<p>This paper is about the cosmological framework of <i>f</i>(<i>R</i>,&#xa0;<i>T</i>) gravity for a flat Friedmann-Lemaitre-Robertson-Walker (<i>FLRW</i>) model of the Universe. It is an approach that combines the <i>f</i>(<i>R</i>,&#xa0;<i>T</i>) function with a mixture of <i>f</i>(<i>R</i>) and <i>f</i>(<i>T</i>), where <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12648_2025_3590_Article_IEq1.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="76" /> </InlineMediaObject> <EquationSource Format="TEX">\(f(R)= R\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mo stretchy="false">(</mo> <mi>R</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>R</mi> </mrow> </math></EquationSource> </InlineEquation>; <i>R</i> the Ricci scalar and the matter term <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12648_2025_3590_Article_IEq2.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="90" /> </InlineMediaObject> <EquationSource Format="TEX">\(f(T)=2\lambda T\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mo stretchy="false">(</mo> <mi>T</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mn>2</mn> <mi>λ</mi> <mi>T</mi> </mrow> </math></EquationSource> </InlineEquation>; <i>T</i> the trace of energy-momentum tensor respectively. The model constraints are deduced by employing Bayesian Statistics and neural network approach with the use of observational Hubble data sets, baryonic acoustic oscillation (BAO) measurements, Pantheon+ compilation of Type Ia supernovae (SNe Ia). An Artificial Neural Networks (<i>ANNs</i>) for parameter estimation using the Hubble data, which trains a fiducial model and obtains the parameter values. A comparison between the results obtained from Bayesian method and <i>ANN</i> has been presented too. Furthermore, we observe that CoLFI is a more efficient method for parameter estimation, particularly for intractable likelihood functions or large cosmological models that need significant resources. Some physical properties of the model are also discussed.</p>

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Constraining cosmological parameters using bayesian MCMC method and artificial neural networks in modified theory of gravity

  • Lokesh Kumar Sharma,
  • Suresh Parekh,
  • Anil Kumar Yadav,
  • Preeti Shrivastava

摘要

This paper is about the cosmological framework of f(RT) gravity for a flat Friedmann-Lemaitre-Robertson-Walker (FLRW) model of the Universe. It is an approach that combines the f(RT) function with a mixture of f(R) and f(T), where \(f(R)= R\) f ( R ) = R ; R the Ricci scalar and the matter term \(f(T)=2\lambda T\) f ( T ) = 2 λ T ; T the trace of energy-momentum tensor respectively. The model constraints are deduced by employing Bayesian Statistics and neural network approach with the use of observational Hubble data sets, baryonic acoustic oscillation (BAO) measurements, Pantheon+ compilation of Type Ia supernovae (SNe Ia). An Artificial Neural Networks (ANNs) for parameter estimation using the Hubble data, which trains a fiducial model and obtains the parameter values. A comparison between the results obtained from Bayesian method and ANN has been presented too. Furthermore, we observe that CoLFI is a more efficient method for parameter estimation, particularly for intractable likelihood functions or large cosmological models that need significant resources. Some physical properties of the model are also discussed.