2018/05/31 by Steffen Gielen, Rodrigo de León Ardón, Rodrigo de Leon Ardon +1
Mathematics · Physics and Astronomy · #BRST quantization #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Diffeomorphism #Dilaton #Formalism (music) #Gauge symmetry #Gauge theory #General relativity #Hamiltonian (control theory) #Hamiltonian lattice gauge theory #Invariant (physics) #Lagrangian #Mathematical physics #Mathematics #Noncommutative and Quantum Gravity Theories #Physics #Pure mathematics #Theoretical physics #Unimodular matrix #gr-qc #hep-th
paper · pdf · doi:10.1088/1361-6382/aadbd1
published as Class. Quantum Grav. 35 (2018), 195009 · 24 pages, 1 table, 1 figure; minor changes to match published version
openalex publication_date 2018/08/21 · arxiv created 2018/08/28 · arxiv updated 2018/09/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract General relativity is usually formulated as a theory with gauge invariance under the diffeomorphism group, but there is a ‘dilaton’ formulation where it is in addition invariant under Weyl transformations, and a ‘unimodular’ formulation where it is only invariant under the smaller group of special diffeomorphisms. Other formulations with the same number of gauge generators, but a different gauge algebra, also exist. These different formulations provide examples of what we call ‘inessential gauge invariance’, ‘symmetry trading’ and ‘linking theories’; they are locally equivalent, but may differ when global properties of the solutions are considered. We discuss these notions in the Lagrangian and Hamiltonian formalism.