共查询到20条相似文献,搜索用时 31 毫秒
1.
Charles Fefferman Jürg Fröhlich Gian Michele Graf 《Communications in Mathematical Physics》1997,190(2):309-330
We prove that the quantum-mechanical ground state energy of a system consisting of an arbitrary number, M, of static nuclei of atomic number ≤Z and of an arbitrary number, N, of Pauli electrons interacting with the quantized, ultraviolet-cutoff radiation field is bounded below by $-K.M, where K is a finite constant depending on Z, on the finestructure constant α and on the ultraviolet cutoff Λ, with , as , and K' independent of Λ.
Received: 4 September 1996/ Accepted: 9 April 1997 相似文献
2.
Alexei Iantchenko 《Communications in Mathematical Physics》1997,184(2):367-385
The electron density of the neutral atoms at the distances , from the nucleus in the limit when the charge of the nucleus Z tends to infinity is well approximated by the function , which is a common limiting value for both the Thomas-Fermi density at the origin and the hydrogen density at infinity.
This conjecture by Lieb is proved in some weak sense by using the Ivrii and Sigal method.
Received: 2 January 1996 / Accepted: 24 July 1996 相似文献
3.
We consider a large atom with nuclear charge Z described by non-relativistic quantum mechanics with classical or quantized electromagnetic field. We prove that the absolute
ground state energy, allowing for minimizing over all possible self-generated electromagnetic fields, is given by the non-magnetic
Thomas-Fermi theory to leading order in the simultaneous Z → ∞, α → 0 limit if Z
α
2 ≤ κ for some universal κ, where α is the fine structure constant. 相似文献
4.
T. M. W. Eyre 《Communications in Mathematical Physics》1998,192(1):9-28
Given a polynomial function f of classical stochastic integrator processes whose differentials satisfy a closed Ito multiplication table, we can express the stochastic derivative of f as
We establish an analogue of this formula in the form of a chaotic decomposition for Z
2-graded theories of quantum stochastic calculus based on the natural coalgebra structure of the universal enveloping superalgebra.
Received: 28 January 1997 / Accepted: 10 June 1997 相似文献
5.
Bernhard Baumgartner Jan Philip Solovej Jakob Yngvason 《Communications in Mathematical Physics》2000,212(3):703-724
Let E(B,Z,N) denote the ground state energy of an atom with N electrons and nuclear charge Z in a homogeneous magnetic field B. We study the asymptotics of E(B,Z,N) as B→∞ with N and Z fixed but arbitrary. It is shown that the leading term has the form (ln B)2
e(Z,N), where e(Z,N) is the ground state energy of a system of N
bosons with delta interactions in one dimension. This extends and refines previously known results for N= 1 on the one hand, and N,Z→∞ with B/Z
3→∞ on the other hand.
Received: 9 December 1999 / Accepted: 15 February 200 相似文献
6.
Virendra Singh 《Pramana》1985,24(1-2):31-37
We propose an analytic perturbative approach for the determination of the Feigenbaum-Cvitanović function and the universal
parameterα occurring in the Feigenbaum scenario of period doubling for approach to chaotic behaviour. We apply the method to the caseZ=2 whereZ is the order of the unique local maximum of the nonlinear map. Our third order approximation givesα=2.5000 as compared to “exact” numerical valueα=2.5029 ... We also obtain a reasonably accurate value of the Feigenbaum-Cvitanović function. 相似文献
7.
NaAgPbP2O7 was prepared with a solid-state reaction. The electrical properties were investigated by using impedance measurements in
the frequency range from 200 Hz to 5 MHz with the TEGAM 3550 ALF automatic bridge monitored by a microcomputer between 581 K
and 703 K. The Z′ and Z″ versus frequency plots are well fitted to an equivalent circuit model. The conductivity data obey the universal power law.
The conductivity in the material is due to the hopping of monovalent ions parallel to (001) plane. 相似文献
8.
The Kac-Wakimoto admissible modules for are studied from the point of view of vertex operator algebras. It is shown that the vertex operator algebra L(l,0) associated to irreducible highest weight modules at admissible level is not rational if l is not a positive integer. However, a suitable change of the Virasoro algebra makes L(l,0) a rational vertex operator algebra whose irreducible modules are exactly these admissible modules for and for which the fusion rules are calculated. It is also shown that the q-dimensions with respect to the new Virasoro algebra are modular functions.
Received: 4 April 1996/Accepted: 1 August 1996 相似文献
9.
The experimental study of the proton-rich nuclei close to the N = Z line is a constant challenge for nuclear spectroscopy, mainly due to the difficulty to produce them with the currently available beam/target combinations. Significant advances on this direction were obtained from experiments performed with the GASP array during the last two years: the yrast line of 84Mo was extended up to 10 + , 88Ru observed for the first time, and the N = Z + 1 line was mapped from 81Zr to 95Ag. These new results allow us to have a more complete image of the transition from the well-deformed shell closure at N,Z = 40 to the spherical-shell closure at N,Z = 50, and highlights some particular effects that can be observed only in the vicinity of the N = Z line.Received: 10 January 2003, Published online: 23 March 2004PACS:
21.10.-k Properties of nuclei; nuclear energy levels - 21.10.Pc Single-particle levels and strength functions - 21.10.Re Collective levels - 23.20.-g Electromagnetic transitions 相似文献
10.
Marko V. Jarić 《Physics letters. A》1984,106(4):172-174
The available data for the polymer volume fraction along the coexistence curves for monodisperse solutions of polystyrene in methylcyclohexane are used to derive the exponent z ≈ 0.61 such that the “correct” order parameter is only a function of ?MZ (M is the polymer's molecular weight while ? is the reduced temperature). It is shown that a knowledge of the “correct” order parameter is unnecessary for a determination of z which is expected to be universal, i.e. independent of the polymer-solvent system. 相似文献
11.
Given a finite dimensional C
*-Hopf algebra H and its dual Ĥ we construct the infinite crossed product and study its superselection sectors in the framework of algebraic quantum field theory. is the observable algebra of a generalized quantum spin chain with H-order and Ĥ-disorder symmetries, where by a duality transformation the role of order and disorder may also appear interchanged. If is a group algebra then becomes an ordinary G-spin model. We classify all DHR-sectors of – relative to some Haag dual vacuum representation – and prove that their symmetry is
described by the Drinfeld double . To achieve this we construct localized coactions
and use a certain compressibility property to prove that they are universal amplimorphisms on . In this way the double can be recovered from the observable algebra as a universal cosymmetry.
Received: 4 September 1995\,/\,Accepted: 3 December 1996 相似文献
12.
A design is proposed and a resolving power is calculated for a detector that monitors the unauthorized transportation of high
Z materials (nuclear materials with Z > 90) using the natural cosmic-ray muon flux. The identification of nuclear materials is based on the strong dependence of
the multiple scattering angle on the matter charge upon traversing the matter by cosmic muons. It is proposed that chambers
assembled from drift aluminum tubes similar to chambers used in the muon system of the ATLAS detector be used as the coordinate
detector for the setup. The calculations show that the proposed variant of the setup makes it possible to detect the presence
of nuclear materials with a weight of about 0.5–1 kg and higher in the inspected volume in a measurement time of several minutes. 相似文献
13.
A braided subfactor determines a coupling matrix Z which commutes with the S- and T-matrices arising from the braiding. Such a coupling matrix is not necessarily of “type I”,
i.e. in general it does not have a block-diagonal structure which can be reinterpreted as the diagonal coupling matrix with
respect to a suitable extension. We show that there are always two intermediate subfactors which correspond to left and right
maximal extensions and which determine “parent” coupling matrices Z
± of type I. Moreover it is shown that if the intermediate subfactors coincide, so that Z
+=Z
−, then Z is related to Z
+ by an automorphism of the extended fusion rules. The intertwining relations of chiral branching coefficients between original
and extended S- and T-matrices are also clarified. None of our results depends on non-degeneracy of the braiding, i.e. the
S- and T-matrices need not be modular. Examples from SO(n) current algebra models illustrate that the parents can be different, Z
+≠Z
−, and that Z need not be related to a type I invariant by such an automorphism.
Received: 8 December 1999 / Accepted: 15 February 2000 相似文献
14.
We present an efficient quantum algorithm for the exact evaluation of either the fully ferromagnetic or anti-ferromagnetic
q-state Potts partition function Z for a family of graphs related to irreducible cyclic codes. This problem is related to the evaluation of the Jones and Tutte
polynomials. We consider the connection between the weight enumerator polynomial from coding theory and Z and exploit the fact that there exists a quantum algorithm for efficiently estimating Gauss sums in order to obtain the weight
enumerator for a certain class of linear codes. In this way we demonstrate that for a certain class of sparse graphs, which
we call Irreducible Cyclic Cocycle Code (ICCCε) graphs, quantum computers provide a polynomial speed up in the difference between the number of edges and vertices of the
graph, and an exponential speed up in q, over the best classical algorithms known to date. 相似文献
15.
We present new experimental data on thick target bremsstrahlung spectra generated from the interaction of energetic electrons
with bulk matter. The ‘photon yields’ in terms of double differential cross-sections (DDCS) are measured for pure elements
of thick targets: Ti (Z = 22), Ag (Z = 47), W (Z = 74) and Pt (Z = 78) under the impact of 10 keV electrons. Comparison of DDCS obtained from the experimental data is made with those predicted
by Monte-Carlo (MC) calculations using PENELOPE code. A close agreement between the experimental data and the MC calculations
is found for all the four targets within the experimental error of 16%. Furthermore, the ratios of DDCS of bremsstrahlung
photons emitted from Ag, W and Pt with those from Ti as a function of photon energy are examined with a relatively lower uncertainty
of about 10% and they are compared with MC calculations. A satisfactory agreement is found between the experiment and the
calculations within some normalizing factors. The variations of DDCS as a function of Z and of photon energy are also studied which show that the DDCS vary closely with Z; however, some deviations are observed for ‘tip’ photons emitted from high Z targets. 相似文献
16.
Within the framework of the discrete Wess–Zumino–Novikov–Witten theory we analyze the structure of vertex operators on a lattice.
In particular, the lattice analogues of operator product expansions and braid relations are discussed. As the main physical
application, a rigorous construction for the discrete counterpart g
n
$ of the group valued field g(x) is provided. We study several automorphisms of the lattice algebras including discretizations of the evolution in the WZNW
model. Our analysis is based on the theory of modular Hopf algebras and its formulation in terms of universal elements. Algebras
of vertex operators and their structure constants are obtained for the deformed universal enveloping algebras . Throughout the whole paper, the abelian WZNW model is used as a simple example to illustrate the steps of our construction.
Received: 16 December 1996 / Accepted: 5 May 1997 相似文献
17.
It is known that ideal metallic glasses fully complying with the Hume-Rothery stabilization mechanism can be expressed by a universal cluster formula of the form [cluster](glue atom)1 or 3. In the present work, it is shown, after a re-examination of the cluster-resonance model, that the number of electrons per unit cluster formula, e/u, is universally 24. The cluster formulas are then the atomic as well as the electronic structural units, mimicking the ‘molecular’ formulas for chemical substances. The origin of different electron number per atom ratios e/a is related to the total number of atoms Z in unit cluster formula, e/a?=?24/Z. The 24 electron formulas are well confirmed in typical binary and ternary bulk metallic glasses. 相似文献
18.
W. Q. Duan 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,59(2):271-276
Identifying universal patterns in complex economic
systems can reveal the dynamics and organizing principles underlying the
process of system evolution. We investigate the scaling behaviours that have
emerged in the international trade system by describing them as a series of
evolving weighted trade networks. The maximum-flow spanning trees (constructed by maximizing the total
weight of the edges) of these networks exhibit two universal scaling
exponents: (1) topological scaling exponent η = 1.30 and (2) flow
scaling exponent ζ = 1.03. 相似文献
19.
Christian Zylka 《Annalen der Physik》1989,501(1):70-73
On the Monotonic Behaviour of Certain Partition Functions under Temperature Equalization We stress that the canonical partition function Z(β1, β2, …, βn) ≡ Z(β) of a thermodynamical system consisting of n independent subsystems is a Schur-convex function. By βi the inverse temperature of the i-th subsystem is denoted. If the internal energy is proportional to β - as e.g. for spin systems in the high temperature approximation - then from the Schur-convexity it follows that arbitrary temperature equalization between the subsystems can only diminish Z(β). 相似文献
20.
Jens Böckenhauer David E. Evans Yasuyuki Kawahigashi 《Communications in Mathematical Physics》1999,208(2):429-487
We consider a type III subfactor N⊂N of finite index with a finite system of braided N-N morphisms which includes the irreducible constituents of the dual canonical endomorphism. We apply α-induction and, developing
further some ideas of Ocneanu, we define chiral generators for the double triangle algebra. Using a new concept of intertwining
braiding fusion relations, we show that the chiral generators can be naturally identified with the α-induced sectors. A matrix
Z is defined and shown to commute with the S- and T-matrices arising from the braiding. If the braiding is non-degenerate,
then Z is a “modular invariant mass matrix” in the usual sense of conformal field theory. We show that in that case the fusion rule
algebra of the dual system of M-M morphisms is generated by the images of both kinds of α-induction, and that the structural information about its irreducible
representations is encoded in the mass matrix Z. Our analysis sheds further light on the connection between (the classifications of) modular invariants and subfactors, and
we will construct and analyze modular invariants from SU(n)
k
loop group subfactors in a forthcoming publication, including the treatment of all SU(2)
k
modular invariants.
Received: 13 April 1999 / Accepted: 13 July 1999 相似文献