共查询到20条相似文献,搜索用时 421 毫秒
1.
F. Clementi M. Gallegati G. Kaniadakis 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,57(2):187-193
Starting from the generalized exponential function
, with exp 0(x)=exp (x), proposed in reference [G. Kaniadakis, Physica A 296, 405 (2001)], the survival function P>(x)=exp κ(-βxα), where x∈R+, α,β>0, and
, is considered in order to analyze the data on personal income distribution for Germany, Italy, and the United Kingdom. The
above defined distribution is a continuous one-parameter deformation of the stretched exponential function P>
0(x)=exp (-βxα)
to which reduces as κ approaches zero
behaving in very different way in the x→0 and x→∞ regions. Its bulk is very close to the stretched exponential one, whereas
its tail decays following the power-law P>(x)∼(2βκ)-1/κx-α/κ. This makes the κ-generalized function particularly suitable to describe simultaneously the income distribution among both
the richest part and the vast majority of the population, generally fitting different curves. An excellent agreement is found
between our theoretical model and the observational data on personal income over their entire range. 相似文献
2.
F. P. Heßberger S. Hofmann D. Ackermann S. Antalic B. Kindler I. Kojouharov P. Kuusiniemi M. Leino B. Lommel R. Mann K. Nishio A. G. Popeko B. Sulignano S. Saro B. Streicher M. Venhart A. V. Yeremin 《The European Physical Journal A - Hadrons and Nuclei》2006,29(2):165-173
The decay of 255No was investigated by means of α-γ spectroscopy. The isotope was produced in the reactions 208Pb(48Ca, n)255No,
, and $238U(22Ne, 5n)255No$. Levels of the daughter nucleus 251Fm were assigned by α-γ coincidence measurements and on the basis of systematics. Level energies were determined precisely
using measured γ-rays. The results are compared with the known level schemes of the lighter
isotones 247Cm and 249Cf as well as with data for 253No. 相似文献
3.
The scattering problem of the
system, in the standard non-relativistic quark model of Isgur-Karl, is solved for the first time, by treating the large five-body
model space, including the NK scattering channel, accurately with the Gaussian expansion method and the Kohn-type coupled-channel variational method. The
calculated NK scattering phase shift shows no resonance in the energy region of the reported pentaquark Θ+(1540) that is, at 0–500 MeV above the NK threshold (1.4–1.9 GeV in mass). The phase shift does show two resonances just above 500 MeV: a broad
+ resonance with a width of Γ ∼ 110 MeV located at ∼ 520 MeV (∼ 2.0 GeV in mass) and a sharp
− resonance with Γ = 0.12 MeV at 540 MeV. 相似文献
4.
G. S. Khadekar Rupali Wanjari Cenap Ozel 《International Journal of Theoretical Physics》2009,48(9):2550-2557
In this study we have analyzed the Kaluza-Klein type Robertson Walker (RW) cosmological model by considering variable cosmological
constant term Λ of the form:
,
and Λ∼ρ in the presence of strange quark matter with domain wall. The various physical aspects of the model are also discussed. 相似文献
5.
Hyperfine structure and isotope shifts in five optical
transitions: 424.5 nm (
–
), 537.2 nm (
–
), 554.5 nm
(
–
), 560.9 nm
(
–
) and 666.0 nm
(
–
)
of Pb II have been measured. As a light source the discharge tube was used.
The hyperfine structure measurements were
performed using metallic isotope 207Pb. For isotope shifts
measurements natural lead was used. The high resolution spectral apparatus consisted of a silver
coated Fabry-Perot etalon and a grating spectrograph combined
with a CCD camera used as a detector. In the analysis of the
spectra a computer simulation technique was used. The hyperfine
structure observations yielded the splitting constants A for
seven levels of Pb II. The isotope shift studies enabled to
separate the mass and the field shifts and to determine values of
changes of the mean square nuclear charge radii. 相似文献
6.
Zhi-Qing Zhang Zhen-Jun Xiao 《The European Physical Journal C - Particles and Fields》2009,59(1):49-66
We calculate the important next-to-leading-order (NLO) contributions to the B→KK
* decays from the vertex corrections, the quark loops, and the magnetic penguins in the perturbative QCD (pQCD) factorization
approach. The pQCD predictions for the CP-averaged branching ratios are
,
,
and Br(B
0→K
+
K
*−+K
−
K
*+)≈1.3×10−7, which agree well with both the experimental upper limits and the predictions based on the QCD factorization approach. Furthermore,
the CP violating asymmetries of the considered decay modes are also evaluated. The NLO pQCD predictions for
and
decays are
and
. 相似文献
7.
We study the effect of step permeability on step instabilities on a growing vicinal face.
When alternation of kinetic coefficients is taken into account, pairing of steps occurs
on the vicinal face.
Irrespective of the step permeability,
the step pairs are stable for a wandering instability.
The bunching of step pairs occurs if the steps are impermeable.
The bunch size increases with time as tβ with β=1/2,
which does not depend on the form of the repulsive interaction
potential between steps.
The repulsion influences
the relation between the step distance in a bunch and the bunch size.
When the repulsive potential ζ with the step distance l
is given by ζ∼l-ν,
the average step distance
in a bunch
decreases as
with α=1/(ν+1).
The exponents, β and α are the same as those in the bunching
induced by the Ehrlich-Schowebel effect in growth. 相似文献
8.
Madjid Mirzavaziri Mohammad Sal Moslehian 《Mathematical Physics, Analysis and Geometry》2009,12(2):109-115
Let σ be a surjective ultraweakly continuous ∗-linear mapping and d be a σ-derivation on a von Neumann algebra . We show that there are a surjective ultraweakly continuous ∗-homomorphism and a Σ-derivation such that D is ultraweakly continuous if and only if so is d. We use this fact to show that the σ-derivation d is automatically ultraweakly continuous. We also prove the converse in the sense that if σ is a linear mapping and d is an ultraweakly continuous ∗-σ-derivation on , then there is an ultraweakly continuous linear mapping such that d is a ∗-Σ-derivation.
相似文献
9.
F. P. Heßberger S. Hofmann D. Ackermann S. Antalic B. Kindler I. Kojouharov P. Kuusiniemi M. Leino B. Lommel R. Mann K. Nishio A. G. Popeko B. Sulignano S. Saro B. Streicher M. Venhart A. V. Yeremin 《The European Physical Journal A - Hadrons and Nuclei》2006,30(3):561-569
The decay of the isotopes 255Rf, 251No and 247Fm produced in the reactions
, and
was investigated by means of α-γ spectroscopy. Previously observed γ transitions in coincidence with α decays of 255Rf were confirmed, their energies and line intensities were measured more precisely, and their multipolarities were determined
as E1. In 251No a new isomeric state at E
* > 1700keV with a half-life of ≈ 2μs was identified. The decay of 247Fm was measured more precisely. A partial level scheme of the daughter nucleus 243Cf could be established. 相似文献
10.
Zhi-Gang Wang 《The European Physical Journal C - Particles and Fields》2009,61(2):321-329
We calculate the masses and the pole residues of the
heavy baryons Ω
c
0(css) and Ω
b
−(bss) with the QCD sum rules. The numerical values
GeV (or
GeV) and
GeV (or
GeV) are in good agreement with the experimental data. 相似文献
11.
We investigate the spectroscopic properties of the 1.5-μm emission from the 4I13/2 → 4I15/2 transition of Er3+ ions in PbO–Bi2O3–Ga2O3–GeO2 glasses for applications in broadband fiber amplifiers. The measured emission peak locates at 1,532 nm with a full width
at half-maximum of ∼45 nm. The glasses exhibit a large stimulated emission cross-section of 0.89 × 10−20 cm2 and a large product of 40.0. Infrared-to-green upconversion occurs simultaneously upon excitation of the 1.5-μm emission with a commercially
available 980 nm laser diode. The green-upconversion intensity has a quadratic dependence on incident pump laser power, indicating
a two-photon process. Energy transfer processes and nonradiative phonon-assisted decays could account for the population of
the 2H11/2 of Er3+. The results indicate the possibility towards the development of lead–bismuth–gallate–germanate based glasses as photonics
devices. 相似文献
12.
For weakly non ergodic systems, the probability density function of a time average observable
is
where
is the value of the observable when the system is in state j=1,…L. p
j
eq is the probability that a member of an ensemble of systems occupies state j in equilibrium. For a particle undergoing a fractional diffusion process in a binding force field, with thermal detailed
balance conditions, p
j
eq is Boltzmann’s canonical probability. Within the unbiased sub-diffusive continuous time random walk model, the exponent 0<α<1 is the anomalous diffusion exponent 〈x
2〉∼t
α
found for free boundary conditions. When α→1 ergodic statistical mechanics is recovered
. We briefly discuss possible physical applications in single particle experiments. 相似文献
13.
After deriving the projected stress tensor in cylindrical geometry for a fluid membrane described by the Helfrich Hamiltonian,
we calculate the average force f exerted by a thermally fluctuating nanotubule of radius R , and its standard deviation
f . We obtain f and
f in terms of the internal membrane tension , the bending rigidity , the temperature k
B
T and a molecular cutoff . We find for f a shift ∼ 1/ with respect to the mean field behavior ∼ . We obtain (
f )2 ∼ R ln(R/b) where b is a molecular length,
f being typically small compared to f . Taking into account the difference between the internal tension and the actual mechanical tension applied to the membrane from which the tubule is drawn, we discuss the amplitude of the fluctuation-induced corrections to
the average force. Our results, obtained in the harmonic approximation, hold for tubules with aspect ratio not larger than
200 , of radius significantly smaller than 100nm, that are connected to a large membrane reservoir, e.g., a giant vesicle. 相似文献
14.
Random Motions at Finite Speed in Higher Dimensions 总被引:1,自引:0,他引:1
Alexander D. Kolesnik 《Journal of statistical physics》2008,131(6):1039-1065
We present a general method of studying the transport process
, t≥0, in the Euclidean space ℝ
m
, m≥2, based on the analysis of the integral transforms of its distributions. We show that the joint characteristic functions
of
are connected with each other by a convolution-type recurrent relation. This enables us to prove that the characteristic function
(Fourier transform) of
in any dimension m≥2 satisfies a convolution-type Volterra integral equation of second kind. We give its solution and obtain the characteristic
function of
in terms of the multiple convolutions of the kernel of the equation with itself. An explicit form of the Laplace transform
of the characteristic function in any dimension is given. The complete solution of the problem of finding the initial conditions
for the governing partial differential equations, is given.
We also show that, under the standard Kac condition on the speed of the motion and on the intensity of the switching Poisson
process, the transition density of the isotropic transport process converges to the transition density of the m-dimensional homogeneous Brownian motion with zero drift and diffusion coefficient depending on the dimension m.
We give the conditional characteristic functions of the isotropic transport process in terms of the inverse Laplace transform
of the powers of the Gauss hypergeometric function. Some important models of the isotropic transport processes in lower dimensions
are considered and some known results are derived as the particular cases of our general model by means of the method developed. 相似文献
15.
Gauhar Abbas B. Ananthanarayan 《The European Physical Journal A - Hadrons and Nuclei》2009,41(1):7-11
We obtain stringent bounds in the 〈r
2
-c plane where these are the scalar radius and the curvature parameters of the scalar K
form factor, respectively, using analyticity and dispersion relation constraints, the knowledge of the form factor from the
well-known Callan-Treiman point , as well as at , which we call the second Callan-Treiman point. The central values of these parameters from a recent determination are accomodated
in the allowed region provided the higher loop corrections to the value of the form factor at the second Callan-Treiman point
reduce the one-loop result by about 3% with . Such a variation in magnitude at the second Callan-Treiman point yields 0.12 fm2
〈r
2
0.21 fm2and 0.56 GeV-4
c
1.47 GeV-4and a strong correlation between them. A smaller value of shifts both bounds to lower values. 相似文献
16.
A. Dewanto A. H. Chan C. H. Oh R. Chen K. Sitaram 《The European Physical Journal C - Particles and Fields》2008,57(3):515-523
We study the evolution of Lee-Yang zeros structure of generalized multiplicity distribution (GMD) in high energy collision.
Starting our study with electron-positron e
+
e
− scattering data, we extend the study by Chan and Chew (Z. Phys. C 55:503, 1992) on TASSO and AMY multiplicity data for
, 22, 34.8, 43.6 and 57 GeV to the ones from DELPHI and OPAL Collaboration for
, 133, 161, 172, 183 and 189 GeV. We compare the results with the Lee-Yang structure for proton-antiproton
at
, 546 and 900 GeV from UA5 Collaboration. Our preliminary result shows that there is indeed a change in the shape and size
of the Lee-Yang zeros with increasing energy, accompanied by the development of the so-called “ear”-like structure in the
Lee-Yang plot. We expect that the development of this “ear”-like structure is related to the “shoulder” structure in the multiplicity
data, which further indicates an ongoing phase transition from soft to semihard scattering. We also extend our prediction
to LHC’s
TeV. Insert your abstract here. 相似文献
17.
We consider one-dimensional (1D) interacting spinless fermions with a non-linear spectrum in a clean quantum wire (non-linear
bosonization). We compute diagrammatically the 1D dynamical structure factor, S(ω,q), beyond the Tomonaga approximation focusing
on it's tails, |ω| ≫vq,
i.e. the 2-pair excitation continuum due to forward scattering. Our methodology reveals three classes of diagrams: two “chiral”
classes which bring divergent contributions in the limits ω→±vq, i.e. near the single-pair excitation continuum, and a “mixed”
class (so-called Aslamasov-Larkin or Altshuler-Shklovskii type diagrams) which is crucial for the f-sum rule to be satisfied.
We relate our approach to the T=0 ones present in the literature. We also consider the
case and show that the 2-pair excitation continuum dominates the single-pair one in the range: |q|T/kF ≪ω±vq ≪T (substantial for q ≪kF). As applications we first derive the small-momentum optical conductivity due to forward scattering: σ∼1/ω for T ≪ω and σ∼T/ω2 for T ≫ω. Next, within the 2-pair excitation continuum, we show that the attenuation rate of a coherent mode of dispersion
Ωq crosses over from
, e.g. γq ∼|q|3 for an acoustic mode, to
, independent of Ωq, as temperature increases. Finally, we show that the 2-pair excitation continuum yields subleading curvature corrections
to the electron-electron scattering rate:
, where V is the dimensionless strength of the interaction. 相似文献
18.
Xiang Liu Zhi-Gang Luo Yan-Rui Liu Shi-Lin Zhu 《The European Physical Journal C - Particles and Fields》2009,61(3):411-428
We perform a systematic study of the possible molecular states composed of a pair of heavy mesons such as
,
,
in the framework of the meson exchange model. The exchanged mesons include the pseudoscalar, scalar and vector mesons. Through
our investigation, we find the following results. (1) The structure X(3764) is not a molecular state. (2) There exists strong attraction in the range r<1 fm for the
system with J=0,1. If future experiments confirm Z
+(4051) as a loosely bound molecular state, its quantum number is probably J
P
=0+. Its partner state Φ
**0 may be searched for in the π
0
χ
c1 channel. (3) Vector meson exchange provides strong attraction in the
channel together with pion exchange. A bound state solution may exist with a reasonable cutoff parameter Λ∼1.4 GeV. X(3872) may be accommodated as a molecular state dynamically although drawing a very definite conclusion needs further investigation.
(4) The
molecular state may exist. 相似文献
19.
R. M. Jennerich A. N. Keiser D. A. Tate 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):81-89
We have obtained Doppler-free spectra of transitions in the
→ 2p2(3P)
and
→
multiplets of atomic nitrogen using saturated absorption spectroscopy. These multiplets consist of
respectively of seven and eight transitions, and have center of gravity wavelengths of 821 nm and 869 nm. Values for the hyperfine
structure coupling constants of all the upper and lower states for these multiplets were obtained for both 14N and 15N. Isotope shifts of three transitions in each multiplet were also measured, and a significant J-dependence to the shifts
was observed. 相似文献
20.
M. Weis P. Bartsch D. Baumann J. Bermuth A. M. Bernstein K. Bohinc R. Böhm M. Ding M. O. Distler I. Ewald J. M. Friedrich J. Friedrich M. Kahrau M. Kohl K. W. Krygier A. Liesenfeld H. Merkel P. Merle U. Müller R. Neuhausen M. M. Pavan Th. Pospischil M. Potokar G. Rosner H. Schmieden M. Seimetz S. Širca A. Wagner Th. Walcher 《The European Physical Journal A - Hadrons and Nuclei》2008,38(1):27-33
The differential cross-sections σ0 = σT + εσL , σLT , and σTT of electroproduction from the proton were measured from threshold up to an additional center-of-mass energy of 40MeV, at a value
of the photon four-momentum transfer of Q
2 = 0.05 GeV2/c2 and a center-of-mass angle of θ = 90° . By an additional out-of-plane measurement with polarized electrons σLT' was determined. This showed for the first time the presence of an imaginary part of the s -wave above the threshold, which is usually interpreted as a unitary cusp. The predictions of the Heavy Baryon Chiral Perturbation Theory
(HBChPT) are in disagreement with these data. On the other hand, the data are somewhat better predicted by the MAID phenomenological
model and are in good agreement with the dynamical model DMT. 相似文献