269 research outputs found
A description of odd mass W-isotopes in the Interacting 2 Boson-Fermion Model
The negative and positive parity low-spin states of the even-odd Tungsten
isotopes, 183,185,187W are studied in the frame work of the Interacting
Boson-Fermion Approximation (IBFA) model. The fermion that is coupled to the
system of bosons is taken to be in the negative parity 2f_7|2, 2f_5\2, 3p_3\2,
3p_1\2 and in the positive parity 1i_13\2 single-particle orbits. The
calculated energies of low-spin energy levels of the odd isotopes are found to
agree well with the experimental data. Also B(E2) values and spectroscopic
factors for single-neutron transfer are calculated and found to be in good
agreement with experimental data
Real forms of the complex twisted N=2 supersymmetric Toda chain hierarchy in real N=1 and twisted N=2 superspaces
Three nonequivalent real forms of the complex twisted N=2 supersymmetric Toda
chain hierarchy (solv-int/9907021) in real N=1 superspace are presented. It is
demonstrated that they possess a global twisted N=2 supersymmetry. We discuss a
new superfield basis in which the supersymmetry transformations are local.
Furthermore, a representation of this hierarchy is given in terms of two
twisted chiral N=2 superfields. The relations to the s-Toda hierarchy by H.
Aratyn, E. Nissimov and S. Pacheva (solv-int/9801021) as well as to the
modified and derivative NLS hierarchies are established
Is there a Jordan geometry underlying quantum physics?
There have been several propositions for a geometric and essentially
non-linear formulation of quantum mechanics. From a purely mathematical point
of view, the point of view of Jordan algebra theory might give new strength to
such approaches: there is a ``Jordan geometry'' belonging to the Jordan part of
the algebra of observables, in the same way as Lie groups belong to the Lie
part. Both the Lie geometry and the Jordan geometry are well-adapted to
describe certain features of quantum theory. We concentrate here on the
mathematical description of the Jordan geometry and raise some questions
concerning possible relations with foundational issues of quantum theory.Comment: 30 page
Differential constraints for the Kaup -- Broer system as a reduction of the 1D Toda lattice
It is shown that some special reduction of infinite 1D Toda lattice gives
differential constraints compatible with the Kaup -- Broer system. A family of
the travelling wave solutions of the Kaup -- Broer system and its higher
version is constructed.Comment: LaTeX, uses IOP styl
Q-stars in extra dimensions
We study q-stars with global and local U(1) symmetry in extra dimensions in
asymptotically anti de Sitter or flat spacetime. The behavior of the mass,
radius and particle number of the star is quite different in 3 dimensions, but
in 5, 6, 8 and 11 dimensions is similar to the behavior in 4.Comment: 18 pages, to appear in Phys. Rev.
Shape changing and accelerating solitons in integrable variable mass sine-Gordon model
Sine-Gordon model with variable mass (VMSG) appears in many physical systems,
ranging from the current through nonuniform Josephson junction to DNA-promoter
dynamics. Such models are usually nonintegrable with solutions found
numerically or peturbatively. We construct a class of VMSG models, integrable
both at classical and quantum level with exact soliton solutions, which can
accelerate, change their shape, width and amplitude simulating realistic
inhomogeneous systems at certain limits.Comment: 6 pages, 4 figures, revised with more physical input, to be published
in Phys. Rev. Let
Grip Force Reveals the Context Sensitivity of Language-Induced Motor Activity during “Action Words
Studies demonstrating the involvement of motor brain structures in language processing typically focus on \ud
time windows beyond the latencies of lexical-semantic access. Consequently, such studies remain inconclusive regarding whether motor brain structures are recruited directly in language processing or through post-linguistic conceptual imagery. In the present study, we introduce a grip-force sensor that allows online measurements of language-induced motor activity during sentence listening. We use this tool to investigate whether language-induced motor activity remains constant or is modulated in negative, as opposed to affirmative, linguistic contexts. Our findings demonstrate that this simple experimental paradigm can be used to study the online crosstalk between language and the motor systems in an ecological and economical manner. Our data further confirm that the motor brain structures that can be called upon during action word processing are not mandatorily involved; the crosstalk is asymmetrically\ud
governed by the linguistic context and not vice versa
On reductions of some KdV-type systems and their link to the quartic He'non-Heiles Hamiltonian
A few 2+1-dimensional equations belonging to the KP and modified KP
hierarchies are shown to be sufficient to provide a unified picture of all the
integrable cases of the cubic and quartic H\'enon-Heiles Hamiltonians.Comment: 12 pages, 3 figures, NATO ARW, 15-19 september 2002, Elb
Equations of the Camassa-Holm Hierarchy
The squared eigenfunctions of the spectral problem associated with the
Camassa-Holm (CH) equation represent a complete basis of functions, which helps
to describe the inverse scattering transform for the CH hierarchy as a
generalized Fourier transform (GFT). All the fundamental properties of the CH
equation, such as the integrals of motion, the description of the equations of
the whole hierarchy, and their Hamiltonian structures, can be naturally
expressed using the completeness relation and the recursion operator, whose
eigenfunctions are the squared solutions. Using the GFT, we explicitly describe
some members of the CH hierarchy, including integrable deformations for the CH
equation. We also show that solutions of some - dimensional members of
the CH hierarchy can be constructed using results for the inverse scattering
transform for the CH equation. We give an example of the peakon solution of one
such equation.Comment: 10 page
Integrable discretizations of derivative nonlinear Schroedinger equations
We propose integrable discretizations of derivative nonlinear Schroedinger
(DNLS) equations such as the Kaup-Newell equation, the Chen-Lee-Liu equation
and the Gerdjikov-Ivanov equation by constructing Lax pairs. The discrete DNLS
systems admit the reduction of complex conjugation between two dependent
variables and possess bi-Hamiltonian structure. Through transformations of
variables and reductions, we obtain novel integrable discretizations of the
nonlinear Schroedinger (NLS), modified KdV (mKdV), mixed NLS, matrix NLS,
matrix KdV, matrix mKdV, coupled NLS, coupled Hirota, coupled Sasa-Satsuma and
Burgers equations. We also discuss integrable discretizations of the
sine-Gordon equation, the massive Thirring model and their generalizations.Comment: 24 pages, LaTeX2e (IOP style), final versio
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