scholarly journals Kinks and branes in models with hyperbolic interactions

2017 ◽  
Vol 32 (26) ◽  
pp. 1750163 ◽  
Author(s):  
D. Bazeia ◽  
Elisama E. M. Lima ◽  
L. Losano
Keyword(s):  
Scalar Field ◽  
Energy Density ◽  
Linear Stability ◽  
Analytical Solutions ◽  
Zero Mode ◽  
Metric Tensor ◽  
First Order ◽  
Standard Formalism ◽  
Density Linear ◽  
Deformation Procedure

In this work, we investigate several models described by a single real scalar field with nonpolynomial interactions, constructed to support topological solutions. We do this using the deformation procedure to introduce a function which allows to construct two distinct families of hyperbolic potentials, controlled by three distinct parameters, in the standard formalism. In this way, the procedure allows us to get analytical solutions, and then investigate the energy density, linear stability and zero mode. We move on and introduce a nonstandard formalism to obtain compact solutions, analytically. We also investigate these hyperbolic models in the braneworld context, considering both the standard and nonstandard possibilities. The results show how to construct distinct braneworld models which are implemented via the first-order formalism and are stable against fluctuation of the metric tensor.

scholarly journals First Order Framework for Gauge k-Vortices

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
D. Bazeia ◽  
L. Losano ◽  
M. A. Marques ◽  
R. Menezes
Keyword(s):  
Scalar Field ◽  
Energy Density ◽  
Boundary Conditions ◽  
Unit Circle ◽  
Analytical Solutions ◽  
Covariant Derivative ◽  
Lagrangian Density ◽  
Kinetic Term ◽  
First Order

We study vortices in generalized Maxwell-Higgs models, with the inclusion of a quadratic kinetic term with the covariant derivative of the scalar field in the Lagrangian density. We discuss the stressless condition and show that the presence of analytical solutions helps us to define the model compatible with the existence of first order equations. A method to decouple the first order equations and to construct the model is then introduced and, as a bonus, we get the energy depending exclusively on a function of the fields calculated from the boundary conditions. We investigate some specific possibilities and find, in particular, a compact vortex configuration in which the energy density is all concentrated in a unit circle.

scholarly journals ON THE QUASI-ISOTROPIC INFLATIONARY SOLUTION

2003 ◽  
Vol 12 (10) ◽  
pp. 1845-1857 ◽  
Author(s):  
GIOVANNI IMPONENTE ◽  
GIOVANNI MONTANI
Keyword(s):  
Scalar Field ◽  
Cosmological Constant ◽  
Small Function ◽  
Inflationary Universe ◽  
Arbitrary Form ◽  
Metric Tensor ◽  
Dominant Term ◽  
First Order ◽  
Effective Cosmological Constant ◽  
Relativistic Matter

In this paper we find a solution for a quasi-isotropic inflationary Universe which allows to introduce in the problem a certain degree of inhomogeneity. We consider a model which generalizes the (flat) FLRW one by introducing a first order inhomogeneous term, whose dynamics is induced by an effective cosmological constant. The 3-metric tensor is constituted by a dominant term, corresponding to an isotropic-like component, while the amplitude of the first order one is controlled by a "small" function η(t). In a Universe filled with ultra relativistic matter and a real self-interacting scalar field, we discuss the resulting dynamics, up to first order in η, when the scalar field performs a slow roll on a plateau of a symmetry breaking configuration and induces an effective cosmological constant. We show how the spatial distribution of the ultra relativistic matter and of the scalar field admits an arbitrary form but nevertheless, due to the required inflationary e-folding, it cannot play a serious dynamical role in tracing the process of structures formation (via the Harrison–Zeldovic spectrum). As a consequence, this paper reinforces the idea that the inflationary scenario is incompatible with a classical origin of the large scale structures.

scholarly journals FINITE TEMPERATURE PHASE TRANSITION OF A SCALAR FIELD ON A FUZZY SPHERE

2008 ◽  
Vol 23 (21) ◽  
pp. 1781-1791 ◽  
Author(s):  
C. R. DAS ◽  
S. DIGAL ◽  
T. R. GOVINDARAJAN
Keyword(s):  
Phase Transition ◽  
Scalar Field ◽  
Finite Temperature ◽  
Zero Mode ◽  
Temperature Phase ◽  
Fuzzy Sphere ◽  
Stable States ◽  
First Order ◽  
Auto Correlation ◽  
Temperature Phase Transition

We study finite temperature phase transition of neutral scalar field on a fuzzy sphere using Monte Carlo simulations. We work with the zero mode in the temporal directions, while the effects of the higher modes are taken care by the temperature dependence of r. In the numerical calculations we use "pseudo-heatbath" method which reduces the auto-correlation considerably. Our results agree with the conventional calculations. We report some new results which show the presence of meta-stable states, first order symmetry breaking transition and existence of multiple triple points in the phase diagram..

SOME COMMENTS ON THE DYNAMICS OF EXTENDED OBJECTS

1998 ◽  
Vol 13 (17) ◽  
pp. 2979-2990 ◽  
Author(s):  
U. KHANAL
Keyword(s):  
Wave Equation ◽  
Energy Density ◽  
Pure Shear ◽  
Equation Of Motion ◽  
Conducting Medium ◽  
Constant Density ◽  
Metric Tensor ◽  
World Volume ◽  
The World ◽  
Hilbert Action

A variational method is used to investigate the dynamics of extended objects. The stationary world volume requires the internal coordinates to propagate as free waves. Stationarity of the action which is the integral of a variable energy density over the world volume leads to the wave equation in a medium, with conductivity given by the gradient of the logarithm of reciprocal energy density, constant density corresponding to free space. The Einstein–Hilbert action for the world curvature gives an equation of motion which, in world space with the Einstein tensor proportional to the metric tensor, reduces to the free wave equation. A similar method applied to the action consisting of the surface area enclosing an incompressible world volume undergoing pure shear again yields the wave equation in a conducting medium. Simultaneous stationarity of the volume can be imposed with a stationary area only in the case of pure shear; stationary Einstein–Hilbert action can also be included and lead to an equation of motion which has a similar interpretation of the wave in the conducting medium. Some Green functions applicable to the medium with constant conductivity are also presented.

Black hole in balance with dark matter

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040050
Author(s):  
Boris E. Meierovich
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Phase Equilibrium ◽  
Vector Field ◽  
Scalar Field ◽  
Total Mass ◽  
Metric Tensor ◽  
Static Solutions ◽  
Tensor Formula ◽  
Galaxy Rotation Curves

Equilibrium of a gravitating scalar field inside a black hole compressed to the state of a boson matter, in balance with a longitudinal vector field (dark matter) from outside is considered. Analytical consideration, confirmed numerically, shows that there exist static solutions of Einstein’s equations with arbitrary high total mass of a black hole, where the component of the metric tensor [Formula: see text] changes its sign twice. The balance of the energy-momentum tensors of the scalar field and the longitudinal vector field at the interface ensures the equilibrium of these phases. Considering a gravitating scalar field as an example, the internal structure of a black hole is revealed. Its phase equilibrium with the longitudinal vector field, describing dark matter on the periphery of a galaxy, determines the dependence of the velocity on the plateau of galaxy rotation curves on the mass of a black hole, located in the center of a galaxy.

LOCALIZATION OF MATTERS ON A NON-Z2-SYMMETRIC THICK BRANE

2010 ◽  
Vol 25 (07) ◽  
pp. 511-523
Author(s):  
JUN LIANG ◽  
YI-SHI DUAN
Keyword(s):  
Vector Field ◽  
Scalar Field ◽  
Yukawa Coupling ◽  
Spinor Field ◽  
Zero Mode ◽  
Parallel Transport ◽  
Type Coupling ◽  
Matter Fields

We study localization of various matter fields on a non-Z2-symmetric scalar thick brane in a pure geometric Weyl integrable manifold in which variations in the length of vectors during parallel transport are allowed and a geometric scalar field is involved in its formulation. It is shown that, for spin 0 scalar field, the massless zero mode can be normalized on the brane. Spin 1 vector field cannot be normalized on the brane. And there is no spinor field which can be trapped on the brane for the case of no Yukawa-type coupling. By introducing the appropriate Yukawa coupling, the left or right chiral fermionic zero mode can be localized on the brane.

scholarly journals Extended multi-scalar field theories in $$(1+1)$$ dimensions

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
A. R. Aguirre ◽  
E. S. Souza
Keyword(s):  
Scalar Field ◽  
Linear Stability ◽  
Explicit Construction ◽  
Field Theories ◽  
Extension Method ◽  
Stability Properties ◽  
Field Systems

AbstractWe present the explicit construction of some multi-scalar field theories in $$(1+1$$ ( 1 + 1 ) dimensions supporting BPS (Bogomol’nyi–Prasad–Sommerfield) kink solutions. The construction is based on the ideas of the so-called extension method. In particular, several new interesting two-scalar and three-scalar field theories are explicitly constructed from non-trivial couplings between well-known one-scalar field theories. The BPS solutions of the original one-field systems will be also BPS solutions of the multi-scalar system by construction, and therefore we will analyse their linear stability properties for the constructed models.

Sign in / Sign up

Export Citation Format

Share Document