Stability of scalar perturbations in scalar-torsion $f(T,\varphi )$ gravity theories in the presence of a matter fluid

Abstract

We study the viability conditions for the absence of ghost, gradient and tachyonic instabilities, in scalar-torsion $f(T,\varphi )$ gravity theories in the presence of a general barotropic perfect fluid. To describe the matter sector, we use the Sorkin-Schutz action and then calculate the second order action for scalar perturbations. For the study of ghost and gradient instabilities, we found that the gravity sector keeps decoupled from the matter sector and then applied the viability conditions for each one separately. Particularly, we verified that this theory is free from ghost and gradient instabilities, obtaining the standard results for matter, and for the gravity sector we checked that the corresponding speed of propagation satisfies $c_{s,g}^2=1$. On the other hand, in the case of tachyonic instability, we obtained the general expressions for the mass eigenvalues and then evaluated them in the scaling matter fixed points of a concrete model of dark energy. Thus, we found a space of parameters where it is possible to have a stable configuration respecting the constraints from the CMB measurements and the BBN constraints for early dark energy. Finally, we have numerically corroborated these results by solving the cosmological equations for a realistic cosmological evolution with phase space trajectories undergoing scaling matter regimes, and then showing that the system presents a stable configuration throughout cosmic evolution.

26 pages, 2 figures, accepted version for publication in JCAP

References in corpus (48)

• Dynamics of dark energy
• The Confrontation between General Relativity and Experiment
• Multi-messenger Observations of a Binary Neutron Star Merger
• Cosmology and the Fate of Dilatation Symmetry
• Large Magellanic Cloud Cepheid Standards Provide a 1% Foundation for the Determination of the Hubble Constant and Stronger Evidence for Physics Beyond LambdaCDM
• Dark torsion as the cosmic speed-up
• Beyond the Cosmological Standard Model
• Einstein's Other Gravity and the Acceleration of the Universe
• Covariant Galileon
• Extra force in $f(R)$ modified theories of gravity
• Strong constraints on cosmological gravity from GW170817 and GRB 170817A
• Implications of the Neutron Star Merger GW170817 for Cosmological Scalar-Tensor Theories
• f(R,L_m) gravity
• Cosmology Intertwined II: The Hubble Constant Tension
• Exploring gravitational theories beyond Horndeski
• Cosmology Intertwined III: $f{\sigma }_8$ and $S_8$
• Modified gravity with arbitrary coupling between matter and geometry
• $f(T,\mathcal{T})$ gravity and cosmology
• Generalizations of teleparallel gravity and local Lorentz symmetry
• Spontaneous Lorentz and Diffeomorphism Violation, Massive Modes, and Gravity
• Nonminimal torsion-matter coupling extension of f(T) gravity
• Coupled and Extended Quintessence: theoretical differences and structure formation
• Update on Coupled Dark Energy and the $H_0$ tension
• Constraining Interactions in Cosmology's Dark Sector
• Challenges for scaling cosmologies
• Tidal Tails Test the Equivalence Principle in the Dark Sector
• Density perturbations in general modified gravitational theories
• Galilean Equivalence for Galactic Dark Matter
• Translation of Einstein's Attempt of a Unified Field Theory with Teleparallelism
• Precision Gravity Tests and the Einstein Equivalence Principle
• A New Force in the Dark Sector?
• Brans-Dicke cosmology with a $\Lambda$- term: a possible solution to $\Lambda$CDM tensions
• Theories of Dark Energy with Screening Mechanisms
• Effective field theory of modified gravity with two scalar fields: dark energy and dark matter
• A note on the equivalence of a barotropic perfect fluid with a K-essence scalar field
• Long Range Interactions in Cosmology: Implications for Neutrinos
• Gauge Structure of Teleparallel Gravity
• Effective field theory approach to modified gravity including Horndeski theory and Hořava-Lifshitz gravity
• Cosmological dynamics of dark energy in scalar-torsion $f(T,\varphi )$ gravity
• Extended Quintessence with non-minimally coupled phantom scalar field
• Non-minimally coupled scalar field cosmology on the phase plane
• On the stability conditions for theories of modified gravity in presence of matter fields
• Generating primordial fluctuations from modified teleparallel gravity with local Lorentz-symmetry breaking
• General formulation of cosmological perturbations in scalar-tensor dark energy coupled to dark matter
• Post-Newtonian limit of generalized scalar-torsion theories of gravity
• Cosmological constrains on minimally and non-minimally coupled scalar field models
• Inflation with teleparallelism: Can torsion generate primordial fluctuations without local Lorentz symmetry?
• Scalar-tensor cosmologies without screening

Cited by in corpus (23)

• Cosmological dynamics of dark energy in scalar-torsion $f(T,\varphi )$ gravity
• Dynamical systems analysis in $f(T,\varphi )$ gravity
• Can $f(T)$ models play a bridge between early and late time Universe?
• Constraining extended teleparallel gravity via cosmography: A model-independent approach
• Unified dark sectors in scalar-torsion theories of gravity
• Scalar induced gravitational waves in modified teleparallel gravity theories
• Revisiting the dynamics of interacting vector-like dark energy
• Noether Symmetry Approach in Scalar-Torsion $f(T,\varphi )$ Gravity
• Ghost and Laplacian Instabilities in the Teleparallel Horndeski Gravity
• Inflation and Primordial Fluctuations in $F(T)$ Gravity's Rainbow
• Revisiting $f(R)$ gravity's rainbow: Inflation and primordial fluctuations
• Cosmological singularities in $f(T,\varphi )$ gravity
• Non-minimally coupled teleparallel scalar field reconstruction of matter bounce scenario
• Dynamics of dark energy in a scalar-vector-torsion theory
• Phase-space analysis of torsion-coupled dilatonic ghost condensate
• Dynamical system analysis in modified Galileon cosmology
• Cosmological Dynamics in Interacting Scalar-Torsion f(T,$\varphi$) Gravity: Investigating Energy and Momentum Couplings
• Dynamical System Analysis for Scalar Field Potential in Teleparallel Gravity
• Gauge invariant perturbations in teleparallel Horndeski gravity
• Late Time Phenomena in $f(T,\mathcal{T})$ Gravity Framework: Role of $H_0$ Priors
• Screening fifth forces in scalar-vector-tensor theories
• Global portraits of nonminimal teleparallel inflation
• Parametrized post-Newtonian formalism in higher-order Teleparallel Gravity