scholarly journals Localization of Massive and Massless Fermions on Two-Field Branes

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Ali Farokhtabar ◽  
Ali Tofighi
Keyword(s):  
Scalar Field ◽  
Yukawa Coupling ◽  
Resonance Spectrum ◽  
Brane World ◽  
Field Equations ◽  
World Model ◽  
Massive Fermion ◽  
Considerable Simplification ◽  
Massless Fermions ◽  
Fermion Localization

We study fermion localization and resonances on a special type of brane-world model supporting brane splitting. In such models one can construct multiwall branes which cause considerable simplification in the field equations. We use a polynomial superpotential to construct this brane. The suitable Yukawa coupling between the background scalar field and the localized fermion is determined. The massive fermion resonance spectrum is obtained. The number of resonances is increased for higher values of Yukawa coupling.

scholarly journals Fermion localization in braneworld teleparallel f(T, B) gravity

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
A. R. P. Moreira ◽  
J. E. G. Silva ◽  
C. A. S. Almeida
Keyword(s):  
Scalar Field ◽  
Yukawa Coupling ◽  
Spinor Field ◽  
Quantum Potential ◽  
Boundary Term ◽  
Dirac Spinor ◽  
Kaluza Klein ◽  
Fermion Localization

AbstractWe study a spin 1/2 fermion in a thick braneworld in the context of teleparallel f(T, B) gravity. Here, f(T, B) is such that $$f_1(T,B)=T+k_1B^{n_1}$$ f 1 ( T , B ) = T + k 1 B n 1 and $$f_2(T,B)=B+k_2T^{n_2}$$ f 2 ( T , B ) = B + k 2 T n 2 , where $$n_{1,2}$$ n 1 , 2 and $$k_{1,2}$$ k 1 , 2 are parameters that control the influence of torsion and the boundary term. We assume Yukawa coupling, where one scalar field is coupled to a Dirac spinor field. We show how the $$n_{1,2}$$ n 1 , 2 and $$k_{1,2}$$ k 1 , 2 parameters control the width of the massless Kaluza–Klein mode, the breadth of non-normalized massive fermionic modes and the properties of the analogue quantum-potential near the origin.

scholarly journals Vacuum Expectation Value Profiles of the Bulk Scalar Field in the Generalized Randall-Sundrum Model

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
A. Tofighi ◽  
M. Moazzen ◽  
A. Farokhtabar
Keyword(s):  
Scalar Field ◽  
Boundary Conditions ◽  
Cosmological Constant ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Brane World ◽  
Dirichlet Boundary Conditions ◽  
World Model ◽  
Expectation Value ◽  
Bulk Scalar Field

In the generalized Randall-Sundrum warped brane-world model the cosmological constant induced on the visible brane can be positive or negative. In this paper we investigate profiles of vacuum expectation value of the bulk scalar field under general Dirichlet and Neumann boundary conditions in the generalized warped brane-world model. We show that the VEV profiles generally depend on the value of the brane cosmological constant. We find that the VEV profiles of the bulk scalar field for a visible brane with negative cosmological constant and positive tension are quite distinct from those of Randall-Sundrum model. In addition we show that the VEV profiles for a visible brane with large positive cosmological constant are also different from those of the Randall-Sundrum model. We also verify that Goldberger and Wise mechanism can work under nonzero Dirichlet boundary conditions in the generalized Randall-Sundrum model.

Fermion localization on branes with non-standard kinetic terms

2018 ◽  
Vol 33 (40) ◽  
pp. 1850235 ◽  
Author(s):  
Masoumeh Moazzen Sorkhi ◽  
Esmaeil Mazani
Keyword(s):  
Scalar Field ◽  
Yukawa Coupling ◽  
Zero Mode ◽  
Scalar Fields ◽  
Coupling Constants ◽  
Warp Factor ◽  
Coupling Mechanism ◽  
Fermion Fields ◽  
Derivative Term ◽  
Fermion Localization

In this paper, by using the Yukawa coupling mechanism, we consider the fermion localization in two types of braneworld models driven by real scalar fields with non-standard dynamics. Because of the existing freedom in the form of the Yukawa coupling, we consider two coupling forms between the background scalar field and spinors where one is arising from the geometry shape of the warp factor and the other is a function of the background scalar field containing a derivative scalar-fermion coupling. With two coupling functions, it is shown that the massless zero mode of fermion fields is localized on both branes with generalized dynamic depending on the values of the coupling constants. However, there is no localized mode when the Yukawa coupling only contains a derivative term of the background scalar field. Furthermore, effects of the parameters of the models on the zero mode and fermion effective potential are addressed.

scholarly journals NON-SINGULAR BLACK-HOLES ON THE BRANE

2004 ◽  
Vol 13 (06) ◽  
pp. 1095-1103 ◽  
Author(s):  
S. SHANKARANARAYANAN ◽  
NARESH DADHICH
Keyword(s):  
Energy Condition ◽  
Null Energy Condition ◽  
Effective Field ◽  
Brane World ◽  
Spherically Symmetric ◽  
Null Condition ◽  
Field Equations ◽  
World Model ◽  
Weyl Curvature ◽  
Black Hole Solutions

We investigate the possibility of obtaining non-singular black-hole solutions in the brane world model by solving the effective field equations for the induced metric on the brane. The Reissner–Nordstrom solution on the brane was obtained by Dadhich et al. by imposing the null energy condition on the 3-brane for a bulk having non-zero Weyl curvature. In this work, we relax the condition of vanishing scalar curvature R, however, retaining the null condition. We have shown that it is possible to obtain a class of static non-singular spherically symmetric brane space–times which admits horizon. We obtain one such class of solution which is a regular version of the Reissner–Nordstrom solution in the standard general relativity.

scholarly journals Considering Late-Time Acceleration in Some Cosmological Models

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
S. Davood Sadatian
Keyword(s):  
Scalar Field ◽  
Lorentz Invariance ◽  
Cosmological Models ◽  
Brane World ◽  
Late Time ◽  
World Model ◽  
Late Time Acceleration ◽  
Invariance Violation ◽  
Lorentz Invariance Violation

We study two cosmological models: a nonminimally coupled scalar field on brane world model and a minimally coupled scalar field on Lorentz invariance violation model. We compare some cosmological results in these scenarios. Also, we consider some types of Rip singularity solution in both models.

scholarly journals INTERPRETING THE M2-BRANE ACTION

2009 ◽  
Vol 24 (10) ◽  
pp. 721-724 ◽  
Author(s):  
SHAMIK BANERJEE ◽  
ASHOKE SEN
Keyword(s):  
Scalar Field ◽  
Azimuthal Angle ◽  
Free Field ◽  
Brane World ◽  
Polar Coordinate System ◽  
Radial Coordinate ◽  
Field Equations ◽  
Yang Mills ◽  
World Volume ◽  
The World

The world-volume theory of multiple M2-branes proposed recently has a free scalar field. For large vev of this scalar field the world-volume action reduces to that of multiple D2-branes with Yang–Mills coupling proportional to the vev. We suggest that the correct interpretation of this scalar field is as the radial position of the M2-brane center of mass in a cylindrical polar coordinate system. Regarding the azimuthal angle as compact we can regard this as a set of coincident D2-branes in type IIA string theory with varying dilaton and metric. We find that the effective world-volume theory on the D2-branes has Yang–Mills coupling proportional to the radial coordinate; furthermore the radial coordinate satisfies free field equations of motion. This agrees with the corresponding results derived from the M2-brane world-volume theory.

scholarly journals BRANE WORLD IN A TOPOLOGICAL BLACK HOLES IN ASYMPTOTICALLY FLAT SPACE–TIME

2001 ◽  
Vol 16 (26) ◽  
pp. 1703-1710 ◽  
Author(s):  
DONAM YOUM
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Scalar Field ◽  
Flat Space ◽  
Space Time ◽  
Brane World ◽  
Black Hole Horizon ◽  
World Model ◽  
Asymptotically Flat ◽  
Bulk Scalar Field

We study static brane configurations in the bulk background of the topological black holes in asymptotically flat space–time and find that such configurations are possible even for flat black hole horizon, unlike the AdS black hole case. We construct the brane world model with an orbifold structure S1/Z2 in such bulk background and study massless bulk scalar field.

scholarly journals Quantum corrections to slow-roll inflation: scalar and tensor modes

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jens O. Andersen ◽  
Magdalena Eriksson ◽  
Anders Tranberg
Keyword(s):  
Scalar Field ◽  
Quantum Corrections ◽  
Tree Level ◽  
Field Equations ◽  
Slow Roll ◽  
Scalar Field Equations ◽  
Slow Rolling ◽  
Different Sources ◽  
Suitable Potential ◽  
Quadratic Order

Abstract Inflation is often described through the dynamics of a scalar field, slow-rolling in a suitable potential. Ultimately, this inflaton must be identified with the expectation value of a quantum field, evolving in a quantum effective potential. The shape of this potential is determined by the underlying tree-level potential, dressed by quantum corrections from the scalar field itself and the metric perturbations. Following [1], we compute the effective scalar field equations and the corrected Friedmann equations to quadratic order in both scalar field, scalar metric and tensor perturbations. We identify the quantum corrections from different sources at leading order in slow-roll, and estimate their magnitude in benchmark models of inflation. We comment on the implications of non-minimal coupling to gravity in this context.

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