2014/07/21 by Xian O. Camanho, Jose D. Edelstein, Juan Maldacena +1 · 2 citations
Physics and Astronomy · #hep-th #gr-qc
paper · pdf · doi:10.1007/jhep02(2016)020
50+22 pages, 13 figures
arxiv created 2014/07/21 · arxiv updated 2017/03/22
We consider higher derivative corrections to the graviton three-point coupling within a weakly coupled theory of gravity. Lorentz invariance allows further structures beyond the one present in the Einstein theory. We argue that these are constrained by causality. We devise a thought experiment involving a high energy scattering process which leads to causality violation if the graviton three-point vertex contains the additional structures. This violation cannot be fixed by adding conventional particles with spins J ≤ 2. But, it can be fixed by adding an infinite tower of extra massive particles with higher spins, J > 2. In AdS theories this implies a constraint on the conformal anomaly coefficients |a - c \over c | \lesssim 1 \over Δgap2 in terms of Δgap, the dimension of the lightest single particle operator with spin J > 2. For inflation, or de Sitter-like solutions, it indicates the existence of massive higher spin particles if the gravity wave non-gaussianity deviates significantly from the one computed in the Einstein theory.