Are $f(R,\mathrm{Matter})$ theories really relevant to cosmology?

Abstract

We examine $f(R,\text{Matter})$ theories that directly couple the curvature $R$ or $R_{\mu \nu }$ with the matter sector in the action, in addition to the universal coupling. We argue that if the matter sector includes the Standard Model (SM), such theories are either inconsistent or already excluded by experiments unless they are a rewriting of $f(R)$ gravity or general relativity. If these theories genuinely couple the SM to curvature, they suffer from the presence of ghost states at energies within their domain of application for cosmological purposes. Therefore, we raise questions about their relevance to cosmology. Moreover, if such theories do not include the SM, they should just be seen as scalar-tensor, vector-tensor, ..., theories, depending on the additional degrees of freedom. They should thus be studied accordingly.}

arXiv comment24 pages, published version, small corrections and precisions. Slightly longer abstract

References in corpus (52)

• An Alternative to Compactification
• 4D Gravity on a Brane in 5D Minkowski Space
• f(R,T) gravity
• Causality, Analyticity and an IR Obstruction to UV Completion
• f(R,L_m) gravity
• Degenerate higher derivative theories beyond Horndeski: evading the Ostrogradski instability
• Avoiding Dark Energy with 1/R Modifications of Gravity
• The Effective Field Theory of Dark Energy
• Maximal freedom at minimum cost: linear large-scale structure in general modifications of gravity
• Essential Building Blocks of Dark Energy
• f(R, T, R_μνT^μν) gravity phenomenology and ΛCDM universe
• Further matters in space-time geometry: $f(R,T,R_{\mu \nu }{T}^{\mu \nu })$ gravity
• Dark Energy or Modified Gravity? An Effective Field Theory Approach
• Palatini form of 1/R gravity
• The EFT-Hedron
• Energy's and amplitudes' positivity
• A unifying description of dark energy
• Effective Field Theory of Dark Energy: a Review
• Dark Matter From f(R,T) Gravity
• Positivity Bounds for Scalar Theories
• $f(R,T_{\mu \nu }{T}^{\mu \nu })$ gravity and Cardassian-like expansion as one of its consequences
• Extremal Effective Field Theories
• Effective Description of Higher-Order Scalar-Tensor Theories
• UV complete me: Positivity Bounds for Particles with Spin
• Signs of Analyticity in Single-Field Inflation
• On the consistency of universally non-minimally coupled $f(R,T,R_{\mu \nu }{T}^{\mu \nu })$ theories
• Positivity Bounds for Massive Spin-1 and Spin-2 Fields
• Symmetries, Sum Rules and Constraints on Effective Field Theories
• Positive Signs in Massive Gravity
• Into the EFThedron and UV constraints from IR consistency
• Reexamining $f(R,T)$ gravity
• Weakly-coupled stealth solution in scordatura degenerate theory
• Slow-roll inflation in f(R,T) gravity and a modified Starobinsky-like inflationary model
• Inflation in $f(R,T)$ Gravity
• Effective field theory approach to modified gravity including Horndeski theory and Hořava-Lifshitz gravity
• A general theory of linear cosmological perturbations: scalar-tensor and vector-tensor theories
• Positivity Bounds on Dark Energy: When Matter Matters
• Measurement of $W^{\pm }{W}^{\pm }$ vector-boson scattering and limits on anomalous quartic gauge couplings with the ATLAS detector
• A general theory of linear cosmological perturbations: stability conditions, the quasistatic limit and dynamics
• The cosmology in f(R,T) gravity without dark energy
• Built-in scordatura in U-DHOST
• Observational signatures of the theories beyond Horndeski
• Slow-roll inflation in $f(R,T)$ gravity with a $RT$ mixing term
• Stealth dark energy in scordatura DHOST theory
• Inflation with $0\le c_{\mathrm{s}}\le 1$
• Parameterised post-Newtonian formalism for the effective field theory of dark energy via screened reconstructed Horndeski theories
• The galaxy rotation curves in the $f(R,T)$ modified gravity formalism
• Dark Energy Nature in Logarithmic $f(R,T)$ Cosmology
• Swampland Criteria and Constraints on Inflation in a $f(R,T)$ Gravity Theory
• Metric-affine Myrzakulov gravity and its generalizations
• Tsallis holographic inflation in $f(R,T)$ gravity: CMB constraints, reheating, and swampland implications
• Galactic rotation curves of spiral galaxies and dark matter in f(R,T) gravity theory

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• Metric-Affine Myrzakulov Gravity Theories: Models, Applications and Theoretical Developments
• Matter really does matter, or Why $f(R,\mathrm{Matter})$ type theories are significant for gravitational physics and cosmology
• Comparison of $f(R,T)$ Gravity with Type Ia Supernovae Data
• On energy-momentum conservation in non-minimal geometry-matter coupling theories
• Lagrangian Identity and Mass Evolution of Particle-like Objects in Nonminimally Coupled Gravity
• Wormhole Solutions and Pre-inflationary Epoch in $F(R,T)$ Gravity with Axion Fields