547 research outputs found
Global Defects in Field Theory with Applications to Condensed Matter
We review investigations on defects in systems described by real scalar
fields in (D,1) space-time dimensions. We first work in one spatial dimension,
with models described by one and two real scalar fields, and in higher
dimensions. We show that when the potential assumes specific form, there are
models which support stable global defects for D arbitrary. We also show how to
find first-order differential equations that solve the equations of motion, and
how to solve models in D dimensions via soluble problems in D=1. We illustrate
the procedure examining specific models and showing how they may be used in
applications in different contexts in condensed matter physics, and in other
areas.Comment: 15 pages, 9 figure
Bloch Brane
We investigate a system described by two real scalar fields coupled with
gravity in (4, 1) dimensions in warped spacetime involving one extra dimension.
The results show that the parameter which controls the way the two scalar
fields interact induces the appearence of thick brane which engenders internal
structure, driving the energy density to localize inside the brane in a very
specific way.Comment: 13 pages, 6 figures; some misprints corrected, to appear in JHE
Alternate route to soliton solutions in hydrogen-bonded chains
In this paper we offer an alternate route for investigating soliton solutions
in hydrogen-bonded chains. This is done by examining a class of systems of two
coupled real scalar fields. We show that this route allows investigating
several models for hydrogen-bonded chains in a unified manner. We also show how
to investigate interesting issues, in particular the one concerning classical
or linear stability of solitonic solutions.Comment: 12 pages. Late
Gravity localization on thick branes: a numerical approach
We introduce a numerical procedure to investigate the spectrum of massive
modes and its contribution for gravity localization on thick branes. After
considering a model with an analytically known Schroedinger potential, we
present the method and discuss its applicability. With this procedure we can
study several models even when the Schroedinger potential is not known
analytically. We discuss both the occurrence of localization of gravity and the
correction to the Newtonian potential given by the massive modes.Comment: 22 pages, 12 figure
Topological Twistons in Crystalline Polyethylene
We introduce an alternate model to describe twistons in crystalline
polyethylene. The model couples torsional and longitudinal degrees of freedom
and appears as an extension of a model that describes only the torsional
motion. We find exact solutions that describe stable topological twistons, in
good agreement with the torsional and longitudinal interactions in
polyethylene.Comment: Latex, 10 pages; some stylistic corrections, to appear in Chemical
Physics Letter
First-order framework and generalized global defect solutions
This work deals with defect structures in models described by scalar fields.
The investigations focus on generalized models, with the kinetic term modified
to allow for a diversity of possibilities. We develop a new framework, in which
we search for first-order differential equations which solve the equations of
motion. The main issue concerns the introduction of a new function, which works
like the superpotential usually considered in the standard situation. We
investigate the problem in the general case, with an arbitrary number of
fields, and we present several explicit examples in the case of a single real
scalar field.Comment: 8 pages, 6 figures; version to appear in PL
Brane Structure from a Scalar Field in Warped Spacetime
We deal with scalar field coupled to gravity in five dimensions in warped
geometry. We investigate models described by potentials that drive the system
to support thick brane solutions that engender internal structure. We find
analytical expressions for the brane solutions, and we show that they are all
linearly stable.Comment: 10 pages, 7 eps figures; version to be published in JCA
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