Quintessence anisotropic stellar models in quadratic and Born-Infeld modified teleparallel Rastall gravity

This study aims to discuss anisotropic solutions that are spherically symmetric in the quintessence field,which describe compact stellar objects in the modified Rastall teleparallel theory of gravity.To achieve this goal,the Krori and Barua arrangement for spherically symmetric components of the line element is incorporated.We explore the field equations by selecting appropriate off-diagonal tetrad fields.Born-Infeld function of torsion f(T)=β√λT+1-1 and power law form h(T)=δTn are used.The Born-Infeld gravity was the first modified teleparallel gravity to discuss inflation.We use the linear equation of state pr=ξρto separate the quintessence density.After obtaining the field equations,we investigate different physical parameters that demonstrate the stability and physical acceptability of the stellar models.We use observational data,such as the mass and radius of the compact star candidates PSRJ 1416-2230,Cen X-3,&4U 1820-30,to ensure the physical plausibility of our findings.

Image encryption technique based on new two-dimensional fractional-order discrete chaotic map and Menezes–Vanstone elliptic curve cryptosystem

We propose a new fractional two-dimensional triangle function combination discrete chaotic map(2D-TFCDM)with the discrete fractional difference.Moreover,the chaos behaviors of the proposed map are observed and the bifurcation diagrams,the largest Lyapunov exponent plot,and the phase portraits are derived,respectively.Finally,with the secret keys generated by Menezes-Vanstone elliptic curve cryptosystem,we apply the discrete fractional map into color image encryption.After that,the image encryption algorithm is analyzed in four aspects and the result indicates that the proposed algorithm is more superior than the other algorithms.

Riemann-Hilbert approach of the complex Sharma-Tasso-Olver equation and its N-soliton solutions

We study the complex Sharma-Tasso-Olver equation using the Riemann-Hilbert approach.The associated Riemann-Hilbert problem for this integrable equation can be naturally constructed by considering the spectral problem of the Lax pair.Subsequently,in the case that the Riemann-Hilbert problem is irregular,the N-soliton solutions of the equation can be deduced.In addition,the three-dimensional graphic of the soliton solutions and wave propagation image are graphically depicted and further discussed.

The Exact Solution of the Space-Time Fractional Modified Kdv-Zakharov-Kuznetsov Equation

In this paper, we get many new analytical solutions of the space-time nonlinear fractional modified KDV-Zakharov Kuznetsov (mKDV-ZK) equation by means of a new approach namely method of undetermined coefficients based on a fractional complex transform. These solutions have physics meanings in natural sciences. This method can be used to other nonlinear fractional differential equations.

Study of bending angle and shadow in a new Schwarzschild-like black hole affected by plasma and non-plasma mediums

In this study,we analyze the models of the deflection angle of a new Schwarzschild-like black hole(BH)and employ the optical metric of the BH.To achieve this,we use the Gaussian curvature of the optical metric and the Gauss-Bonnet theorem,known as the Gibbons-Werner technique,to determine the deflection angle.Furthermore,we examine the deflection angle in the presence of a plasma medium and the effect of the plasma medium on the deflection angle.The deflection angle of the BH solution in the gauged super-gravity is computed using the Keeton-Petters approach.Utilizing the ray-tracing technique,we investigate the shadow of the corresponding BH and analyze the plots of the deflection angle and shadow to verify the influence of the plasma and algebraic thermodynamic parameters on the deflection angle and shadow.

Thermal analysis and Joule-Thomson expansion of black hole exhibiting metric-affine gravity

This study examines a recently hypothesized black hole,which is a perfect solution of metric-affine gravity with a positive cosmological constant,and its thermodynamic features as well as the Joule-Thomson expansion.We develop some thermodynamical quantities,such as volume,Gibbs free energy,and heat capacity,using the entropy and Hawking temperature.We also examine the first law of thermodynamics and thermal fluctuations,which might eliminate certain black hole instabilities.In this regard,a phase transition from unstable to stable is conceivable when the first law order corrections are present.In addition,we study the efficiency of this system as a heat engine and the effect of metric-affine gravity for the physical parameters q_(e),q_(m),κ_(s),κ_(d),and κ_(sh).Further,we study the Joule-Thomson coefficient and inversion temperature,and observe the isenthalpic curves in the Ti−Pi plane.In metric-affine gravity,a comparison is made between a van der Waals fluid and a black hole to study their similarities and differences.

Super Jaulent-Miodek hierarchy and its super Hamiltonian structure~ conservation laws and its self-consistent sources

A super Jaulent-Miodek hierarchy and its super Hamiltonian structures are constructed by means of a kind of Lie super algebras and super trace identity. Moreover, the self-consistent sources of the super Jaulent-Miodek hierarchy is presented based on the theory of self-consistent sources. Further- more, the infinite conservation laws of the super Jaulent-Miodek hierarchy are also obtained. It is worth noting that as even variables are boson variables, odd variables are fermi variables in the spectral problem, the commutator is different from the ordinary one.

IMPROVED FRACTIONAL SUB-EQUATION METHOD AND ITS APPLICATIONS TO FRACTIONAL PARTIAL DIFFERENTIAL EQUATIONS

Based on an improved fractional sub-equation method involving Jumarie＇s mo- dified Riemann-Liouville derivative, we construct analytical solutions of space-time fractional compound KdV-Burgers equation and coupled Burgers＇ equations. These results not only reveal that the method is very effective and simple in studying solu- tions to the fractional partial differential equation, but also include some new exact solutions.

Constructing super D-Kaup-Newell hierarchy and its nonlinear integrable coupling with self-consistent sources

How to construct new super integrable equation hierarchy is an important problem.In this paper,a new Lax pair is proposed and the super D-Kaup-Newell hierarchy is generated,then a nonlinear integrable coupling of the super D-Kaup-Newcll hierarchy is constructed.The super Hamiltonian structures of coupling equation hierarchy is derived with the aid of the super variational identity.Finally,the self-consistent sources of super integrable coupling hierarchy is established.It is indicated that this method is a straightforward and efficient way to construct the super integrable equation hierarchy.

Riemann-Hilbert problems and N-soliton solutions of the nonlocal reverse space-time Chen-Lee-Liu equation

In this paper,the N-soliton solutions to the nonlocal reverse space-time Chen-Lee-Liu equation have been derived.Under the nonlocal symmetry reduction to the matrix spectral problem,the nonlocal reverse space-time Chen-Lee-Liu equation can be obtained.Based on the spectral problem,the specific matrix Riemann-Hilbert problem is constructed for this nonlocal equation.Through solving this associated Riemann-Hilbert problem,the N-soliton solutions to this nonlocal equation can be obtained in the case of the jump matrix as an identity matrix.

THE FRACTIONAL QUADRATIC-FORM IDENTITY AND BI-HAMILTONIAN STRUCTURES OF AN INTEGRABLE COUPLING OF THE FRACTIONAL COUPLED BURGERS HIERARCHY

Based on a general isospectral problem of fractional order and the fractional quadratic-form identity by Yue and Xia, the new integrable coupling of fractional coupled Burgers hierarchy and its fractional bi-Hamiltonian structures are obtained.

THE INTEGRABLE COUPLINGS OF THE GENERALIZED COUPLED mKdV HIERARCHY AND ITS HAMILTONIAN STRUCTURES

We construct a loop algebra 3 , then a new 4×4 isospectral problem is presented. By Tu scheme, the generalized coupled mKdV equation hierarchy is derived. Based on an expanding loop algebra F3 of the loop algebra 3 , the integrable couplings of the generalized coupled mKdV hierarchy is solved. Finally, the Hamiltonian structures of the integrable couplings of the generalized coupled mKdV hierarchy is obtained by the quadratic-form identity.