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1.
By applying the supersymmetric approach we rigorously prove smoothness of the averaged density of states for a three dimensional
random band matrix ensemble, in the limit of infinite volume and fixed band width. We also prove that the resulting expression
for the density of states coincides with the Wigner semicircle with a precision 1/W
2
, for W large but fixed.
Received: 6 February 2002 / Accepted: 17 July 2002 Published online: 7 November 2002
RID="*"
ID="*" Supported by NSF grant DMS 9729992 相似文献
2.
Fraydoun Rezakhanlou 《Communications in Mathematical Physics》2003,232(2):327-375
We examine a system of particles in which the particles travel deterministically in between stochastic collisions. The collisions
are elastic and occur with probability ɛ
d
when two particles are at a distance σ. When the number of particles N goes to infinity and Nɛ
d
goes to a nonzero constant, we show that the particle density converges to a solution of the Enskog Equation.
Received: 29 January 2002 / Accepted: 30 July 2002 Published online: 14 November 2002
RID="*"
ID="*" Research supported in part by NSF Grant DMS-0072666 相似文献
3.
We use equivariant methods to define and study the orbifold K-theory of an orbifold X. Adapting techniques from equivariant K-theory, we construct a Chern character and exhibit a multiplicative decomposition
for K
*
orb
(X)⊗ℚ, in particular showing that it is additively isomorphic to the orbifold cohomology of X. A number of examples are provided. We then use the theory of projective representations to define the notion of twisted
orbifold K–theory in the presence of discrete torsion. An explicit expression for this is obtained in the case of a global
quotient.
Received: 21 August 2001 / Accepted: 27 January 2003
Published online: 13 May 2003
RID="*"
ID="*" Both authors were partially supported by the NSF
RID="*"
ID="*" Both authors were partially supported by the NSF
Communicated by R.H. Dijkgraaf 相似文献
4.
Aldo Procacci Benedetto Scoppola Victor Gerasimov 《Communications in Mathematical Physics》2003,235(2):215-231
Given an infinite graph 𝔾 quasi-transitive and amenable with maximum degree Δ, we show that reduced ground state degeneracy
per site W
r
(𝔾, q) of the q-state antiferromagnetic Potts model at zero temperature on 𝔾 is analytic in the variable 1/q, whenever |2Δe
3
/q|<1. This result proves, in an even stronger formulation, a conjecture originally sketched in [12] and explicitly formulated
in [16 and 19], based on which a sufficient condition for W
r
(𝔾, q) to be analytic at 1/q=0 is that 𝔾 is a regular lattice.
Received: 16 January 2002 / Accepted: 17 October 2002 Published online: 18 February 2003
RID="*"
ID="*" Partially supported by CNPq (Brazil)
RID="**"
ID="**" Partially supported by CNR, G.N.F.M. (Italy)
Communicated by H. Spohn 相似文献
5.
Remco van der Hofstad Frank den Hollander Gordon Slade 《Communications in Mathematical Physics》2002,231(3):435-461
We construct the incipient infinite cluster measure (IIC) for sufficiently spread-out oriented percolation on ℤ
d
× ℤ+, for d +1 > 4+1. We consider two different constructions. For the first construction, we define ℙ
n
(E) by taking the probability of the intersection of an event E with the event that the origin is connected to (x,n) ℤ
d
× ℤ+, summing this probability over x ℤ
d
, and normalising the sum to get a probability measure. We let n → ∞ and prove existence of a limiting measure ℙ∞, the IIC. For the second construction, we condition the connected cluster of the origin in critical oriented percolation
to survive to time n, and let n → ∞. Under the assumption that the critical survival probability is asymptotic to a multiple of n
−1, we prove existence of a limiting measure ℚ∞, with ℚ∞ = ℙ∞. In addition, we study the asymptotic behaviour of the size of the level set of the cluster of the origin, and the dimension
of the cluster of the origin, under ℙ∞. Our methods involve minor extensions of the lace expansion methods used in a previous paper to relate critical oriented
percolation to super-Brownian motion, for d+1 > 4+1.
Received: 13 December 2001 / Accepted: 11 July 2002 Published online: 29 October 2002
RID="*"
ID="*" Present address: Department of Mathematics and Computer Science, Eindhoven University of Technology, P.O. Box 513,
5600 MB Eindhoven, The Netherlands. E-mail: rhofstad@win.tue.nl 相似文献
6.
Paolo Buttà Emanuele Caglioti Carlo Marchioro 《Communications in Mathematical Physics》2003,233(3):545-569
We study the time evolution of a charged particle moving in a medium under the action of a constant electric field E. In the framework of fully Hamiltonian models, we discuss conditions on the particle/medium interaction which are necessary for the particle to reach a finite limit
velocity. We first consider the case when the charged particle is confined in an unbounded tube of ℝ3. The electric field E is directed along the symmetry axis of the tube and the particle also interacts with an infinitely many particle system.
The background system initial conditions are chosen in a set which is typical for any reasonable thermodynamic (equilibrium
or non-equilibrium) state. We prove that, for large E and bounded interactions between the charged particle and the background, the velocity v(t) of the charged particle does not reach a finite limit velocity, but it increases to infinite as: |v(t)−Et|≤C
0
(1+t), where C
0
is a constant independent of E. As a corollary we obtain that, if the initial conditions of the background system are distributed according to any Gibbs
state, then the average velocity of the charged particle diverges as time goes to infinite. This result is obtained for E large enough in comparison with the mean energy of the Gibbs state. We next study the one-dimensional case, in which the
estimates can be improved. We finally discuss, at an heuristic level, the existence of a finite limit velocity for unbounded interactions, and give some suggestions about the case of small electric fields.
Received: 7 March 2002 / Accepted: 23 September 2002 Published online: 8 January 2003
RID="*"
ID="*" Work partially supported by the GNFM-INDAM and the Italian Ministry of the University.
Communicated by J.L. Lebowitz 相似文献
7.
M. Samsel-Czekała G. Kontrym-Sznajd G. Döring W. Schülke J. Kwiatkowska F. Maniawski S. Kaprzyk A. Bansil 《Applied Physics A: Materials Science & Processing》2003,77(1):87-92
A reconstruction technique based on the solution of the Radon transform in terms of Jacobi polynomials is used to obtain the
3D electron momentum density, ϱ(p), from nine high-resolution Compton profiles (CPs) for a Cu0.9Al0.1 disordered alloy single crystal. The method was also applied to theoretical CPs computed within the Korringa–Kohn–Rostoker
coherent potential approximation (KKR-CPA) first-principles scheme for the same nine orientations of the crystal. The experimental
ϱ(p) is in satisfactory agreement with the theoretical ϱ(p), shows most details of the Fermi surface (FS) and exhibits electron correlation effects. We comment on the map of the FS
obtained by folding the reconstructed ϱ(p) into the first Brillouin zone, which yields the occupation number density, ϱ(k). A test of the validity of data via a consistency condition (within our reconstruction algorithm) as well as the propagation
of experimental noise in the reconstruction of both ϱ(p) and ϱ(k) are investigated.
Received: 24 October 2001 / Accepted: 20 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +48-71/344-10-29, E-mail: samsel@int.pan.wroc.pl 相似文献
8.
S. Borri P. Cancio P. De Natale G. Giusfredi D. Mazzotti F. Tamassia 《Applied physics. B, Lasers and optics》2003,76(4):473-477
We analyzed the spectroscopic performance of a difference-frequency source that utilizes a 5-W Yb-fiber amplifier for the
“signal” radiation in order to increase the “idler” power generated around 4.3 μm. The amplifier is seeded by a monolithic-cavity
Nd:YAG laser at 1064 nm. The intensity noise spectral density of the “idler” radiation was characterized. Cavity-enhanced
saturated-absorption spectroscopy was also performed to test the frequency resolution. In particular, we observed the Lamb-dip
spectrum of the ro-vibrational (0000-0001)R(0)transition of 17O12C16O in natural abundance. To our knowledge, this is the first observation of that transition by the Lamb-dip technique.
Received: 19 December 2002 / Revised version: 3 February 2003 / Published online: 16 April 2003
RID="*"
ID="*"Corresponding author. Fax: +39-055/4572-451, E-mail: mazzotti@inoa.it 相似文献
9.
We report on the experimental study of the excitation mechanism of fluorescence in a 10000-ppm wt. Tm+3-doped ZBLAN fiber. Visible (at 453 nm and 480 nm) and near-infrared (∼800 nm) radiations were studied under excitation at
1.064 μm. The up-conversion mechanisms responsible are investigated, based on experimental data. The results show that the3
H
4 and the 1
D
2 levels are predominantly excited by ion-ion cross-relaxation processes.
Received: 19 August 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. Fax: +41/31-631-3765, E-mail: Reda.El-Agmy@iap.unibe.ch 相似文献
10.
Ilka Agricola 《Communications in Mathematical Physics》2003,232(3):535-563
Given a reductive homogeneous space M=G/H endowed with a naturally reductive metric, we study the one-parameter family of connections ∇
t
joining the canonical and the Levi-Civita connection (t=0, 1/2). We show that the Dirac operator D
t
corresponding to t=1/3 is the so-called ``cubic' Dirac operator recently introduced by B. Kostant, and derive the formula for its square for
any t, thus generalizing the classical Parthasarathy formula on symmetric spaces. Applications include the existence of a new G-invariant first order differential operator on spinors and an eigenvalue estimate for the first eigenvalue of D
1/3. This geometric situation can be used for constructing Riemannian manifolds which are Ricci flat and admit a parallel spinor
with respect to some metric connection ∇ whose torsion T≠ 0 is a 3-form, the geometric model for the common sector of string theories. We present some results about solutions to
the string equations and a detailed discussion of a 5-dimensional example.
Received: 19 February 2002 / Accepted: 26 August 2002 Published online: 22 November 2002
RID="*"
ID="*" This work was supported by the SFB 288 ``Differential geometry and quantum physics' of the Deutsche Forschungsgemeinschaft
and the Max-Planck Society. 相似文献
11.
Consider an infinite system of particles evolving in a one dimensional lattice according to symmetric random walks with hard
core interaction. We investigate the behavior of a tagged particle under the action of an external constant driving force.
We prove that the diffusively rescaled position of the test particle εX(ε-2
t), t > 0, converges in probability, as ε→ 0, to a deterministic function v(t). The function v(⋅) depends on the initial distribution of the random environment through a non-linear parabolic equation. This law of large
numbers for the position of the tracer particle is deduced from the hydrodynamical limit of an inhomogeneous one dimensional
symmetric zero range process with an asymmetry at the origin. An Einstein relation is satisfied asymptotically when the external
force is small.
Received: 5 December 1996 / Accepted: 30 June 1997 相似文献
12.
Jérôme Daligault 《Journal of statistical physics》2011,143(6):1189-1246
We present a theory for the construction of renormalized kinetic equations to describe the dynamics of classical systems of
particles in or out of equilibrium. A closed, self-consistent set of evolution equations is derived for the single-particle phase-space distribution function f, the correlation function C=〈δfδf〉, the retarded and advanced density response functions χ
R,A
=δf/δφ to an external potential φ, and the associated memory functions Σ
R,A,C
. The basis of the theory is an effective action functional Ω of external potentials φ that contains all information about the dynamical properties of the system. In particular, its functional derivatives generate
successively the single-particle phase-space density f and all the correlation and density response functions, which are coupled through an infinite hierarchy of evolution equations.
Traditional renormalization techniques (involving Legendre transform and vertex functions) are then used to perform the closure
of the hierarchy through memory functions. The latter satisfy functional equations that can be used to devise systematic approximations
that automatically imply the conservation laws of mass, momentum and energy. The present formulation can be equally regarded
as (i) a generalization to dynamical problems of the density functional theory of fluids in equilibrium and (ii) as the classical
mechanical counterpart of the theory of non-equilibrium Green’s functions in quantum field theory. It unifies and encompasses
previous results for classical Hamiltonian systems with any initial conditions. For equilibrium states, the theory reduces
to the equilibrium memory function approach used in the kinetic theory of fluids in thermal equilibrium. For non-equilibrium
fluids, popular closures of the BBGKY hierarchy (e.g. Landau, Boltzmann, Lenard-Balescu-Guernsey) are simply recovered and
we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose and we discuss the correspondence
with the seminal approaches of Martin-Siggia-Rose and of Rose. 相似文献
13.
We present the first photoacoustic spectrometer for gas sensing employing both the fundamental and the frequency-doubled radiation
of a continuously tunable high-pressure CO2 laser with room temperature operation. A quasi-phase-matched diffusion-bonded GaAs crystal is used in the system for second-harmonic
generation. A pulsed photoacoustic detection scheme with a non-resonant cell, equipped with an 80-microphone array, is employed.
The wide continuous tuning range in the fundamental (9.2–10.7 μm) and the frequency-doubled (4.6–5.35 μm) regimes, together
with the narrow linewidth of 540 MHz (0.018 cm-1) for the 10-μm region and of 1050 MHz (0.0315 cm-1) for the 5-μm region, allow the measurement of gas mixtures, individual species and isotope discrimination. This is illustrated
with measurements on NO and CO2. The measured isotope ratio 15
NO/14
NO=(3.58±0.55)×10-3 agrees well with the literature (3.700×10-3) and demonstrates the good selectivity of the system.
Received: 30 April 2002 / Revised version: 10 June 2002 / Published online: 2 September 2002
RID="*"
ID="*"Corresponding author. Fax: +41-1/633-1077, E-mail: sigrist@iqe.phys.ethz.ch 相似文献
14.
The aim of this paper is two-fold. First, we define symplectic maps between Hitchin systems related to holomorphic bundles
of different degrees. We call these maps the Symplectic Hecke Correspondence (SHC) of the corresponding Higgs bundles. They
are constructed by means of the modification of the underlying holomorphic bundles. SHC allows to construct B?cklund transformations
in the Hitchin systems defined over Riemann curves with marked points. We apply the general scheme to the elliptic Calogero-Moser
(CM) system and construct SHC to an integrable SL(N,ℂ) Euler-Arnold top (the elliptic SL(N,ℂ)-rotator). Next, we propose a generalization of the Hitchin approach to 2d integrable theories related to the Higgs bundles
of infinite rank. The main example is an integrable two-dimensional version of the two-body elliptic CM system. The previous
construction allows us to define SHC between the two-dimensional elliptic CM system and the Landau-Lifshitz equation.
Received: 19 April 2002 / Accepted: 14 November 2002
Published online: 18 February 2003
RID="*"
ID="*" On leave from Institute of Oceanology, Moscow, Russia
RID="**"
ID="**" On leave from Institute of Theoretical and Experimental Physics, Moscow, Russia
Communicated by L. Takhtajan 相似文献
15.
F. Finster N. Kamran J. Smoller S.-T. Yau 《Communications in Mathematical Physics》2002,230(2):201-244
The Cauchy problem is considered for the massive Dirac equation in the non-extreme Kerr–Newman geometry, for smooth initial
data with compact support outside the event horizon and bounded angular momentum. We prove that the Dirac wave function decays
in at least at the rate t
−5/6. For generic initial data, this rate of decay is sharp. We derive a formula for the probability p that the Dirac particle escapes to infinity. For various conditions on the initial data, we show that p = 0, 1 or 0 < p < 1. The proofs are based on a refined analysis of the Dirac propagator constructed in [4].
Received: 20 August 2001 / Accepted: 22 January 2002
RID="*"
ID="*"Present address: NWF I – Mathematik, Universit?t Regensburg, 93040 Regensburg, Germany.?E-mail: felix.finster@mathematik.uni-regensburg.de
RID="**"
ID="**"Research supported by NSERC grant # RGPIN 105490-1998.
RID="***"
ID="***"Research supported in part by the NSF, Grant No. DMS-0103998.
RID="****"
ID="****"Research supported in part by the NSF, Grant No. 33-585-7510-2-30. 相似文献
16.
We formalize a classification of pair interactions based on the convergence properties of the forces acting on particles as a function of system size. We do so by considering the behavior of the probability distribution function
(PDF) P(F) of the force field F in a particle distribution in the limit that the size of the system is taken to infinity at constant particle density, i.e.,
in the “usual” thermodynamic limit. For a pair interaction potential V(r) with V(r→∞)∼1/r
γ
defining a bounded pair force, we show that P(F) converges continuously to a well-defined and rapidly decreasing PDF if and only if the pair force is absolutely integrable, i.e., for γ>d−1, where d is the spatial dimension. We refer to this case as dynamically short-range, because the dominant contribution to the force on a typical particle in this limit arises from particles in a finite neighborhood
around it. For the dynamically long-range case, i.e., γ≤d−1, on the other hand, the dominant contribution to the force comes from the mean field due to the bulk, which becomes undefined
in this limit. We discuss also how, for γ≤d−1 (and notably, for the case of gravity, γ=d−2) P(F) may, in some cases, be defined in a weaker sense. This involves a regularization of the force summation which is generalization
of the procedure employed to define gravitational forces in an infinite static homogeneous universe. We explain that the relevant
classification in this context is, however, that which divides pair forces with γ>d−2 (or γ<d−2), for which the PDF of the difference in forces is defined (or not defined) in the infinite system limit, without any regularization. In the former case dynamics can, as
for the (marginal) case of gravity, be defined consistently in an infinite uniform system. 相似文献
17.
Efficient room-temperature operation of 4
F
3/24
I
9/2 transitions in diode-end-pumped Nd:YAG lasers at 946 nm and 938.5 nm is reported. 7.0-W continuous-wave output power at 946 nm
and 3.9 W at 938.5 nm have been obtained. An analytical model has been developed for the quasi-three-level laser including
the influence of energy-transfer upconversion. Frequency doubling of these transitions in periodically poled KTP generated
blue light at 473 nm and 469 nm. Both single-pass extra-cavity as well as intracavity schemes have been investigated.
Received: 31 July 2002 / Published online: 5 February 2003
RID="*"
ID="*"Corresponding author. Fax: +46-8/750-5430, E-mail: stefan.bjurshagen@acreo.se 相似文献
18.
We present an experimental study of non-linear selective reflection (SR) at a quartz–Cs-vapor interface in a V-type three-level
scheme. The non-linear selective reflection at the Cs D2 resonance line (6
S
1/2F=4→6
P
3/2) is monitored with and without pumping. The sub-Doppler reflection spectrum is observed and the effect of pumping on the
signal of the selective reflection is investigated. The experimental result is in agreement with the theoretical calculation.
Received: 16 April 2002 / Revised version: 12 June 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +86-351/701-1500, E-mail: zhaojm@sxu.edu.cn 相似文献
19.
A portable modular gas sensor for measuring the 13C/12C isotopic ratio in CO2 with a precision of 0.8‰(±1σ) was developed for volcanic gas emission studies. This sensor employed a difference frequency generation (DFG)-based spectroscopic
source operating at 4.35 μm (∼2300 cm-1) in combination with a dual-chamber gas absorption cell. Direct absorption spectroscopy using this specially designed cell
permitted rapid comparisons of isotopic ratios of a gas sample and a reference standard for appropriately selected CO2 absorption lines. Special attention was given to minimizing undesirable precision degrading effects, in particular temperature
and pressure fluctuations.
Received: 16 April 2002 / Revised version: 28 May 2002 / Published online: 21 August 2002
RID="*"
ID="*"Corresponding author. Fax: +1-713/5245237, E-mail: fkt@rice.edu 相似文献
20.
G. Schrems M.P. Delamare N. Arnold P. Leiderer D. Bäuerle 《Applied Physics A: Materials Science & Processing》2003,76(5):847-849
The influence of the ‘storage time’ τs on the threshold fluence φcl and the efficiency in dry laser cleaning is investigated. τs denotes the time between the deposition of particles and the cleaning. As a model system we employed silica spheres with
diameters of 500 nm and 1500 nm on commercial silicon wafers and single-pulse KrF excimer laser radiation (τFWHM=28 ns). For the 1500-nm silica spheres, φcl was found to increase from about 65 mJ/cm2 to 125 mJ/cm2 for storage times of 4 h and 362 h, respectively. For 500-nm silica spheres the increase in the threshold fluence was less
than 20% for storage times up to 386 h.
Received: 12 July 2002 / Accepted: 12 July 2002 / Published online: 29 January 2003
RID="*"
ID="*"Corresponding author. E-mail:dieter.baeurle@jku.at 相似文献