Can metric-affine gravity be saved?
Like general relativity, metric-affine gravity should be a viable effective quantum theory; otherwise, it is a mathematical curiosity without physical application. Assuming a perturbative quantum field theory, the universal, flat limit of metric-affine gravity offers a good foundation for model-building only when symmetry constraints are themselves sufficient to get rid of ghosts and tachyons in the spectrum of propagating particle states, without requiring any further tuning of the couplings. Using this symmetry-first criterion, we find that for parity-preserving models with a totally symmetric distortion, only massless spin-one and spin-three modes are possible besides the graviton. Moreover, no viable models result from gauge symmetries generated by a scalar field.
Authors
- Alessandro Santoni (ORCID: https://orcid.org/0000-0002-0932-1869)
- Will Barker (ORCID: https://orcid.org/0000-0002-1501-3221)
- C. De Marzo (ORCID: https://orcid.org/0000-0002-3741-2055)
Institutions
- TU Wien (AT)
- Pontificia Universidad Católica de Chile (CL)
- Czech Academy of Sciences, Institute of Chemical Process Fundamentals (CZ)
- FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ)
- Institute for Research in Fundamental Sciences (IR)
Publication Details
- Journal
- Physical review. D/Physical review. D.
- Published
- 2025-08-15
- DOI
- https://doi.org/10.1103/1xqx-f57g
- Citations
- 3
- Primary Topic
- Cosmology and Gravitation Theories
- Type
- article
- Field-Weighted Citation Impact
- 3.46
Funders
- Department for Business, Energy and Industrial Strategy, UK Government
- UK Research and Innovation
- University of Cambridge
- European Commission
- Eesti Teadusagentuur
- Akademie Věd České Republiky
- Agencia Nacional de Investigación y Desarrollo
- Girton College, University of Cambridge
- Science and Technology Facilities Council
- European Research Council
- Research Executive Agency
- Comisión Nacional de Investigación Científica y Tecnológica
- H2020 Marie Skłodowska-Curie Actions
- HORIZON EUROPE Marie Sklodowska-Curie Actions