<p>In this paper, two-fluid cosmological models have been investigated in five-dimensional Kaluza–Klein spacetime, where one fluid represents the barotropic fluid of the universe and another fluid is chosen to model dark energy. The Einstein’s field equations have been solved for interacting as well as the non-interacting two-fluid scenario and physical behaviour of parameters are discussed in view of results obtained from current observations.The cosmological models presented in the article are best described by quintessence dark energy cosmological models of the universe. The total density parameter (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13370_2025_1277_Article_IEq1.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="18" /> </InlineMediaObject> <EquationSource Format="TEX">$\varOmega $</EquationSource> <EquationSource Format="MATHML"><math> <mi>Ω</mi> </math></EquationSource> </InlineEquation>) value remains the same either two-fluid are interacting or non-interacting. Our models are consistent with the current lambda-CDM model of the universe and show that <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13370_2025_1277_Article_IEq2.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="59" /> </InlineMediaObject> <EquationSource Format="TEX">$q\to -1$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>q</mi> <mo stretchy="false">→</mo> <mo>-</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13370_2025_1277_Article_IEq3.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="66" /> </InlineMediaObject> <EquationSource Format="TEX">$j\left(t\right)\to 1$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>j</mi> <mfenced close=")" open="("> <mi>t</mi> </mfenced> <mo stretchy="false">→</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation> as <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13370_2025_1277_Article_IEq4.gif" Format="GIF" Height="13" Rendition="HTML" Resolution="72" Type="Linedraw" Width="54" /> </InlineMediaObject> <EquationSource Format="TEX">$t\to \infty $</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>t</mi> <mo stretchy="false">→</mo> <mi>∞</mi> </mrow> </math></EquationSource> </InlineEquation>.</p>

Two-fluid cosmological models in five-dimensional Kaluza–Klein spacetime

期刊论文
发表日期：

2025年2月9日

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Sanjay Oli,
B. Santhosh

摘要

In this paper, two-fluid cosmological models have been investigated in five-dimensional Kaluza–Klein spacetime, where one fluid represents the barotropic fluid of the universe and another fluid is chosen to model dark energy. The Einstein’s field equations have been solved for interacting as well as the non-interacting two-fluid scenario and physical behaviour of parameters are discussed in view of results obtained from current observations.The cosmological models presented in the article are best described by quintessence dark energy cosmological models of the universe. The total density parameter ( $\varOmega $ $Ω$ ) value remains the same either two-fluid are interacting or non-interacting. Our models are consistent with the current lambda-CDM model of the universe and show that $q\to -1$ $q \to - 1$ and $j\left(t\right)\to 1$ $j (t) \to 1$ as $t\to \infty $ $t \to \infty$ .