共查询到20条相似文献,搜索用时 531 毫秒
1.
Ch. Lisdat N. Vanhaecke D. Comparat P. Pillet 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):299-309
Two-photon photoassociation spectra in a Λ-type excitation scheme are analysed under the systematically varied experimental conditions of frequency detunings and laser
intensities. Line shape fits are presented as well as the investigation of intensity and detuning dependent line shifts. From
both we determine the attained spectroscopic precision, that is corrected for a systematic line shift due to the thermal distribution
of atoms in the trap. An energy correction for this effect is given. Information about the feasibility of generating translationally
cold molecules in a well defined rotational and vibrational level by the photoassociation process is derived from the analysis.
Received 21 May 2002 Published online 15 October 2002
RID="a"
ID="a"Current address e-mail: christian.lisdat@ptb.de
RID="b"
ID="b"e-mail: pierre.pillet@lac.u-psud.fr 相似文献
2.
R. Jung S. Gerlach R. Schumann G. von Oppen U. Eichmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):415-419
We report on the first successful loading of a magneto-optical trap (MOT) with metastable He atoms from a Stark-slower. Thereby,
deceleration of the atoms relies on laser-atom interaction in an inhomogeneous electric field. We show that the results obtained
are comparable with early results from other groups achieved with a Zeeman slower. The Stark slower, which is able to fully
control the final velocity of the atomic He beam, is the first step in achieving complete spin independent kinematic control
based solely on electric fields.
Received 2 October 2002 / Received in final form 20 January 2003 Published online 29 April 2003
RID="a"
ID="a"e-mail: eichmann@mbi-berlin.de 相似文献
3.
G. Modugno G. Roati M. Inguscio M.S. Santos G.D. Telles L.G. Marcassa V.S. Bagnato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):409-413
We report a comparative investigation of trap loss rates in a magneto-optical trap for two potassium isotopes, 39K and 40K, as a function of trap light intensity. The isotopes present a quite similar behavior for the loss rates at high intensities,
and a sudden increase of the loss rates at low intensities is present in both cases. While for 39K such increase can be explained assuming that the major contribution to the losses comes from hyperfine changing collisions,
a different loss mechanism must be considered for 40K, which has an inverted ground state hyperfine structure. The experimental results of both isotopes are well reproduced by
an alternative model based on radiative escape as the dominant loss mechanism.
Received 1st May 2002 / Received in final form 19 October 2002 Published online 4 March 2003
RID="a"
ID="a"Alternative address: Dipartimento di Fisica, Universitá di Trento, 38050 Povo (Tn), Italy.
RID="b"
ID="b"e-mail: marcassa@if.sc.usp.br 相似文献
4.
5.
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
6.
I. Lubashevsky P. Wagner R. Mahnke 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(2):243-247
This paper introduces a car following model where the driving scheme takes into account the deficiencies of human decision
making in a general way. Additionally, it improves certain shortcomings of most of the models currently in use: it is stochastic
but has a continuous acceleration. This is achieved at the cost of formulating the model in terms of the time derivative of
the acceleration, making it non-Newtonian. However, the recipe for construction of bounded rational driver models proposed
in this paper seems to be very general and can be applied to most, if not all of the traditional car-following models.
Received 18 November 2002 / Received in final form 6 February 2003 Published online 1st April 2003
RID="a"
ID="a"e-mail: ialub@fpl.gpi.ru
RID="b"
ID="b"e-mail: peter.wagner@dlr.de
RID="c"
ID="c"e-mail: reinhard.mahnke@physik.uni-rostock.de 相似文献
7.
Z.P. Karkuszewski K. Sacha A. Smerzi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):251-254
We study a Bose-Einstein condensate trapped in an asymmetric double well potential. Solutions of the time-independent Gross-Pitaevskii
equation reveal intrinsic loops in the energy (or chemical potential) level behavior when the shape of the potential is varied.
We investigate the corresponding behavior of the quantum (many-body) energy levels. Applying the two-mode approximation to
the bosonic field operators, we show that the quantum energy levels create an anti-crossing net inside the region bounded
by the loop of the mean field solution.
Received 6 March 2002 / Received in final form 19 September 2002 Published online 15 November 2002
RID="a"
ID="a"e-mail: smerzi@cnls.lanl.gov 相似文献
8.
B. Eckhardt R. Pandit 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(3):373-378
We consider the effects of a shear on velocity fluctuations in a flow. The shear gives rise to a transient amplification that
not only influences the amplitude of perturbations but also their time correlations. We show that, in the presence of white
noise, time correlations of transversal velocity components are exponential and that correlations of the longitudinal components
are exponential with an algebraic prefactor. Cross correlations between transversal and downstream components are strongly
asymmetric and provide a clear indication of non-normal amplification. We suggest experimental tests of our predictions.
Received 26 February 2002 / Received in final form 11 March 2003 Published online 20 June 2003
RID="a"
ID="a"e-mail: bruno.eckhardt@physik.uni-marburg.de
RID="b"
ID="b"Also at: Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India 相似文献
9.
10.
R. Neugart 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):35-39
Lasers have played an important role for the development of new spectroscopy techniques yielding spins, electromagnetic moments
and charge radii of many unstable nuclei. More recently, similar techniques have been introduced to manipulate atoms and thus
to prepare beams or samples of radioactive atoms for various applications including nuclear spectroscopy and decay studies.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: rainer.neugart@uni-mainz.de 相似文献
11.
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
12.
M. Kajita 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):337-342
Cold collisions between electrostatically trapped linear polar molecules are theoretically investigated. It is consequently
shown that the inelestic collision cross-section is determined by S-wave scattering alone, while the contribution of D-wave
scattering to the elastic collision cross-section becomes significant when the electric field strength is high. It is also
shown that as the temperature decreases, it becomes difficult to obtain the evaporative cooling effect without collision loss.
Received 12 September 2002 / Received in final form 21 November 2002 Published online 29 April 2003
RID="a"
ID="a"e-mail: kajita@crl.go.jp 相似文献
13.
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
14.
D.A. Trifonov 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):349-353
A survey on the generalizations of Heisenberg uncertainty relation and a general scheme for their entangled extensions to
several states and observables is presented. The scheme is illustrated on the examples of one and two states and canonical
quantum observables, and spin and quasi-spin components. Several new uncertainty relations are displayed.
Received 10 October 2001 / Received in final form 6 March 2002 Published online 2 October 2002
RID="a"
ID="a"e-mail: dtrif@inrne.bas.bg 相似文献
15.
M. Lontano D. Ryutov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):347-351
We demonstrate the in situ detection of cold 87Rb atoms near a dielectric surface using the absorption of a weak, resonant evanescent wave. We have used this technique in
time of flight experiments determining the density of atoms falling on the surface. A quantitative understanding of the measured
curve was obtained using a detailed calculation of the evanescent intensity distribution. We have also used it to detect atoms
trapped near the surface in a standing-wave optical dipole potential. This trap was loaded by inelastic bouncing on a strong,
repulsive evanescent potential. We estimate that we trap 1.5×104 atoms at a density 100 times higher than the falling atoms.
Received 14 May 2002 Published online 8 October 2002
RID="a"
ID="a"e-mail: spreeuw@science.uva.nl 相似文献
16.
Entrance channel potentials in nucleus-nucleus collisions, relevant for the synthesis of superheavy elements, are systematically
studied within a semi-microscopic approach, where microscopic nuclear densities of the colliding spherical or deformed nuclei
are used in semi-classical expressions of the energy-density functional. From experimental data on fusion windows evidence
is found that the existence of pockets in the entrance channel potentials is crucial for fusion. Criteria for the choice of
the best collision systems for the synthesis of superheavy elements are discussed.
Received: 14 May 2002 / Accepted: 6 June 2002 / Published online: 26 November 2002
RID="a"
ID="a"e-mail: v.denisov@gsi.de, denisov@kinr.kiev.ua
RID="b"
ID="b"e-mail: w.nrnbrg@gsi.de
Communicated by P. Schuck 相似文献
17.
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
18.
J. Gemmer G. Mahler 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(2):249-257
For a closed bi-partite quantum system partitioned into system proper and environment we interpret the microcanonical and
the canonical condition as constraints for the interaction between those two subsystems. In both cases the possible pure-state
trajectories are confined to certain regions in Hilbert space. We show that in a properly defined thermodynamical limit almost
all states within those accessible regions represent states of some maximum local entropy. For the microcanonical condition
this dominant state still depends on the initial state; for the canonical condition it coincides with that defined by Jaynes'
principle. It is these states which thermodynamical systems should generically evolve into.
Received 13 June 2002 / Received in final form 14 November 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: jochen@theol.physik.uni-stuttgart.de 相似文献
19.
A.V. Volotka V.M. Shabaev G. Plunien G. Soff 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):51-56
The finite nuclear size effect on the hyperfine splitting of low-Z hydrogen-like atoms is studied in the external field approximation. A simple non-relativistic formula is proposed which expresses
the nuclear size correction to the hyperfine splitting in terms of moments of the nuclear charge and magnetization distribution.
The numerical results obtained via this formula are compared with corresponding results derived by means of the Zemach formula. A relativistic formula for the
nuclear size correction to the hyperfine splitting is also derived.
Received 18 March 2002 / Received in final form 14 November 2002 Published online 28 January 2003
RID="a"
ID="a"e-mail: plunien@physik.tu-dresden.de 相似文献
20.
T. Briant P.F. Cohadon M. Pinard A. Heidmann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):131-140
We describe an experiment in which the quadratures of the position of an harmonically-bound mirror are observed at the attometer
level. We have studied the Brownian motion of the mirror, both in the free regime and in the cold-damped regime when an external
viscous force is applied by radiation pressure. We have also studied the thermal-noise squeezing when the external force is
parametrically modulated. We have observed both the % theoretical limit of squeezing at low gain and the parametric oscillation
of the mirror for a large gain.
Received 9 July 2002 Published online 29 October 2002
RID="a"
ID="a"e-mail: heidmann@spectro.jussieu.fr
RID="b"
ID="b"Unité mixte de recherche du Centre National de la Recherche Scientifique, de l'école Normale Supérieure et de l'Université
Pierre et Marie Curie. Website: www.spectro.jussieu.fr/Mesure 相似文献