共查询到20条相似文献,搜索用时 78 毫秒
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2.
H. Hansen G. Chanfray D. Davesne P. Schuck 《The European Physical Journal A - Hadrons and Nuclei》2002,14(4):397-411
An application of a self-consistent version of RPA to quantum field theory with broken symmetry is presented. Although our
approach can be applied to any bosonic field theory, we specifically study the ϕ4 theory in 1 + 1 dimensions. We show that the standard RPA approach leads to an instability which can be removed when going
to a superior version, i.e. the renormalized RPA. We present a method based on the so-called charging formula of the many-electron problem to calculate
the correlation energy and the RPA effective potential.
Received: 18 February 2002 / Accepted: 8 May 2002 相似文献
3.
R.P. Duperray K.V. Protasov A.Yu. Voronin 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):27-34
The experimental data of the antideuteron production in proton-proton and proton-nucleus collisions are analyzed within a
simple model based on the diagrammatic approach to the coalescence model. This model is shown to be able to reproduce most
of the existing data without any additional parameter.
Received: 18 April 2002 / Accepted: 30 August 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: duperray@isn.in2p3.fr
RID="b"
ID="b"e-mail: protasov@isn.in2p3.fr
RID="c"
ID="c"e-mail: avoronin@aha.ru
Communicated by A. Molinari 相似文献
4.
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
5.
We study the lateral and transverse diffusion of amphiphiles in two-component bilayer membranes, using a coarse-grained model
for amphiphilic molecules and combined Monte Carlo-Molecular Dynamics simulations. Membrane structural properties, such as
the mean thickness, are also measured. The dependence of such properties on membrane composition, inter-molecular interactions,
and amphiphile stiffness is determined. In particular, we show that addition of shorter amphiphiles drives the model membrane
towards a more fluid state, with increased amphiphile lateral diffusion rates. These results can be understood in the framework
of a simple free-volume model. Furthermore, we observe an increase in the trans-membrane diffusion when the interaction energy
of amphiphiles with their neighboring molecules is decreased.
Received: 6 December 2002 / Accepted: 17 April 2003 / Published online: 27 May 2003
RID="a"
ID="a"e-mail: imparato@mpikg-golm.mpg.de
RID="b"
ID="b"e-mail: shillcock@mpikg-golm.mpg.de
RID="c"
ID="c"e-mail: lipowsky@mpikg-golm.mpg.de 相似文献
6.
We study the quark mass expansion of the magnetic moments of the nucleon in a chiral effective field theory including nucleons,
pions and delta-resonances as explicit degrees of freedom. We point out that the usual power counting applied so far to this
problem misses important quark mass structures generated via an intermediate isovector M1 nucleon-delta transition. We propose a modified power counting and compare the resulting chiral extrapolation function to
available (quenched) lattice data. The extrapolation is found to work surprisingly well, given that the lattice data result
from rather large quark masses. Our calculation raises the hope that extrapolations of lattice data utilizing chiral effective
field theory might be applicable over a wider range in quark masses than previously thought, and we discuss some open questions
in this context. Furthermore, we observe that within the current lattice data uncertainties the extrapolations presented here
are consistent with the Padé fit ansatz introduced by the Adelaide group a few years ago.
Received: 23 April 2002 / Accepted: 18 July 2002 / Published online: 17 December 2002
RID="c"
ID="c"e-mail: themmert@physik.tu-muenchen.de
RID="d"
ID="d"e-mail: weise@ect.it
Communicated by A. Sch?fer 相似文献
7.
B.L. Birbrair V.I. Ryazanov 《The European Physical Journal A - Hadrons and Nuclei》2002,15(3):343-349
The experimental data on the doorway states for one-nucleon transfer reactions permit to reveal the many-particle nucleon-nucleon
forces resulting from the nonlinearity of strong interaction. The three-particle and four-particle forces are found to be
of the same magnitude as the two-particle ones in contrast to the finding from the few-nucleon systems. The origin of this
difference is explained.
Received: 14 May 2002 / Accepted: 4 June 2002 / Published online: 19 November 2002
RID="a"
ID="a"e-mail: birbrair@thd.pnpi.spb.ru
Communicated by V.V. Anisovich 相似文献
8.
L.L. Salcedo 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):71-94
The multiscattering problem is studied in the matrix density formalism. We study how to isolate the quasi-classical degrees
of freedom in order to connect them with a cascade approach. The different problems that arise, as well as their possible
solutions, are discussed and exemplified with a pion-nucleus model.
Received: 24 May 2002 / Accepted: 25 July 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: salcedo@ugr.es
Communicated by A. Sch?fer 相似文献
9.
N. Singhal V. Prasad M. Mohan 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):293-298
The molecular dynamics of polar diatomic molecule, interacting with linearly and circularly polarised laser field is studied.
Non-perturbative quasi-energy technique is used to determine the rotational field surfaces. Degeneracy in different M-levels
is found to be removed in the presence of circularly polarised electromagnetic radiation. In this paper, we present the calculations
exhibiting the dynamics of rotational excitation of a linear molecule and characteristic features of spectra which become
observable in considered fields.
Received 22 March 2002 / Received in final form 15 July 2002 Published online 6 November 2002
RID="a"
ID="a"e-mail: nsinghal@physics.du.ac.in
RID="b"
ID="b"e-mail: vnautiyal@himalaya.du.ac.in
RID="c"
ID="c"e-mail: manmohan@physics.du.ac.in 相似文献
10.
G. Benenti G. Casati S. Montangero D.L. Shepelyansky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):285-293
We investigate the transition to quantum chaos, induced by static imperfections, for an operating quantum computer that simulates
efficiently a dynamical quantum system, the sawtooth map. For the different dynamical regimes of the map, we discuss the quantum
chaos border induced by static imperfections by analyzing the statistical properties of the quantum computer eigenvalues.
For small imperfection strengths the level spacing statistics is close to the case of quasi-integrable systems while above
the border it is described by the random matrix theory. We have found that the border drops exponentially with the number
of qubits, both in the ergodic and quasi-integrable dynamical regimes of the map characterized by a complex phase space structure.
On the contrary, the regime with integrable map dynamics remains more stable against static imperfections since in this case
the border drops only algebraically with the number of qubits.
Received 19 June 2002 / Received in final form 30 September 2002 Published online 17 Decembre 2002
RID="a"
ID="a"e-mail: dima@irsamc.ups-tlse.fr
RID="b"
ID="b"UMR 5626 du CNRS 相似文献
11.
Yakov Itin 《Annals of Physics》2004,312(1):60-83
We formulate a premetric version of classical electrodynamics in terms of the excitation and the field strength F=(E,B). A local, linear, and symmetric spacetime relation between H and F is assumed. It yields, if electric/magnetic reciprocity is postulated, a Lorentzian metric of spacetime thereby excluding Euclidean signature (which is, nevertheless, discussed in some detail). Moreover, we determine the Dufay law (repulsion of like charges and attraction of opposite ones), the Lenz rule (the relative sign in Faraday’s law), and the sign of the electromagnetic energy. In this way, we get a systematic understanding of the sign rules and the sign conventions in electrodynamics. The question in the title of the paper is answered affirmatively. 相似文献
12.
A. Neußer H. Hübel G.B. Hagemann S. Bhattacharya P. Bringel D. Curien O. Dorvaux J. Domscheit F. Hannachi D.R. Jensen A. Lopez-Martens E. Mergel N. Nenoff A.K. Singh 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):439-441
First evidence is presented for triaxial superdeformation in 170Hf. High-spin states in this nucleus have been investigated in a γ-ray coincidence measurement using the EUROBALL spectrometer
array. A new band was discovered which has moments of inertia that are very similar to the ones of triaxial superdeformed
bands in neighbouring Hf and Lu nuclei. The intensities with which these bands are populated are different from what may be
expected from calculated potential-energy minima.
Received: 11 September 2002 / Accepted: 15 October 2002 / Published online: 10 December 2002
RID="a"
ID="a"e-mail: neusser@iskp.uni-bonn.de
Communicated by D. Schwalm 相似文献
13.
E. Api naniz F. Plazaola J.S. Garitaonandia 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(2):167-177
Tight Binding Linear Muffin-Tin Orbital (TB-LMTO) electronic calculations are presented for the magnetic and structural properties
of ordered and disordered FeAl alloys. The total energy, bulk modulus, lattice parameter and magnetic moments of B2, D03 and
B32 ordered structures and A2 disordered structure were calculated for different compositions. The different structures are
obtained by varying the position of Fe and Al atoms in a BCC superstructure. In this way, we examine the order-disorder transition
that takes place in these alloys. Disordered alloys present both larger Fe magnetic moment and lattice parameter than ordered
ones. In this work comparison of the calculated quantities with available experimental results is provided and it can be concluded
that the results are in quantitative agreement with the experimental trends.
Received 7 May 2002 / Received in final form 20 September 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: eaf@we.lc.ehu.es 相似文献
14.
D.I. Pushkarov 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):295-300
In this work we present a full selfconsistent set of nonlinear equations which unifies the nonlinear elasticity theory equations,
the Boltzmannn transport theory and the Maxwell equations for quasiparticles with arbitrary dispersion laws in nonstationarily
deformed crystals with arbitrary (but linear) constitutive relations. Transformations to replace the Galilean ones are obtained,
the quasiparticle mechanics in a Hamiltonian form is deduced, and a Boltzmann-type transport equation (valid in the whole
Brillouin zone) is derived. The theory may be applied to metals, semiconductors, quantum crystals, low-dimensional structures
etc.
Received 20 October 2001 Published online 2 October 2002
RID="a"
ID="a"e-mail: dipushk@issp.bas.bg 相似文献
15.
G. De Ninno D. Fanelli C. Bruni M.E. Couprie 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):269-277
The temporal dynamics of a storage-ring Free Electron Laser is here investigated with particular attention to the case in
which an external modulation is applied to the laser-electron beam detuning. The system is shown to produce bifurcations as
well as chaotic regimes. The peculiarities of this phenomenon with respect to the analogous behaviour displayed by conventional
laser sources are pointed out. Theoretical results, obtained by means of a phenomenological model reproducing the evolution
of the main statistical parameters of the system, are shown to be in a good agreement with experiments carried out on the
Super-ACO Free Electron Laser.
Received 27 March 2002 / Received in final form 17 July 2002 Published online 21 January 2003
RID="a"
ID="a"Present address: Sincrotone Trieste, 34012 Trieste, Italy.
RID="b"
ID="b"e-mail: fanelli@nada.kth.se 相似文献
16.
K.-I. Tezuka 《The European Physical Journal C - Particles and Fields》2002,25(3):465-468
We construct Poisson brackets at the boundaries of open strings and membranes with constant background fields which are compatible
with their boundary conditions. The boundary conditions are treated as primary constraints which give infinitely many secondary
constraints. We show explicitly that we need only two (the primary one and one of the secondary ones) constraints to determine
the Poisson brackets of strings. We apply this to membranes by using canonical transformations.
Received: 2 May 2002 / Revised version: 29 May 2002 / Published online: 16 August 2002
RID="a"
ID="a" e-mail: tezuka@physics.s.chiba-u.ac.jp 相似文献
17.
D. Batani F. Strati B. Telaro Th. Löwer T. Hall A. Benuzzi-Mounaix M. Koenig 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):99-107
In this paper we describe the quality requirements that a shock wave must fulfil to make equation of state (EOS) measurements
possible: planarity, no-preheating and stationarity of the shock. Experimental measurements have been performed at the Max
Planck Institut für Quantenoptik (Garching). We also present simple analytical models that allow to verify shock stationarity
and absence of preheating.
Received 17 June 2002 Published online 21 January 2003
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ID="a"e-mail: batani@mib.infn.it
RID="b"
ID="b"Present address: Pro-beam, Behrinsta?e 6, 85152 Planegg b. München, Germany.
RID="c"
ID="c"UMR 7605 相似文献
18.
In Rydberg atoms subject to static and harmonic collinear electric fields, intrashell transition can be induced by the first
order perturbation from a small perpendicular electric or magnetic field, or by effects of the second order in the major fields.
Both mechanisms lead to resonances that are suppressed under certain conditions, and high-frequency interference oscillations
in case of non-adiabatic field switching. Recent measurements of microwave ionization signals show very rich and fascinating
structures similar to the ones predicted for intrashell mixing. We show that the observed ionization structures may be explained
by diabatic electric-field ionization and the consistent use of perturbation theory for intrashell mixing. In particular,
the dominant oscillation frequency is successfully interpreted in terms of interference between first and second order transition
amplitudes. New predictions are provided. The present approach gives a comprehensive picture of intrashell transitions, which
may be tested in future experiments designed to observe such transitions directly.
Received 2 May 2002 / Received in final form 23 September 2002 Published online 21 January 2003
RID="a"
ID="a"e-mail: Valentin.Ostrovsky@pobox.spbu.ru
RID="b"
ID="b"e-mail: horsdal@ifa.au.dk 相似文献
19.
A. Sacchetti 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(2):229-232
Here we consider the dynamics of a two-level system under an external time-dependent field. We show that in the case of a
bichromatic field the dynamical localization effect is strongly sensitive with respect to the commensurability of the driving
frequencies.
Received 8 May 2002 / Received in final form 4 July 2002 Published online 24 September 2002
RID="a"
ID="a"e-mail: Sacchetti@unimo.it 相似文献
20.
A. Borah S. Ghosh S. Nandy 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):221-225
The novel inelastic collision properties of two-soliton interaction for an n-component coupled higher order nonlinear Schr?dinger equation are studied. Some interesting features of three soliton interactions,
related to the integrability of the n-component coupled higher order nonlinear Schr?dinger equation are also discussed.
Received 17 April 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: abhijit@iitg.ernet.in
RID="b"
ID="b"e-mail: sasanka@iitg.ernet.in
RID="c"
ID="c"e-mail: sudipta@iitg.ernet.in 相似文献