In this paper, the construction of thin-shell wormholes is crafted from two Bardeen anti-de Sitter black holes by using the cut and paste approach in the f(R) theory of gravity. The f(R)=R+αRn+βR−m gravity model is considered to obtain the wormhole solutions. The stability is checked for linear perturbation around some static solution. The concavity nature of the potential function is examined by variation

In this paper, Lie symmetry analysis method is applied to time fractional Burgers equation, Korteweg-de Vries equation and generalized reaction-diffusion equation with delays, respectively. The Lie symmetries for fractional partial differential equations with delays (DFPDEs) are obtained, and the group classifications of the equations are established. The obtained group generators are used to reduce

In this paper, the novel exact solitary wave solutions for the generalized nonlinear Schrödinger equation with parabolic nonlinear (NL) law employing the improved cosh(Γ(ϖ))−sech(Γ(ϖ)) function scheme and the combined cos(Γ(ϖ))−sec(Γ(ϖ)) function scheme are found. Diverse collections of hyperbolic and trigonometric function solutions acquired rely on a map between the considered equation and an auxiliary

Symmetric trace-free tensors are used in many areas of physics, including electromagnetism, relativistic celestial mechanics and geodesy, as well as in the study of gravitational radiation and gravitational lensing. Their use allows integration of the relevant wave propagation equations to arbitrary order. We present an improved iterative method for the trace-free decomposition of symmetric tensors

We present an analysis of fermionic dark matter (DM) in the context of 6-dimensional Effective Field Theory (EFT). We also compared the result generated via 6-dimensional EFT analysis with the current experimental results for dark matter searches. These experiments are methodically categorized as direct and indirect searches and present some constraints on dark matter model parameters of 6-dimensional

Many models of dark energy have been proposed to describe the universe since the beginning of the Big Bang. In this study, we present a new model of agegraphic dark energy based on the three generalized uncertainty principles KMM (Kempf, Mangan, Mann), Nouicer and GUP∗ (higher orders generalized uncertainty principle). Using the obtained relations from three types of Generalized Uncertainty Principle

While the Bekenstein–Hawking entropy is the unique notion of entropy that makes classical black hole thermodynamics consistent, alternative entropy notions (Rényi, Tsallis, and generalized constructs) abound in the literature. We explore conditions under which they are part of a consistent horizon thermodynamics for certain classes of modified gravity black holes. We provide examples in which black

Black holes have been a subject of investigation over years not only because they have interesting physical properties, but also because they seem to be the appropriate tool for studying gravity in quantum scale. A lot of effort has been made to understand the aspects of spacetime on the quantum scale. Among several possibilities, the approach which includes noncommutativity of spacetime proves to

In this paper, we introduce the generalized Legendre transformation for the GUP Hamiltonian. From this, we define the non-canonical momentum. We interpret the momentum in GUP as the non-canonical momentum. We construct the GUP Lagrangian for some GUP models.

The ModMax model of nonlinear electrodynamics (NED) is investigated in the absence of the linear term. The linear term is itself a ModMax model, however, the nonlinear term is not. First, in (3+1)-dimensional Minkowski spacetime, we introduce the electromagnetic theory in this NED model. We find the vacuum electric permittivity and magnetic permeability which both are in tensor form. This shows that

Quantum fields are considered as generators of infinite-dimensional Clifford algebra Cl(∞), which can be either orthogonal (in the case of fermions) or symplectic (in the case of bosons). A generic quantum state can be expressed as a superposition of the basis elements of Cl(∞), with the superposition coefficients being multiparticle complex-valued wavefunctions. The basis elements, that are products

In the paper, on account of the Kummer confluent hypergeometric series of first type, we suggest the Turań-type inequalities for the hypergeometric supersine and supercosine functions by using the Cauchy–Bunyakovsky–Schwarz inequality.

In this paper, we present a comprehensive study on the (4+1)-Fokas equation that includes new solutions and conservation laws of the equation. Specifically, for the first time, new shrunken-periodic and fascinating interactions on the bright soliton background have been investigated. Furthermore, a bright, dark, dipole soliton, tripole soliton, multipole soliton, periodic, doubly-periodic, damped-periodic

This paper deals with an anisotropic cosmological model in the modified theory of f(Q)-gravity filled with bulk-viscosity fluid. We investigated the modified f(Q)-gravity with quadratic form f(Q)=−αQ2, where Q is the non-metricity scalar and α is a positive constant, in Locally-Rotationally Symmetric (LRS) Bianchi type-I space time universe. We have solved the modified Einstein’s field equations with

In this paper, we investigate a non-interacting model considering a spatially anisotropic and homogeneous Bianchi type-I Universe, filled with Barrow holographic dark energy (BHDE) and pressureless dark matter. We examine some important cosmological parameters for the evolutionary report and to witness adequate nature in BHDE model as including deceleration parameter, the jerk parameter, equation of

In this paper, we investigate the gravitational lensing for power-Maxwell charged quintessence black hole (BH) without cosmological constant in Rastall’s theory of gravity in both the strong-field limit and weak-field limit. Furthermore, we discuss the gravitational lensing by the linear electrodynamic (LE) and nonlinear electrodynamic (NLE) Maxwell field with the equation of state (EoS) parameter

In this paper, in an extended theory of gravity, we have presented bouncing cosmological model at the backdrop of an isotropic, homogeneous space-time, in the presence of general relativistic hydrodynamics (GRH). The scale factor has been chosen in such a manner that with appropriate normalization, the quintom bouncing scenario can be assessed. Accordingly, the bounce occurs at t=0 and the corresponding

In this paper, we have investigated a spatially homogeneous and anisotropic accelerating Universe in Lyra’s geometry. Einstein’s field equations are solved explicitly by assuming dependent relation among the directional scale factors. In this paper, we use observational H(z) data (OHD) and Pantheon compilation of recent type Ia supernovae (SN Ia) data to constrain the model parameters of the Universe

In this paper, Yamabe solitons, gradient Yamabe solitons and gradient ρ-Einstein solitons have been investigated on 3-dimensional f-Kenmotsu manifolds. Moreover, we characterize 3-dimensional f-Kenmotsu manifolds admitting ∗-Ricci solitons and gradient ∗-Ricci solitons, respectively.

This paper explores the aspects of compact stars in f(T,𝒯) gravity, where T and 𝒯 express the torsion and trace of the energy–momentum tensor. To achieve this goal, we consider a spherically symmetric spacetime with an anisotropic source of fluid. In particular, the Krori–Barua (KB) spacetime is considered to explore the solution of compact stars. In addition, we select three specific types of compact

The main goal of this paper is to study the weak gravitational lensing by Horndeski black hole in weak field approximation. In order to do so, we exploit the Gibbons–Werner method to the optical geometry of Horndeski black hole and implement the Gauss–Bonnet theorem to accomplish the deflection angle of light in weak field region. Furthermore, we have endeavored to extend the scale of our work by comprising

Quantum hydrodynamics described by Madelung equations is analyzed in the framework of symplectic geometry i.e. in covariant phase space approach to geometric field theory. The pre-symplectic manifolds providing the phase spaces describing the Hamiltonian dynamics of quantum fluid are constructed from the set of all solutions of Madelung equations and their corresponding Lagrangian densities. The Madelung

We compute analytically the radiative quantum corrections, up to next-to-leading loop order, to the universal critical exponents for both massless and massive O(N) λϕ4 scalar squeezed field theories for probing the universality hypothesis. For that, we employ six distinct and independent methods. The outcomes for the universal squeezed critical exponents obtained through these methods are identical

In this study, we consider a time-fractional shallow water wave model which was introduced by Gear and Grimshaw. This model represents the dynamics of two-layered shallow water waves in oceans and rivers. Also it covers many shallow water wave models with special values taken to parameters. By performing the group invariant analysis approach for the governing system with Riemann–Liouville derivative

In this paper, we obtain Euler’s and De Moivre’s formulas for the 4×4 matrix representation of Pauli quaternions. Moreover, we provide De Moivre’s formula for the light-like Pauli quaternions. Additionally, we give the nth roots of the matrix representation of Pauli quaternions. Moreover, we exemplify some of the results with illustrative examples to support the main formulas.

The aim of this paper is to investigate and analyze the behavior of charged compact stars in the modified f(R,ϕ,χ) theory of gravity. When solving the field equations, we assume that Krori– Barua space-time describes the geometry of the inner space [K. Krori and J. Barua, A singularity-free solution for a charged fluid sphere in general relativity, J. Phys. A Math. Gen.8 (1975) 508]. We further analyzed

In this paper, we consider certain analytical features of a stochastic model that can explain competition among species and simultaneous predation on the competing species from a geometric perspective. This allows us to build a systematic description of models admitting singular Lagrangians. The model equations are shown to admit a Jacobi Last Multiplier which allows us to construct an appropriate

In this work, we study some parameterizations of the deceleration parameter and investigate the accretion of the fluid in these parameterized models upon the higher-dimensional black hole (BH) and wormholes. For the undergoing analysis, (n+2)-dimensional wormhole (proposed by Morris and Thorne) and Schwarzschild BH were chosen in the backdrop of higher-dimensional Friedmann–Robertson–Walker (FRW) space-time

This work will proceed to examine the dynamics of collapsing charged string cloud in a spherically symmetric rainbow metric. This is the framework that allows new stars and compact objects to emerge. The dynamical variables (mass density, string tension) and their physical existence as energy conditions are computed and visually depicted. We also calculated the duration and radius of development of

In this work, we model two event horizons associated with a null Cartan curve as two lightlike hypersurfaces, respectively. We define a lightlike surface and a spacelike surface whose images coincide with the sets of critical values of two event horizons, and meanwhile we present two curves whose images coincide with the sets of critical values of these two surfaces, respectively. Using the singularity

Ever since a new symmetry was found for the imperfect fluid with vorticity, the question of the effect of perturbations on the symmetry itself has been raised. This new symmetry arose when realizing that local four-velocity gauge-like transformations would render the left-hand side of the Einstein equations invariant because the metric tensor would be invariant under this new kind of local transformations

Conformal symmetries act as a source to investigate and classify exact solutions of the Einstein field equations (EFEs) via conformal vector fields (CVFs). It is well known that such classification leads to an important class of symmetries known as Killing symmetry which is the source of generating conservation laws of physics. In this paper, first we explore various classes of Kantowski–Sachs (KS)

In this paper, we study the perturbative regime in the static patch of de Sitter metric in the Regge–Wheeler formalism. After realizing that perturbative regime in a de Sitter spacetime depicted in terms of usual spherical coordinates cannot be extended up to the cosmological horizon, we study perturbative equations, in particular the axial ones, in terms of the tortoise coordinate r∗. We show that

This work applies the contact formalism of classical mechanics and classical field theory, introduced by Herglotz and later developed in the context of contact geometry, to describe electromagnetic systems with dissipation. In particular, we study an electron in a non-perfect conductor and a variation of the cyclotron radiation. In order to apply the contact formalism to a system governed by the Lorentz

The contact geometric structure of the thermodynamic phase space is used to introduce a novel symplectic structure on the tangent bundle of the equilibrium space. Moreover, it turns out that the equilibrium space can be interpreted as a Lagrange submanifold of the corresponding tangent bundle, if the fundamental equation is known explicitly. As a consequence, Hamiltonians can be defined that describe

In this contribution, we investigate hierarchical nature of large-scale structure clustering through the oscillatory nature of the solutions of the Schrödinger-like Friedmann equation in a modified gravitational background described by the f(R) gravity theory. We find the cosmological solutions to the Schrödinger equation for different ranges of n of the Rn toy model for both radiation and matter-dominated

In this paper, we studied a higher-dimensional space and time fractional model, namely, the (3+1)-dimensional dissipative Burgers equation which can be used to describe the shallow water waves phenomena. Here, the analyzed tool is the Lie symmetry scheme in the sense of the Riemann–Liouville fractional derivative. First of all, the symmetry of this considered equation was yielded. Then, based on the

To date, a mathematically consistent construction of effective rotating black hole models in the context of Loop Quantum Gravity (LQG) is still lacking. In this work, we start with the assumption that rotating LQG black hole metrics can be effectively obtained using Newman–Janis Algorithm. Then, based on a few extra fair assumptions on the seed metric functions, we make a conjecture on what a rotating

By considering the back-reaction of the spacetime through the spherically symmetric quantum fluctuations of the background metric, Kazakov and Solodukhin removed the singularity of the Schwarzschild black hole. This regular Schwarzschild black hole has a spherical central region with a radius of the order of the Planck length. On the other hand, due to the positively accelerating expansion of the Universe

This work reports the effect of thermal radiation on singularities in the presence of holographic Ricci dark energy (HRDE) with generalized IR cut-off. The Eckart approach has been considered to initiate the study. The density of HRDE, which is a just particular cases of general Nojiri–Odintsov (NO) HDE [S. Nojiri and S. D. Odintsov, Unifying phantom inflation with late-time acceleration: Scalar phantom-non-phantom

The physical meaning and mathematical meaning of nonmetricity on Weyl manifold and the application of dual affine connection for it are discussed. In viewpoint from affine connection, Weyl 1-form in Weyl manifold is recognized as nonmetricity and causes scale change with conformal invariance under parallel transport. On manifolds expressing spacetime and material space, Weyl 1-form is equivalent to

Starting from two matrix spectral problems associated with the real special orthogonal Lie algebra so(3,ℝ), two non-isospectral hierarchies of Ablowitz–Kaup–Newell–Segur (AKNS) type and Kaup–Newell (KN) type are constructed. In addition, we enlarge the two spectral problems and then obtain non-isospectral Z2𝜀 integrable couplings of AKNS type and KN type by solving the expanded non-isospectral zero

The improved description of the planets’ interior is provided. We examine the modified gravity effects on the Earth-like planets composed of the iron core and silicate mantle. We confirm that the mass–radius relations as well as density profiles differ with respect to the commonly adopted Newtonian models.

The problem of FLRW universes can be seen in the excellent works of A. Friedmann, G. Lemaître, H. P. Robertson, A. G. Walker. The key of obtaining FLRW universes with or without cosmological constant is related to the special form of the contravariant energy–momentum tensor which describes a perfect fluid with components Tij=(ρ0+p0)uiuj−p0gij because such a “matter” leads to FLRW conditions R11=R22=R33

A new class of conformal invariants for a given spacetime M is introduced exploiting the conformal geometry of any light ray Γ. Each congruence of light rays passing through a given point p defines the sky S(p) of such point. The new conformal invariants are defined on the bundle of skies of the spacetime M, being called sky invariants accordingly. The natural conformal covariant derivative defined

In this paper, first, we find the necessary and sufficient condition for a Riemannian manifold to be the locally warped product. Then we investigate the existence of different types of gradient solitons, such as gradient (almost) Yamabe soliton, conformal soliton and gradient Ricci soliton on the twisted product manifolds. We also study the concircular flatness condition on a twisted product and examine

In this work, we studied the gravitational collapse of a spherically symmetric radiating star consisting of perfect fluid (baryonic) in the background of dark energy (DE) with an equation of state pDE=ωρDE. The effect of DE on the singularity formation has been discussed in two separate cases: first when only DE is present, and the other, with a combination of both baryonic and DE interaction. We have

This paper studies (2+1)-dimensional stochastic chiral nonlinear Schrödinger equation dynamically. A number of novel solutions such as periodic, singular, dark and bright solitons solutions are retrieved. The extraction of these solutions is helped by three efficient and robust integration tools such as the Kudryashov’s R function method, Jacobi elliptic function method (JEFM) and the modified auxiliary

This paper investigates the cross-kink and solitary wave solutions to the nonlinear vibration and dispersive wave systems. The solutions include periodic, cross-kink and solitary wave solutions. The bilinear form is considered in terms of Hirota derivatives. Accordingly, we utilize the Cole–Hopf algorithm to get the exact solutions of the (2+1)-dimensional modified dispersive water-wave system. The

In this work, we continue the systematic study of observable effects emerging from modified dispersion relations. We study the motion of test particles subject to a general first-order modification of the general relativistic dispersion relation as well as subject to the κ-Poincaré dispersion relation in spherical symmetry. We derive the corrections to the photon sphere, the black hole shadow, the

In this paper, we examine gravitational radiation in higher order non-local gravity described by the non-local gravitational Lagrangian density ℒg=R+∑h=1nahR□−hR. This non-local theory of gravitation always exhibits the tensor transverse gravitational radiation for k12=0, corresponding to the angular frequency ω1, composed of two standard (+) and (×) polarization modes, massless and of helicity 2.

In this work, the relativistic quantum oscillator under the Lorentz symmetry violation environment defined by an arbitrary constant vector field vμ is analyzed. We solve the generalized Klein–Gordon oscillator with different vector field configurations and obtained the bound-states solutions. After that, we insert a static Coulomb-type scalar potential in the wave equation and solve the generalized

I propose using the group SL(4, ℝ) as a generalization of the Dirac group SL(2, ℂ) used in quantum mechanics, in an attempt to match the symmetries of the ‘internal’ spacetime of elementary particles to the symmetries of the ‘external’ spacetime of general relativity. While my conclusions do not amount to a new model or theory, they do highlight some specific points where there are apparent conflicts

This paper concerns with the similarity solutions using Lie group theoretic method for one-dimensional unsteady isothermal flow behind the shock wave in the mixture of non-ideal gas and small solid particles in rotating medium. Group theoretic technique brings the different possible cases of potential solutions with the power law, particular case of power law and exponential law shock paths with the

The nonlinear generalized modified Emden-type equations (GMEE) are known to be linearizable into simple harmonic oscillator (HO) or damped harmonic oscillators (DHO) via some nonlocal transformations. Hereby, we show that the structure of the nonlocal transformation and the linearizability into HO or DHO determines the nature/structure of the dynamical forces involved (hence, determine the structure

This paper aims to study some invariants and conservation laws relevant to electromagnetic and gravitational fields by means of the rotational transformations of octonion coordinate systems. The scholars utilize the octonions to analyze the electromagnetic and gravitational fields simultaneously, including the octonion field potential, field strength, field source, linear momentum, angular momentum

We prove that an almost pseudo 𝒵 symmetric spacetime with Codazzi type of 𝒵 tensor is perfect fluid whose velocity vector field Bi is parallel. The energy density σ of such perfect fluid spacetime is constant and the state equation is obtained. Also, this spacetime is shown to be a static spacetime. Next, it is shown that such spacetime is a GRW spacetime with Einstein fiber. This kind of spacetime

By introducing a new coordinate condition we divide the cylindrical spacetime of Levi-Civita (LC) into a sourceful inner (ρ ≤ ρ0 = const.) and vacuum outer (ρ ≥ ρ0) regions. The emergent fluid with zero radial pressure confined to the finely-tuned inner region serves to make the spacetime regular in a natural way. At ρ = 0 the LC spacetime becomes ‘Cartesian flat’ so that no deficit angle arises.

This is an overview on certain higher structural constructions in physics. Main motivations of our current attempt are as follows: (i) to provide a brief introduction to the basics of derived algebraic geometry, (ii) to understand how certain derived objects naturally appear in physics and give rise to a formal mathematical treatment, and (iii) to investigate how the notion of a factorization algebra

This paper aims to determine the anisotropic solutions for static spherically symmetric spacetime via gravitational decoupling technique in the context of f(G,T) gravity, where G indicates the Gauss–Bonnet term and T represents trace of the energy-momentum tensor. The additional source, present alongside the isotropic seed source in the sphere, induces anisotropy in the system. In order to decouple