A comment on the matter-graviton coupling
Abstract
We point out a generic inconsistency of the coupling of ordinary gravity as described by general relativity with matter invariant under the subgroup of unimodular diffeomorphisms (TDiffs), and some previously studied exceptions are pointed out. The most general Lagrangian invariant under TDiff up to dimension five operators is determined, and restrictions on parameters coming from existing observations are studied in some cases.
0
Turn this paper into a lesson
ArcXiv compiles a structured reading guide from this paper's metadata: plain-English importance, contributions, prerequisite concepts, which sections to read first, flashcards, and a quiz. Grounded in the abstract, never invented.