272 research outputs found
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
A novel connection between scalar field theories and quantum mechanics
This work deals with scalar field theories and supersymmetric quantum
mechanics. The investigation is inspired by a recent result, which shows how to
use the reconstruction mechanism to describe two distinct field theories from
the very same quantum mechanics potential, and by an older work, which
describes the deformation procedure that offers an interesting way to generate
and solve new scalar field theories, starting from a given model of current
interest. We use the procedure to unveil a new route, from which one can
describe families of scalar field theories that engender the very same quantum
mechanics potential. The approach can be applied algorithmically, and
implemented to generate models that give rise to distinct quantum mechanics
systems as well.Comment: 5 pages, 9 figures. To appear in EP
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
First-order formalism for bent brane
This work deals with braneworld scenarios in the presence of real scalar
field with standard dynamics. We show that the first-order formalism, which
exists in the case of flat brane, can be extended to bent brane, for both de
Sitter and anti-de Sitter geometry. We illustrate the results with some
examples of current interest to high energy physics.Comment: RevTex, 6 pages; version to appear in PL
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
Defect structures in sine-Gordon-like models
We investigate several models described by real scalar fields, searching for
topological defects. Some models are described by a single field, and support
one or two topological sectors, and others are two-field models, which support
several topological sectors. Almost all the defect structures that we find are
stable and finite energy solutions of first-order differential equations that
solve the corresponding equations of motion. In particular, for the double
sine-Gordon model we show how to find small and large BPS solutions as
deformations of the BPS solution of the model. And also, for most of
the two field models we find the corresponding integrating factors, which lead
to the complete set of BPS solutions, nicely unveiling how they bifurcate among
the several topological sectors.Comment: RevTex, 18 pages, 17 figures; Version to appear in Physica
The orbit method solution for the deformed three coupled scalar fields
In this work, we present a deformed solutions starting from systems of three
coupled scalar fields with super-potential by orbit
method. First, we deform the corresponding super-potential and obtain defect
solutions. It is shown that how to construct new models altogether with its
defect solutions in terms of the non-deformed model. Therefore, we draw the
graph of super-potential and different fields in terms of So we observe
that the graphs for deformed and non - deformed cases are changed by the scale.Comment: 9 pages, 5 figure
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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