<p>This research focuses on parametrization of deceleration parameter within the structure of modified symmetric teleparallel gravity or <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq2.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="41" /> </InlineMediaObject> <EquationSource Format="TEX">\(f\left(Q\right)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mfenced close=")" open="("> <mi>Q</mi> </mfenced> </mrow> </math></EquationSource> </InlineEquation> gravity, where <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq3.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(Q\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>Q</mi> </math></EquationSource> </InlineEquation> represents the nonmetricity scalar. To explore evolutionary timeline of the Universe, we considered the logarithmic form: <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq4.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="149" /> </InlineMediaObject> <EquationSource Format="TEX">\(f\left(Q\right)=m+n \text\,{\rm{{ln}}}(Q)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mfenced close=")" open="("> <mi>Q</mi> </mfenced> <mo>=</mo> <mi>m</mi> <mo>+</mo> <mi>n</mi> <mspace width="0.166667em" /> <mi mathvariant="normal">ln</mi> <mrow> <mo stretchy="false">(</mo> <mi>Q</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>, where <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq5.gif" Format="GIF" Height="10" Rendition="HTML" Resolution="72" Type="Linedraw" Width="18" /> </InlineMediaObject> <EquationSource Format="TEX">\(m\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>m</mi> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq6.gif" Format="GIF" Height="10" Rendition="HTML" Resolution="72" Type="Linedraw" Width="14" /> </InlineMediaObject> <EquationSource Format="TEX">\(n\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>n</mi> </math></EquationSource> </InlineEquation> are constants. In this context, we utilize a particular form of deceleration parameter given by <InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq7.gif" Format="GIF" Height="28" Rendition="HTML" Resolution="72" Type="Linedraw" Width="129" /> </InlineMediaObject> <EquationSource Format="TEX">\(q\left(z\right)=\frac{1}{2}+\frac{{q}_{1}z+{q}_{2}}{{(1+z)}^{2}},\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>q</mi> <mfenced close=")" open="("> <mi>z</mi> </mfenced> <mo>=</mo> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> <mo>+</mo> <mfrac> <mrow> <msub> <mi>q</mi> <mn>1</mn> </msub> <mi>z</mi> <mo>+</mo> <msub> <mi>q</mi> <mn>2</mn> </msub> </mrow> <msup> <mrow> <mo stretchy="false">(</mo> <mn>1</mn> <mo>+</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mn>2</mn> </msup> </mfrac> <mo>,</mo> </mrow> </math></EquationSource> </InlineEquation> where <InlineEquation ID="IEq8"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq8.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\({q}_{1}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>q</mi> <mn>1</mn> </msub> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq9"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq9.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\({q}_{2}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>q</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation> and redshift, <InlineEquation ID="IEq10"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq10.gif" Format="GIF" Height="10" Rendition="HTML" Resolution="72" Type="Linedraw" Width="11" /> </InlineMediaObject> <EquationSource Format="TEX">\(z\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>z</mi> </math></EquationSource> </InlineEquation> are the parameters. This form allows a transition from a decelerating phase to an accelerating phase. Solution for the Hubble parameter is derived using the given parametric form of <InlineEquation ID="IEq11"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="12036_2025_10089_Article_IEq11.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="12" /> </InlineMediaObject> <EquationSource Format="TEX">\(q\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>q</mi> </math></EquationSource> </InlineEquation>, which is then applied to the Friedmann equations. Following this, we estimated the model parameters’ best-fit values by using 115 supernovae Ia data points and Planck Collaboration (2018). We also focus on testing energy conditions in the context of cosmological acceleration. Moreover, we analysed the evolution of density, pressure, equation of state (EoS) parameter and <i>Om</i>(<i>z</i>) diagnostics to understand accelerated expansion phase of the Universe.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Logarithmic \({\varvec{f}}({\varvec{Q}})\) gravity with parametrization of deceleration parameter and energy conditions

  • S. N. Bayaskar,
  • A. A. Q. Shoeb,
  • A. A. Dhanagare,
  • U. T. Arbat

摘要

This research focuses on parametrization of deceleration parameter within the structure of modified symmetric teleparallel gravity or \(f\left(Q\right)\) f Q gravity, where \(Q\) Q represents the nonmetricity scalar. To explore evolutionary timeline of the Universe, we considered the logarithmic form: \(f\left(Q\right)=m+n \text\,{\rm{{ln}}}(Q)\) f Q = m + n ln ( Q ) , where \(m\) m and \(n\) n are constants. In this context, we utilize a particular form of deceleration parameter given by \(q\left(z\right)=\frac{1}{2}+\frac{{q}_{1}z+{q}_{2}}{{(1+z)}^{2}},\) q z = 1 2 + q 1 z + q 2 ( 1 + z ) 2 , where \({q}_{1}\) q 1 , \({q}_{2}\) q 2 and redshift, \(z\) z are the parameters. This form allows a transition from a decelerating phase to an accelerating phase. Solution for the Hubble parameter is derived using the given parametric form of \(q\) q , which is then applied to the Friedmann equations. Following this, we estimated the model parameters’ best-fit values by using 115 supernovae Ia data points and Planck Collaboration (2018). We also focus on testing energy conditions in the context of cosmological acceleration. Moreover, we analysed the evolution of density, pressure, equation of state (EoS) parameter and Om(z) diagnostics to understand accelerated expansion phase of the Universe.