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1.
R. Rajaraman 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):157-162
We present here an elementary pedagogical introduction to CPN solitons in quantum Hall systems. We begin with a brief introduction to both CPN models and to quantum Hall (QH) physics. We then focus on spin and layer-spin degrees of freedom in QH systems and point
out that these are in fact CPN fields for N
= 1 and N
= 3. Excitations in these degrees of freedom will be shown to be topologically non-trivial soliton solutions of the corresponding
CPN field equations. We conclude with a brief summary of our own recent work in this area, done with Sankalpa Ghosh.
Received 17 November 2001 Published online 2 October 2002
RID="a"
ID="a"e-mail: doug0700@mail.jnu.ac.in 相似文献
2.
V.S. Gerdjikov A. Kyuldjiev G. Marmo G. Vilasi 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):177-181
We consider generalizations of the standard Hamiltonian dynamics to complex dynamical variables and introduce the notions
of real Hamiltonian form in analogy with the notion of real forms for a simple Lie algebra. Thus to each real Hamiltonian
system we are able to relate several nonequivalent ones. On the example of the complex Toda chain we demonstrate how starting
from a known integrable Hamiltonian system (e.g. the Toda chain) one can complexify it and then project onto different real forms.
Received 18 October 2001 / Received in final form 24 May 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: gerjikov@inrne.bas.bg 相似文献
3.
W.J. Zakrzewski 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):217-219
In this talk we introduce a Weierstrass-like system of equations corresponding to CP
N
-1 fields in two dimensions. Then using this representation we introduce a vector in R
N
2-1 and treating this vector as the radius vector of a surface immersed in R
N
2-1 we discuss to what extent the associated metric describes the geometry of the CP
N
-1 maps. We show that for the holomorphic maps - the correspondence is exact; while for the more general fields we have to go
beyond the Weierstrass system and add extra terms.
Received 1st August 2001 / Received in final form 18 October 2001 Published online 2 October 2002
RID="a"
ID="a"Work done in collaboration with M. Grundland e-mail: w.j.zakrzewski@durham.ac.uk 相似文献
4.
5.
E. Nissimov S. Pacheva 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):197-201
The recently proposed supersymmetric extensions of reduced Kadomtsev-Petviashvili (KP) integrable hierarchies in N = 1, 2 superspace are shown to contain in the purely bosonic limit new types of ordinary non-supersymmetric integrable systems.
The latter are coupled systems of several multi-component non-linear Schr?dinger-like hierarchies whose basic nonlinear evolution
equations contain additional quintic and higher-derivative nonlinear terms. Also, we obtain the N = 2 supersymmetric extension of Toda chain model as Darboux-B?cklund orbit of the simplest reduced N = 2 super-KP hierarchy and find its explicit solution.
Received 13 September 2001 Published online 2 October 2002
RID="a"
ID="a"e-mail: nissimov@inrne.bas.bg
RID="b"
ID="b"e-mail: svetlana@inrne.bas.bg 相似文献
6.
V.S. Gerdjikov G.G. Grahovski N.A. Kostov 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):243-248
The class of nonlinear evolution equations (NLEE) - gauge equivalent to the N-wave equations related to the simple Lie algebra are derived and analyzed. They are written in terms of (x, t) ∈ satisfying r = rank nonlinear constraints. The corresponding Lax pairs and the time evolution of the scattering data are found. The Zakharov-Shabat
dressing method is appropriately modified to construct their soliton solutions.
Received 20 October 2001 / Received in final form 30 April 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: gerjikov@inrne.bas.bg 相似文献
7.
J. Barré F. Bouchet T. Dauxois S. Ruffo 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(4):577-591
We study an analytically tractable model with long-range interactions for which an out-of-equilibrium very long-lived coherent structure spontaneously appears. The dynamics of this model is indeed
very peculiar: a bicluster forms at low energy and is stable for very long time, contrary to statistical mechanics predictions. We first explain the
onset of the structure, by approximating the short time dynamics with a forced Burgers equation. The emergence of the bicluster
is the signature of the shock waves present in the associated hydrodynamical equations. The striking quantitative agreement
with the dynamics of the particles fully confirms this procedure. We then show that a very fast timescale can be singled out
from a slower motion. This enables us to use an adiabatic approximation to derive an effective Hamiltonian that describes
very well the long time dynamics. We then get an explanation of the very long time stability of the bicluster: this out-of-equilibrium
state corresponds to a statistical equilibrium of an effective mean-field dynamics.
Received 28 February 2002 / Received in final form 24 July 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: Thierry.Dauxois@ens-lyon.fr
RID="b"
ID="b"UMR-CNRS 5672
RID="c"
ID="c"UMR 5582 相似文献
8.
F. Azaiez M. Belleguic D. Sohler M. Stanoiu Zs. Dombrádi O. Sorlin J. Timár F. Amorini D. Baiborodin A. Bauchet F. Becker C. Borcea C. Bourgeois Z. Dlouhy C. Donzaud J. Duprat D. Guillemaud-Mueller F. Ibrahim M.J. Lopez R. Lucas S.M. Lukyanov V. Maslov J. Mrazek C. Moore F. Nowacki B.M. Nyakó Yu.-E. Penionzhkevich M.G. Saint-Laurent F. Sarazin J.A. Scarpaci G. Sletten C. Stodel M. Taylor C. Theisen G. Voltolini 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):93-97
The structure of neutron-rich light nuclei around N = 20 and 28 has been investigated at GANIL by means of in-beam gamma-spectroscopy using fragmentation reactions of 36S and 48Ca beams on a Be target. Gamma-decay of relatively high-lying excited states have been measured for the first time in nuclei
around 32Mg and 44S. Level schemes are proposed and discussed for a large number of these neutron-rich nuclei around N = 20 and N = 28.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: azaiez@ipno.in2p3.fr 相似文献
9.
E. Caurier F. Nowacki A. Poves 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):145-150
Recent shell model calculations for the neutron-rich nuclei around the magic numbers N = 20, N = 28 and N = 40 are reviewed. We stress two points: i) The crucial role played by the monopole part of the effective interaction that
determines the evolution of the spherical mean field. In particular, the reduction in the quasiparticle gaps at the magic
numbers can erode or even erase the shell closures. ii) The rich variety of structures that can be found in these situations,
with coexisting deformed and spherical states, rapid changes of behaviour with N or Z, and the massive occurrence of intruder states as ground states.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: alfredo.poves@uam.es 相似文献
10.
P. Mierzyński K. Pomorski 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):311-314
Strutinsky shell corrections for the cesium-coated fullerenes were investigated. The single particle levels of electrons are
obtained using the spherical mean-field potential of a shifted Wood-Saxon type. The parameters of the potential are adjusted
to reproduce the experimental ionization energies of the Cs(N) clusters and the magic numbers observed in their photo-ionization spectra of the C60Cs(N) aggregates.
Received 24 May 2002 / Received in final form 9 July 2002 Published online 15 October 2002
RID="*"
ID="*"This work has been partly supported by the Polish Committee for Scientific Research under Contract No. 2P03B 115 19
and by the Program of Scientific Exchange between the IN2P3-France and the Polish Research Institution No. 99-95.
RID="b"
ID="b"e-mail: Krzysztof.Pomorski@umcs.lublin.pl 相似文献
11.
P. von Brentano C. Fransen A. Gade A. Lisetskiy N. Pietralla 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):99-103
Due to the recent development of radioactive beam production, various direct reaction studies in reversed kinematics have
been made to investigate the behavior of the N = 20 shell closure in the neutron-rich region. Coulomb excitation, proton inelastic scattering, and fragmentation of unstable
nuclei have been studied with γ-ray detection.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: motobaya@rikkyo.ne.jp 相似文献
12.
Large spin systems as given by magnetic macromolecules or two-dimensional spin arrays rule out an exact diagonalization of
the Hamiltonian. Nevertheless, it is possible to derive upper and lower bounds of the minimal energies, i.e. the smallest energies for a given total spin S. The energy bounds are derived under additional assumptions on the topology of the coupling between the spins. The upper
bound follows from “n-cyclicity", which roughly means that the graph of interactions can be wrapped round a ring with n vertices. The lower bound improves earlier results and follows from “n-homogeneity", i.e. from the assumption that the set of spins can be decomposed into n subsets where the interactions inside and between spins of different subsets fulfill certain homogeneity conditions. Many
Heisenberg spin systems comply with both concepts such that both bounds are available. By investigating small systems which
can be numerically diagonalized we find that the upper bounds are considerably closer to the true minimal energies than the
lower ones.
Received 22 October 2002 / Received in final form 4 April 2003 Published online 20 June 2003
RID="a"
ID="a"e-mail: jschnack@uos.de 相似文献
13.
M.P. Rekalo E. Tomasi-Gustafsson 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):575-581
The associative charm particles production in nucleon-nucleon collisions N + N↦Λc(Σc) + ˉD + N, is described in a general way and the spin and isospin structure of the corresponding matrix elements are derived. Using
an analogy with strange-particle (ΛK) production, the D-meson exchange model is considered in detail. Estimations of the energy behavior of the threshold cross-sections show a large
dependence on the form of the phenomenological hadron form factors and indicate that, at threshold, the cross-section is three
orders of magnitude smaller than for strange-particle production.
Received: 18 October 2002 / Accepted: 5 December 2002 / Published online: 18 March 2003
RID="a"
ID="a"Permanent address: National Science Center KFTI, 310108 Kharkov, Ukraine.
RID="b"
ID="b"e-mail: etomasi@cea.fr
Communicated by V.V. Anisovich 相似文献
14.
K. Knorr L. Ehm M. Hytha B. Winkler W. Depmeier 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(3):297-303
The high-pressure behaviour of PbS was investigated by angular dispersive X-ray powder diffraction up to pressures of 6.8
GPa. Experiments were accompanied by first principles calculations at the density functional theory level. By combining both
methods reliable data for the elastic properties of rock-salt type α- and high-pressure β-PbS could be obtained. β-PbS could be determined to crystallise in the CrB-type (B33), with space group Cmcm. The reversible ferro-elastic α/β transition is of first order. It is accompanied by a large volume discontinuity of about 5% and a coexistence region of the
two phases. A gliding mechanism of {001} bilayers along one of the cubic 〈110〉 directions governs the phase transition which can be described in terms of group/subgroup relationships via a common subgroup, despite its reconstructive character. The quadrupling of the primitive unit cell indicates a wave vector
(0, 0,π/
a
) on the Δ-line of the Brillouin zone.
Received 11 October 2002 Published online 14 February 2003
RID="a"
ID="a"Also at: Institute of Physics of the Czech Academy of Sciences, Cukrovarnicka 10, 16253 Praha 6, Czech Republic e-mail: knorr@min.uni-kiel.de
RID="b"
ID="b"Present address: University of Cambridge, Cavendish Laboratory (TCM), Madingley Road, Cambridge CB3 0HE, UK
RID="c"
ID="c"Present address: Johann-Wolfgang Goethe Universit?t, Mineralogisches Institut, Kristallographie, Senckenberganlage 30, D 60054 Frankfurt a.M.,
Germany 相似文献
15.
D.C. Radford C. Baktash A. Galindo-Uribarri C.J. Gross T.A. Lewis P.E. Mueller P.A. Hausladen D. Shapira D.W. Stracener C.-H. Yu B. Fuentes E. Padilla D.J. Hartley C.J. Barton M. Caprio N.V. Zamfir 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):171-173
The Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory has recently produced the world's first post-accelerated
beams of heavy neutron-rich nuclei. The first experiments with these beam are described, and the results discussed. B(E2;0+ → 2+) values for neutron-rich 126,128Sn and 132,134,136Te isotopes have been measured by Coulomb excitation in inverse kinematics. The results for 132Te and 134Te (N = 80, 82) show excellent agreement with systematics of lighter Te isotopes, but the B(E2) value for 136Te (N = 84) is unexpectedly small. Single-neutron transfer reactions with a 134Te beam on natBe and 13C targets at energies just above the Coulomb barrier have also been studied.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: radford@mail.phy.ornl.gov 相似文献
16.
D. Schwarzhans D. Zimmermann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):193-198
The absorption spectrum of NaAr has been investigated with high resolution using a supersonic beam of molecules and a tunable
dye laser. About 3 300 absorption lines due to the transition A
2
Π ←
X and B
2
Σ ←
X have been observed. In addition, we observed the spectral distribution of the fluorescence for a particular absorption line.
From all experimental data the X
2
Σ
+
interaction potential has been deduced in a fully quantum-mechanical method of approach. The potential is given in terms
of an analytical Hartree-Fock-Dispersion function. For the equilibrium parameters of the X state we get R
e
= 5.01(1) ? and D
e
= 41.6(2)
cm
-1
.
Received 28 August 2002 / Received in final form 15 October 2002 Published online 17 December 2002
RID="a"
ID="a"Now at Knick Elektronische Messger?te, Beuckestr. 22, 14163 Berlin, Germany.
RID="b"
ID="b"e-mail: dz@kalium.physik.tu-berlin.de 相似文献
17.
N. Cavadini Th. Strässle P. Allenspach P.C. Canfield Ph. Bourges 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(3):377-384
The magnetic excitations in the antiferromagnetic phase of HoNi2B2C are studied by inelastic neutron scattering on single crystals for the first time. Spectra measured at constant T
= 2 K along symmetry directions of the reciprocal space are well explained in terms of crystal electric field (CEF) magnetic
excitons within the J
= 8 ground state multiplet of Ho3+. Very modest bandwidth with planar energy dispersion describes the magnetic exciton dynamics. A perturbative model approach
consisting of the CEF states in the effective exchange mean-field provides a simple but applicable characterization of the
experimental observations. The microscopic determination of the relevant exchange parameters is discussed in connection with
previous works on the subject.
Received 25 February 2002 / Received in final form 13 May 2002 Published online 14 October 2002
RID="a"
ID="a"e-mail: nordal.cavadini@psi.ch 相似文献
18.
Z. Gulácsi 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(3):295-301
We report for the first time exact ground-states deduced for the D
= 2 dimensional generic periodic Anderson model at finite U, the Hamiltonian of the model not containing direct hopping terms for f-electrons (
t
f
= 0). The deduced itinerant phase presents non-Fermi liquid properties in the normal phase, emerges for real hybridization matrix
elements, and not requires anisotropic unit cell. In order to deduce these results, the plaquette operator procedure has been
generalised to a block operator technique which uses blocks higher than an unit cell and contains f-operator contributions acting only on a single central site of the block.
Received 1st July 2002 / Received in final form 16 September 2002 Published online 19 December 2002
RID="a"
ID="a"e-mail: gulacsi@heavy-ion.atomki.hu 相似文献
19.
Roger M Guenoun P Muller F Belloni L Delsanti M 《The European physical journal. E, Soft matter》2002,9(4):313-326
The concentration profiles of monomers and counterions in star-branched polyelectrolyte micelles are calculated through Monte
Carlo simulations, using the freely jointed chain model. We have investigated the onset of different regimes corresponding
to the spherical and Manning condensation of counterions as a function of the strength of the Coulomb coupling. The Monte
Carlo results are in fair agreement with the predictions of Self-Consistent-Field analytical models. We have simulated a real
system of diblock copolymer micelles of (sodium-polystyrene-sulfonate)(NaPSS)-(polyethylene-propylene)(PEP) with f = 54 hydrophilic branches of N = 251 monomers at room temperature in salt-free solution. The calculated form factor compares nicely with our neutron scattering
data.
Received 18 July 2002 and Received in final form 11 October 2002
RID="a"
ID="a"e-mail: roger@drecam.saclay.cea.fr 相似文献
20.
S.V. Dordevic D.N. Basov R.C. Dynes B. Ruzicka V. Vescoli L. Degiorgi H. Berger R. Gaál L. Forró E. Bucher 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(1):15-23
We present a comprehensive analysis of the optical constants of the two-dimensional dichalcogenide materials 2
H
-
TaSe
2
and 2
H
-
NbSe
2
, in an attempt to address the physics of two-dimensional correlated systems. The title compounds were studied over several
decades in frequency, from the far-infrared to the ultraviolet. Measurements with linearly polarized light have allowed us
to obtain both the in-plane and out-of-plane components of the conductivity tensor. Although the electromagnetic response
of dichalcogenides is strongly anisotropic, both the in-plane and out-of-plane components of the conductivity tensor share
many common features, including the presence of a well-defined metallic component, as well as a “mid-infrared band”. We discuss
the implications of these results in the context of the spectroscopic results of other classes of low-dimensional conductors
such as the high-temperature superconducting cuprates. In particular, the analysis of the redistribution of the spectral weight
as a function of temperature, as well as the behavior of the quasiparticles relaxation rate, points to significant distinctions
between the charge dynamics of dichalcogenides and other classes of low dimensional conductors.
Received 28 October 2002 / Received in final form 10 March 2003 Published online 23 May 2003
RID="a"
ID="a"e-mail: degiorgi@solid.phys.ethz.ch 相似文献