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This article examines the cosmic evolution in the framework of symmetric teleparallel theory, characterized by the function of non-metricity scalar $(\mathcal{Q})$. We use the e-folding number and reconstruction method with a suitable parametrization of the scale factor to obtain the functional form of symmetric teleparallel theory. Using this reconstructed model, we examine the behavior of different cosmographic parameters to demonstrate the bouncing scenarios of the cosmos by considering the contraction and expansion phases of cosmos before and after the bouncing point, respectively. It is found that the null energy condition is violated which shows that the singularity issue can be resolved in this extended theoretical framework. Moreover, we observe that the acceleration occurs near the bouncing point and the reconstructed model aligns with the current cosmic expansion. Finally, we check the validity of second law of thermodynamics in the bouncing framework of our model., Comment: 26 pages, 8 figures, Accepted Eur. Phys. J. C (2024)

This article aims to investigate various anisotropic stellar models in the background of $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ gravity, where $\mathcal{Q}=\mathcal{R}_{\varphi\vartheta}\mathcal{T}^{\varphi\vartheta}$. In this regard, we adopt two standard models as $\mathcal{R}+\zeta\mathcal{Q}$ and $\mathcal{R}+\zeta\mathcal{R}\mathcal{Q}$, where $\zeta$ symbolizes an arbitrary coupling parameter. We take spherical interior geometry and find solution to the modified gravitational field equations corresponding to each model by employing the `Tolman IV' spacetime. We need an additional constraint to close the system of field equations, thus the $\mathbb{MIT}$ bag model equation of state is chosen. The effects of modified theory on physical properties of six compact stars like PSR J 1614 2230,~SMC X-1,~Cen X-3,~PSR J 1903+327,~SAX J 1808.4-3658 and 4U 1820-30 are analyzed by using their respective masses and radii. We also determine the values of three unknowns involving in Tolman IV solution as well as the bag constant for each star at the hypersurface. Furthermore, various characteristics of the resulting solutions are examined through graphical interpretation for $\zeta=\pm5$. Finally, we explore the stability of the compact objects through two different approaches. We conclude that our model-I produces physically acceptable structures corresponding to each star candidate for both values of $\zeta$ whereas model-II is stable only for $\zeta=5$., Comment: 39 pages, 10 figures

In this paper, we extend the Finch-Skea isotropic ansatz representing a self-gravitating interior to two anisotropic spherical solutions within the context of Rastall gravity. For this purpose, we use a newly developed technique, named as gravitational decoupling approach through the minimal geometric deformation. The junction conditions that provide the governing rules for the smooth matching of the interior and exterior geometries at the hypersurface are formulated with the outer geometry depicted by the Schwarzschild spacetime. We check the physical viability of both solutions through energy conditions for two fixed values of the Rastall parameter. The behavior of the equation of state parameters, surface redshift and compactness function are also investigated. Finally, we study the stability of the resulting solutions through Herrera cracking approach and the causality condition. It is concluded that the chosen parametric values provide stable structure only for the solution corresponding to the pressure-like constraint., Comment: 31 pages, 10 figures

This paper focuses on developing a generalized ghost dark energy model $f\mathcal{(Q,T)}$ through the correspondence scheme for a non-interacting scenario involving pressureless matter and a power-law scale factor. We analyze the cosmological implications of our model using the equation of state parameter, $\omega_{GGDE}-\omega'_{GGDE}$ and the $r-s$ planes. We also examine stability of the model by considering squared speed of sound parameter. The equation of state parameter shows the phantom era, while the squared speed of sound indicates a stable generalized ghost dark energy model throughout the cosmic evolution. The $\omega_{GGDE}-\omega'_{GGDE}$ plane depicts a freezing region, whereas the $r-s$ plane corresponds to the Chaplygin gas model. We conclude that our results are consistent with the current observational data., Comment: 30 pages, 6 figures. arXiv admin note: text overlap with arXiv:2405.04548

Our manuscript aims to analysis the viability and stability of anisotropic stellar objects in the modified symmetric teleparallel gravity. A particular model of this extended theory is considered to formulate explicit field equations which govern the interaction between matter and geometry. The configuration of static spherical symmetric structures is examined through the Finch-Skea solution. However, the values of unknown constants in the metric potentials are evaluated by the Darmois junction conditions. For the viability of proposed stellar objects, the physical parameters including density, pressure, anisotropy, mass, energy constraints, compactness function and redshift are analyzed. Furthermore, stability of the proposed stellar objects is investigated by causality condition, Herrera cracking approach and adiabatic index. Our findings indicate that the proposed stellar objects are viable as well as stable in the presence of correction terms., Comment: 24 pages, 11 figures, Accepted

In this paper, we investigate $f(Q)$ gravity ($Q$ represents the non-metricity) to explore its cosmological implications of the two non-interacting dark energy models. We use the correspondence scenario to find the pilgrim and generalized ghost pilgrim dark energy $f(Q)$ gravity models for a Friedmann-Robertson-Walker universe with pressureless matter and a power-law scale factor. The reconstructed models explain the observed rapid expansion of the universe using astronomical observations. We also examine the physical properties of the model, including its equation of state parameter, $(\omega_{D}-\omega^{\prime}_{D})$ and $(r-s)$-planes and the squared speed of sound. It is found that our results are consistent with the interacting pilgrim dark energy model in the same gravity., Comment: 35 pages, 14 figures

This paper constructs three different anisotropic extensions of the existing isotropic solution to the modified field equations through the gravitational decoupling in $f(\mathbb{R},\mathbb{T})$ theory. For this, we take a static sphere that is initially filled with the isotropic fluid and then add a new gravitational source producing anisotropy in the system. The field equations now correspond to the total matter configuration. We transform the radial metric component to split these equations into two sets characterizing their parent sources. The unknowns comprising in the first set are determined by considering the Buchdahl isotropic solution. On the other hand, we employ different constraints related to the additional gravitational source and make the second system solvable. Further, the constant triplet in Buchdahl solution is calculated by means of matching criteria between the interior and exterior geometries at the spherical boundary. The mass and radius of a compact star LMC X-4 are used to analyze the physical relevancy of the developed models. We conclude that our resulting models II and III are in well-agreement with acceptability conditions for the considered values of the parameters., Comment: 34 pages, 16 figures

The main objective of this article is to investigate the viability of bouncing cosmological scenarios using different forms of scale factors with perfect matter configuration in the framework of extended symmetric teleparallel theory. This modified proposal is defined by the function $f(Q,T)$, where $Q$ characterizes non-metricity and $T$ denotes the trace of energy-momentum tensor. We investigate the modified field equations of this theory using different parametric values of the Hubble parameter and non-metricity to derive viable solutions. These solutions are relevant in various cosmological bounce models such as symmetric-bounce, super-bounce, oscillatory-bounce, matter-bounce and exponential-bounce models. Furthermore, we examine the behavior of energy density and pressure to analyze the characteristics of dark energy. A comprehensive analysis is also conducted to explore the behavior of the equation of state parameter and deceleration parameter to examine the evolutionary eras of the cosmos. Our findings show that the $f(Q,T)$ gravity describes the cosmic expansion in the vicinity of the bouncing point during the early and late times of cosmic evolution., Comment: 31 pages, 23 figures, The European Physical Journal C (Accepted)

This paper explores the viability and stability of compact stellar objects characterized by anisotropic matter in the framework of $f(\mathrm{Q},\mathrm{T})$ theory, where $\mathrm{Q}$ denotes non-metricity and $\mathrm{T}$ represents the trace of the energy-momentum tensor. We consider a specific model of this theory to obtain explicit expressions for the field equations governing the behavior of matter and geometry in this context. Furthermore, the Karmarkar condition is employed to assess the configuration of static spherically symmetric structures. The values of unknown constants in the metric potentials are determined through matching conditions of the interior and exterior spacetimes. Various physical quantities such as fluid parameters, energy constraints, equation of state parameters, mass, compactness and redshift are graphically analyzed to evaluate the viability of the considered compact stars. The Tolman-Oppenheimer-Volkoff equation is used to examine the equilibrium state of the stellar models. Moreover, the stability of the proposed compact stars is investigated through sound speed and adiabatic index methods. This study concludes that the proposed compact stars analyzed in this theoretical framework are viable and stable, as all the required conditions are satisfied., Comment: 46 pages, 14 figures

This paper aims to examine the composition of various spherically symmetric star models which are coupled with anisotropic configuration in $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ gravity, where $\mathcal{Q}=\mathcal{R}_{\chi\xi}\mathcal{T}^{\chi\xi}$. We discuss the physical features of compact objects by employing bag model equation of state and construct the modified field equations in terms of Krori-Barua ansatz involving unknowns ($A,B,C$). The observational data of 4U 1820-30,~Vela X-I,~SAX J 1808.4-3658,~RXJ 1856-37 and Her X-I is used to calculate these unknowns and bag constant $\mathfrak{B_c}$. Further, we observe the behavior of energy density, radial and tangential pressure as well as anisotropy through graphical interpretation for a viable model $\mathcal{R}+\varrho\mathcal{Q}$ of this gravity. For a particular value of the coupling constant $\varrho$, we study the behavior of mass, compactness, redshift and the energy bounds. The stability of the considered stars is also checked by using two criteria. We conclude that our developed structure in this gravity is in well-agreement with all the physical requirements., Comment: 28 pages, 8 figures

The present work explores different evolutionary phases of isotropically homogeneous and flat cosmos filled with dust fluid in non-minimally coupled gravity. We consider different models of this gravity to discuss the presence of symmetry generators together with conserved integrals using Nother Gauge symmetry scheme. In most of the cases, we obtain temporal and scaling symmetries that yield conservation of energy and linear momentum, respectively. In the absence of contracted Ricci and energy-momentum tensors, we obtain maximum symmetries but none of them correspond to any standard symmetry or conservation law. We formulate exact solutions and construct graphical analysis of standard cosmological parameters. We observe realistic nature of new models via squared speed of sound, viability conditions suggested by Dolgov-Kawasaki instability and state-finder parameters. We investigate the behavior of fractional densities and check the compatibility with Planck 2018 observational data. The new models are stable and viable preserving compatibility with $\Lambda$CDM and Chaplygin gas models. It is concluded that most of the solutions favor accelerated cosmic expansion., Comment: 31 pages, 11 figures

The main purpose of this paper is to obtain physically stable stellar models coupled with anisotropic matter distribution in the context of $f(\mathcal{R},\mathrm{T}^{2})$ theory. For this, we consider a static spherical geometry and formulate modified field equations containing various unknowns such as matter determinants and metric potentials. We then obtain a unique solution to these equations by employing Durgapal-Fuloria ansatz possessing a constant doublet. We also use matching criteria to calculate the values of these constants by considering the Schwarzschild exterior spacetime. Two different viable models of this modified theory are adopted to analyze the behavior of effective matter variables, anisotropy, energy conditions, compactness and redshift in the interiors of Her X-1, PSR J0348-0432, LMC X-4, SMC X-1, Cen X-3, and SAX J 1808.4-3658 star candidates. We also check the stability of these models by using three different physical tests. It is concluded that our considered stars satisfy all the physical requirements and are stable in this modified gravity for the considered parametric values., Comment: 28 pages, 10 figures

In this paper, we investigate the anisotropic interior spherically symmetric solutions by utilizing the extended gravitational decoupling method in the background of $f(G,T)$ gravity, where $G$ and $T$ signify the Gauss-Bonnet term and trace of the stress-energy tensor, respectively. The anisotropy in the interior geometry arises with the inclusion of an additional source in the isotropic configuration. In this technique, the temporal and radial potentials are decoupled which split the field equations into two independent sets. Both sets individually represent the isotropic and anisotropic configurations, respectively. The solution corresponding to the first set is determined by using the Krori-Barua metric potentials whereas the second set contains unknown which are solved with the help of some constraints. The ultimate anisotropic results are evaluated by combining the solutions of both distributions. The influence of decoupling parameter is examined on the matter variables as well as anisotropic factor. We illustrate the viable and stable features of the constructed solutions by using energy constraints and three stability criteria, respectively. Finally, we conclude that the obtained solutions are viable as well as stable for the whole domain of the coupling parameter., Comment: 33 pages, 9 figures

This paper studies the reconstruction criterion in the framework of $f(Q,T)$ gravity using ghost dark energy model, where $Q$ represents the non-metricity and $T$ is the trace of energy-momentum tensor. In this regard, the correspondence scenario for a non-interacting scheme is used to construct the ghost dark energy $f(Q,T)$ model. We consider the flat Friedmann-Robertson-Walker universe with power-law scale factor and pressure-less matter. We investigate the behavior of equation of state parameter and examine the stability of ghost dark energy model via squared speed of sound parameter. The equation of state parameter depicts the phantom era, while the squared speed of sound reveals stable ghost dark energy model for the entire cosmic evolutionary paradigm. Finally, we study the cosmography of the $\omega_{GDE}-\omega'_{GDE}$ and $r-s$ planes that correspond to freezing region and Chaplygin gas model, respectively. It is concluded that the reconstructed ghost dark energy model represents the evolution of the cosmos for suitable choices of the parametric values., Comment: 34 pages, 6 figures

This paper investigates the effects of electromagnetic field on the gravitational collapse in $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ theory, where $\mathcal{Q} = \mathcal{R}_{\varphi\vartheta} \mathcal{T}^{\varphi\vartheta}$. For this, we assume dynamical cylindrically symmetric self-gravitating geometry which is coupled with generalized anisotropic matter distribution as well as dissipation flux. We adopt the model $\mathcal{R}+\Phi\sqrt{\mathcal{T}}+\Psi\mathcal{Q}$ to formulate the corresponding dynamical and transport equations by employing the Misner-Sharp as well as M\"{u}ler-Israel Stewart formalisms, where $\Phi$ and $\Psi$ are real-valued coupling constants. The influence of state variables, heat dissipation, charge and the bulk viscosity on the collapsing phenomenon is then studied by establishing some relations between these evolution equations. Moreover, the Weyl scalar and the modified field equations are expressed in terms of each other. We apply some constraints on the considered modified model and the fluid configuration to obtain conformally flat spacetime. Finally, we address different cases to check how the modified corrections and charge affect the collapse rate of cylindrical matter source., Comment: 25 pages, no figure

This paper investigated the viable traversable wormhole solutions through Karmarkar condition in the context of $f(\mathcal{G},T)$ theory. A static spherical spacetime with anisotropic matter configuration is used to study the wormhole geometry. Karmarkar condition is used to develop a viable shape function for a static wormhole structure. A wormhole geometry is constructed using the resulting shape function that satisfies all the required conditions and connects the asymptotically flat regions of the spacetime. To assess the viability of traversable wormhole geometries, the energy conditions are analyzed by various models of this theory. Further, their stable state is investigated through sound speed and adiabatic index. This investigation demonstrates the presence of viable traversable wormhole solutions in the modified theory., Comment: 31 pages, 26 figures

In this paper, we consider isotropic solution and extend it to two different exact well-behaved spherical anisotropic solutions through minimal geometric deformation method in $f(R,T,R_{\rho\eta}T^{\rho\eta})$ gravity. We only deform the radial metric component that separates the field equations into two sets corresponding to their original sources. The first set corresponds to perfect matter distribution while the other set exhibits the effects of additional source, i.e., anisotropy. The isotropic system is resolved by assuming the metric potentials proposed by Krori-Barua while the second set needs one constraint to be solved. The physical acceptability and consistency of the obtained solutions are analyzed through graphical analysis of effective matter components and energy bounds. We also examine mass, surface redshift and compactness of the resulting solutions. For particular values of the decoupling parameter, our both solutions turn out to be viable and stable. We conclude that this curvature-matter coupling gravity provides more stable solutions corresponding to a self-gravitating geometry., Comment: 29 pages, 10 figures

The main objective of this manuscript is to investigate the bouncing cosmology in the background of $f(\mathcal{Q})$ gravity, where $\mathcal{Q}$ defines the non-metricity. For this purpose, we use the reconstruction approach and consider a flat Friedmann-Robertson-Walker spacetime with perfect matter configuration. We examine how the first contracting phase gives the expansion by using a temporal derivative of the scale factor, i.e., $\dot{a}<0$, $\dot{a}=0$ and $\dot{a}>0$ give contraction, bounce point and expansion phases, respectively. Further, we use the order reduction method to solve the modified field equations as these are very difficult due to the presence of additional non-linear expressions. It is analyzed that the original singularity of the universe diminishes for the required bounce conditions. We conclude that the acceleration occurs near the bouncing point and the considered $f(\mathcal{Q})$ models are consistent with the current cosmic accelerated expansion., Comment: 23 pages, 8 figures

The main objective of this article is to study the viable compact stellar structures in non-Riemannian geometry, i.e., $f(\mathbb{Q},T)$ theory, where $\mathbb{Q}$ defines the non-metricity and $T$ represents trace of the stress-energy tensor. In this perspective, we consider a static spherical metric with anisotropic matter configuration to examine the geometry of considered compact stars. A specific model of this theory is used to derive the explicit expressions of energy density and pressure components that govern the relationship between matter and geometry. The unknown parameters are evaluated by using the continuity of inner and outer spacetimes to examine the configuration of spherical stellar structures. Physical parameters such as fluid characteristics, energy constraints and equation of state parameters are analyzed to examine the viability of the considered stellar objects. Further, we use Tolman-Oppenheimer-Volkoff equation, sound speed and adiabatic index methods to analyze the equilibrium state and stability of the proposed stellar objects. The rigorous analysis and satisfaction of necessary conditions lead to the conclusion that the stellar objects studied in this framework are viable and stable., Comment: 39 pages, 9 figures

In this manuscript, we use the correspondence principle to construct the generalized ghost dark energy $f(Q)$ model, where $Q$ is the non-metricity. For this purpose, we use the Friedman-Robertson-Walker universe model with power-law scale factor. The energy density in this model linearly depends on the Hubble parameter, with a sub-leading term of $H^{2}$, resulting in an energy density $\rho_D=\xi H+\zeta H^{2}$, where $\xi$ and $\zeta$ are arbitrary constants. We reconstruct interacting fluid scenario of this dark energy with dark matter. The reformulated $f(Q)$ gravity model shows how different epochs of the cosmic history can be reproduced by this modified gravity model. The physical characteristics of the model are discussed through the equation of state parameter with the planes of $\omega_{D}-\omega'_{D}$ and $r-s$. We also explore the stability criteria for the interacting model using the squared speed of sound. The equation of state parameter indicates phantom phase of the universe and the squared speed of sound represents stability of the interacting model. The $(\omega_{D}-\omega^{\prime}_{D})$-plane indicates freezing region, while the $(r-s)$-plane corresponds to the Chaplygin gas. We conclude that our findings coincide with the latest observational data., Comment: 34 pages, 6 figures

In this paper, we use the embedding class-I technique to examine the effect of charge on traversable wormhole geometry in the context of $f(\mathcal{G})$ theory, where $\mathcal{G}$ is the Gauss-Bonnet term. For this purpose, we consider static spherical spacetime with anisotropic matter configuration to investigate the wormhole geometry. The Karmarkar condition is used to develop a shape function for the static wormhole structure. Using this developed shape function, we construct a wormhole geometry that satisfies all the required constraints and connects asymptotically flat regions of the spacetime. To analyze the existence of traversable wormhole geometry, we evaluate the behavior of energy conditions for various models of this theory. This study reveals that viable traversable wormhole solutions exist in this modified theory., Comment: 37 pages, 10 figures. arXiv admin note: text overlap with arXiv:2311.05502

This paper focuses on the analysis of static spherically symmetric anisotropic solutions in the presence of electromagnetic field through the gravitational decoupling approach in $f(\mathcal{R},\mathcal{T},\mathcal{R}_{\gamma\upsilon}\mathcal{T}^{\gamma\upsilon})$ gravity. We use geometric deformation only on radial metric function and obtain two sets of the field equations. The first set deals with isotropic fluid while the second set yields the influence of anisotropic source. We consider the modified Krori-Barua charged isotropic solution for spherical self-gravitating star to deal with the isotropic system. The second set of the field equations is solved by taking two different constraints. We then investigate physical acceptability of the obtained solutions through graphical analysis of the effective physical variables and energy conditions. We also analyze the effects of charge on different parameters, (i.e., mass, compactness and redshift) for the resulting solutions. It is found that our both solutions are viable as well as stable for specific values of the decoupling parameter $\varphi$ and charge. We conclude that a self-gravitating star shows more stable behavior in this gravity., Comment: 30 pages, 8 figures

The main objective of this paper is to investigate the impact of $f(\mathcal{Q},\mathcal{T})$ gravity on the geometry of anisotropic compact stellar objects, where $\mathcal{Q}$ is non-metricity and $\mathcal{T}$ is the trace of the energy-momentum tensor. In this perspective, we use the physically viable non-singular solutions to examine the configuration of static spherically symmetric structures. We consider a specific model of this theory to examine various physical quantities in the interior of the proposed compact stars. These quantities include fluid parameters, anisotropy, energy constraints, equation of state parameters, mass, compactness and redshift. The Tolman-Oppenheimer-Volkoff equation is used to examine the equilibrium state of stellar models, while the stability of the proposed compact stars is investigated through sound speed and adiabatic index methods. It is found that the proposed compact stars are viable and stable in the context of this theory., Comment: 31 pages, 12 figures

This paper uses the gravitational decoupling through the minimal geometric deformation approach and extends a known isotropic solution for a self-gravitating interior to two types of anisotropic spherical solutions in Rastall gravity in the presence of electromagnetic field. By deforming only the radial metric component, the field equations are decoupled into two sets, the first of which corresponds to an isotropic distribution of matter while the second set contains the anisotropic source. We obtain a solution of the first set by employing the charged isotropic Finch-Skea ansatz, whereas a solution for the second set is obtained by adopting two mimic constraints on the pressure and density. The matching conditions at the stellar surface are explored with the exterior geometry given by the deformed Reissner-Nordstr$\ddot{o}$m spacetime. For the two fixed values of the Rastall and charge parameters, we investigate physical features of both solutions through graphical analysis of the energy conditions, equation of state parameters, surface redshift and compactness function. The stability of both solutions is also studied through the Herrera cracking approach and causality condition. We deduce that while both solutions are physically viable, only the solution corresponding to the pressure-like constraint is stable., Comment: 38 pages, 16 figures

This article examines the dynamics of gravitational collapse in $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ gravity, where $\mathcal{Q}=\mathcal{R}_{\mathrm{ab}}\mathcal{T}^{\mathrm{ab}}$. We consider self-gravitating anisotropic cylindrical geometry whose interior is filled with dissipative matter configuration and match it with exterior cylindrically symmetric spacetime at the hypersurface through junction conditions. We employ the Misner-Sharp and M\"{u}ler-Israel Stewart formalisms to derive the dynamical as well as transport equations corresponding to the model $\mathcal{R}+\Phi\sqrt{\mathcal{T}}+\Psi\mathcal{Q}$, where $\Phi$ and $\Psi$ are arbitrary coupling constants. We then establish some relations between these equations through which the impact of effective matter variables, heat dissipation and the bulk viscosity on the collapse rate is studied. Further, we express the Weyl scalar in terms of the effective matter sector. We also obtain the conformal flatness by applying some restrictions on the considered model and taking dust configuration into the account. Finally, we investigate various cases to check whether the modified corrections increase or decrease the collapse rate., Comment: 23 pages, no figure

This paper discusses the gravitational collapse of dynamical self-gravitating fluid distribution in $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ gravity, where $\mathcal{Q}=\mathcal{R}_{\varphi\vartheta}\mathcal{T}^{\varphi\vartheta}$. In this regard, we assume a charged anisotropic spherical geometry involving dissipation flux and adopt standard model of the form $\mathcal{R}+\Phi\sqrt{\mathcal{T}}+\Psi\mathcal{Q}$, where $\Phi$ and $\Psi$ symbolize real-valued coupling parameters. The Misner-Sharp as well as M\"{u}ler-Israel Stewart mechanisms are employed to formulate the corresponding dynamical and transport equations. We then interlink these evolution equations which help to study the impact of state variables, heat dissipation, modified corrections and charge on the collapse rate. The Weyl scalar is further expressed in terms of the modified field equations. The necessary and sufficient condition of conformal flatness of the considered configuration and homogeneous energy density is obtained by applying some constraints on the model along with disappearing charge and anisotropy. Finally, we discuss different cases to investigate how the spherical matter source is affected by the charge and modified corrections., Comment: 30 pages, no figure

This paper investigates the greybody factor for a non accelerated black hole with modified Maxwell electrodynamics in an anti-de Sitter regime. For this purpose, we compute the radial equation for a massless scalar field with the help of Klein-Gordon equation. We then formulate effective potential by transforming this equation into Schrodinger wave equation. We analyze the graphical behavior of effective potential for different values of mass, parameter characterizing the modified Maxwell theory, anti-de Sitter radius and electromagnetic charge parameters. The exact solutions are computed at two different horizons, i.e., event and cosmological horizons through the radial equation. Furthermore, we match the obtained solutions in an intermediate regime to enhance feasibility of the greybody factor over the entire domain and check its behavior graphically. It is found that the greybody factor has a direct relation with the radius, electromagnetic charge as well as angular momentum of the black hole and an inverse relation with the anti-de Sitter radius and modification parameter. We conclude that the modified Maxwell solution reduces the emission rate of the black hole., Comment: 27 pages, 9 figures

In this paper, we formulate two exact charged solutions to the field equations by extending the domain of existing anisotropic models with the help of minimal gravitational decoupling in $f(\mathbb{R},\mathbb{T})$ theory. For this, the anisotropic fluid distribution is considered as a seed source that is extended through the inclusion of a new gravitational source. The influence of the later matter configuration is controlled by the decoupling parameter. We formulate the field equations corresponding to the total matter source that are then decoupled into two distinct sets by implementing a transformation only on the radial metric coefficient. Both of these under-determined sets correspond to their parent sources. Some well-behaved forms of the metric potentials are taken into account to deal with the first set of equations. On the other hand, we solve the second set corresponding to an additional source by taking different constraints on the matter sector. We then consider the radius and mass of a compact star $4U~1820-30$ to analyze the physical feasibility of the resulting solutions for a particular modified model. It is concluded that our resulting solutions show stable behavior for certain values of the decoupling parameter and charge., Comment: 34 pages, 11 figures

In this paper, we investigate how charge and modified terms affect the viability and stability of traversable wormhole geometry in the framework of $f(R,G)$ theory, where $R$ is the Ricci scalar and $G$ is the Gauss-Bonnet term. For this purpose, we develop a shape function through the Karmarkar condition to examine the wormhole geometry. The resulting shape function satisfies all the necessary conditions and establishes a connection between the asymptotically flat regions of the spacetime. The behavior of energy conditions and sound speed is checked in the presence of higher-order curvature terms and electromagnetic field to analyze the existence of stable traversable wormhole geometry. It is found that the traversable wormhole solutions are viable and stable in this modified theory., Comment: 27 pages, 4 figures

This paper aims to formulate certain scalar factors associated with matter variables for self-gravitating non-static cylindrical geometry by considering a standard model $\mathcal{R}+\zeta\mathcal{Q}$ of $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ gravity, where $\mathcal{Q}=\mathcal{R}_{\varphi\vartheta}\mathcal{T}^{\varphi\vartheta}$ and $\zeta$ is the arbitrary coupling parameter. We split the Riemann tensor orthogonally to calculate four scalars and deduce $\mathcal{Y}_{TF}$ as complexity factor for the fluid configuration. This scalar incorporates the influence of inhomogeneous energy density, heat flux and pressure anisotropy along with correction terms of the modified gravity. We discuss the dynamics of cylinder by considering two simplest modes of structural evolution. We then take $\mathcal{Y}_{TF}=0$ with homologous condition to determine the solution for dissipative as well as non-dissipative scenarios. Finally, we discuss the criterion under which the complexity-free condition shows stable behavior throughout the evolution. It is concluded that complex functional of this theory results in a more complex structure., Comment: 27 pages, no figure

This paper examines the structure of a gravitationally vacuum star (also known as gravastar) in the background of ${f}(\Re,\mathcal{T}^{2})$ theory. This hypothetical object can be treated as a substitute of a black hole, with three regions: (i) the internal region, (ii) the intrinsic shell and (iii) the outer region. We examine these geometries using Finch-Skea metric for radial metric component along with particular $f(\Re,\mathcal{T}^{2})$ model. We determine singularity-free solution for both the inner as well as thin-shell domains. The smooth matching of the interior region with external Schwarzschild spacetime is obtained through Israel matching constraints. Finally, we study various characteristics of gravastar domains including equation of state parameter, proper length, entropy, energy as well as surface redshift. It is found that the compact gravastar structure is a viable alternate to the black hole in the perspective of this gravity., Comment: 20 pages, 6 figures, to appear in MPLA

This paper constructs two immediate extensions of the existing anisotropic solutions in the context of Einstein-Maxwell framework by employing minimal geometric deformation. To achieve this, we assume a static spherical interior initially filled with anisotropic fluid and call it a seed source. We extend this matter configuration by including a new source whose impact on the self-gravitating system is governed by a decoupling parameter. The charged field equations analogous to the total fluid source are formulated. We then implement a transformation on the radial metric potential that divides the field equations into two new under-determined systems, corresponding to the initial and new sources. The first of them is addressed by taking two well-known metric ansatz so that the number of unknowns can be tackled. Further, the vanishing of total anisotropy and complexity-free constraints are used to solve the second set. The estimated radius and mass of a compact star $4U~1820-30$ is utilized to interpret the resulting solutions graphically for different values of the charge and decoupling parameter $\omega$. We conclude that our both developed models are physically acceptable for all parametric values except $\omega=1$., Comment: 35 pages, 14 figures

In this paper, we determine the electromagnetic effects on the complexity factor of radiating anisotropic cylindrical geometry in the background of $f(G,\mathcal{T})$ theory. The self-gravitating objects possessing inhomogeneous energy density, pressure anisotropy, heat flux, charge and correction terms appear to encounter the complexity producing phase. Herrera's orthogonal splitting method is used to identify the scalar functions in which the factor that incorporates all of the fundamental aspects of the system is assumed to be the complexity factor. We also look at the evolution of charged cylindrical matter source by selecting homologous pattern as the most basic evolutionary mode. In addition to this, homologous and complexity free conditions are utilized to address dissipative as well as non-dissipative scenarios. The complexity producing parameters throughout the evolutionary process are assessed at the end. It is concluded that the complexity of the astrophysical entities is elevated due to the contribution of charge and modified terms of this theory., Comment: 28 pages, no figure

This paper discusses the interior distribution of several anisotropic star models coupled with an electromagnetic field in the context of $f(\mathcal{R},\mathcal{T},\mathcal{Q})$ gravity, where $\mathcal{Q}=\mathcal{R}_{\beta\xi}\mathcal{T}^{\beta\xi}$. In this regard, a standard model of this modified gravity is taken as $\mathcal{R}+\nu_{3}\mathcal{R}_{\beta\xi}\mathcal{T}^{\beta\xi}$, where $\nu_{3}$ symbolizes an arbitrary coupling constant. We assume a charged spherically symmetric metric that represents the interior geometry of compact quark stars and develop the corresponding modified field equations. These equations are then solved with the help of metric potentials of Tolman IV spacetime and a linear bag model equation of state. We consider the experimental data (i.e., radii and masses) of different quark models such as SMC X-4, SAX J 1808.4-3658, Her X-I and 4U 1820-30 to analyze how the charge and modified corrections affect their physical characteristics. The viability and stability of the resulting model is also checked for the considered star candidates with two different values of $\nu_{3}$. We conclude that only two models, Her X-I and 4U 1820-30 show stable behavior in this modified framework for both values of the coupling constant., Comment: 36 pages, 9 figures, Accepted for publication in Physica Scripta

This paper examines the effects of charge on traversable wormhole structure in $f(R,T)$ theory. For this purpose, we use the embedding class-I approach to build a wormhole shape function from the static spherically symmetric spacetime. The developed shape function satisfies all the required conditions and connects two asymptotically flat regions of spacetime. We consider different models of this modified theory to examine the traversable wormhole solutions through null energy condition and also check their stable state. We conclude that viable and stable wormhole solutions are obtained under the influence of charge in this gravitational theory., Comment: 21 pages, 5 figures

This paper investigates the geometry of compact stellar objects via Noether symmetry strategy in the framework of curvature-matter coupled gravity. For this purpose, we assume the specific model of this theory to evaluate Noether equations, symmetry generators and corresponding conserved parameters. We use conserved parameters to examine some fascinating attributes of the compact objects for suitable values of the model parameters. It is analyzed that compact objects in this theory depend on the conserved quantities and model parameters. We find that the obtained solutions provide the viability of this process as they are compatible with the astrophysical data., Comment: 22 pages, 10 figures

In this paper, we adopt minimal gravitational decoupling scheme to extend a non-static spherically symmetric isotropic composition to anisotropic interior in $f(\mathcal{R},\mathcal{T},\mathcal{R}_{\mathrm{a}\mathrm{b}}\mathcal{T}^{\mathrm{a}\mathrm{b}})$ theory. A geometric deformation is applied only on $g_{rr}$ metric component through which the modified field equations are separated into two sets, each of them correspond to their parent (seed and newly added) source. An isotropic model suggested by the Friedmann-Lemaitre-Robertson-Walker metric is adopted to reduce the unknowns in the first set. We then obtain an isotropic solution by making use of a linear equation of state and a particular form of the scale factor. A density-like constraint is chosen to solve the other sector containing the deformation function and multiple components of an additional matter source. Further, the graphical interpretation of the developed model is carried out to analyze how a decoupling parameter and modified gravity influence the evolutionary phases of the universe. It is concluded that only the radiation-dominated era meets stability criteria everywhere in this matter-geometry coupled theory., Comment: 30 pages, 10 figures