Physics

In this paper, we have examined the Sharma-Mittal holographic dark energy model (SMHDE) in the framework of an isotropic and spatially homogeneous flat Friedmann-Robertson-Walker(FRW) Universe by considering different values of parameter δ and R , where the infrared cut-off is taken care by the Hubble horizon. We examined the SMHDE model through the analysis of Statefinder hierarchy and the growth rate of perturbation. The evolutionary trajectories of the statefinder hierarchy S 1 3 , S 2 3 S 1 4 , S 2 4 versus redshift z, show satisfactory behavior throughout the Universe evaluation. One promising tool for investigating the dark energy models is the composite null diagnostic(CND) { S 1 3 −ϵ} , where the evolutionary trajectories of the S 1 3 −ϵ pair present different property and the departure from Λ CDM could be well evaluated. Additionally, we investigated the dynamical analysis of the model by ω D − ω ′ D pair analysis.

In particle physics, study of the symmetry plays very important role in order to get useful information about the nature. The classification and arrangements of subatomic particles is also necessary to study particle physics. Particles which are building blocks of nature are quarks, gluons and leptons. Baryons and Mesons composed of quarks were arranged by Gell-Mann and Okubo in their well-known Eight-Fold way up to SU(3) symmetry. Standard model of particles is composed of these particles. Particles in SU(4) also make some multiplets. However all the baryons with spin JP= 3/2+ and 1/2+ in these multiplets have not been observed till date. We have studied properties of the multiplets having spin JP= 3/2+ in an early work. In this paper the SU(4) multiplets with spin JP= 1/2+ have been organized and studied in an easy way. As a result some clues about the masses and iso-spins of the unknown baryons have been obtained. These approximations about the characteristics of the unidentified baryons have been recorded in this article. Mass formula for the baryons having spin JP= 1/2+ in SU(4) multiplets have been extracted.

Elaborating on multidimensional geometrical representation of physical reality, an exposition is given of the potentialities of generalizing currently used representations to predict possible physical phenomena that are susceptible of experimental verification following K. Popper's teaching. The case of expanding the number of dimensions, through the introduction of energy among them, is addressed. Namely, after showing that Deformed Minkowski space thus obtained is a generalized Lagrange space, some properties characterizing it are identified, including curvature (related to gravitational interaction); deflection (connectable to asymmetry) and torsion (related to anisotropy). The gauge transformations commonly used for fields, are extended to include the transformation of the metrics. A list is given of available experimental evidences not easy to be interpreted, at present, by means of the more established models, such as the standard model with its variants aimed at overcoming its descriptive limits; these evidences could be candidates to verify the predictions stemming from the mentioned properties of the Deformed Minkowski space. Concrete opportunities are suggested for an experimental exploration of phenomena, either already performed but still lacking a widely accepted explanation, or conceivable in application of the approach here presented, but not tackled until now. A tentative list is given with reference to experimental infrastructures already in operation, the performances of which can be expanded with limited additional resources.

We investigate extensions of Malcev algebras and give an explicit example of extended algebras. We present a new algebraic identity, which can be regarded as a generalization of the Jacobi identity or the Malcev identity. As applications to gravity, we demonstrate that the extended algebra can be linked with general relativity.

We present solutions of the Einstein equations that extend the static Schwarzschild solution in empty space into regions of non-zero energy density ρ and radial pressure p=wρ , where w is a constant equation of state parameter. For simplicity we focus mainly on solutions with constant ρ . For w=0 we find solutions both with and without a singularity at the origin. Possible applications to galaxies are considered, where we find enhanced velocity rotation curves towards the edge of a galaxy. We propose that our explicit non-singular solution with w=−1 describes the interior of a black hole, which is a form of vacuum energy, and verify that its entropy is consistent with the Bekenstein-Hawking entropy. We propose that this idea can perhaps be applied to dark energy, if one views the latter as arising from black holes as pockets of vacuum energy. We estimate the density of the resulting dark energy to be ρ Λ ≈ 10 −30 g/ cm 3 , which is close to the measured value for the observable universe. We also present solutions with non-constant ρ∝1/ r 2 .

We obtain the Maxwell`s equations used the supersymmetric action based on the actions for the scalar and spinor fields, which are built on the invariants of the electromagnetic field. We analyze the pulse instability in the framework of nonlinear electrodynamics without the approximation of slowly varying amplitudes and phases. We observe the collapse of an extremely short pulse. Within the framework of the Schwinger mechanism, the creation of scalar and spin particles is estimated.

In this paper, we study a cosmological model in the background of FLRW space time by assuming an appropriate parametrization in the form of a differential equation in terms of energy density of scalar field ρ ϕ , which is defined as Energy Density Scalar Field Differential equation (EDSFD) parametrization. This EDSFD parametrization leads to a required phase transition from early deceleration to present cosmic acceleration. This parametrization is used to reconstruct the equation of state parameter ω ϕ (z) to examine the evolutionary history of the universe in a flat FLRW space time. Here, we constrain the model parameter using the various observational datasets of Hubble parameter H(z) , latest Union 2.1 compilation dataset SNeIa , BAO , joint dataset H(z)+SNeIa and H(z)+SNeIa+BAO for detail analysis of the behaviour of physical parameters and we find its best fit present value. Also, we study the dynamics of our parametric model, briefly analyse the behaviours of the physical features using some diagnostic tools, and examine the viability of our model.

In this work we explore the boundary conditions in the Einstein-Hilbert action, by considering a displacement from the Riemannian manifold to an extended one. The latter is characterized by including spinor fields into the quantum geometric description of a noncommutative spacetime. These fields are defined on the background spacetime, emerging from the expectation value of the quantum structure of spacetime generated by matrices that comply with a Clifford algebra. We demonstrate that spinor fields are candidate to describe all known interactions in physics, with gravitation included. In this framework we demonstrate that the cosmological constant Λ , is originated exclusively by massive fermion fields that would be the primordial components of dark energy, during the inflationary expansion of an universe that describes a de Sitter expansion.

We introduce a new class of higgs type complex-valued scalar fields U with Feynman propagator ∼1/ p 4 and consider the matching to the traditional fields with propagator ∼1/ p 2 in the viewpoint of effective potentials at tree level. With some particular postulations on the convergence and the causality, there are a wealth of potential forms generated by the fields U , such as the linear, logarithmic, and Coulomb potentials, which might serve as sources of effects such as the confinement, dark energy, dark matter, electromagnetism and gravitation. Moreover, in some limit cases, we get some deductions, such as: a nonlinear Klein-Gordon equation, a linear QED, a mass spectrum with generation structure and a seesaw mechanism on gauge symmetry and flavor symmetry; and, the propagator ∼1/ p 4 would provide a possible way to construct a renormalizable gravitation theory and to solve the non-perturbative problems.

Renormalization group methods are applied to the scalar field theory of a finite quantum field theory. It is demonstrated that the triviality problem in scalar field theory, the Higgs boson mass hierarchy problem and the stability of the vacuum are resolved in the theory. The scalar Higgs field has no Landau pole.