1,153 research outputs found
Effective action of a five-dimensional domain wall
We calculate the four-dimensional low-energy effective action for the
perturbations of a two-scalar domain wall model in five dimensions. Comparison
of the effective action to the Nambu-Goto action reveals the presence of an
additional coupling between the light scalar field and the massless translation
mode (branon excitation), which can be written in terms of the curvature scalar
of the induced metric. We comment on the impact of this interaction to branon
physics.Comment: 24 page
Multi-instantons in seven dimensions
We consider the self-dual Yang-Mills equations in seven dimensions. Modifying
the t'Hooft construction of instantons in , we find -instanton
solutions which depend on effective parameters and are -invariant.Comment: 9 pages, LaTeX, no figure
Zero-brane approach to quantization of biscalar field theory about topological kink-bell solution
We study the properties of the topologically nontrivial doublet solution
arisen in the biscalar theory with a fourth-power potential introducing an
example of the spontaneous breaking of symmetry. We rule out the zero-brane
(non-minimal point particle) action for this doublet as a particle with
curvature. When quantizing it as the theory with higher derivatives, we
calculate the quantum corrections to the mass of the doublet which could not be
obtained by means of the perturbation theory.Comment: some references were adde
Existence and Stability of Non-Trivial Scalar Field Configurations in Orbifolded Extra Dimensions
We consider the existence and stability of static configurations of a scalar
field in a five dimensional spacetime in which the extra spatial dimension is
compactified on an orbifold. For a wide class of potentials with
multiple minima there exist a finite number of such configurations, with total
number depending on the size of the orbifold interval. However, a
Sturm-Liouville stability analysis demonstrates that all such configurations
with nodes in the interval are unstable. Nodeless static solutions, of which
there may be more than one for a given potential, are far more interesting, and
we present and prove a powerful general criterion that allows a simple
determination of which of these nodeless solutions are stable. We demonstrate
our general results by specializing to a number of specific examples, one of
which may be analyzed entirely analytically.Comment: 23 pages, 7 figures, references added, factor of two corrected in
kink energy definition, submitted to PR
The Association and Dissociation Tendencies of the Coaxial and Non- Coaxial Components of Shear Strength of Soils to Environment
Soil is rock on its way to ocean. It undergoes many changes during the travel. The important factors which influence the geo-technical behavior of soil are : Grain size and Shape, Gradation, Water, Parent rock materials and Environment. The Geo-technical behavior of fine grains in soil is highly complex than coarse grains. A pure cohesive soil has pure shear or coaxial shear component only. A pure friction soil has Non-coaxial or simple shear component only. Normally a soil sample is a mixture of coarse and fine grains. The shear strength is shared between coaxial and non-coaxial component of the total shear strength of soil. The environment influences the Geo-technical behavior of soil. The coaxial and non-coaxial components of shear strength (coax and non-coax) of soil accepts and adjusts to reach a new equilibrium in stability. In this paper the association and dissociation of coax and non-coax with environmental conditions starting from laboratory and ending in marine environment through examples, illustrations and documented, reliable data available in literature
Aharonov-Bohm effect in higher genus materials
Flux periodicity of conducting electrons on a closed surface with genus two
(double torus) are investigated theoretically. We examine flux
periodicity of the ground-state energy and of the wave functions as a function
of applied magnetic field. A fundamental flux period of the ground-state energy
is twice a fundamental unit of magnetic flux for uniformly applied magnetic
field, which is shown to be valid for a simple ladder geometry and carbon
double torus. Flux periodicity of the wave functions in a double torus is
complicate as compared with a simple torus (), and an adiabatic addition
of magnetic fluxes does not provide a good quantum number for the energy
eigenstates. The results are extended to higher genus materials and the
implications of the results are discussed.Comment: 4 pages, 6 figure
Non-topological gravitating defects in five-dimensional anti-de Sitter space
A class of five-dimensional warped solutions is presented. The geometry is
everywhere regular and tends to five-dimensional anti-de Sitter space for large
absolute values of the bulk coordinate. The physical features of the solutions
change depending on the value of an integer parameter. In particular, a set of
solutions describes generalized gravitating kinks where the scalar field
interpolates between two different minima of the potential. The other category
of solutions describes instead gravitating defects where the scalar profile is
always finite and reaches the same constant asymptote both for positive and
negative values of the bulk coordinate. In this sense the profiles are
non-topological. The physical features of the zero modes are discussed.Comment: 9 pages, 4 figure
Soliton Trap in Strained Graphene Nanoribbons
The wavefunction of a massless fermion consists of two chiralities,
left-handed and right-handed, which are eigenstates of the chiral operator. The
theory of weak interactions of elementally particle physics is not symmetric
about the two chiralities, and such a symmetry breaking theory is referred to
as a chiral gauge theory. The chiral gauge theory can be applied to the
massless Dirac particles of graphene. In this paper we show within the
framework of the chiral gauge theory for graphene that a topological soliton
exists near the boundary of a graphene nanoribbon in the presence of a strain.
This soliton is a zero-energy state connecting two chiralities and is an
elementally excitation transporting a pseudospin. The soliton should be
observable by means of a scanning tunneling microscopy experiment.Comment: 7 pages, 4 figure
Interaction of human recombinant αA- and αB-crystallins with early and late unfolding intermediates of citrate synthase on its thermal denaturation
AbstractWe have investigated the role of recombinant human αA- and αB-crystallins in the heat-induced inactivation and aggregation of citrate synthase. Homo-multimers of both αA- and αB-crystallins confer protection against heat-induced inactivation in a concentration-dependent manner and also prevent aggregation. Interaction of crystallins with early unfolding intermediates of citrate synthase reduces their partitioning into aggregation-prone intermediates. This appears to result in enhanced population of early unfolding intermediates that can be reactivated by its substrate, oxaloacetate. Both these homo-multimers do not form a stable complex with the early unfolding intermediates. However, they can form a soluble, stable complex with aggregation-prone late unfolding intermediates. This soluble complex formation prevents aggregation. Thus, it appears that the chaperone activity of α-crystallin involves both transient and stable interactions depending on the nature of intermediates on the unfolding pathway; one leads to reactivation of the enzyme activity while the other prevents aggregation
Routing in Extremely Mobile Networks
We consider the problem of routing in a highly mobile network which is never fully connected. We describe algorithms that allow to route a packet toward a remote destinations. The packet bounces from connected components to connected components, thanks to node mobility
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