DOMAIN WALLS IN HIGHER DIMENSIONS

1998 ◽  
Vol 07 (01) ◽  
pp. 81-88
Author(s):  
A. BANERJEE ◽  
AJANTA DAS
Keyword(s):  
Energy Density ◽  
Exact Solutions ◽  
Domain Walls ◽  
Stress Component ◽  
Higher Dimensions ◽  
Dimensional Spacetime ◽  
Thick Domain Walls

Thick domain walls with nonvanishing stress component in the direction perpendicular to the plain of the wall are considered. Their exact solutions are obtained in the background of a five-dimensional spacetime. There may be both expanding and collapsing walls. The energy density decreases on both sides of the walls and the spacetime in all cases is found to be reflection symmetric with respect to the walls.

STRING COSMOLOGIES IN HIGHER DIMENSIONS

1993 ◽  
Vol 02 (01) ◽  
pp. 105-112 ◽  
Author(s):  
S. CHATTERJEE ◽  
N. BANERJEE ◽  
B. BHUI
Keyword(s):  
Equation Of State ◽  
Energy Density ◽  
Cosmological Model ◽  
Exact Solutions ◽  
Source Term ◽  
Bianchi Type ◽  
Dynamical Behavior ◽  
Higher Dimensions ◽  
Type I ◽  
Multidimensional Models

We extend to higher dimensions an earlier work of Letelier where a Bianchi type I cosmological model with massive strings as source term is studied. Exact solutions are obtained assuming either an equation of state between the energy density and tension density of the string or an explicit form of one of the metric coefficients. The dynamical behavior of the models is studied and a comparison is made with the analogous four-dimensional case where it is interestingly observed that the string dominated phase lasts a longer period in multidimensional models compared to its four-dimensional analogs. The Kantowski-Sachs type of metric is also briefly discussed.

Collapsing solutions in higher-dimensional spacetime

2019 ◽  
Vol 28 (09) ◽  
pp. 1950117
Author(s):  
Hassan Shah ◽  
Zahid Ahmad ◽  
Suhail Khan
Keyword(s):  
Energy Density ◽  
Higher Dimensions ◽  
Spherically Symmetric ◽  
Field Equations ◽  
Dimensional Spacetime ◽  
Higher Dimensional

We investigate higher-dimensional spherically symmetric anisotropic collapsing solutions of the field equations. Our aim is to check the effects of higher dimensions on the density and pressures profile of the collapsing fluid. It has been observed that the energy density, radial and tangential pressures of the collapsing system are strongly affected by higher dimensions. It also comes out that the anisotropy of the collapsing system becomes constant in higher dimensions.

Thick domain walls in non-magnetic ferroics

2016 ◽  
Vol 503 (1) ◽  
pp. 163-179 ◽  
Author(s):  
A. K. Tagantsev ◽  
K. Shapovalov ◽  
P. V. Yudin
Keyword(s):  
Domain Walls ◽  
Thick Domain Walls

scholarly journals Evolution of a domain wall in expanding universe: inflation and after it

2018 ◽  
Vol 191 ◽  
pp. 08004
Author(s):  
A.D. Dolgov ◽  
S.I. Godunov ◽  
A.S. Rudenko
Keyword(s):  
Domain Wall ◽  
Hubble Parameter ◽  
Domain Walls ◽  
Flat Space ◽  
Space Time ◽  
Time Dependent ◽  
Expanding Universe ◽  
Large Size ◽  
Dependent Parameter ◽  
Thick Domain Walls

We study the evolution of thick domain walls in the expanding universe. We have found that the domain wall evolution crucially depends on the time-dependent parameter C(t) = 1/(H(t)δ0)2, where H(t) is the Hubble parameter and δ0 is the width of the wall in flat space-time. For C(t) > 2 the physical width of the wall, a(t)δ(t), tends with time to constant value δ0, which is microscopically small. Otherwise, when C(t) ≤ 2, the wall steadily expands and can grow up to a cosmologically large size.

scholarly journals NEGATIVE ENERGY DENSITIES IN QUANTUM FIELD THEORY

2010 ◽  
Vol 25 (11) ◽  
pp. 2355-2363 ◽  
Author(s):  
L. H. FORD
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Energy Density ◽  
Negative Energy ◽  
Mean Value ◽  
Quantum Field ◽  
Two Dimensional ◽  
Vacuum Fluctuations ◽  
Negative Energy Density ◽  
Dimensional Spacetime

Quantum field theory allows for the suppression of vacuum fluctuations, leading to sub-vacuum phenomena. One of these is the appearance of local negative energy density. Selected aspects of negative energy will be reviewed, including the quantum inequalities which limit its magnitude and duration. However, these inequalities allow the possibility that negative energy and related effects might be observable. Some recent proposals for experiments to search for sub-vacuum phenomena will be discussed. Fluctuations of the energy density around its mean value will also be considered, and some recent results on a probability distribution for the energy density in two dimensional spacetime are summarized.

scholarly journals On f(R) Theories in Two-Dimensional Spacetime

2012 ◽  
Vol 2012 ◽  
pp. 1-11
Author(s):  
M. A. Ahmed
Keyword(s):  
Exact Solutions ◽  
Ricci Scalar ◽  
Two Dimensional ◽  
Field Equations ◽  
Dimensional Spacetime ◽  
Set Up

In recent years, theories in which the Einstein-Hilbert Lagrangian is replaced by a function f(R) of the Ricci Scalar have been extensively studied in four-dimensional spacetime. In this paper we carry out an analysis of such theories in two-dimensional spacetime with focus on cosmological implications. Solutions to the cosmological field equations are obtained and their properties are analysed. Inflationary solutions are also obtained and discussed. Quantization is then carried out, the Wheeler-DeWitt equation is set up, and its exact solutions are obtained.

SOME PERIODIC AND BLOW-UP SOLUTIONS FOR LANDAU–LIFSHITZ EQUATION

2011 ◽  
Vol 26 (32) ◽  
pp. 2437-2452 ◽  
Author(s):  
PENGHONG ZHONG ◽  
SHU WANG ◽  
SHENGTAO CHEN
Keyword(s):  
Exact Solution ◽  
Periodic Solution ◽  
Exact Solutions ◽  
Finite Time ◽  
Blow Up ◽  
Three Dimensional ◽  
Ferromagnetic Materials ◽  
Lifshitz Equation ◽  
Dimensional Spacetime ◽  
Vortex Solution

In this paper, we construct the exact solution of two- or three-dimensional spacetime Landau–Lifshitz equation raised in the ferromagnetic materials. Under suitable transformations, some exact solutions are obtained in the radially symmetric coordinates and nonsymmetric coordinates. The type of solutions cover the finite time blow-up solution, vortex solution and periodic solution. In the end, we sketch some solutions and their spatial curvatures.

scholarly journals MOTION OF A TEST PARTICLE IN THE TRANSVERSE SPACE OF Dp-BRANES

2012 ◽  
Vol 21 (11) ◽  
pp. 1250056 ◽  
Author(s):  
ANINDITA BHATTACHARJEE ◽  
ASHOK DAS ◽  
LEVI GREENWOOD ◽  
SUDHAKAR PANDA
Keyword(s):  
Test Particle ◽  
Massive Particle ◽  
Higher Dimensions ◽  
Geodesic Equation ◽  
Point Particle ◽  
Elliptic Motion ◽  
Dimensional Spacetime ◽  
Extended Sources ◽  
Bound Orbits ◽  
Schwarzschild Background

We investigate the motion of a test particle in higher dimensions due to the presence of extended sources like Dp-branes by studying the motion in the transverse space of the brane. This is contrasted with the motion of a point particle in the Schwarzschild background in higher dimensions. Since Dp-branes are specific to 10-dimensional spacetime and exact solutions of geodesic equations for this particular spacetime has not been possible so far for the Schwarzschild background, we focus here to find the leading order solution of the geodesic equation (for motion of light rays). This enables us to compute the bending of light in both the backgrounds. We show that contrary to the well known result of no noncircular bound orbits for a massive particle, in Schwarzschild background, for d ≥ 5, the Dp-brane background does allow bound elliptic motion only for p = 6 and the perihelion of the ellipse regresses instead of advancement. We also find that circular orbits for photon are allowed only for p ≤ 3.

Sign in / Sign up

Export Citation Format

Share Document