2016/08/31 by Clifford Cheung, Grant N. Remmen · 1 citation
Physics and Astronomy · #hep-th #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevlett.118.051601
published as Phys. Rev. Lett. 118, 051601 (2017) · 6 pages
arxiv created 2017/02/01 · arxiv updated 2017/02/02
We study the Gauss-Bonnet (GB) term as the leading higher-curvature correction to pure Einstein gravity. Assuming a tree-level ultraviolet completion free of ghosts or tachyons, we prove that the GB term has a nonnegative coefficient in dimensions greater than four. Our result follows from unitarity of the spectral representation for a general ultraviolet completion of the GB term.