostrogradsky instability. We report several appealing new predictions of this theory,…

• FD
  Fonds De La Recherche Scientifique - FNRS

  Award: IISN 4.4517.08
• NC
  Narodowe Centrum Nauki

  Award: UMO-2016/23/P/ST2/04240
• HM
  H2020 Marie Skłodowska-Curie Actions

  Award: 665778