The abelian higgs sunspot endowed with a local conformal symmetry

We show that the requirement of alocal conformal symmetry of the Abelian Higgs sunspot leads, at least formally, to a complex-valued electromagnetic potential, whose imaginary part is a conformal compensating potential. It is shown that there exists a fundamental difference between conformal and ordinary electromagnetic fields; whereas the ordinary total magnetic flux of a spot is quantized its conformal analogue has to vanish if the Higgs field is to be single-valued. We further stress that such a complex-valued Abelian Higgs field configuration mimics quite well, under certain conditions (all the salient features of) the classical Abelian Higgs sunspot.     

Charged stellar model with three layers

We establish new charged stellar models from the Einstein-Maxwell field equations for relativistic superdense objects outfitted with three layers.The core layer...     

Non-relativistic matter and dark energy in a quantum conformal model

We consider a generalization of the Standard Model whose action displays conformal invariance in d dimensions. The model contains a strongly coupled dark matter sector which breaks conformal symmetry dynamically. The model evades conformal anomaly and leads to identically zero vacuum energy in flat space-time. Hence it does not suffer from the problem of fine tuning of the cosmological constant. We determine the contribution of non-relativistic matter to the energy-momentum tensor and determine a parameter regime in which it approximately reduces to the standard result. We show how dark energy and dark matter arises in this model. We discuss the parameter range for which the model reduces to the ΛCDM model and hence is consistent with observations.     

Magnetostatic stiff-fluid model of cylindrical symmetry in general relativity

We study the static stiff-fluid model for perfect fluid distributions in the presence of incident magnetic field. The magnetic field is surrounded by static stiff fluid of infinite electric conductivity and it is due to the electric current flowing along theZ-axis. The various physical and geometrical properties together with the state of model in absence of magnetic field are also discussed.     

Quantum wormhole with conformal scalar field

In this paper I use the Hartle-Hawking method to discuss quantum wormhole with conformal scalar field. I derive the corresponding Wheeler-De Witt equation, calculate the wormhole wave function, which is found to be the product of two harmonic solutions. Analysis of the wave function reveals that the probability density of the wormhole appearing at a = 0 is zero, that the most probable radius of the wormhole base state is the Planck length and that the wormhole is mostly likely to be in a state of small Φ value.     

Domain walls with spherical symmetry

In this paper, we have evaluated solutions for Domain walls with sphericalsymmetry in four and five dimensional space time. Exact solutions ofEinstein equations coupled to scalar field with a potential V() are presented. Here scalar field depends both on radial and timecoordinates. Pressures perpendicular to the wall are taken to benon-zero. The solutions are obtained using functional separability ofmetric coefficients. Also we study the gravitational effects on testparticles.Pacs Nos: 04.20jb, 98.80 Bp     

Relativistic isotropic stellar model in f(R,T) gravity with Durgapal- IV metric

In this work, a new static, non-singular, spherically symmetric fluid model has been obtained in the background of $f(R,T)$ gravity. Here we consider the isotropic metric potentials of Durgapal-IV (Durgapal, 1982) solution as input to handle the Einstein field equations in $f(R,T)$ environment. For different coupling parameter values of $\chi$, graphical representations of the physical parameters have been demonstrated to describe the analytical results more clearly. It should be highlighted that the results of General Relativity (GR) are given by $\chi =0$. With the use of both analytical discussion and graphical illustrations, a thorough comparison of our results with the GR outcomes is also covered. The numerical values of the various physical attributes have been given for various coupling parameter $\chi$ values in order to discuss the impact of this parameter. Here we apply our solution by considering the compact star candidate LMC X-4 (Rawls et al., 2011) with mass $=(1.04\pm 0.09)M_{\odot }$ and radius $=8.301_{-0.2}^{+0.2}$ km. respectively, to analyze both analytically and graphically. To confirm the physical acceptance of our model, we discuss certain physical properties of our obtained solution such as energy conditions, causality, hydrostatic equilibrium through a modified Tolman–Oppenheimer–Volkoff (TOV) conservation equation, pressure–density ratio, etc. Also, our solution is well-behaved and free from any singularity at the center. From our present study, it is observed that all of our obtained results fall within the physically admissible regime, indicating the viability of our model.     

Magneto-viscous fluid cosmological model of plane symmetry in general relativity

The object of this paper is to investigate the behaviour of magnetic field in a viscous fluid cosmological model. Various physical and geometrical properties of the model have also been discussed.     

Semi-empirical model of absorption and scattering by isotropic fractal aggregates of spheres

Existing models of scattering by fractal aggregates of spheres are generally accurate but somewhat complicated and time consuming. Therefore, they are not easily usable for atmospheric studies that need intensive computations. We propose here a simple and fast model, based on Mie scattering and a set of empirical rules, that determines the scattering and absorption cross sections as well as the intensity phase function of isotropic fractal aggregates of identical spheres. This model is 10–50 times faster than the mean field model it is based on, and is easily derivable from a regular Mie code. The parameters of the present model are optimized for values of the real refractive index between 1.2 and 2.2, for imaginary refractive index less than 1 and for the product of real refractive index and spherical size parameter less than 10. This range was chosen as representative of typical particles in planetary atmospheres, for example, Titans aerosols.     

New properties of scalar-field dynamics in an isotropic cosmological model on the brane

We investigate some aspects of the scalar-field dynamics on the brane that differ from the corresponding regimes in standard cosmology. We consider asymptotic solutions near singularity, inflation and rebound conditions, and some features of chaos in the model on the brane. Our results are compared with their analogs in classical cosmology.     

Second order terms of the galactic velocity field. Cycindrical symmetry model

One of the most important applications of the Astrometry is the study of the motions in our Galaxy. In this sense, an effort has been made to determine the kinematic parameters of the galactic rotation in the solar neighbourhood when the galactic velocity field is expanded until the second order terms of its Taylor development. For this purpose, it has been necessary to use a larger sample of stars and better distributed in galactic latitude than hitherto. As a first study, we present here the solution method applied and the results obtained when the hypothesis of cylindrical symmetry is made. The small correlations obtained between the second order partial derivatives indicate that some of these parameters can be solved at present. Furthermore, we have obtained a good concordance between our values and the hypothesis made by several previous authors concerning these terms: Trumpler and Weaver (1962), Clube (1974) and Brosche and Schwan (1981).     

Shear-free and cavity models with plane symmetry

This paper aims to explore anisotropic planar analytical models for dissipative as well as non-dissipative matter distributions. We relate the Weyl tensor and physical variables of matter distribution. Darmois junction conditions are formulated on internal and external hypersurfaces. It is found that our dissipative models show the presence of cavity with non-zero expansion. Finally, we investigate two types of solutions with zero shear as well as heat flux by a specific choice of the mass function and by restricting pressure.     

An explosion with cylindrical symmetry in magnetogasdynamics

The propagation of magnetogasdynamic cylindrical shock waves in an exponentially increasing medium including the effects of the azimuthal magnetic field, is investigated. The shock wave moves with variable velocity and the total energy of the wave is variable. It is shown that the magnetic field has its significant effect on the pressure flow velocity and the inner expanding vacuum region.     

Viscous fluid cosmological model of cylindrical symmetry in the presence of magnetic field

A general solution of cylindrical symmetry in which distribution consists of an electrically neutral viscous fluid with an infinite electrical conductivity in presence of magnetic field, has been obtained. The behaviour of magnetic field on the model has been clearly interpreted. Various physical and geometrical properties have also been discussed.     

Radio spectra of synchrotron sources with spherical symmetry

This paper deals with the radio spectra of synchrotron sources with spherically symmetric non-homogeneities. It is pointed out that the Type-c spectra can be produced by such a non-homogeneity even if the source is optically thin. This model is particularly advantageous in interpreting sources with no compact characteristics and yet showing a Type-c spectrum, and the observed decrease in source size with increasing frequency. In addition, it is possible to give a uniform interpretation of the four spectral types on the basis of such a non-homogeneity.     

Coordinates for perturbed keplerian systems with axial symmetry

A coordinate system is defined on the phase space of a perturbed Keplerian system after the mean anomaly has been averaged out, for the purpose of explaining how eliminating the longitude of the ascending node reduces the orbital space to a two-dimensional sphere in case the system admits an axial symmetry. Concomitantly, on the submanifold of direct osculating ellipses, the CDM variables are replaced by functions which form the basis of a Poisson algebra isomorphic to the Lie algebra so(3) of the rotation group SO(3); furthermore, in these variables, the doubly reduced phase flow appears like a rotation of the reduced phase space.     

Long-term evolution of spheroidal galaxies with locally isotropic velocity distribution

The short-term evolution of spheroidal galaxies has been explored by S. Chandrasekhar et al. and G. S. Sunder et al. In this paper, we study their long-term evolution with Laskar's method of frequency analysis. The main new results are as follows: (1) There exists a unique equilibrium, which is spherically symmetric. This equilibrium has a critical linear stability. (2) Generally speaking, the semi-axes exhibit quasiperiodic or nearly quasi-periodic (in a time scale longer than a Hubble time) oscillations around the radius of the above-mentioned equilibrium, so the equilibrium is practically stable. (3) There are cases in which one of the semi-axes tends fast to zero while the other to some finite value. The limit state is generally planar rather than linear, i.e. it is the symmetric semi-axis that tends to zero. This implies that some disk galaxies may have originated from spheroidal pregalaxy material.