In this study, we investigate the late-time accelerated expansion of the universe within the framework of non-minimally coupled <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$f(Q, L_m)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mo stretchy="false">(</mo> <mi>Q</mi> <mo>,</mo> <msub> <mi>L</mi> <mi>m</mi> </msub> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> gravity, where Q is the non-metricity scalar and <InlineEquation ID="IEq4"> <EquationSource Format="TEX">$L_m$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>L</mi> <mi>m</mi> </msub> </math></EquationSource> </InlineEquation> is the matter Lagrangian. We derive modified Friedmann equations in a flat Friedmann–Lemaître–Robertson–Walker (FLRW) metric background and employ the Gong-Zhang equation of state (EoS) parametrization, allowing an analytical form of the Hubble parameter <InlineEquation ID="IEq5"> <EquationSource Format="TEX">$H\!(z)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>H</mi> <mspace width="-0.166667em" /> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>. The model parameters are constrained using recent cosmic chronometers (CC) and Pantheon+SH0ES Type Ia supernova datasets through Markov Chain Monte Carlo (MCMC)-based chi-squared minimization. We analyze various cosmological quantities, including the deceleration parameter, EoS parameter, jerk, snap, lerk, and diagnostic tools such as Om(z) and the statefinder pair (r, s). Our findings indicate a viable transition from deceleration to acceleration and reveal a quintessence-like evolution of dark energy (DE). Furthermore, energy conditions are tested, showing a violation of the strong energy condition, consistent with current cosmic acceleration. The results establish that the <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$f(Q, L_m)$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mo stretchy="false">(</mo> <mi>Q</mi> <mo>,</mo> <msub> <mi>L</mi> <mi>m</mi> </msub> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> framework with non-minimal coupling and a parametrized EoS provides a compelling alternative to <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$\Lambda $</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="normal">Λ</mi> </math></EquationSource> </InlineEquation>CDM in describing cosmic acceleration.

Exploring dark energy via non-minimal coupling in ${\varvec{f}}({\varvec{Q,L}}_{{\varvec{m}}})$ gravity with Gong-Zhang parametrization

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发表日期：

2026年7月21日

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Yash B. Ingole,
K. V. Somwanshi,
S. N. Bayaskar

摘要

In this study, we investigate the late-time accelerated expansion of the universe within the framework of non-minimally coupled $f(Q, L_m)$ $f (Q, L_{m})$ gravity, where Q is the non-metricity scalar and $L_m$ $L_{m}$ is the matter Lagrangian. We derive modified Friedmann equations in a flat Friedmann–Lemaître–Robertson–Walker (FLRW) metric background and employ the Gong-Zhang equation of state (EoS) parametrization, allowing an analytical form of the Hubble parameter $H\!(z)$ $H (z)$ . The model parameters are constrained using recent cosmic chronometers (CC) and Pantheon+SH0ES Type Ia supernova datasets through Markov Chain Monte Carlo (MCMC)-based chi-squared minimization. We analyze various cosmological quantities, including the deceleration parameter, EoS parameter, jerk, snap, lerk, and diagnostic tools such as Om(z) and the statefinder pair (r, s). Our findings indicate a viable transition from deceleration to acceleration and reveal a quintessence-like evolution of dark energy (DE). Furthermore, energy conditions are tested, showing a violation of the strong energy condition, consistent with current cosmic acceleration. The results establish that the $f(Q, L_m)$ $f (Q, L_{m})$ framework with non-minimal coupling and a parametrized EoS provides a compelling alternative to $\Lambda $ $Λ$ CDM in describing cosmic acceleration.

Exploring dark energy via non-minimal coupling in \({\varvec{f}}({\varvec{Q,L}}_{{\varvec{m}}})\) gravity with Gong-Zhang parametrization

摘要