scholarly journals Internal structure of cuscuton Bloch brane

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
D. Bazeia ◽  
D. A. Ferreira ◽  
M. A. Marques
Keyword(s):  
Energy Density ◽  
Internal Structure ◽  
Analytical Solutions ◽  
Extra Dimension ◽  
Field Configuration ◽  
Warp Factor ◽  
Novel Behavior ◽  
Thick Branes

AbstractThis work deals with thick branes in bulk with a single extra dimension modeled by a two-field configuration. We first consider the inclusion of the cuscuton to also control the dynamics of one of the fields and investigate how it contributes to change the internal structure of the configuration in two distinct situations, with the standard and the asymmetric Bloch brane. The results show that the branes get a rich internal structure, with the geometry presenting a novel behavior which is also governed by the parameter that controls the strength of the cuscuton term. We also study the case where the dynamics of one of the two fields is only described by the cuscuton. All the models support analytical solutions which are stable against fluctuations in the metric, and the main results unveil significant modifications in the warp factor and energy density of the branes.

scholarly journals Smooth braneworld models possibility in modified gravities

2015 ◽  
Vol 24 (11) ◽  
pp. 1550089 ◽  
Author(s):  
G. P. de Brito ◽  
J. M. Hoff da Silva ◽  
P. Michel L. T. da Silva ◽  
A. de Souza Dutra
Keyword(s):  
Scalar Field ◽  
Extra Dimension ◽  
Field Potential ◽  
Dimensional Case ◽  
Consistency Conditions ◽  
Thick Branes

In this paper, it is shown that the consideration of the braneworld consistency conditions within the framework of bulk modified gravities allows for the existence of thick branes in the five-dimensional case with compact extra dimension. On studying the specific consistency conditions in the Brans–Dicke gravity, we were able to show that the brane generating scalar field potential is relevant for relaxing the gravitational constraints.

BIG BANG NUCLEOSYNTHESIS WITH A CONSTANT VACUUM ENERGY MOTIVATED BY CYCLIC COSMOLOGY

2011 ◽  
Vol 26 (02) ◽  
pp. 331-339
Author(s):  
S. KALITA ◽  
H. L. DUORAH ◽  
K. DUORAH
Keyword(s):  
Energy Density ◽  
Extra Dimension ◽  
Vacuum Energy ◽  
Mass Difference ◽  
Big Bang ◽  
Upper Bounds ◽  
Rapid Expansion ◽  
Vacuum Energy Density ◽  
Temperature Relation ◽  
Freeze Out

Abundances of primordial deuterium, [Formula: see text] and helium, Yp, are examined by modifying the early universe expansion rate and hence the time–temperature relation, including a constant vacuum energy motivated by the cyclic scenario of brane cosmology. Enhancement of abundances with respect to standard BBN prediction is found. Rapid expansion leads to early freeze-out of weak interaction and hence to an enhanced neutron fraction at elevated freeze-out temperature, which in turn results in more helium. Nucleosynthesis at a much lower temperature (due to rapid expansion) faces a larger Coulomb barrier and leaves more deuterium behind, which is also implied by a lower baryon-to-photon ratio (η) as we increase the vacuum energy density. The change in the helium fraction agrees within orders of magnitudes with that found by the effect of more neutrino flavors on Yp. Elevation of the neutron fraction at freeze-out is revealed by decrease in the neutron–proton mass difference (Q) from 1.293 MeV to 1.279 MeV, which is consistent with the study of the influence of extra dimension size on BBN. The lowest Q value corresponds to the highest vacuum energy and also to the largest size of the extra dimension. The upper limit on vacuum energy density is found by estimating the contribution from nonbaryonic dark matter by using X-ray emission from galaxy clusters and taking a flat spatial geometry, which is found to be the cosmological constant (Λ) observed today, so that the abundances do not run beyond the observational upper bounds. The allowed range of ΩΛ, 0.786 ≤ Ω Λ ≤ 0.844, makes Yp and [Formula: see text] lie within the observational upper bounds, which yields a Big Bang equivalence of the Λ universe. This is expected to further motivate the cyclic scenario, which incorporates a small and constant vacuum energy density tied to spacetime.

scholarly journals Dynamics of Hyperbolically Symmetric Fluids

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1568 ◽  
Author(s):  
Luis Herrera ◽  
Alicia Di Prisco ◽  
Justo Ospino
Keyword(s):  
Energy Density ◽  
Physical Properties ◽  
Central Region ◽  
Analytical Solutions ◽  
Fluid Element ◽  
Exact Analytical Solutions ◽  
Thermodynamical Properties ◽  
Dissipative Fluid ◽  
Inner Region ◽  
Vacuum Cavity

We study the general properties of dissipative fluid distributions endowed with hyperbolical symmetry. Their physical properties are analyzed in detail. It is shown that the energy density is necessarily negative, and the central region cannot be attained by any fluid element. We describe this inner region by a vacuum cavity around the center. By assuming a causal transport equation some interesting thermodynamical properties of these fluids are found. Several exact analytical solutions, which evolve in the quasi–homologous regime and satisfy the vanishing complexity factor condition, are exhibited.

scholarly journals New analytical solutions for bosonic field trapping in thick branes

2014 ◽  
Vol 731 ◽  
pp. 131-135 ◽  
Author(s):  
R.R. Landim ◽  
G. Alencar ◽  
M.O. Tahim ◽  
R.N. Costa Filho
Keyword(s):  
Analytical Solutions ◽  
Field Trapping ◽  
Bosonic Field ◽  
Thick Branes

scholarly journals Analytical solutions for fermions on a thick brane with a piecewise and smooth warp factor

2017 ◽  
Vol 32 (35) ◽  
pp. 1750193
Author(s):  
R. R. Landim ◽  
M. O. Tahim ◽  
G. Alencar ◽  
R. N. Costa Filho
Keyword(s):  
Analytical Solutions ◽  
Analytical Methods ◽  
Scalar Fields ◽  
Warp Factor ◽  
Fermion Localization

In this paper, we study analytical solutions for fermion localization in Randall–Sundrum (RS) models. We show that there exist special couplings between scalar fields and fermions giving us discrete massive localizable modes. Besides this we obtain resonances in some models by analytical methods.

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.

CONSTANT GAUGE FIELDS AND SYMMETRY BREAKING ON TORUS

1990 ◽  
Vol 05 (25) ◽  
pp. 2021-2029 ◽  
Author(s):  
CHOON-LIN HO
Keyword(s):  
Gauge Theory ◽  
Energy Density ◽  
Symmetry Breaking ◽  
Lower Energy ◽  
Field Configuration ◽  
Gauge Fields ◽  
Constant Field ◽  
Vacuum Gauge ◽  
Massless Fermion ◽  
Lower Energy Density

We examine symmetry breaking in an SU(2) gauge theory with a massless fermion defined on space-time manifold R1, d−3 × T2. Vacuum gauge field configuration is taken to have a constant field strength on the torus. Effective Potential in this background is evaluated and compared with that of pure gauge vacuum configuration. It is found that, in d ≡ 5, 7 (mod 8), vacuum with sufficiently large color magnetic flux on the torus could have lower energy density. This result applies to a U(1) theory as well. For SU(2) theory, the symmetry is broken to U(1).

scholarly journals Analytical solutions for cosmological perturbations in a one-component universe with shear stress

2015 ◽  
Vol 24 (08) ◽  
pp. 1550063 ◽  
Author(s):  
Matej Škovran
Keyword(s):  
Shear Stress ◽  
Energy Density ◽  
Shear Modulus ◽  
Ideal Fluid ◽  
Analytical Solutions ◽  
Elastic Solid ◽  
Explicit Solutions ◽  
Cosmological Perturbations ◽  
Flat Universe ◽  
Tensor Perturbations

We construct explicit solutions for scalar, vector and tensor perturbations in a less known setting, a flat universe filled by an isotropic elastic solid with pressure and shear modulus proportional to energy density. The solutions generalize the well-known formulas for cosmological perturbations in a universe filled by ideal fluid.

scholarly journals Quintessence and effective AdS brane geometries

2015 ◽  
Vol 30 (13) ◽  
pp. 1550065 ◽  
Author(s):  
K. Priyabrat Pandey ◽  
Abhishek K. Singh ◽  
Sunita Singh ◽  
Supriya Kar
Keyword(s):  
Black Hole ◽  
Energy Density ◽  
Extra Dimension ◽  
Vacuum Energy ◽  
Bound State ◽  
Second Order ◽  
The Other ◽  
Vacuum Energy Density ◽  
Curvature Scalar

A geometric torsion dynamics leading to an effective curvature in a second-order formalism on a D4-brane is revisited with a renewed interest. We obtain two effective AdS 4 brane geometries on a vacuum created pair of [Formula: see text]-brane. One of them is shown to describe an AdS Schwarzschild spinning black hole and the other is shown to describe a spinning black hole bound state. It is argued that a D-instanton in a vacuum created anti-D3-brane within a pair may describe a quintessence. It may seem to incorporate a varying vacuum energy density in a brane universe. We consider the effective curvature scalar on S1 × S1 to analyze torsionless geometries on a vacuum created pair of [Formula: see text]-brane. The emergent AdS 3 brane is shown to describe a Schwarzschild and a Reissner–Nordstrom (RN) geometries in the presence of extra dimension(s).

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.

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