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1.
K. Christensen N. Farid G. Pruessner M. Stapleton 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,62(3):331-336
We derive general properties of the finite-size scaling of
probability density functions and show that when the apparent
exponent
of a probability density is less than 1, the
associated finite-size scaling ansatz has a scaling exponent τ
equal to 1, provided that the fraction of events in the universal
scaling part of the probability density function is non-vanishing in
the thermodynamic limit.
We find the general result that τ≥1 and
.
Moreover, we show that if the scaling function
approaches a
non-zero constant for small arguments,
, then
.
However, if the scaling function vanishes for small arguments,
, then τ= 1, again assuming a
non-vanishing fraction of universal events.
Finally, we apply the formalism developed to examples from the literature,
including some where misunderstandings of the theory of scaling have led to erroneous conclusions. 相似文献
2.
B. Bonello P. Doussineau V. Dupuis A. Levelut 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(2):219-225
The isothermal aging of the asymmetry induced in the
disordered dielectric crystal
(x=0.027) submitted to the biasing electric field
E, is investigated. To this end, the response of the
complex dielectric constant to infinitesimal field changes
, applied to the sample after a variable aging delay, has been measured
for different magnitudes of E and after different aging delays. Two different
experimental procedures have been used: in both cases the response strongly
depends on the time spent under field. For short aging delays, the response
has a strong contribution proportional to δE and a weak quadratic
contribution proportional to
. As time elapses,
the linear and the quadratic contributions age in opposite ways: the former
decreases whereas the latter increases. This paradoxical behaviour is
analyzed in the framework of a model which attributes aging and the related
effects (rejuvenation, memory) to the evolution of polarization domain
walls: the decrease of the linear contribution is related to the decrease of
the total wall area, while the increase of the quadratic term is attributed
to wall reconformations. 相似文献
3.
D. Bensimon R. Zeyher 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,59(2):141-150
Phase fluctuations of a d-wave superconducting order parameter are
theoretically studied in the context of high-Tc cuprates. We consider
an extended t-J model describing electrons in a layer which also contains
long-range Coulomb interactions. The constraint of having at most singly
occupied sites is enforced by an additional Hubbard term. The Heisenberg interaction is decoupled by a d-wave order parameter
in the particle-particle channel. Assuming first that the equilibrium state has long-range phase order, the effective action
is derived perturbatively for small fluctuations within a path integral formalism, in the presence of the
Coulomb and Hubbard interaction terms. In a second step, a more general
derivation of
is performed in terms of a gradient
expansion which only assumes that the gradients of the order parameter are
small whereas the value of the phase may be large. We show that in the
phase-only approximation the resulting
reduces in
leading order in the field gradients to the perturbative one which thus allows to treat also the case without long-range phase
order or vortices. Our result generalizes previous
expressions for
to the case of interacting electrons,
is explicitly gauge invariant, and avoids problematic singular
gauge transformations. 相似文献
4.
I. Vilfan 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(2):277-284
The properties of
nanowires were investigated with
ab initio calculations based on the density-functional theory.
The molecules build weakly coupled one-dimensional chains, like
and Mo6S9-xIx, and the crystals are
strongly uniaxial in their mechanical and electronic properties.
The calculated moduli of elasticity and resilience along the chain axis are
c11 = 320 GPa and ER = 0.53 GPa, respectively.
The electronic band structure and optical conductivity indicate
that the
crystals are good quasi-one-dimensional conductors.
The frequency-dependent complex dielectric tensor ε, calculated
in the random-phase approximation, shows a strong Drude peak in
ε∥, i.e., for the electric field polarised parallel to
the chain axis, and several peaks related to interband transitions.
The electron energy loss spectrum is weakly anisotropic and has a strong peak
at the plasma frequency ħωp ≈20 eV.
The stability analysis shows that
is metastable against the
formation of the layered
. 相似文献
5.
Surface structures in the Te/Ni(111) system are revealed by using reflection high-energy electron diffraction combined with X-ray and ultraviolet photoelectron spectroscopies. At a 0.33 mono-layer (ML)-Te/Ni(111) surface, a reversible structural phase transition is observed with a transition temperature Tc of 380
C. The diffraction pattern from the low temperature phase is accompanied by streaks. The high and low temperature phases are characterized by
and
rectangle, respectively. The mechanism of the phase transition is explained by the order-disorder transition with a rumpled chain model. Both 0.51 ML- and 0.44 ML-Te/Ni(111) surfaces exhibit the complex diffraction patterns accompanied by diffuse streaks. These surface structures are characterized by the
rectangle and
, respectively. All diffuse streaks obtained at the above surfaces are consistently interpreted in the view of the ill-ordered arrangements of the well-ordered
linear chains. It is shown that the
linear structure is the key in the Te/Ni(111) system.Received: 1 December 2003, Published online: 20 April 2004PACS:
61.14.Hg Low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED) - 68.65.-k Low-dimensional, mesoscopic, and nanoscale systems: structure and nonelectronic properties - 64.60.Cn Order-disorder transformations; statistical mechanics of model systems 相似文献
6.
It is shown that the fluctuations of the jamming coverage upon Random Sequential Adsorption (RSA) (
), decay with the lattice size according to the power-law
, with
,where D is the dimension of the substrate and
is the fractal dimension of the set of sites belonging to the substrate where the RSA process actually takes place. This result is in excellent agreement with the figure recently reported by Vandewalle et al. [Eur. Phys. J. B 14, 407 (2000)], namely
for the RSA of needles with D = 2 and
, that gives
. Furthermore, our prediction is in excellent agreement with different previous numerical results. The derived relationships are also confirmed by means of extensive numerical simulations applied to the RSA of dimers on both stochastic and deterministic fractal substrates.Received: 17 October 2003, Published online: 8 December 2003PACS:
05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion - 02.50.-r Probability theory, stochastic processes, and statistics 相似文献
7.
Granular films of Co-cluster/C60 mixtures have been prepared by the co-deposition of well defined Co clusters (mean diameter
4.5 nm) and C60 fullerenes onto a cold (
35 K) substrate. Films having a Co cluster volume fraction
show a resistivity
, typical for tunneling with a Coulomb barrier. The tunneling magnetoresistance (TMR) has a value of TMR (
% for
and is decreasing by almost one order of magnitude going to
. We explain this unusual decrease of the TMR with increasing
as caused by electron-doping of the C60 fullerenes due to the known charge transfer process occurring between transition metal surface and C60. Increasing electron doping may lead to an increasing probability for spin-flip processes within the tunneling barrier, resulting in a decrease of the TMR.Received: 17 March 2004, Published online: 3 August 2004PACS:
75.47.-m Magnetotransport phenomena; materials for magnetotransport - 73.40.Gk Tunneling - 73.40.Rw Metal-insulator-metal structures 相似文献
8.
The production rates and substructure of jets have been studied in charged current deep inelastic e
+
p scattering for Q
2 > 200 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb-1. Inclusive jet cross sections are presented for jets with transverse energies
GeV and pseudorapidities in the range
. Dijet cross sections are presented for events with a jet having
GeV and a second jet having
GeV. Measurements of the mean subjet multiplicity,
, of the inclusive jet sample are presented. Predictions based on parton-shower Monte Carlo models and next-to-leading-order QCD calculations are compared to the measurements. The value of
, determined from
at
for jets with
GeV, is
. The mean subjet multiplicity as a function of Q
2 is found to be consistent with that measured in NC DIS.Received: 5 June 2003, Published online: 10 October 2003 相似文献
9.
The results of first-principles theoretical study of the structural, electronic and optical properties of beryllium monochalcogenides BeTe, BeSe and BeS, performed using the full potential linearized augmented plane wave (FP-LAPW) method are presented. The calculated structural parameters and band gaps compare very well with previous theoretical results. The trends of the band gap pressure coefficients and volume deformation potentials for these II-VI compounds are investigated. The linear pressure coefficients for the
X and
band gaps increase with decrease in anion atomic weight. The dependence of the direct and indirect band gaps on the relative change of lattice constant are found to follow almost the same type of trends in each of these compounds. The volume deformation potential (
) for the direct (
) and indirect (
) gaps are positive, but negative for the indirect (
) gap. Furthermore,
, for
transitions decreases with increase in anion atomic number whereas
, increases. The optical properties have also been calculated. From the reflectivity spectra, the compounds will be useful for optical applications. The variation of the band gaps with respect to the application of pressure and the origin of some of the peaks in the optical spectra are discussed in terms the calculated electronic structure.Received: 26 September 2003, Published online: 18 June 2004PACS:
71.15.Ap Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.) - 71.15.Mb Density functional theory, local density approximation, gradient and other corrections - 71.20.Nr Semiconductor compounds 相似文献
10.
We give a multiresolution partition of pure point parts of diffraction patterns of one-dimensional aperiodic sets. When an aperiodic set is related to the Golden Ratio, denoted by
, it is well known that the pure point part of its diffractive measure is supported by the extension ring of
, denoted by
. The partition we give is based on the formalism of the so called
-integers, denoted by
. The set of
-integers is a selfsimilar set obeying
,
. The pure point spectrum is then partitioned with respect to this Russian doll like sequence of subsets
. Thus we deduce the partition of the pure point part of the diffractive measure of aperiodic sets.Received: 24 March 2004, Published online: 12 July 2004PACS:
61.44.Br Quasicrystals - 61.10.Dp Theories of diffraction and scattering 相似文献
11.
N. Andrenacci M. Capezzali H. Beck 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,53(4):417-432
In order to obtain information about the internal structure of fluctuating Cooper pairs in the pseudogap state and below the
transition temperature of high Tc superconductors, we solve
the Bethe-Salpeter equation for the two-electron propagator in order to calculate a “pair structure function”
that depends on the internal distance
between the partners and on the center of mass momentum P of the pair. We use an attractive Hubbard model with a local potential
for s-wave and a separable potential for d-wave symmetry. The amplitude of gP for small ρ depends on temperature, chemical potential and interaction symmetry, but the ρ dependence itself is rather insensitive
to the interaction strength. Asymptotically gP decreases as an inverse power of ρ for weak coupling, but exponentially when a pseudogap develops for stronger interaction.
Some possibilities of observing the pair structure experimentally are mentioned. 相似文献
12.
A. Ehresmann W. Kielich L. Werner Ph. V. Demekhin D. V. Omel''yanenko V. L. Sukhorukov K.-H. Schartner H. Schmoranzer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(2):235-246
Dispersed fluorescence from fragments formed after the de-excitation of the
1s-1π* resonances of N*O and NO* has been
measured in the spectral range of 118–142 nm. This range is dominated by
lines of atomic nitrogen and oxygen fragments and by the
bands in the NO+ ion which result from the participator Auger decay of the 1s-1π* resonances.
Ab-initio calculations of the transition probabilities between vibrational
levels during the reaction NO
N*O
⇒ NO
were used to explain the observed intensity dependence for the
fluorescence bands on the exciting-photon energy across
the resonances and on both v′ and v′′
vibrational quantum numbers. The multiplet structure of the 1s-1π* resonance and lifetime vibrational interference explain the observed exciting-photon energy dependence of the
fluorescence
intensity. A strong spin-orbit coupling between singlet and triplet states
of NO+ is proposed to reduce additional cascade population of the
state via radiative transitions from the
and
states and to explain
remaining differences between measured and calculated integral fluorescence
intensities. 相似文献
13.
We investigate the phonon thermal conductivity
of doped
based on out-of-plane thermal conductivity measurements. When room temperature is approached the temperature dependence of
strongly deviates from the T-1-decrease which is usually expected for heat transport by acoustic phonons. Instead,
decreases much weaker or even increases with rising temperature. Simple arguments suggest that such unusual temperature dependencies of
are caused by heat transport via dispersive optical phonons.Received: 20 October 2003, Published online: 20 April 2004PACS:
66.70. + f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves - 74.72.Dn La-based cuprates - 44.10. + i Heat conduction 相似文献
14.
A presence of a Meissner-Ochsenfeld effect in a gas of spin 1/2 fermions with an interaction
, where
is a volume of a region
in real space which is taken by thesystem and
with
,
satisfying Fermi anticommutation relations, is investigated. The effect proves to be weaker than in BCS by a factor 3/4 at T = 0, implying a greater penetration depth
of external magnetic field. V
4 is nonzero only within a thin layer of 1-fermion energies around the chemical potential .Received: 14 June 2004, Published online: 12 October 2004PACS:
74.20.-z Theories and models of superconducting state - 74.20.Fg BCS theory and its development 相似文献
15.
H. Y. Zhang Y. P. Zhang T. Y. Shang Y. Zheng G. J. Ren P. Wang J. Q. Yao 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(1):37-40
The band structures of symmetrical Fibonacci sequences
(SFS) composed of positive and negative refractive index materials are
studied with a transfer matrix method. A new type of omnidirectional
zero-
gaps is found in the SFS. In contrast to the Bragg gaps, such
an omnidirectional zero-
gap is insensitive to the incident angles
and polarization, and is invariant upon the change of the ratio of the
thicknesses of two media. It is found that omnidirectional zero-
gap exists in all the SFS, and it is rather stable and independence of the
structure sequence. 相似文献
16.
We have investigated, in the framework of proximity effect theory, the interface transparency
of superconducting/normal metal layered systems which consist of Nb and high paramagnetic Pd deposited by dc magnetron sputtering. The obtained
value is relatively high, as expected by theoretical arguments. This leads to a large value of the ratio
although Pd does not exhibit any magnetic ordering.Received: 12 December 2003, Published online: 20 April 2004PACS:
74.45. + c Proximity effects; Andreev effect; SN and SNS junctions - 74.78.Fk Multilayers, superlattices, heterostructuresS.L. Prischepa: Permanent address: State University of Computer Science and RadioElectronics, P. Brovka street 6, 220600, Minsk, Belarus 相似文献
17.
The effects of the open boundaries on the dynamical behavior of the optimal velocity traffic flow models with a delay time
allowing the car to reach its optimal velocity is studied using numerical simulations. The particles could enter the chain with a given injecting rate probability
, and could leave the system with a given extracting rate probability
. In the absence of the variation of the delay time
, it is found that the transition from unstable to metastable and from metastable to stable state occur under the effect of the probabilities rates
and
. However, for a fixed value of
, there exist a critical value of the extraction rate
above which the wave density disappears and the metastable state appears and a critical value
above which the metastable state disappears while the stable state appears.
and
depend on the values of
and the variation of the delay time
. Indeed
and
increase when increasing
and/or decreasing
. The flow of vehicles is calculated as a function of
,
and
for a fixed value of
. Phase diagrams in the (
) plane exhibits four different phases namely, unstable, metastable, stable. The transition line between stable phase and the unstable one is curved and it is of first order type. While the transition between stable (unstable) phase and the metastable phase are of second order type. The region of the metastable phase shrinks with increasing the variation of the delay time
and disappears completely above a critical value
.Received: 23 July 2003, Published online: 8 December 2003PACS:
05.50. + q Lattice theory and statistics (Ising, Potts, etc.) - 64.60.Cn Order-disorder transformations; statistical mechanics of model systems - 75.30.Kz Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.) - 82.20.Wt Computational modeling; simulation 相似文献
18.
Zhi-Gang Wang Wei-Min Yang Shao-Long Wan 《The European Physical Journal C - Particles and Fields》2004,37(2):223-231
Making the assumption of explicit isospin violation arising from f
0(980)-a
0(980) mixing, we take the point of view that the scalar mesons f
0(980) and a
0(980) have both strange and non-strange quark-antiquark components and evaluate the strong coupling constants
within the framework of the light-cone QCD sum rules approach. The large strong scalar-KK couplings through both the
and
components
,
,
and
will support the hadronic dressing mechanism; furthermore, in spite of the constituent structure differences between the f
0(980) and a
0(980) mesons, the strange components have larger strong coupling constants with the K
+
K
- state than the corresponding non-strange ones,
and
. From the existing controversial values, we cannot reach a general consensus on the strong coupling constants
and the mixing angles.Received: 9 January 2004, Revised: 23 July 2004, Published online: 2 September 2004 相似文献
19.
The Standard Model constraints on
which can be derived from the
decays are revisited in some depth. As experimental inputs, the
,
decays complemented by the
decays, the CP parameters
and
, and/or the value of
as determined by the global CKM fit are used. The constraints discussed here are model independent in the sense that they rely only on Isospin symmetry, following the Gronau-London proposal. A new bound on
and the function
are introduced. While another bound applied to BABAR results is shown to imply that
is negative. The Grossman-Quinn bound is rediscussed. A close form expression is given for
as a function of the measurements. Various scenarios for the future of the isospin analysis are explored. To probe the Standard Model the
plane is introduced.Received: 17 December 2004, Published online: 25 January 2005 相似文献
20.
D. Varshney N. Kaurav 《The European Physical Journal B - Condensed Matter and Complex Systems》2004,40(2):129-136
The temperature-dependent resistivity of the perovskite manganites La1-x
Ca
x
MnO3, with x = 0.33, is theoretically analysed within the framework of the classical electron-phonon model of resistivity, i.e., the Bloch-Gruneisen model. Due to inherent acoustic (low-frequency) phonons (
as well as high-frequency optical phonons (
, the contributions to the resistivity have first been estimated. The acoustic phonons of the oxygen-breathing mode yield a relatively larger contribution to the resistivity compared to the contribution of optical phonons. Furthermore, the nature of phonons changes around T = 167 K exhibiting a crossover from an acoustic to optical phonon regime with elevated temperature. The contribution to resistivity estimated by considering both phonons, i.e.
and
, when subtracted from thin film data, infers a power temperature dependence over most of the temperature range. The quadratic temperature dependence of
is understood in terms of electron-electron scattering. Moreover, in the higher temperature limit, the difference can be varies linearly with T
4.5 in accordance with the electron-magnon scattering in the double exchange process. Within the proposed scheme, the present numerical analysis of temperature dependent resistivity shows similar results as those revealed by experiment.Received: 8 April 2004, Published online: 12 August 2004PACS:
5.47.Gk Colossal magnetoresistance - 72.15.-v Electronic conduction in metals and alloys - 74.25.Kc Phonons - 75.30.Ds Spin wavesD. Varshney: dvboson.sop@dauniv.ac.in 相似文献