共查询到20条相似文献,搜索用时 31 毫秒
1.
B. Leblanc E. Lutton F. Axel 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(4):619-628
We present the first application of Genetic Algorithms to the analysis of data from an aperiodically ordered system, high
resolution X-Ray diffraction spectra from multilayer heterostructures arranged according to a deterministic or random scheme.
This method paves the way to the solution of the “inverse problem”, that is the retrieval of the generating disorder from
the investigation of the spectra of an unknown sample having non crystallographic, non quasi-crystallographic order.
Received 18 March 2002 / Received in final form 3 July 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: Evelyne.Lutton@inria.fr
RID="b"
ID="b"CNRS UMR 8502 相似文献
2.
M. Terraneo B. Georgeot D.L. Shepelyansky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):127-130
We show that dissipative classical dynamics converging to a strange attractor can be simulated on a quantum computer. Such
quantum computations allow to investigate efficiently the small scale structure of strange attractors, yielding new information
inaccessible to classical computers. This opens new possibilities for quantum simulations of various dissipative processes
in nature.
Received 10 August 2002 Published online 29 October 2002
RID="a"
ID="a"e-mail: dima@irsamc.ups-tlse.fr
RID="b"
ID="b"UMR 5626 du CNRS 相似文献
3.
R. Berthet S. Fauve R. Labbé 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(2):237-242
We present a study of sound propagation through a single vortex by direct numerical simulations (DNS) compared to experimental
measurements. We analyse the amplitude and the phase shift of the sound wave when it interacts with the vortical flow and
we display the focusing effects produced by the vortex. We show that the turbulent fluctuations have a little effect on the
sound phase shift whereas they induce a strong defocusing effect on the sound amplitude.
Received 9 October 2002 / Received in final form 20 January 2003 Published online 1st April 2003
RID="a"
ID="a"e-mail: rberthet@lps.ens.fr
RID="b"
ID="b"UMR CNRS 8550 相似文献
4.
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
5.
F. Gervais N. Petit C. Popon P. Buvat 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):47-52
The reflectivity spectrum of a polyaniline CSA-doped in presence of m-cresol has been measured over the wide wavenumber range
25-15,000 cm-1 (0.003-1.9 eV) for three different doping levels. Since spectra cannot be fitted correctly with the conventional Drude model,
several extensions are tested. A model derived from the factorized form of the dielectric response and including the effect
of Anderson localization in disordered metals, is proposed and found to yield good fit to data with a satisfactory physical
meaning. Data are reduced to a small number of parameters potentially useful for further comparison with other conducting
polymers or even other non-Drude conducting media like oxides.
Received 6 February 2002 / Received in final form 12 August 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: gervais@delphi.phys.univ-tours.fr
RID="b"
ID="b"UMR 6157 CNRS/CEA 相似文献
6.
D. Vignolles A. Audouard L. Brossard S. Pesotskii R. Lyubovskii M. Nardone E. Haanappel R. Lyubovskaya 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):53-61
Interlayer magnetoresistance and magnetisation of the quasi-two dimensional organic metal (BEDT-TTF)8Hg4Cl12(C6H5Br)2 have been investigated in pulsed magnetic fields extending up to 60 T and 33 T, respectively. About fifteen fundamental frequencies,
composed of linear combinations of only three basic frequencies, are observed in the oscillatory spectra of the magnetoresistance.
The dependencies of the oscillation amplitude on the temperature and on the magnitude and orientation of the magnetic field
are analyzed in the framework of the conventional two-dimensional Lifshitz-Kosevitch (LK) model. This model is implemented
by damping factors which accounts for the magnetic breakthrough occurring between electron and hole orbits yielding conventional
Shubnikov-de Haas closed orbits (model of Falicov and Stachowiak) and quantum interferometers. In particular, a quantum interferometer
enclosing an area equal to the first Brillouin zone area is evidenced. The LK model consistently accounts for the temperature
and magnetic field dependence of the oscillation amplitude of this interferometer. On the contrary, although this model formally
accounts for almost all of the observed oscillatory components, it fails to give consistent quantitative data in most other
cases.
Received 4 September 2002 / Received in final form 14 November 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: audouard@insa-tlse.fr
RID="b"
ID="b"UMR 5830: Unité Mixte de Recherche CNRS - Université Paul Sabatier - INSA de Toulouse
RID="c"
ID="c"UMS 5642: Unité Mixte de Service CNRS - Université Paul Sabatier - INSA de Toulouse 相似文献
7.
S. Villain-Guillot C. Josserand 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):305-309
We develop a new technique describing the non linear growth of interfaces. We apply this analytical approach to the one dimensional
Cahn-Hilliard equation. The dynamics is captured through a solvability condition performed over a particular family of quasi-static
solutions. The main result is that the dynamics along this particular class of solutions can be expressed in terms of a simple
ordinary differential equation. The density profile of the stationary regime found at the end of the non-linear growth is
also well characterized. Numerical simulations are compared in a satisfactory way with the analytical results through three
different fitting methods and asymptotic dynamics are well recovered, even far from the region where the approximations hold.
Received 16 October 2001 / Received in final form 15 March 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: josseran@lmm.jussieu.fr
RID="b"
ID="b"UMR CNRS 7607 相似文献
8.
L.F. Lemmens F. Brosens J.T. Devreese 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(2):195-202
A full analysis of domain structure using a micromagnetic model is developed in order to get a clear insight into the behaviour
of transverse initial susceptibility as a function of dc applied field for thin films and bilayers exhibiting both in-plane
and perpendicular anisotropy. The numerical simulations are in good agreement with available experimental results in case
of single layers with the so-called stripe domain pattern while some predictions are done for bilayers. As the main result,
it is shown that in low field, the transverse initial susceptible cannot be interpreted without the knowledge of the static
domain pattern while, above saturation, it is only affected by the in-plane anisotropy.
Received 10 October 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: ml@lpmtm.univ-paris13.fr
RID="b"
ID="b"UMR CNRS 8634 相似文献
9.
A. Pautrat A. Daignere C. Goupil Ch. Simon B. Andrzejewski A.I. Rykov S. Tajima 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(3):279-284
We report complex impedance measurements in an untwinned YBaCuO crystal. Our broad frequency range covers both the quasi static
response and the resistive response of the vortex lattice. It allow us to characterize the irreversibility line without the
need of any frequency dependent pinning parameters. We confirm the validity of the two modes model of vortex dynamic, and
extract both the surface critical current and the flux flow resistivity around the first order transition Tm. This latter is identified by the abrupt loss of pinning and by an unexpected step of (T) at Tm.
Received 22 November 2002 / Received in final form 17 February 2003 Published online 20 June 2003
RID="a"
ID="a"e-mail: alain.pautrat@ismra.fr
RID="b"
ID="b"UMR 6508 associée au CNRS 相似文献
10.
M.A. Gaveau M. Briant P.R. Fournier J.M. Mestdagh J.P. Visticot F. Calvo S. Baudrand F. Spiegelman 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(2):153-161
Spectroscopic experiments have been performed, providing emission and excitation spectra of calcium atoms trapped on argon
clusters of average size 2 000. The two experimental spectra fall in the vicinity of the calcium resonance line 1P 1 → 1S0 at 422.9 nm. The excitation spectrum consists in two bands located on each side of the resonance line of the free calcium.
In addition, Monte Carlo calculations, coupled to Diatomics-In-Molecule potentials are employed to simulate the absorption
spectrum of a single calcium atom in the environment of a large argon cluster of average size 300. The theoretical absorption
spectrum confirms the existence of two bands, and shows that these bands are characteristic of a calcium atom located at the
surface of the argon cluster and correspond to the excited 4p orbital of calcium either perpendicular or parallel to the cluster surface. The precise comparison between the shape of the
absorption spectrum and that of the fluorescence excitation spectrum shows different intensity ratios. This could suggest
the existence of a non adiabatic energy transfer that quenches partly the fluorescence of trapped calcium. Another explanation,
although less likely, could be a substantial dependence of the calcium oscillator strength according to the alignment of the
calcium excited orbital with respect to the cluster surface. The emission spectrum always shows a band in the red of the resonance
line which is assigned to the emission of calcium remaining trapped on the cluster. When exciting the blue band of the excitation
spectrum, the emission spectrum shows a second, weak, component that is assigned to calcium atoms ejected from the argon clusters,
indicating a competition between ejection and solvation.
Received 7 May 2002 Published online 1st October 2002
RID="a"
ID="a"e-mail: jmm@drecam.saclay.cea.fr
RID="b"
ID="b"URA 2453 du CNRS
RID="c"
ID="c"UMR 5626 du CNRS 相似文献
11.
B. Macke B. Ségard 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):125-141
This paper deals with the apparent superluminal propagation of electromagnetic pulses in a linear dispersive medium. One specifically
examines the possibility that the pulse leaving the medium may be nearly identical to the incident one (low distortion) and
in significant advance of it (strongly negative group-delays). Favourable conditions are obtained in a dilute medium where
the required anomalous dispersion originates in an ensemble of narrow absorption or gain lines. Analytical expressions of
the advancement of the pulse centre-of-gravity and of the lowest order distortion are established from the transfer-function
of the medium. The experiments already achieved with arrangements involving a single absorption-line or a gain-doublet are
analysed in detail and compared. The considerable difficulties to overcome in order to attain advancements comparable to the
pulse width without important distortion are pointed out. New and promising schemes involving a narrow dip in a gain profile
or absorption-doublets are proposed.
Received 4 July 2002 / Received in final form 8 November 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: bruno.macke@univ-lille1.fr
RID="b"
ID="b"Unité Mixte de Recherche de l'Université et du CNRS (UMR 8523) 相似文献
12.
S. Kazamias F. Weihe D. Douillet C. Valentin T. Planchon S. Sebban G. Grillon F. Augé D. Hulin Ph. Balcou 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):353-359
We report a systematic study of high order harmonic generation with an infrared laser apertured by an iris, as a function
of the aperture size. Measurements were made of harmonic generation efficiency for different gas species, laser energies and
focal geometries. Harmonic efficiencies as a function of aperture show a characteristic peaked shape, which is independent
of gas species and harmonic order. A one dimensional, time dependent simulation of harmonic generation in a gas cell, taking
into account experimentally measured transverse coherence of the laser, closely reproduces the observed behaviours. We show
that the aperture diameter which maximizes harmonic yield is the result of a compromise between considerations of focal geometry
and ionization (which favour small apertures); and harmonic dipole amplitude and phase (which favour large apertures).
Received 31 May 2002 Published online 24 September 2002
RID="a"
ID="a"e-mail: kazamias@ensta.fr
RID="b"
ID="b"UMR 7639 du CNRS 相似文献
13.
P. Berthault H. Desvaux 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):65-73
NMR of laser-polarized xenon is used to probe the dissolution behaviour of the noble gas in different liquids. The dissolution
and self-relaxation rates are extracted via a macroscopic model, and comparison of the decay rate of the xenon magnetization in deuterated and non-deuterated solvent
pairs allows the determination of the pure dipole-dipole contribution to relaxation. A transient convective effect, tentatively
assigned to the xenon concentration gradient, is observed and characterized by diffusion encoding MRI experiments. The flow
of xenon penetrates inside the solvent near the walls of the NMR tube, the longitudinal images showing a “” shape, the transverse ones a “O” shape. This convection effect has implications for delivery conditions of laser-polarized
xenon in continuous flow experiments and magnetic resonance imaging.
Received 29 April 2002 / Received in final form 26 July 2002 Published online 22 October 2002
RID="a"
ID="a"e-mail: hdesvaux@cea.fr
RID="b"
ID="b"URA CNRS/CEA 331 相似文献
14.
R. Fiore A. Flachi L.L. Jenkovszky A.I. Lengyel V.K. Magas 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):505-515
An explicit model realizing parton-hadron duality and fitting the data is suggested. Complex nonlinear Regge trajectories
are important ingredients of the model. The inclusion of Δ and N* trajectories should account for all resonances in the direct channel. The exotic trajectory is responsible for the smooth
background.
Received: 7 June 2002 / Accepted: 3 July 2002 / Published online: 10 December 2002
RID="a"
ID="a"e-mail: fiore@cs.infn.it
RID="b"
ID="b"e-mail: flachi@ifae.es
RID="c"
ID="c"e-mail: jenk@gluk.org
RID="d"
ID="d"e-mail: sasha@len.uzhgorod.ua
RID="e"
ID="e"e-mail: vladimir@cfif.ist.utl.pt
Communicated by V.V. Anisovich 相似文献
15.
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
RID="a"
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
16.
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
17.
B. Viaris de Lesegno J.C. Karam M. Boustimi F. Perales C. Mainos J. Reinhardt J. Baudon V. Bocvarski D. Grancharova F. Pereira Dos Santos T. Durt H. Haberland J. Robert 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):25-34
A new Stern Gerlach interferometer operating with a nozzle beam of metastable argon atoms Ar* (3p5 4s, 3
P
2) is described. The selection of incoming (polarisation) and outgoing (analysis) Zeeman sublevels is achieved by use of laser
induced transitions at two wavelengths, 811.5 nm (closed J = 2 → J = 3 transition) and 801.5 nm (open J = 2 → J = 2 transition). Linear superpositions of Zeeman sublevels, just beyond the polariser and just before the analyser, are prepared
by means of two zones where Majorana transitions take place. In between, a controlled magnetic field configuration (the phase
object) is produced within a triple μ-metal shielding. Standard interference patterns are obtained by scanning the field and
detecting the atoms by secondary electron emission from a Faraday cup. When a static radial magnetic gradient is used, the
beam profile is modulated by interference. The transverse pattern, which can be translated at will by adding a homogeneous
field, is observed for the first time using a multi-channel electron multiplier followed by a phosphor screen and a CCD camera.
The results satisfactorily agree with all theoretical predictions.
Received 27 June 2002 / Received in final form 20 September 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: perales@lpl.univ-paris13.fr
RID="b"
ID="b"UMR 7538 du CNRS 相似文献
18.
D. Bucurescu A. Gadea Ghe. Căta-Danil I. Căta-Danil M. Ivaşcu N. Mărginean C. Rusu L. Stroe C.A. Ur 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):469-474
High-spin states in the 97Tc nucleus have been studied by in-beam γ-ray spectroscopy with the reaction 82Se(19F,4nγ) at 68 MeV incident energy. Excited states have been observed up to about 8 MeV excitation and spin 43/2. The observed
level scheme is compared with results of shell model calculations.
Received: 22 November 2002 / Accepted: 23 December 2002 / Published online: 18 March 2003
RID="a"
ID="a"e-mail: bucurescu@tandem.nipne.ro
RID="b"
ID="b"Present address: INFN, Laboratori Nazionali di Legnaro, Legnaro, Italy.
RID="b"
ID="b"Present address: INFN, Laboratori Nazionali di Legnaro, Legnaro, Italy.
RID="b"
ID="b"Present address: INFN, Laboratori Nazionali di Legnaro, Legnaro, Italy.
RID="c"
ID="c"Present address: Università di Padova, Padova, Italy.
Communicated by C. Signorini 相似文献
19.
D. Vrel S. Dubois E.M. Heian N. Karnatak M.-F. Beaufort 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(1):31-39
A simple method to calculate thermal diffusivity in situ after a combustion synthesis reaction is presented. The combustion reaction was analyzed via time-resolved X-ray diffraction analysis and infrared thermography. Thermal diffusivity was estimated and used to calculate
temperature profiles based on temperature profiles one second earlier. For a sample of TiC formed from Ti and C, a value of
2.00×10-6±0.20×10-6 m2 s-1 was calculated for temperatures between 1000 and 1900 K. This method is rapid and can avoid some problems associated with
furnace-based measurements of thermal diffusivity, such as recrystallization and destruction of non-equilibrium phases.
Received 29 November 2002 / Received in final form 19 March 2003 Published online 23 May 2003
RID="a"
ID="a"e-mail: vrel@limhp.univ-paris13.fr
RID="b"
ID="b"UPR 1311
RID="c"
ID="c"UMR 6630 相似文献
20.
L. Raymond J.-M. Laugier S. Schäfer G. Albinet 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(3):355-364
Binary disordered systems are usually obtained by mixing two ingredients in variable proportions: conductor and insulator,
or conductor and super-conductor. They present very specific properties, in particular the second-order percolation phase
transition, with its fractal geometry and the multi-fractal properties of the current moments. These systems are naturally
modeled by regular bi-dimensional or tri-dimensional lattices, on which sites or bonds are chosen randomly with given probabilities.
The two significant parameters are the ratio h = σ
1/σ of the complex conductances, σ and σ
1, of the two components, and their relative abundances p (or, respectively, 1 - p). In this article, we calculate the impedance of the composite by two independent methods: the so-called spectral method,
which diagonalises Kirchhoff's Laws via a Green function formalism, and the Exact Numerical Renormalization method (ENR). These methods are applied to mixtures of
resistors and capacitors (R-C systems), simulating e.g. ionic conductor-insulator systems, and to composites constituted of resistive inductances and capacitors (LR-C systems),
representing metal inclusions in a dielectric bulk. The frequency dependent impedances of the latter composites present very
intricate structures in the vicinity of the percolation threshold. In this paper, we analyse the LR-C behavior of compounds
formed by the inclusion of small conducting clusters (“n-legged animals”) in a dielectric medium. We investigate in particular their absorption spectra who present a pattern of sharp
lines at very specific frequencies of the incident electromagnetic field, the goal being to identify the signature of each
animal. This enables us to make suggestions of how to build compounds with specific absorption or transmission properties
in a given frequency domain.
Received 16 August 2002 Published online 14 February 2003
RID="a"
ID="a"e-mail: laurent.raymond@l2mp.fr
RID="b"
ID="b"e-mail: steffen.schaefer@l2mp.fr
RID="c"
ID="c"UMR CNRS 6137 相似文献