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1.
Consider a gauge fieldF and a scalar field with a self-couplingV() as well as the standard coupling betweenF and . If 02V()·V(), there are no classical lumps. IfV()=||4 the system is conformally invariant and all the energy radiates out along the light cone.Research supported in part by NSF grants MCS 77-01340 and MCS 78-03567 相似文献
2.
Existence and uniqueness results are established for solutions to the Becker-Döring cluster equations. The density is shown to be a conserved quantity. Under hypotheses applying to a model of a quenched binary alloy the asymptotic behaviour of solutions with rapidly decaying initial data is determined. Denoting the set of equilibrium solutions byc
(), 0
s
, the principal result is that if the initial density 0
s
then the solution converges strongly toc
(o), while if 0 >
s
the solution converges weak* toc
(s). In the latter case the excess density 0–
s
corresponds to the formation of larger and larger clusters, i.e. condensation. The main tools for studying the asymptotic behaviour are the use of a Lyapunov function with desirable continuity properties, obtained from a known Lyapunov function by the addition of a special multiple of the density, and a maximum principle for solutions. 相似文献
3.
Z. Frait 《Czechoslovak Journal of Physics》1961,11(5):360-368
The paper gives the results of measuring ferromagnetic resonance on thin cobalt films, vacuum deposited on unheated glass slides. The values of the (g-factor, the width of the curve, the effective stress and uniaxial induced anisotropy were determined as a function of the thickness of the film from measurements of the ferromagnetic absorption in a magnetic field normal and parallel to the surface of the film. Measurements were carried out on a frequency of 9200 MHz and on film thicknesses of 180 to 1800 Å. A qualitative explanation of the observed dependences is given.
The author thanks V. Kamberský and Z. Málek, C. Sc., for providing some of the cobalt films and for help in depositing and measuring the thicknesses, S. Kadeková and M. Polcarová for valuable advice in determining the structure of the films, J. Míová for carefully plotting the results of measurements and Z. Málek and O. tirand for carefully reading the paper and for valuable discussions. 相似文献
, . , , g-, , , . 9200 MHz 180–1800 Å. .
The author thanks V. Kamberský and Z. Málek, C. Sc., for providing some of the cobalt films and for help in depositing and measuring the thicknesses, S. Kadeková and M. Polcarová for valuable advice in determining the structure of the films, J. Míová for carefully plotting the results of measurements and Z. Málek and O. tirand for carefully reading the paper and for valuable discussions. 相似文献
4.
5.
Piotr Podleś 《Letters in Mathematical Physics》1989,18(2):107-119
Three-dimensional differential calculus on quantum spheres S
infc
sup2
,]–1, 1[{0}, c[0, ], is introduced and investigated. Spectra of generalized Laplacians are found. These operators are expressed by generalized directional derivatives. Classical limits of these objects are obtained and a simple approach to quantum mechanics on a quantum sphere is presented. 相似文献
6.
We prove that in the ergodic region [T>J
2(1 + r)] the deviation of the total free energy of the Hopfield neural network converges in distribution asN to a (shifted) Gaussian variable. Moreover, the free energy per site converges in probability to lim(1/N)ln
N
. 相似文献
7.
Anders Martin-Löf 《Communications in Mathematical Physics》1973,32(1):75-92
For the Ising model with nearest neighbour interaction it is shown that the spin correlations
A
B
-
A
B
decrease exponentially asd(A, B) in a pure phase when the temperature is well belowT
c. This is used to prove that the free energyF(,h) is infinitely differentiable in and has one sided derivatives inh of all orders forh=0. The bounds are also used to prove that the central limit theorem holds for several variables such as e.g. the total energy and the total magnetization of the system, the limit distribution being gaussian with variances determined by the second derivatives ofF(,h). 相似文献
8.
E. Duering R. Blumenfeld D. J. Bergman A. Aharony M. Murat 《Journal of statistical physics》1992,67(1-2):113-121
The current and logarithm-of-the-current distributionsn(i) andn(ln i) on bond diluted two-dimensional random-resistor networks at the percolation threshold are studied by a modified transfer matrix method. Thek th moment (–9k8) of n(ln i) i.e., ln i&k, is found to scale with the linear sizeL as (InL)(k). The exponents (k) are not inconsistent with the recent theoretical prediction (k)=k, with deviations which may be attributed to severe finitesize effects. For small currents, ln n(y)–, yielding information on the threshold below which the multifractality of
(i) breaks down. Our numerical results for the moments of the currents are consistent with other available results. 相似文献
9.
H. Albrecht H. Meierling E. F. Wassermann H. Zähres F. T. Hedgcock 《Zeitschrift für Physik B Condensed Matter》1982,49(3):213-220
The impurity contribution to the resistivity in zero field (T) of dilute hexagonal single crystals of ZnMn, CdMn and MgMn has been studied in the mK range on samples cut parallel () and perpendicular () to thec-axis, using a SQUID technique for the measurements. Typical spin glass behavior is found in (T) as well as (T) for all alloys, with Kondo like logarithmic increases at higher temperatures and maxima atT
m at lower temperatures, indicating the influence of impurity interactions. The differences in the corresponding isotropic resistivity poly(T) between the three systems can qualitatively be understood within the framework of a theoretical model by Larsen, describing (T) as a function of universal quantitiesT/T
K and RKKY/T
K
, where RKKY is the RKKY-interaction strength andT
K the Kondo temperature. With respect to the two lattice directions studied, the behavior of (T and (T is anisotropic in the Kondo regime as well as in the range where ordering becomes important. While the anisotropy in the Kondo slope can be understood by an anisotropic unitarity limit, the understanding of the anisotropy in region where impurity interactions are important remains problematic.Dedicated to Prof. Dr. S. Methfessel on the occasion of his 60th birthday 相似文献
10.
D. Babala 《Czechoslovak Journal of Physics》1960,10(9):628-632
The cross-section for the two-quantum annihilation-in-flight of partially polarized beams of particles, obtained by using the polarization density matrix, is given. The formula includes the special results of L. A. Page [1]. The annihilation of a longitudinally polarized positron with a transversally polarized electron is discussed. Computations are made in a centre-of-mass system with summing over photon polarizations.
Abbreviated version of a diploma-thesis for the degree graduate physicist.
The author wishes to express his sincere gratitude to Professor V. Votruba and Dr. L. Valenta for suggesting this work and for many helpful discussions and criticisms. 相似文献
. . . . . .
Abbreviated version of a diploma-thesis for the degree graduate physicist.
The author wishes to express his sincere gratitude to Professor V. Votruba and Dr. L. Valenta for suggesting this work and for many helpful discussions and criticisms. 相似文献
11.
András Sütő 《Communications in Mathematical Physics》1987,111(3):409-415
The spectrum (H) of the tight binding Fibonacci Hamiltonian (H
mn=
m,n+1+
m+1,n
+
m,n
v(n),v(n)=
((n–1)), 1/ is the golden number) is shown to coincide with the dynamical spectrum, the set on which an infinite subsequence of traces of transfer matrices is bounded. The point spectrum is absent for any , and (H) is a Cantor set for 4. Combining this with Casdagli's earlier result, one finds that the spectrum is singular continuous for 16.On leave from the Central Research Institute for Physics, Budapest, Hungary 相似文献
12.
For 2D percolation we slightly improve a result of Chayes and Chayes to the effect that the critical exponent for the percolation probability isstrictly less than 1. The same argument is applied to prove that ifL():={(x, y):x=r cos, y=r sin for some r0, or} and():=limpp
c
[log(p–p
c
)]–1 log Pcr {itO is connected to by an occupied path inL()}, then() is strictly decreasing in on [0, 2]. Similarly, limn [–logn]–1 logP
cr {itO is connected by an occupied path inL()() to the exterior of [–n, n]×[–n, n] is strictly decreasing in on [0, 2]. 相似文献
13.
For a -dimensional system of particles with the two-body potentialq(r)+
v
K(r) and density , it is proved under fairly weak conditions onq andK that the canonical pressure (, ) and chemical potential (, ) tend to definite limits when 0. The limiting functions are absolutely continuous and are given in terms of the derivative of the limiting free energy density
which was found in Part I. 相似文献
14.
R. Sbidl 《Czechoslovak Journal of Physics》1960,10(12):931-948
Zusammenfassung Es wurden einige neue Versuche über die Exöelektronenemission aus Alkalihalogeniden durchgeführt und auf Grund derer Ergebnisse und aller bis jetzt bekannten experimentallen Kenntnisse die Hauptfragen der Exoelektronenemission diskutiert.
Ich habe die angenehme Pflicht meinen Mitarbeitern Milada Kotíková und Václav Stelka zu danken. Herrn G. Sc. Stanislav Koc danke ich für das sorgfältige Durchlesen des Textes und Herrn Dr. A. Bohun für das Borgen seiner im Drucke sich befindenden Arbeiten. 相似文献
-
.
Ich habe die angenehme Pflicht meinen Mitarbeitern Milada Kotíková und Václav Stelka zu danken. Herrn G. Sc. Stanislav Koc danke ich für das sorgfältige Durchlesen des Textes und Herrn Dr. A. Bohun für das Borgen seiner im Drucke sich befindenden Arbeiten. 相似文献
15.
W. Schott V. N. Baturin W. H. Breunlich T. Case H. Daniel F. J. Hartmann M. Jeitler P. Kammel K. Lou E. M. Maev J. Marton M. Mühlbauer C. Petitjean G. E. Petrov Yu. V. Petrov G. G. Semenchuk Yu. V. Smirenin A. A. Vorobyov P. Wojciechowski J. Zmeskal 《Hyperfine Interactions》1993,82(1-4):471-481
The triton energy of the muon capture reaction 3He t+v, where 3 He is the ground state of muonic3He, has been measured in order to investigate a possible heavy v admixture into the flavour with high sensitivity. 3 He has been formed via the pd fusion reaction by stopping – in an ionization chamber (IC) filled with an H/D gas mixture of 3% D concentration at a pressure of 161 bar. In a first short experiment 650 triton events were observed yielding an upper limit for the -heavy v mixing strength of 2.3×10–3 atE
0v=60 MeV. 相似文献
16.
Pierre van Baal 《Communications in Mathematical Physics》1983,92(1):1-18
We give a simplified construction of twist eating configurations, based on a theorem due to Frobenius. These configurations are defined through the equation:U
U
U
+
U
+
=exp(2in
/N) withU
SU(N), =1 tod andn
an antisymmetric matrix with integer entries. In the (Twisted)-Eguchi-Kawai model they yield extrema some of which survive forN. Comparison is made with the Monte Carlo data of the internal energy in the small coupling region. 相似文献
17.
CdSb single crystals were prepared by zone melting in a boat both with and without a seed crystal in a stream of pure hydrogen or in a sealed and evacuated tube. The zone moved with a velocity of 1–20 cm/hour. Zone melting in an evacuated tube was used to prepare CdSb single crystals of high purity containing 1015 acceptors/cm3 at room temperature. During zone refining the stoichiometry is damaged; the front part of the ingot is enriched by cadmium and the end of the ingot by antimony; the enrichment is of an order of several percent after 10 passages of the zone. In the middle part of the ingot the stoichiometric compound remains unchanged. CdSb single crystals grow even by directional cooling of the melt of the stoichiometric compound without a seed crystal.
The author died 28. 5. 1961. 相似文献
CdSb CdSb
CdSb 1–20 cm/, . CdSb CdSb , 1015 cm3 . ; , . . . CdSb .
The author died 28. 5. 1961. 相似文献
18.
G. F. Chew 《Foundations of Physics》1995,25(9):1283-1333
An unorthodox cosmology is based on a notion of standpoint, distinguishing past from future, realized through Hilbert-space representation of the complex conformai group for 3+1spacetime and associated coherent states. Physical (approximate) symmetry attaches to eight-parameter complex Poincaré displacements, interpretable as growth of standpoint age (one parameter), boost of matter energy-momentum in standpoint rest frame (three parameters) and displacement of matter location in a compact U(1)O(4)/O(3) spacetime attached to standpoint (four parameters). An initial condition (at big bang) is characterized by a huge dimensionless parameter that breaks dilation invariance. Four major length scales are recognized, called Planck, particle, lab, and Hubble, with separations controlled by ; all physical concepts, including spacetime, depend on wideness of scale separation. 相似文献
19.
The results of an experimental investigation of the parameters of the surface helical instability (SHI) in germanium are presented. The dependence of the amplitude of the current oscillations of the helical wave and frequency on the electric E and magnetic B fields with E and B significantly exceeding the threshold values Et and Bt are presented for the case of nonequilibrium (for temperatures T < 343°K) and equilibrium (T 343°K) plasma. It is shown that for small supercriticality (E = (E-Et)/Et 1, = ( -t)/t 1) > the square of the amplitude of the current oscillations and the frequency shift are proportional to the supercriticality, i.e., the regime for excitation of SHI is soft.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 18–21, May, 1981. 相似文献
20.
Richard Mould 《Foundations of Physics》1995,25(11):1621-1629
The observer in physics has always referred to someone who stands on the outside of a system looking in. In this paper an inside observer is defined, and an experiment is proposed that tests a given formulation of the problem of measurement in quantum mechanics. 相似文献