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1.
A new metric which we call the intrinsic metric is introduced on the states of the generalized logic of quantum mechanics. It is shown that every automorphism on is an isometry. A norm can be defined on the linear spanE of which reduces to the intrinsic metric on. IfX is the completion ofE then every automorphism, on has a unique extension to a linear isometry onX. A comparison is made between these results and those of Kroniff.  相似文献   

2.
We study a one-dimensional lattice gas where particles jump stochastically obeying an exclusion rule and having a small drift toward regions of higher concentration. We prove convergence in the continuum limit to a nonlinear parabolic equation whenever the initial density profile satisfies suitable conditions which depend on the strengtha of the drift. There is a critical valuea c ofa. Fora<a c, the density values are unrestricted, while foraa c, they should all be to the right or to the left of a given interval (a). The diffusion coefficient of the limiting equation can be continued analytically to (a), and, in the interior of (a), it has negative values which should correspond to particle aggregation phenomena. We also show that the dynamics can be obtained as a limit of a Kawasaki evolution associated to a Kac potential. The coefficienta plays the role of the inverse temperature. The critical value ofa coincides with the critical inverse temperature in the van der Waals limit and (a) with the spinodal region. It is finally seen that in a scaling intermediate between the microscopic and the hydrodynamic, the system evolves according to an integrodifferential equation. The instanton solutions of this equation, as studied by Dal Passo and De Mottoni, are then related to the phase transition region in the thermodynamic phase diagram; analogies with the Cahn-Hilliard equations are also discussed.This paper is dedicated to Jerry Percus with great affection on the occasion of his 65th birthday.  相似文献   

3.
It is shown that to each choice of conformal factor for the conformal metric on future null Infinity (+) there is associated an equivalence class of slicings of +. Each slicing in turn gives rise to a family of null hypersurfaces in the physical space-time.Supported by NSF Grant No. GP-35773X1.  相似文献   

4.
There are series solutions for characteristic boundary value problems for fields on black hole backgrounds that converge when the data are given on = +, or on = +, but may not converge when the data are given on , or on + +. We specialize to oscillatory data of frequency and calculate approximate reflection and transmission coefficientsR() andT(), using a field generated by data on = +, and again, using a field generated by data on . The first calculation gives qualitatively good results at all frequencies at each order of approximation, and quantitatively better results at higher orders of approximation; the second calculation, using the series which may not converge, gives bad results except at very high frequencies. Thus for the physically unnatural case of a field that vanishes on and goes toe iv on + we have a series that is convergent, and uniformly so with respect to frequency, while for the natural case of a field that vanishes on and goes toe iv on we are limited to high frequencies. It is argued that a frequency-dependent renormalization of a series of the first type provides an approximation scheme that is convergent, and uniformly so with respect to frequency, for the physically important problems of the second type. The difficulties posed by the -dependent renormalization for the study of incident pulses are discussed.  相似文献   

5.
In general relativity, conservation of energy and momentum is expressed by an equation of the form /x= 0, where –gT represents the total energy, momentum, and stress. This equation arises from the divergence formula dV v = (/x v )d 4 d. Here we show that this formula fails to account properly for the system of basis vectors e(x). We obtain the (invariant) divergence formula e dV v = e (/x v + )d 4 d. Conservation of energy and momentum is therefore expressed by the covariant equation (/x v ) + = 0. We go on to calculate the variation of the action under uniform displacements in space-time. This calculation yields the covariant equation of conservation, as well as the fully symmetric energy tensor . Finally, we discuss the transfer of energy and momentum, within the context of Einstein's theory of gravitation.  相似文献   

6.
In this paper we prove that if there is a naked singularity, then there will be some null geodesic, reaching + from the singularity, which does not satisfy the strong curvature condition regardless of whether causality is violated or not. Assuming that a naked singularity is a strong curvature singularity only sufficiently far to the future, we prove that strong causality is violated arbitrarily close to +.Work partially supported by the Nuffield Foundation and by the Consiglio Nazionale delle Ricerche of Italy under contract N.CT 81.00532.02.  相似文献   

7.
The tangent bundle X of a Calabi-Yau threefoldX is the only known example of a stable bundle with non-trivial restriction to any rational curve onX. By deforming the direct sum of X and the trivial line bundle one can try to obtain new examples. We use algebro-geometric techniques to derive results in this direction. The relation to the finiteness of rational curves on Calabi-Yau threefolds is discussed.  相似文献   

8.
For automorphism groups of operator algebras we show how properties of the difference t – ' t are reflected in relations between the generators , . Indeed for a von Neumann algebraM with separable predual we show that if t – 't 0.28 for smallt, then = 0(+)°-1 where is an inner automorphism ofM and is a bounded derivation ofM. If the difference t – ' t =O(t) ast ; 0, then = + and if t – ' t 0.28 for allt then =. We prove analogous results for unitary groups on a Hilbert space andC 0,C 0 * groups on a Banach space.This paper subsumes an earlier work of the same title which appeared as a report from Z.I.F. der Universität BielefeldWith partial support of the U.S. National Science Foundation  相似文献   

9.
10.
Pairs of gamma quanta, giving a sum equal to the binding energy of the last neutron in a Co60 isotope, were studied during radiation capture on a Co59 nucleus. The energies of the gamma quanta giving such cascades were determined and an attempt was made to determine the relative intensities of the different cascades.
- Co59
Co59 -, Co60. -, , .


In conclusion the authors thank J. Vávra for cooperation in the measurements.  相似文献   

11.
12.
In this paper, we prove the following improved Vitali–Hahn–Saks measure convergence theorem: Let (L, 0, 1) be a Boolean algebra with the sequential completeness property, (G, ) be an Abelian topological group, be a nonnegative finitely additive measure defined on L, {n: n N} be a sequence of finitely additive s-bounded G-valued measures defined on L, too. If for each a L, {n(a)}n N is a -convergent sequence, for each nN, when { (a)} convergent to 0, {n(a)} is -convergent, then when { (a)} convergent to 0, {n(a)} are -convergent uniformly with respect to nN  相似文献   

13.
A survey is given of the results of measuring the radioactivity of rain-out from 1. 11. 1956 to 1. 2. 1960 and of fall-out from 1. 11. 1958 to 1. 2. 1960.The temporary cessation of nuclear weapon tests from 1. 11. 1958 became apparent in the second half-year after the cessation (from 1. 5 to 31. 10. 1959) by a decrease in the cumulative activity to 45% of the value for the first half-year (from 1. 11. 1958 to 30. 4. 1959). At the end of 1959 another decrease was apparent.It was shown on the basis of long-term investigation into the activity that the samples of fall-out with greater activity contain relatively very little admixture from earlier nuclear tests so that in the period of a few weeks to months the sets of fission products may be regarded as practically isolated. The exponentn in the relationA=at –n is most frequently 1.2 for the period of the first four mounths and for older samples is most oftenn=1.5. The energy of the beta and gamma rays from fall-out was estimated on the basis of absorption measurements. It was shown that the quality of the beta radiation varies with the age of the samples.A brief survey is given of the results of determining the Sr 90 content in fall-out and milk, and of the methods of physical evidence of Sr 90 used.
1. 11. 1956 1. 2. 1960 1. 11. 1958 1. 2. 1960. 1. 11. 1958 , ( 1. 5. 31. 10. 1959) 45% ( 1. 11. 1958 30. 4. 1959). 1959 . . , , . n A=at –n 4 1,2; n=1,5. - - . , - . Sr90 . Sr90.


The author thanks Prof. F. Bhounek, member of the Czechoslovak Academy of Sciences, for valuable advice during this work.  相似文献   

14.
We present exact explicit expressions for the row spin-spin correlation functions 00 n0 in the isotropicd= 2 Ising model, in terms of elliptic integrals, forn 5. We also give a general structural formula for 00 n0.  相似文献   

15.
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   

16.
Let S() be the S-matrix at energy for an abstract scattering system. We derive a bound, in terms of the interaction, on integrals of the form h () S()- HS 2 d, where denotes the Hilbert-Schmidt norm.Supported by the Swiss National Science Foundation.  相似文献   

17.
LetE(g) be the vacuum energy for theP(ø)2 Hamiltonian with space cutoffg(x)0 and coupling constant 0. For suitable families of cutoffsg1, the vacuum energy per unit volume converges; i.e., –E(g)/g(x)dx (). We obtain bounds on the dependence of () for large and small . These lead to estimates forE(g) as a functional ofg that permit a weakening of the standard regularity conditions forg. Typical of such estimates is the linear lower bound, –E(g)const g(x)2 dx, valid for allg0 provided thatP is normalized so thatP(0)=0. Finally we show that the perturbation series for () is asymptotic to second order.Research partially supported by AFOSR under Contract No. F 44620-71-C-0108.Postal address after September 30, 1972: via A. Falcone 70, 80127, Napoli, Italy.  相似文献   

18.
19.
The purpose of this paper is to review and to extend, wherever possible, the Kramers-Kronig relations, sum rules, and symmetry properties for the electrodynamic transport tensors of a linear plasma medium. For complete generality, we consider both nonrelativistic and relativistic plasmas with and without external magnetic fields. Our study is carried out first within the framework of classical electrodynamics. We then exploit the statistical-mechanical fluctuation-dissipation theorem to further obtain the Onsager symmetry relations and Kubo sum-rule frequency moments. Of special significance is the emergence of a variety of new Kramers-Kronig formulae andf-sum rules for the inverse dispersion tensor.Nomenclature E(k,) electric field intensity - Ê(k,) electric field in absence of plasma particles, - (k,) electric field due to the plasma particles (=E-Ê) - B(k,) magnetic induction - D(k,) electric induction - H(k,) magnetic field strength - B 0 constant external magnetic field - A 0 vector potential corresponding toB 0 - (k,),j(k, co) charge and current densities due to the plasma particles - (k,),J(k,) charge and current densities of the external agency - (k,,B 0) dielectric tensor of the plasma medium in the presence of B0 - (k,,B 0) diamagnetic tensor - (k, co,B 0) (k,,B 0) – 1, electric polarizability tensor - (k,,B 0) magnetic polarizability tensor - (k,,B 0) ordinary conductivity tensor - (k,,B 0) external conductivity tensor - D(k,,B 0) n2T–(k,,B 0), dispersion tensor, where T=1-kk is the transverse projection tensor (k being the unit vector in the direction ofk) andn = kc/ the index of refraction - n2T – 1, = vacuum wave operator (value of D in vacuum) - 1/2( + ), Hermitian part of - ^ 1/2( – ), Anti-Hermitian part of a - , real and imaginary parts of a - R(r,t) dissipated power per unit volume of plasma - U total energy absorbed by the plasma - R(k,) E*(k,) · (k,,b 0) ·E(k,) corresponding spectral energy density - W(r,t) 1/20E2(r, 0 + (l/20) B2(r,t), field energy density - W(k,) 1/20E*k,) ·E(k,) + (l/20)B *(k,) · B(k,), energy content in a certain domain of (k,)-space for a single mode - x i,p i,v i coordinate, momentum, and velocity of ith electron - i [1–(i 2/c2)]–1/2 - X j,P j,V j coordinate, momentum, and velocity of jth ion - {A q}, {Eq} field coordinates and momenta - jk(t),J k(t) perturbations in the microscopic electron and ion current densities due to the presence of the small external vector potential agencyâ(r,t) = (1/L3) âk(t) expi k ·r - Liouville distribution function = 0 + - 0 macrocanonical distribution function characterizing the equilibrium state of the system in the infinite past - small perturbation due toA - H0 Hamiltonian of equilibrium system which includes interaction - H Hamiltonian for the interaction between the system and the small external perturbing agencyA - 0 = dR()0 expectation value of any quantity over the equilibrium ensemble (dR is an element of hypervolume in -phase space) - G(12) two-particle distribution function - F(1) one-particle distribution function - g(¦x2 – x1 ¦) [G(12)/F(1)F(2)] – 1, pair correlation function - N total number of electron in volume L3 - n 0 equilibrium density (of electrons) - –1 temperature (in energy units) - 0 (n0e2/m0)1/2, equilibrium electron plasma frequency - c ¦e ¦–B 0/m, electron frequency - –1 ( 0/n0e2)1/2, Debye length - 0 (n0Ze2/M0)1/2, equilibrium ion plasma frequency - c ZeB0/M, ion cyclotron frequency  相似文献   

20.
Two solutionsT andT of the braid equation acting onA A (whereA is a Hopf algebra) are described. IfA is a cocommutative, thenT=. IfA is commutative, thenT= ( denotes the flip: (a b) =b a for anya,b A).Supported by a grant of the Ministry of Education of Poland.  相似文献   

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