1,722 research outputs found
On the relation between p-adic and ordinary strings
The amplitudes for the tree-level scattering of the open string tachyons,
generalised to the field of p-adic numbers, define the p-adic string theory.
There is empirical evidence of its relation to the ordinary string theory in
the p_to_1 limit. We revisit this limit from a worldsheet perspective and argue
that it is naturally thought of as a continuum limit in the sense of the
renormalisation group.Comment: 13 pages harvmac (b), 2 eps figures; v2: revtex, shortened, published
versio
The SO(N) principal chiral field on a half-line
We investigate the integrability of the SO(N) principal chiral model on a
half-line, and find that mixed Dirichlet/Neumann boundary conditions (as well
as pure Dirichlet or Neumann) lead to infinitely many conserved charges
classically in involution. We use an anomaly-counting method to show that at
least one non-trivial example survives quantization, compare our results with
the proposed reflection matrices, and, based on these, make some preliminary
remarks about expected boundary bound-states.Comment: 7 pages, Late
Boundary bound states and boundary bootstrap in the sine-Gordon model with Dirichlet boundary conditions.
We present a complete study of boundary bound states and related boundary
S-matrices for the sine-Gordon model with Dirichlet boundary conditions. Our
approach is based partly on the bootstrap procedure, and partly on the explicit
solution of the inhomogeneous XXZ model with boundary magnetic field and of the
boundary Thirring model. We identify boundary bound states with new ``boundary
strings'' in the Bethe ansatz. The boundary energy is also computed.Comment: 25 pages, harvmac macros Report USC-95-001
Performance of Concrete Exposed to Corrosive Environment
A comprehensive programme to investigate the behaviour of portland cement concrete exposed to corrosive environment was chalked out in this short duration study.The programme composed of compressive strength study, weight loss study , effect of carbonation, pH test study and study of ultrasonic pulse velocity test. Investigation to study the performance of portland cement concrete of M20 strength exposed to corrosive environment ( 5% H2SO4 Solution, 5% HC 1 Solution, 10% (NH4SO4 Solution and 10% NaOH Sol- ution ) revealed that the concrete cube deteriorated more in acidic environment than alkaline environment. The stre-ngth of PCC exposed to aggressive medium reduced signif- icantly after exposure of 28 days. This reduction in strength was mainly due to expansive salt formation . The formation of expansive salt also resulted in loss of cem-entitious properties and loss of weight. The concrete exposed to H2SO4 solution was found least durable . This study also shows that higher the ultrasonic pulse velocity lower is the corrosion . This paper presents an approach of investigation along with analysis of test results of PCC exposed to corrosive environment
Customized physical and structural features of phosphate-based glass-ceramics: role of ag nanoparticles and ho3+ impurities
The effects of silver nanoparticles (Ag NPs) embedment on the physical and structural characteristics of the holmium ions (Ho3+) activated phosphate-based glass-ceramics were assessed. Two series of such glass-ceramics were prepared using the melt-quenching and characterized. In the first series, the Ag NPs were nucleated from the incorporated AgCl via the redox process. In the second series, the pure Ag nanopowder was directly added. The overall properties of these glass-ceramics were strongly sensitive to the cooling procedure and NPs addition strategies, leading to different density and refractive index modifications in the two series. The recorded O1s XPS peaks were exploited to determine the bridging to non-bridging oxygen ratios in the studied glass-ceramics network that enabled to unfold the differences in the observed inferences. A compelling correlation among various attributes in the achieved glass-ceramics was established. Briefly, the overall traits of the proposed glass-ceramics were tailored by regulating the preparation conditions
Zeta Nonlocal Scalar Fields
We consider some nonlocal and nonpolynomial scalar field models originated
from p-adic string theory. Infinite number of spacetime derivatives is
determined by the operator valued Riemann zeta function through d'Alembertian
in its argument. Construction of the corresponding Lagrangians L starts
with the exact Lagrangian for effective field of p-adic tachyon
string, which is generalized replacing p by arbitrary natural number n and then
taken a sum of over all n. The corresponding new objects we
call zeta scalar strings. Some basic classical field properties of these fields
are obtained and presented in this paper. In particular, some solutions of the
equations of motion and their tachyon spectra are studied. Field theory with
Riemann zeta function dynamics is interesting in its own right as well.Comment: 13 pages, submitted to Theoretical and Mathematical Physic
Direct Calculation of Breather S Matrices
We formulate a systematic Bethe-Ansatz approach for computing bound-state
(``breather'') S matrices for integrable quantum spin chains. We use this
approach to calculate the breather boundary S matrix for the open XXZ spin
chain with diagonal boundary fields. We also compute the soliton boundary S
matrix in the critical regime.Comment: 23 pages, LaTeX, 1 eps figur
Boundary breathers in the sinh-Gordon model
We present an investigation of the boundary breather states of the
sinh-Gordon model restricted to a half-line. The classical boundary breathers
are presented for a two parameter family of integrable boundary conditions.
Restricting to the case of boundary conditions which preserve the \phi -->
-\phi symmetry of the bulk theory, the energy spectrum of the boundary states
is computed in two ways: firstly, by using the bootstrap technique and
subsequently, by using a WKB approximation. Requiring that the two descriptions
of the spectrum agree with each other allows a determination of the
relationship between the boundary parameter, the bulk coupling constant, and
the parameter appearing in the reflection factor derived by Ghoshal to describe
the scattering of the sinh-Gordon particle from the boundary.Comment: 16 pages amslate
Hypergraph topological quantities for tagged social networks
Recent years have witnessed the emergence of a new class of social networks,
that require us to move beyond previously employed representations of complex
graph structures. A notable example is that of the folksonomy, an online
process where users collaboratively employ tags to resources to impart
structure to an otherwise undifferentiated database. In a recent paper[1] we
proposed a mathematical model that represents these structures as tripartite
hypergraphs and defined basic topological quantities of interest. In this paper
we extend our model by defining additional quantities such as edge
distributions, vertex similarity and correlations as well as clustering. We
then empirically measure these quantities on two real life folksonomies, the
popular online photo sharing site Flickr and the bookmarking site CiteULike. We
find that these systems share similar qualitative features with the majority of
complex networks that have been previously studied. We propose that the
quantities and methodology described here can be used as a standard tool in
measuring the structure of tagged networks.Comment: 8 pages, 9 figures, revte
- …