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Friedmann Equations of FRW Universe in Scalar-tensor Gravity, f(R) Gravity and First Law of Thermodynamics

5 Pith papers cite this work. Polarity classification is still indexing.

5 Pith papers citing it
abstract

In the paper, hep-th/0501055 (R.G. Cai and S.P. Kim, JHEP {\bf 0502}, 050 (2005)), it is shown that by applying the first law of thermodynamics to the apparent horizon of an FRW universe and assuming the geometric entropy given by a quarter of the apparent horizon area, one can derive the Friedmann equations describing the dynamics of the universe with any spatial curvature; using the entropy formula for the static spherically symmetric black holes in Gauss-Bonnet gravity and in more general Lovelock gravity, where the entropy is not proportional to the horizon area, one can also obtain the corresponding Friedmann equations in each gravity. In this note we extend the study of hep-th/0501055 to the cases of scalar-tensor gravity and $f(R)$ gravity, and discuss the implication of results.

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2026 4 2011 1

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UNVERDICTED 5

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representative citing papers

Observational constraints on Luciano-Saridakis entropic cosmology

astro-ph.CO · 2026-03-03 · unverdicted · novelty 6.0

First background-level constraints on Luciano-Saridakis entropic cosmology using CC, Pantheon+ with SH0ES, DESI DR2 BAO and compressed Planck data show robust fit, 2sigma exclusion of LambdaCDM, and potential Hubble tension alleviation.

Modified Entropy from Action Principle

gr-qc · 2026-05-28 · unverdicted · novelty 5.0

Authors add f(R, K) to the Einstein-Hilbert action, obtain higher-derivative-free modified Friedmann equations for flat FRW, and derive a general apparent-horizon entropy expression usable for multiple entropy models.

Modified Gravity and Cosmology

astro-ph.CO · 2011-06-13 · unverdicted · novelty 2.0

A comprehensive review of modified gravity theories and their cosmological consequences, including a parameterized post-Friedmannian formalism for constraining deviations from General Relativity.

citing papers explorer

Showing 5 of 5 citing papers.

  • Observational constraints on Luciano-Saridakis entropic cosmology astro-ph.CO · 2026-03-03 · unverdicted · none · ref 33 · internal anchor

    First background-level constraints on Luciano-Saridakis entropic cosmology using CC, Pantheon+ with SH0ES, DESI DR2 BAO and compressed Planck data show robust fit, 2sigma exclusion of LambdaCDM, and potential Hubble tension alleviation.

  • Modified Entropy from Action Principle gr-qc · 2026-05-28 · unverdicted · none · ref 18 · internal anchor

    Authors add f(R, K) to the Einstein-Hilbert action, obtain higher-derivative-free modified Friedmann equations for flat FRW, and derive a general apparent-horizon entropy expression usable for multiple entropy models.

  • Constraints on Kaniadakis Cosmology from Starobinsky Inflation and Primordial Tensor Perturbations gr-qc · 2026-05-20 · unverdicted · none · ref 46 · internal anchor

    Kaniadakis entropic cosmology modifies early-universe dynamics and is constrained by its predictions for Starobinsky inflation and the primordial tensor spectrum using current CMB and gravitational-wave observations.

  • Hamilton-Jacobi Approach to Inflationary Scenarios through Extended Entropies: An Observational Perspective astro-ph.CO · 2026-05-17 · unverdicted · none · ref 28 · internal anchor

    Hamilton-Jacobi analysis of slow-roll inflation with non-Bekenstein-Hawking entropies yields fitted entropy parameters (δ≈1.1-1.2, α∼10^{-14}, K∼10^{-17}) consistent with ns and r data.

  • Modified Gravity and Cosmology astro-ph.CO · 2011-06-13 · unverdicted · none · ref 16

    A comprehensive review of modified gravity theories and their cosmological consequences, including a parameterized post-Friedmannian formalism for constraining deviations from General Relativity.