共查询到20条相似文献,搜索用时 15 毫秒
1.
E. Abad J. Ortega Y. J. Dappe F. Flores 《Applied Physics A: Materials Science & Processing》2009,95(1):119-124
A local orbital DFT-approach combined with a “scissor”-operator is used to obtain the Charge Neutrality Level and the screening
parameter in the benzene/Au(111) and C60/Au(111) interfaces. The “pillow” dipole and interface Fermi level are also calculated. The total dipole induced across the
interface is compared with the experimental evidences: while the agreement for C60/Au(111) is excellent, for benzene/Au(111), some discrepancies appear that are discussed in the light of other models. 相似文献
2.
Julien Dubédat 《Journal of statistical physics》2006,123(6):1183-1218
Schramm-Loewner Evolutions (SLEs) have proved an efficient way to describe a single continuous random conformally invariant interface in a simply-connected planar domain; the admissible probability distributions are parameterized by a single positive parameter κ. As shown in, Ref. 8 the coexistence of n interfaces in such a domain implies algebraic (“commutation”) conditions. In the most interesting situations, the admissible laws on systems of n interfaces are parameterized by κ and the solution of a particular (finite rank) holonomic system.The study of solutions of differential systems, in particular their global behaviour, often involves the use of integral representations. In the present article, we provide Euler integral representations for solutions of holonomic systems arising from SLE commutation. Applications to critical percolation (general crossing formulae), Loop-Erased Random Walks (direct derivation of Fomin’s formulae in the scaling limit), and Uniform Spanning Trees are discussed. The connection with conformal restriction and Poissonized non-intersection for chordal SLEs is also studied. 相似文献
3.
R. E. Kastner 《Foundations of Physics》2009,39(10):1139-1144
A modified version of Young’s experiment by Shahriar Afshar indirectly reveals the presence of a fully articulated interference
pattern prior to the post-selection of a particle in a “which-slit” basis. While this experiment does not constitute a violation
of Bohr’s Complementarity Principle as claimed by Afshar, both he and many of his critics incorrectly assume that a commonly
used relationship between visibility parameter V and “which-way” parameter K has crucial relevance to his experiment. It is argued here that this relationship does not apply to this experimental situation
and that it is wrong to make any use of it in support of claims for or against the bearing of this experiment on Complementarity. 相似文献
4.
D. I. Dimitrov L. I. Klushin A. Skvortsov A. Milchev K. Binder 《The European physical journal. E, Soft matter》2009,29(1):9-25
A flexible polymer chain under good solvent conditions, end-grafted on a flat repulsive substrate surface and compressed by
a piston of circular cross-section with radius L may undergo the so-called “escape transition” when the height of the piston D above the substrate and the chain length N are in a suitable range. In this transition, the chain conformation changes from a quasi-two-dimensional self-avoiding walk
of “blobs” of diameter D to an inhomogeneous “flower” state, consisting of a “stem” (stretched string of blobs extending from the grafting site to
the piston border) and a “crown” outside of the confining piston. The theory of this transition is developed using a Landau
free-energy approach, based on a suitably defined (global) order parameter and taking also effects due to the finite chain
length N into account. The parameters of the theory are determined in terms of known properties of limiting cases (unconfined mushroom,
chain confined between infinite parallel walls). Due to the non-existence of a local order parameter density, the transition
has very unconventional properties (negative compressibility in equilibrium, non-equivalence between statistical ensembles
in the thermodynamic limit, etc.). The reasons for this very unusual behavior are discussed in detail. Using Molecular Dynamics
(MD) simulation for a simple bead-spring model, with N in the range 50
N
300 , a comprehensive study of both static and dynamic properties of the polymer chain was performed. Even though for the
considered rather short chains the escape transition is still strongly rounded, the order parameter distribution does reveal
the emerging transition clearly. Time autocorrelation functions of the order parameter and first passage times and their distribution
indicate clearly the strong slowing down associated with the chain escape. The theory developed here is in good agreement
with all these simulation results. 相似文献
5.
Antonino Marciano 《Czechoslovak Journal of Physics》2005,55(11):1479-1485
I summarize results recently obtained in collaboration with Amelino-Camelia, Bruno and Mandanici (preprint University of Rome
“La Sapienza”, August, 2005) that concern an analysis of the path of a massless particle in a q-de Sitter space-time and an approximation scheme suitable for the corresponding analysis in a quantum FRW Universe. On the
basis of some arguments in the quantum-gravity literature, the q deformation parameter is assumed to depend on both the Planck scale and the curvature, leading to results that are significantly
different from those of other studies of Planck-scale effects in cosmology, where the possibility of an interplay between
curvature and Planck scale was ignored.
Presented at the International Colloquium “Integrable Systems and Quantum Symmetries”, Prague, 16–18 June 2005. 相似文献
6.
H. L. Kwok 《Applied physics. B, Lasers and optics》2009,94(2):279-282
Organic field-effect transistors (OFETs) have received significant attention recently because of the potential application
in low-cost flexible electronics. The physics behind their operation are relatively complex and require careful consideration
particularly with respect to the effect of charge trapping at the insulator–semiconductor interface and field effect in a
region with a thickness of a few molecular layers. Recent studies have shown that the so-called “onset” voltage (V
onset) in the rubrene OFET can vary significantly depending on past illumination and bias history. It is therefore important to
define the role of the interface trap states in more concrete terms and show how they may affect device performance. In this
work, we propose an equivalent-circuit model for the OFET to include mechanism(s) linked to trapping. This includes the existence
of a light-sensitive “resistor” controlling charge flow into/out of the interface trap states. Based on the proposed equivalent-circuit
model, an analytical expression of V
onset is derived showing how it can depend on gate bias and illumination. Using data from the literature, we analyzed the I–V characteristics of a rubrene OFET after pulsed illumination and a tetracene OFET during steady-state illumination. 相似文献
7.
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9.
Bickel T 《The European physical journal. E, Soft matter》2006,20(4):379-385
The dynamics of a tracer molecule near a fluid membrane is investigated, with particular emphasis given to the interplay between
the instantaneous position of the particle and membrane fluctuations. It is found that hydrodynamic interactions creates memory
effects in the diffusion process. The random motion of the particle is then shown to cross over from a “bulk” to a “surface”
diffusive mode, in a way that crucially depends on the elastic properties of the interface. 相似文献
10.
As quantum information science approaches the goal of constructing quantum computers, understanding loss of information through
decoherence becomes increasingly important. The information about a system that can be obtained from its environment can facilitate
quantum control and error correction. Moreover, observers gain most of their information indirectly, by monitoring (primarily
photon) environments of the “objects of interest.” Exactly how this information is inscribed in the environment is essential
for the emergence of “the classical” from the quantum substrate. In this paper, we examine how many-qubit (or many-spin) environments
can store information about a single system. The information lost to the environment can be stored redundantly, or it can
be encoded in entangled modes of the environment. We go on to show that randomly chosen states of the environment almost always
encode the information so that an observer must capture a majority of the environment to deduce the system’s state. Conversely,
in the states produced by a typical decoherence process, information about a particular observable of the system is stored
redundantly. This selective proliferation of “the fittest information” (known as Quantum Darwinism) plays a key role in choosing
the preferred, effectively classical observables of macroscopic systems. The developing appreciation that the environment
functions not just as a garbage dump, but as a communication channel, is extending our understanding of the environment’s
role in the quantum-classical transition beyond the traditional paradigm of decoherence. 相似文献
11.
A. N. Vall I. A. Perevalova O. N. Soldatenko A. A. Vladimirov 《Physics of Particles and Nuclei》2009,40(7):1030-1058
The group-theoretical generalization of the impact parameter for elastic A + B → A + B processes is considered and analyzed in the work. The generalized impact parameter is identified with the vector of the closest
approach of two particles. It is shown that after the procedure of standard quantization the components of the impact parameter’s
vector, together with the components of the relative orbital’s angular momentum form SO(3.1) algebra from which we identify the SO(2.1) subalgebra. The spectrum of the Casimir operator for this subalgebra defines the allowed values of the impact parameter
squared. The expansion coefficients of the elastic amplitude as a function on the SO(2.1) group define the profile function; an analogue of the partial wave on the O(3) group. The expansion itself is the generalization of the eikonal representation of the amplitude and is valid in the entire
range of scattering angles. It also correctly describes the region of small impact parameters. The unitarity equation for
the amplitude is solved and, as a consequence, the algebraic equation for the profile function, local in the impact parameter,
is obtained. The simplest phenomenological models for cross sections (total, elastic, and inelastic) are analyzed in the framework
of the solutions obtained. The next step in the development of the group-theoretical approach proposed in the work is associated
with construction of a complete orthonormal basis in the one-particle Fock space where the particle is characterized by a
particular energy and a particular value of its “impact parameter” relative to a point “O”. This point is related to the target
particle’s coordinate (in the laboratory reference frame) or the beam’s collision point (center-of-mass system). This formalism
allows for obtaining the relation between the escape parameter’s distribution function of particle C in the A + B → C + D process and the corresponding production amplitude of this particle in an angular interval. The resulting distribution function
provides important physical information on the spatial structure of the production region of particle C. 相似文献
12.
We study the dynamics of strongly dissipative Hénon-like maps, around the first bifurcation parameter a* at which the uniform hyperbolicity is destroyed by the formation of tangencies inside the limit set. We prove that a* is a full Lebesgue density point of the set of parameters for which Lebesgue almost every initial point diverges to infinity
under positive iteration. A key ingredient is that a* corresponds to the “non-recurrence of every critical point”, reminiscent of Misiurewicz parameters in one-dimensional dynamics.
Adapting on the one hand Benedicks & Carleson’s parameter exclusion argument, we construct a set of “good parameters” having
a* as a full density point. Adapting Benedicks & Viana’s volume control argument on the other, we analyze Lebesgue typical
dynamics corresponding to these good parameters. 相似文献
13.
We discuss the possibility of making the initial definitions of mutually different (possibly interacting, or even entangled) systems in the context of decoherence theory. We point out relativity of the concept of elementary physical system as well as point out complementarity of the different possible divisions of a composite system into “subsystems,” thus eventually sharpening the issue of “what is system.” 相似文献
14.
B. Lamine M.-T. Jaekel S. Reynaud 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(2):165-176
We study the decoherence of atomic interferometers due to the scattering of stochastic gravitational waves. We evaluate the
“direct” gravitational effect registered by the phase of the matter waves as well as the “indirect” effect registered by the
light waves used as beam-splitters and mirrors for the matter waves. Considering as an example the space project HYPER, we
show that both effects are negligible for the presently studied interferometers.
Received 15 February 2002 / Received in final form 12 April 2002 Published online 19 July 2002 相似文献
15.
M. Raşa D. Bica A. Philipse L. Vékás 《The European physical journal. E, Soft matter》2002,7(3):209-220
The aim of the paper is to study the deviation of magnetic properties of the magnetic fluids prepared for this study, from
ideal (Langevin) behaviour, i.e. to estimate particle interaction influence and dimensions and influence of particle aggregates, as well as to explain the
related effects observed. We also determine the particle coupling parameter, the particle nonmagnetic layer thickness, and
the particle distribution, which are fundamental for sample characterization. A comparison of the studied magnetic fluids
with each other, with respect to microstructure formation and particle interaction strength is finally done. For these purposes,
a concentration dependence study, following the proposed “dilution series approach”, is performed. Three series of dilutions
of three types of magnetic fluids were prepared and analyzed.
Received 27 August 2001 相似文献
16.
Wolfgang Häusler 《Zeitschrift für Physik B Condensed Matter》1995,99(1):551-560
The lowest excitations of a repulsively interacting few particle system are investigated within correlated “pocket state”
basis functions. For long range interaction and non-isotropic confining potentials the method becomes exact, in the limit
of large mean inter-particle distancesr
s. The multiplet structure of the many-electron energy levels is explained and the ratios δ between the lowest excitation energies,
which are related to the electron spin, are determined quantitatively using group theoretical means. The δ are independent
of the detailed form of the inter-particle repulsion and of sufficiently larger
s. The obtained δ-values are confirmed by available numerical data. The method is applied to 1D and 2D quantum dots. 相似文献
17.
Themodel of degenerate weakly nonideal Bose gas is considered without the assumption on the C-number nature of creation and annihilation operators of particles in the zero-momentum state. It was shown that the “density-density”
Green’s function pole defines the Bogolyubov spectrum of phonon-roton-type collective excitations. The single-particle excitation
spectrum is characterized by the gap whose value is defined by the particle density in the “condensate”. 相似文献
18.
Sun Guoya Xing D.Y. Shen R. Lin H.Q. 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(1):33-38
The Nambu spinor Green's function approach is applied to calculating the density of states (DOS) and superconducting order
parameter in normal-metal/insulator/ferromagnet/superconductor (NM/I/FM/SC) junctions. It is found that the s-wave superconductivity and ferromagnetism can coexist near the FM/SC interface, which is induced by proximity effect. On
the SC side, the spin-dependent DOS appears both within and without the energy gap. On the FM side, the superconducting order
parameter displays a damped oscillation and the DOS exhibits some superconducting behavior. The calculated result for the
DOS in FM for “0 state” and “π state” can reproduce recent tunneling spectra in Al/Al2O3/PdNi/Nb tunnel junctions.
Received 1st July 2002 Published online 19 November 2002 相似文献
19.
R. I. Bogdanov M. P. Bogdanov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(2):269-275
New calculated data on estimation of the density of particle fluxes are presented. These particles move freely in a surrounding
medium during the constant transit time and are then rescattered under the potential force field weakly perturbed by generalized
viscosity forces. An anharmonic potential on a phase straight line is taken as a potential, and the generalized viscosity
force corresponds to a small viscosity coefficient affinely dependent on the phase coordinate. The word “small’ here means
that the order of the generalized viscosity forces is less than two. The particle fluxes correspond to the periodic motion
of particles, asymptotically stable (unstable) states (“in” and “out” states) as t → (−) + ∞ that have basins of attraction (repulsion) with a positive measure. 相似文献
20.
The flow pattern around a thin strip horizontally towed at constant velocity in a continuously stratified liquid is visualized
by conventional “Vertical slit-Foucault’s knife”, “Maksoutov’s slit-thread” and “horizontal slit-regular grating” methods.
Using these sensitive high-resolution methods enables to reveal new kind of the streaky structure including a sequence of
thin sloping interfaces both on the strip surface and inside its wake. When velocity or distance from the strip increases,
the streaks may be turned into the sloping or nearly horizontal interfaces. Reconnections of outer edges of the streaks result
in appearance of a set of symmetrical “butterfly-like” vortices, which are perturbed by a shear flow inside the downstream
wake. Lift forces caused by a slope of the strip produce an asymmetry of the wake and lead to fast degeneration ofthe streaky
structures. 相似文献