共查询到20条相似文献,搜索用时 515 毫秒
1.
Zdeněk Knittl 《Czechoslovak Journal of Physics》1959,9(1):91-94
The paper deals with the problem of the anomalous divergence of an infinite geometric series of complex amplitudes, pointed out by Berning. It is shown that the paradox is of a formal mathematical nature and has no consequences for multiple beam interference as a method of derivation.
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2.
Akitaka Kishimoto 《Letters in Mathematical Physics》1979,3(3):193-196
If the energy spectrum of an extremal invariant state is not the whole real line, it is shown that is either pure or uniquely decomposed into mutually disjoint pure states in the way that =-1
F
0
t
dt where is a pure state satisfying = with >0. Next we give a slightly generalized version of Borchers' theorem [1] on the innerness of some automorphism group of a von Neumann algebra with a spectrum condition. 相似文献
3.
A. D. W. B. Crumey 《Communications in Mathematical Physics》1987,111(2):167-179
The classical non-linear Schrödinger equation associated with a symmetric Lie algebra =km is known to possess a class of conserved quantities which from a realization of the algebrak []. The construction is now extended to provide a realization of the Kac-Moody algebrak[, –1] (with central extension). One can then define auxiliary quantities to obtain the full algebra [, –1]. This leads to the formal linearization of the system. 相似文献
4.
Consider a self adjoint quantic hamiltonian:P(h)=p(x, hD
x) whereh>0 is the Planck's constant andp some smooth classical observable on the phase space R2n
. When the classical flow on a compact energy shell {p=} is ergodic we prove that in the limith 0 almost all the eigenfunctions ofP(h) whose energy is near of are distributed according to the Liouville measure on {p=}.In the high energy case ( +) this sort of problem was considered by A. Schnirelman, S. Zelditch, and Y. Colin de Verdière. 相似文献
5.
Akira Sakai 《Journal of statistical physics》2001,104(1-2):111-143
The contact process is a model of spread of an infectious disease. Combining with the result of ref. 1, we prove that the critical exponents take on the mean-field values for sufficiently high dimensional nearest-neighbor models and for sufficiently spread-out models with d>4:()–
c as
c and ()(
c–)–1 as
c, where () and () are the spread probability and the susceptibility of the infection respectively, and
c is the critical infection rate. Our results imply that the upper critical dimension for the contact process is at most 4. 相似文献
6.
The uniform nearest particle system (UNPS) is studied, which is a continuoustime Markov process with state space
. The rigorous upper bound
(mf)
= ( – 1)/ for the order parameter
2, is given by the correlation identity and the FKG inequality. Then an improvement of this bound
(mf)
is shown in a similar fashion;
C( – 1)/|log( – 1) for >1. Recently, Mountford proved that the critical value c=1. Combining his result and our improved bound implies that if the critical exponent exists, it is strictly greater than the mean-field value 1 in the weak sense. 相似文献
7.
Alan D. Sokal 《Journal of statistical physics》1981,25(1):25-50
A variety of rigorous inequalities for critical exponents is proved. Most notable is the low-temperature Josephson inequalitydv +2 2–. Others are 1 1 +v, 1 1
, 1,d 1 + 1/ (for d),dv, 3 + (for d), 4 , and 2m 2m+2 (form 2). The hypotheses vary; all inequalities are true for the spin-1/2 Ising model with nearest-neighbor ferromagnetic pair interactions.NSF Predoctoral Fellow (1976–1979). Research supported in part by NSF Grant PHY 78-23952. 相似文献
8.
G. Rideau 《Letters in Mathematical Physics》1984,8(5):421-433
Let U(a, ) be a representation of the Poincaré group with mass and helicity zero, realized in the space of C
-functions with compact support on 3, without the origin. Let U
(2)(a, ) denote the tensorial product of U(a, ) by itself. We explicitly determine the cocycles of extension of U(a, ) by U
(2)(a, ) and we prove that the nontrivial cohomology is indexed by (u(),),u()D
1
]0,3\,. 相似文献
9.
Paul G. Federbush 《Communications in Mathematical Physics》1981,81(3):327-340
A cluster expansion is developed and applied to study the perturbation ()4 of the massless lattice field in dimension 3. The method is loosely inspired by the work of Gawedzki and Kupiainen on block spin techniques for the
system. The cluster expansion is given in terms of expansion coefficients for the field as a sum of certain special block spin functions. These functions are chosen with a large number of moments zero, so that the interaction couples spatially separated functions with an interaction falling off as a high inverse power of the separation distance. The present techniques, with some technical development, should work for broad classes of other models, including the lattice dipole gas and the
model. Models (,,;
)2s
, >1/2, are essentially included in the present work.This work was supported in part by the National Science Foundation under Grant No. PHY 79-05688 相似文献
10.
The dependence of the magnetostriction constant of different materials in the form of a wire on the elastic elongation was measured. With pure nickel the magnetostriction constant is independent of the elastic deformation. All three alloys of iron and nickel and the triple alloy Fe-Ni-Co exhibit a linear dependence on the deformation, which differs for different crystallographic texture. In two iron-nickel alloys the dependence of the magnetostriction constants of the single crystal on the elastic deformation was calculated from measurements on polycrystals having different crystallographic textures. In the triple alloy Fe-Ni -Co a considerable linear decrease in the volume magnetostriction with the elastic elongation was also found. The observed changes can be explained by assuming the influence of the lattice deformation on the spinorbital interaction in alloys.
A preliminary report on some of the results of this paper was given at the conference on magnetism in Kyoto (Japan) in September 1961.
In conclusion the authors thank Z. Frait C. Sc. and S. Libovický for remarks, J. Míová for help in the measurements, members of the chemical department of our institute for annealing and analyzing the samples and members of the Metal Research Institute in Panenské Beany for their exceptional helpfulness in preparing the wires. 相似文献
-
. . - Fe-Ni-Co , . - . , Fe-Ni-Co . - .
A preliminary report on some of the results of this paper was given at the conference on magnetism in Kyoto (Japan) in September 1961.
In conclusion the authors thank Z. Frait C. Sc. and S. Libovický for remarks, J. Míová for help in the measurements, members of the chemical department of our institute for annealing and analyzing the samples and members of the Metal Research Institute in Panenské Beany for their exceptional helpfulness in preparing the wires. 相似文献
11.
Juraj Dubinský Pavel Chaloupka Václav Petržílka Lenka Tomášková 《Czechoslovak Journal of Physics》1956,6(1):29-33
( - .). , - , - , - . , D=30 40% , ; D=50 60%. . 相似文献
12.
By analyzing the Bethe-Salpeter equation for even ()2 models we show that for weak coupling the mass spectrum is discrete and of finite multiplicity below 2m. Moreover on even states of energy less than 4(m–) we show that theS matrix is unitary. Herem is the physical mass and =()0 as 0. Our results rely essentially only on a simple assumption about the analyticity of the Bethe-Salpeter kernel which has been verified for weak coupling. For the interaction 4, (/m
o
2
1) we show that there are no even bound states of energy less than 4(m–).Work supported in part by NSF, Grant MPS 74-13252 相似文献
13.
Z. Šroubek 《Czechoslovak Journal of Physics》1961,11(9):634-643
The theory of double quantum transitions of the M=±2 type, with regard to inhomogeneously broadened spin systems is studied in this paper with the approximation
2T2T3 1. We suppose that the inhomogeneous broadening is formed by an inhomogeneous crystal field. The obtained results describe the magnitude of absorption as a function of the h.f. power and also describe the shape of the absorption curve. It is demonstrated that in inhomogeneously broadened spin systems the absorption curve of double quantum transitions has the form of the difference of two different Lorentz's curves and that at the saturation (
2T2T1 1) the absorption increases with the cube of the h.f. field intensity. The shape of the curves is expressed by means of phenomenological relaxation constants of the system.
M=±2 2T2T3 1. , - . . , ( 2T2T1 1) . .相似文献
14.
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15.
R. Weder 《Communications in Mathematical Physics》1978,60(3):291-299
We develop a new, unified, method to construct a closed (selfad-joint in 2) extension of a partial differential operator in all the spaces
p
(
n
) 1p. Our method is not only an unified approach but it is also very efficient. We obtain very weak conditions on the potentials. 相似文献
16.
Adéla Kochanovská 《Czechoslovak Journal of Physics》1959,9(3):348-360
By accurate measurements of the lattice parameter of aluminium, silver and gold by K
1
radiation of copper and cobalt it is proved that the values determined by the radiation of cobalt are systematically lower than those determined by the radiation of copper. A semiquantitative analysis of the influence of spectral asymmetry on the determination of the parameter from X-ray diffraction lines is carried out and it is proved that this influence is defined not only by the index of asymmetry of the emission line but also by the broadening of the corresponding diffraction line. From this analysis it follows that the differences in the parameter measured when using radiation of cobalt and copper, can be explained by the influence of the spectral asymmetry of the emission lines K
1
of these radiations.
In conclusion the author thanks J. Bedná for careful measurement of the thermal expansion of the photographic film and advice when keeping the samples at constant temperature, J. ermák and J. Kratochvíl for numerous helpful remarks and J. Laek for preparing the samples of powdered gold. 相似文献
1
, K 1 , , , . , , , . , , , K 1.
In conclusion the author thanks J. Bedná for careful measurement of the thermal expansion of the photographic film and advice when keeping the samples at constant temperature, J. ermák and J. Kratochvíl for numerous helpful remarks and J. Laek for preparing the samples of powdered gold. 相似文献
17.
Dirk Saher 《Zeitschrift für Physik B Condensed Matter》1991,85(1):105-110
We study the change of an quasienergy spectrum upon variation of the weight of a perturbation in the Floquet operatorF=F
0e–iV
. Employing ideas from level dynamics and random matrix-theory we show that the distribution of nearest-neighbor spacings can display effectively irreversible behavior. Small deviations from equilibrium relax in a certain collision time which scales with the numberN of levels as collN
–3/2. 相似文献
18.
19.
HOLZER W. PENZKOFER A. GONG S.-H. BLAU W. J. DAVEY A. P. 《Optical and Quantum Electronics》1998,30(1):1-14
The effective stimulated emission cross-section spectra, em,eff(), the stimulated emission cross-section spectra, em(), and the excited-state absorption cross-section spectra, ex()=em()–em,eff(), of the conjugated polymers poly(2,5-dioctadecyloxy-paraphenylene-ethynylene-co-2,5-thienyl) (OPT) and poly(2,5-dioctadecyloxy-paraphenylene-ethynylene-co-2,5-pyridinyl) (OPP) in tetrahydrofuran are determined in the fluorescence region. em,eff() determined by a fluorescence amplification technique is found to be small compared to em() indicating that ex() is nearly as large as em(). The laser excitation to the wide inhomogeneously broadened S1-absorption band leads to the formation of spectrally structured inhomogeneously broadened lattice relaxed exciton conformations extending on average over two monomer units which are thought to be responsible for upper-to-lower-state stimulated emission and lower-to-upper-state (excited-state) absorption. 相似文献
20.
Václav Bartošek 《Czechoslovak Journal of Physics》1956,6(5):505-512
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