The fate of boundary terms in dimensional reductions
Robert J. Saskowski · Modern Physics Letters A · 2025
Gibbons–Hawking–York (GHY) terms are typically neglected when performing dimensional reductions of gravitational theories. We consider the reduction of such terms for both two-derivative and four-derivative theories in general dimensions. We demonstrate a robust consistency wherein the GHY term in the original, higher-dimensional theory translates directly to the appropriate GHY term in the dimensionally reduced theory. In particular, this gives a novel way of generating such terms for higher-derivative corrections. We carry out this procedure for Gauss–Bonnet, Chern–Simons modified, and [Formula: see text] gravities to derive novel boundary terms.