6,758 research outputs found
Multiple Quantum NMR Dynamics in Dipolar Ordered Spin Systems
We investigate analytically and numerically the Multiple Quantum (MQ) NMR
dynamics in systems of nuclear spins 1/2 coupled by the dipole-dipole
interactions in the case of the dipolar ordered initial state. We suggest two
different methods of MQ NMR. One of them is based on the measurement of the
dipolar temperature in the quasi-equilibrium state which establishes after the
time of order T2 after the MQ NMR experiment. The other method uses an
additional resonance 45^0 -pulse after the preparation period of the standard
MQ NMR experiment in solids. Many-spin clusters and correlations are created
faster in such experiments than in the usual MQ NMR experiments and can be used
for the investigation of many-spin dynamics of nuclear spins in solids.Comment: 11 pages, 3 figures. accepted for publication in Physical Review
On Graph-Theoretic Identifications of Adinkras, Supersymmetry Representations and Superfields
In this paper we discuss off-shell representations of N-extended
supersymmetry in one dimension, ie, N-extended supersymmetric quantum
mechanics, and following earlier work on the subject codify them in terms of
certain graphs, called Adinkras. This framework provides a method of generating
all Adinkras with the same topology, and so also all the corresponding
irreducible supersymmetric multiplets. We develop some graph theoretic
techniques to understand these diagrams in terms of a relatively small amount
of information, namely, at what heights various vertices of the graph should be
"hung".
We then show how Adinkras that are the graphs of N-dimensional cubes can be
obtained as the Adinkra for superfields satisfying constraints that involve
superderivatives. This dramatically widens the range of supermultiplets that
can be described using the superspace formalism and organizes them. Other
topologies for Adinkras are possible, and we show that it is reasonable that
these are also the result of constraining superfields using superderivatives.
The family of Adinkras with an N-cubical topology, and so also the sequence
of corresponding irreducible supersymmetric multiplets, are arranged in a
cyclical sequence called the main sequence. We produce the N=1 and N=2 main
sequences in detail, and indicate some aspects of the situation for higher N.Comment: LaTeX, 58 pages, 52 illustrations in color; minor typos correcte
An Exact Solution for the Lattice Gas Model in One Dimension
A simple method to obtain a canonical partition function for one dimensional
lattice gas model is presented. The simplification is based upon rewriting a
sum over all possible configurations to a sum over numbers of clusters in the
system.Comment: 6 pages, LaTe
On the Construction and the Structure of Off-Shell Supermultiplet Quotients
Recent efforts to classify representations of supersymmetry with no central
charge have focused on supermultiplets that are aptly depicted by Adinkras,
wherein every supersymmetry generator transforms each component field into
precisely one other component field or its derivative. Herein, we study
gauge-quotients of direct sums of Adinkras by a supersymmetric image of another
Adinkra and thus solve a puzzle from Ref.[2]: The so-defined supermultiplets do
not produce Adinkras but more general types of supermultiplets, each depicted
as a connected network of Adinkras. Iterating this gauge-quotient construction
then yields an indefinite sequence of ever larger supermultiplets, reminiscent
of Weyl's construction that is known to produce all finite-dimensional unitary
representations in Lie algebras.Comment: 20 pages, revised to clarify the problem addressed and solve
Local border traffic as an efficient tool for developing cross-border cooperation
Local border traffic (LBT) is a tool for cooperation between the EU member states and neighbouring countries. It emerged as a measure to mitigate the barrier effect of the EU’s external border. In 2006, the European Parliament authorised the EU member states to conclude bilateral agreements on a simplified border crossing regime in border areas. This article analyses local border traffic as a cross-border cooperation tool. The territory described in the study includes the external borders of the EU (and Norway) with the Russian Federation and the Republic of Belarus. The article will be of interest to specialists in international and, particularly, in cross-border cooperation. The authors analyse the mechanism of local border traffic and identify possible trends based on the general socioeconomic situation and foreign policy background in Russia, Belarus, and the EU (Norway). The article employs the cartographic method to enhance the visual component of the study. It is concluded that the LBT mechanism is effective and it has a positive effect on the development of border contacts between countries. There is a need to continue the dialogue between Russia, Belarus and the EU countries on both expanding the geographical scope of the LBT mechanism and ensuring its qualitative development
Spin 1 inversion: a Majorana tensor force for deuteron alpha scattering
We demonstrate, for the first time, successful S-matrix to potential
inversion for spin one projectiles with non-diagonal yielding a
interaction. The method is a generalization of the
iterative-perturbative, IP, method. We present a test case indicating the
degree of uniqueness of the potential. The method is adapted, using established
procedures, into direct observable to potential inversion, fitting ,
, , and for d + alpha scattering over
a range of energies near 10 MeV. The interaction which we find is
very different from that proposed elsewhere, both real and imaginary parts
being very different for odd and even parity channels.Comment: 7 pages Revtex, 4 ps figure
Oxidative dehydrogenation of 2,3,5-trimethyl-1,4-hydroquinone in the presence of titanium dioxide hydrogel
Liquid-phase oxidative dehydrogenation of 2,3,5-trimethyl-1,4-hydroquinone in the presence of titanium dioxide hydrogel was studied by a kinetic method. Associative interactions between the substrate, oxidant, and gel were detected by voltammetry and ESR and IR spectroscopy.Russian Foundation for Basic Researc
The process of regionalization of the state-territorial structure in modern european countries : constitutional and legal forms
Purpose: The paper attempts to identify the constitutional and legal forms of the regionalization process on the example of individual European countries. Design / Methodology / Approach: The authors put forward a hypothesis according to which each type of regionalization of the state-territorial structure ends with the adoption of the relevant normative legal act of constitutional significance. Findings: As a result of the study, the authors concluded that each type of regionalization process is accompanied by the adoption of an appropriate regulatory legal act. Given the fact that regionalization is inextricably linked with the state structure, it as an internal process of changing the constitutional and legal status of territorial units. Practical implications: Authors' development could be applied to improve the legal framework of Russia and European countries. Originality/Value: The contribution of the article is the authors' comprehensive approach in studying the regionalization concept, applying the historical, legislative and territorial background.peer-reviewe
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