Merging matter and geometry in the same Lagrangian

Ludwig, Hendrik; Capozziello, Salvatore

doi:10.1016/j.physletb.2015.11.023

Cited by 16 publications

(35 citation statements)

References 42 publications

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“…The only way to avoid this shortcoming is to conjecture that one of the apparent tunings hypothetically originates from something more fundamental. For instance, the theory presented in [31] may be one possible justification from a fundamental perspective. There, the universal coupling would come from the way matter and geometry are made intrinsically inseparable in an original f (R, L m ) action.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Dilatons with intrinsic decouplings

Hees

2016

Phys. Rev. D

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In this paper, we show that there exists a class of dilaton models with non-trivial scalar-Ricci and scalar-matter couplings that strongly reduces observational deviations from general relativity in the dust limit. Essentially, depending on the coupling between the dilaton and the fundamental matter fields, various strengths of decoupling can appear. They range from no decoupling at all to a total decoupling state. In this latter case, the theory becomes indistinguishable from general relativity (in the dust limit), as all dilatonic effects can be re-absorbed through a simple change of unit.Furthermore, for particular decouplings, we show that the phenomenology used to constrain theories from universality of free fall observations is significantly different from what is commonly used. Finally, from a fundamental perspective, the class of non-dynamical decouplings proposed in this paper might play a role in the current non-observation of any deviation from general relativity (in both tests of the equivalence principle and of the parametrized post-Newtonian formalism).PACS numbers: 04.60.Cf,04.25.Nx,04.80.Cc,95.35.+d,95.36.+x Keywords: scalar-tensor theory, string dilaton, equivalence principle, universality of free fall, post-Newtonian phenomenology 1 Note that the scalar field ϕ is dimensionless and is related to the scalar field φ used in [6] by ϕ =κφ withκ 2 = 4πG/c 4 .

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Section: Conclusion and Discussionmentioning

confidence: 99%

Dilatons with intrinsic decouplings

Hees

2016

Phys. Rev. D

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“…It is possible to merger geometry and matter in the same action. An enlightening discussion regarding this question was presented in [1], in which an action like…”

Section: Introductionmentioning

confidence: 99%

“…was proposed, with κ = 8π G/c 4 , G the gravitational constant, c the speed of light, g the metric determinant, L the matter lagrangian 1 and R the Ricci scalar.…”

Section: Introductionmentioning

confidence: 99%

Hydrostatic equilibrium configurations of neutron stars in a non-minimal geometry-matter coupling theory of gravity

et al. 2020

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In this work we analyze hydrostatic equilibrium configurations of neutron stars in a non-minimal geometrymatter coupling (GMC) theory of gravity. We begin with the derivation of the hydrostatic equilibrium equations for the f (R, L) gravity theory, where R and L are the Ricci scalar and Lagrangian of matter, respectively. We assume f (R, L) = R/2 + [1 + σ R]L, with σ constant. To describe matter inside neutron stars we assume a relativistic polytropic equation of state p = Kρ γ , with ρ being the energy density, K and γ = 5/3 being constants. We also consider the more realistic equation of state (EoS) known as SLy4, which is a Skyrme type one based on effective nuclear interaction. We show that in this theory it is possible to reach the mass of massive pulsars, such as PSR J2215 + 5135, for both equations of state. Also, results for mass-radius relation in GMC gravity are strongly dependent on the stiffness of the EoS.

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“…Indeed, one can show that it classically corresponds to Eq. (1) with the identification √ φ = −κL m /R [5]. 5 Equation (10) leads to the following equations of motion…”

Section: An Almost Equivalent Theorymentioning

confidence: 99%

“…A surprising theory that goes beyond this assumption has recently been suggested [5]. It is based on a f (R, L m ) action in four dimensions [6].…”

Section: Introductionmentioning

confidence: 99%

Rethinking the link between matter and geometry

Minazzoli

2018

Phys. Rev. D

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In the present manuscript, I examine an intriguing relation at the classical level between general relativity and a theory where matter couples uniquely multiplicatively to geometry in the Lagrangian density. Interestingly, the gravitational constant G is replaced by a novel fundamental constant, whose value is not tied to any classical phenomenon; while the value of G itself becomes related to the dynamics of the universe. I concentrate on different aspects of the Equivalence Principle, as the theory is expected to violate all of its different formulations.

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Merging matter and geometry in the same Lagrangian

Cited by 16 publications

References 42 publications

Dilatons with intrinsic decouplings

Dilatons with intrinsic decouplings

Hydrostatic equilibrium configurations of neutron stars in a non-minimal geometry-matter coupling theory of gravity

Rethinking the link between matter and geometry

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