In this article, we have investigated a string cosmological model within the context of f(R, T) gravity theory in a homogeneous yet anisotropic higher-dimensional (HD) Bianchi Type-III space-time. A cosmic string is considered as the source of the energy-momentum tensor and <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$f(R,T) = R + 2f(T)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mo stretchy="false">(</mo> <mi>R</mi> <mo>,</mo> <mi>T</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>R</mi> <mo>+</mo> <mn>2</mn> <mi>f</mi> <mo stretchy="false">(</mo> <mi>T</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>. The solutions to the associated field equations were derived by assuming the shear scalar <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\sigma$</EquationSource> <EquationSource Format="MATHML"><math> <mi>σ</mi> </math></EquationSource> </InlineEquation> to be proportional to the expansion scalar <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\theta$</EquationSource> <EquationSource Format="MATHML"><math> <mi>θ</mi> </math></EquationSource> </InlineEquation>, resulting in <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\xi = \chi ^{n}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>ξ</mi> <mo>=</mo> <msup> <mi>χ</mi> <mi>n</mi> </msup> </mrow> </math></EquationSource> </InlineEquation>. Then we determine the best fit ranges of the model parameters using the updated H(z) data, which includes 31 H(z) measurements from cosmic chronometers (CC) and 1048 data points from the Pantheon supernova compilation. Additionally, we have computed and examined various physical and kinematic attributes of the cosmological parameters, including the equation of state(EoS), jerk parameter, snap parameter and evaluated the energy conditions of the model along with its stability criteria. Moreover, we have illustrated the behavior of the cosmological parameters graphically for specific fixed values of the observational constants.

String cosmological model in f(R, T) gravity with the analysis of certain cosmic parameters

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发表日期：

2025年8月15日

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Asem Jotin Meitei,
Kangujam Priyokumar Singh

摘要

In this article, we have investigated a string cosmological model within the context of f(R, T) gravity theory in a homogeneous yet anisotropic higher-dimensional (HD) Bianchi Type-III space-time. A cosmic string is considered as the source of the energy-momentum tensor and $f(R,T) = R + 2f(T)$ $f (R, T) = R + 2 f (T)$ . The solutions to the associated field equations were derived by assuming the shear scalar $\sigma$ $σ$ to be proportional to the expansion scalar $\theta$ $θ$ , resulting in $\xi = \chi ^{n}$ $ξ = χ^{n}$ . Then we determine the best fit ranges of the model parameters using the updated H(z) data, which includes 31 H(z) measurements from cosmic chronometers (CC) and 1048 data points from the Pantheon supernova compilation. Additionally, we have computed and examined various physical and kinematic attributes of the cosmological parameters, including the equation of state(EoS), jerk parameter, snap parameter and evaluated the energy conditions of the model along with its stability criteria. Moreover, we have illustrated the behavior of the cosmological parameters graphically for specific fixed values of the observational constants.