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1.
It is shown that if the Brans-Dicke equations have the solution,g ij generated by the trace free sourceT n (T-O) then there exists an adjoint solution –1, 2gij of these equations generated by the source -2 T u. An example is considered.  相似文献   

2.
The k theory is compared with the multilinear theory of scalar fields 1, 2, ..., k having the same mass as that of . In particular, it is shown that Feynman integrals encountered in the 3 theory are not necessarily present also in the 1 2 3 theory, but they are if they correspond to planar Feynman graphs having no tadpole part. Furthermore, a necessary and sufficient condition for the presence of a 3 Feynman integral in the 1 2 2 theory is found. Those considerations are applications of graph theory, especially of the coloring problem of graphs, to Feynman graphs.  相似文献   

3.
The quantum harmonic oscillator is described in terms of two basic sets of coordinates: linear coordinates x, px and angular coordinates ei, P (action-angle variables). The angular coordinate ei is assumed unitary, the conjugate momentum p is assumed Hermitian, and ei and p are assumed to be a canonical pair. Two transformations are defined connecting the angular coordinates to the linear coordinates. It is found that x, px can be physical, i.e., Hermitian and canonical, only under constraints on the p eigenvalue spectrum. The conclusion is that ei can be a unitary operator. A parallel analysis of the classical harmonic oscillator is done with equivalent results.  相似文献   

4.
The renormalization group technique is used to study rigorously the ()4 perturbation of the massless lattice field in dimensionsd2. Asymptoticity of the perturbation expansion in powers of is established for the free energy density. This is achieved by using Kadanoff's block spin transformation successively to integrate out high momentum degrees of freedom and by applying ideas previously used by Gallavotti and Balaban in the context of the ultraviolet problems. The method works for arbitrary semibounded polynomials in and .Supported in part by the National Science Foundation under Grant No. PHY 79-16812On leave from Department of Mathematical Methods of Physics, University, PL-00-682 Warsaw, Poland  相似文献   

5.
We consider two dimensional boson field theories with an interaction potentialV (). We show how to define a cut-off, renormalised Hamiltonian for a certain class of non-polynomialV (), which are defined via an integral transform. We formulate precisely a variational argument devised by Coleman, obtaining a constraint on the coupling constant of the theory with generalV (), and illustrate the argument with several examples.  相似文献   

6.
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   

7.
A Higgs vacuum field is characterized by the set of conditionsD =0, which lead to a generalized Meissner effect and partially determine the vector potentialA in terms of . Applying this method to the Weinberg-Salam theory, we assert that there exist stringlike configurations in which a pair of magnetic poles are bound by a flux string of theZ 0 field, with an energy scale in the TeV range. We also point out that pure gauges in non-Abelian gauge theories are not well-defined due to topological singularities. In order to be meaningful, they must be enlarged to a class of almost pure gauges which include the various known topological configurations.Work supported in part by the U.S. Department of Energy, San Francisco Office, and by the Sherman Fairchild Distinguished Scholars Program.On leave from the University of Chicago.  相似文献   

8.
Under weak technical assumptions on a net of local von Neumann algebras {A(O)} in a Hilbert space , which are fulfilled by any net associated to a quantum field satisfying the standard axioms, it is shown that for every vector state in there exist observables localized in complementary wedge-shaped regions in Minkowski space-time that maximally violate Bell's inequalities in the state . If, in addition, the algebras corresponding to wedge-shaped regions are injective (which is known to be true in many examples), then the maximal violation occurs in any state on () given by a density matrix.  相似文献   

9.
The continuum form of the Gauss-Hertz principle is extended to include the time domain as well as space. The Schrödinger equation and general relativity are derived by this method. The equivalence of the principle is shown to that of the Hamiltonian method where the energy is the expression –[ 2 +A·2 A], with being the difference between the acceleration potential and potential energy density, andA being the difference between the vector potentials of the acceleration field and the force field. The goal of Hertz to demonstrate a third arrangement of the principles of mechanics...which starts with... time, space and mass has apparently been achieved for relativity and for quantum mechanics, in addition to those classical equations previously found.  相似文献   

10.
We consider quantum systems driven by Hamiltonians of the formH+W(t), where the spectrum ofH consists of an infinite set of bands andW(t) depends arbitrarily on time. Let H (t) denote the expectation value ofH with respect to the evolution at timet of an initial state . We prove upper bounds of the type H (t)=O(t ), >0, under conditions on the strength ofW(t) with respect toH. Neither growth of the gaps between the bands nor smoothness ofW(t) is required. Similar estimates are shown for the expectation value of functions ofH. Sufficient conditions to have uniformly bounded expectation values are made explicit and the consequences on other approaches to quantum stability are discussed.  相似文献   

11.
The newly proposed anisotropic fiber structures with cylindrical polar principal axes appear to be an interesting novel class of special lightguides. In this paper, some interesting results relating to such fibers are derived which, to the knowledge of this author, have not yet been reported in the literature. It is found that, ifn c0 ( )1/2>n zc0( r )1/2, TE01 will be the fundament mode with a range of single-mode operation given by 2.61n zc0 (2 r )1/2 /a<2.61n c0(2 )1/2. On the other hand, ifn zc0 ( r )1/2>n c0( )1/2, then TM01 becomes the fundamental mode whose single-mode operation range is 2.61n c0 (2 )1/2 /a<2.61n zc0(2 r )1/2.  相似文献   

12.
We investigate the statistical and dimensional properties of uniform star polymers attached by the branching vertex of degreef in a wedge geometry in three dimensions and described by the wedge angles and. We show that the growth constant is equal to f , where is the self-avoiding walk limit. Thef and (, ) dependences of the corresponding critical exponent f (, ) are studied using Monte Carlo techniques. In the casef=1, our results are compared with existing predictions obtained from series expansion and renormalization group methods. We have also estimated the amplitudes for the mean square radius of gyration and the mean square end-to-end branch length. Our results for the ratio of the mean square radius of gyration of anf-star to that of a linear polymer of the same degree of polymerization attached in a similar wedge, and the analogous ratio for the mean square end-to-end branch length, are consistent with these ratios being lattice-independent quantities.  相似文献   

13.
We study the long-time relaxation of magnetization in a disordered linear chain of Ising spins from an initially aligned state. The coupling constants are ferromagnetic and nearest-neighbor only, taking valuesJ 0 andJ 1 with probabilitiesp and 1–p, respectively. The time evolution of the system is governed by the Glauber master equation. It is shown that for large timest, the magnetizationM(t) varies as [exp(–0 t](t), where 0 is a function of the stronger bond strengthJ 0 only, and (t) decreases slower than an exponential. For very long times, we find that ln (t) varies as –t 1/3. For low enough temperatures, there is an intermediate time regime when ln (t) varies as –t 1/2. The results can be extended to more general probability distributions of ferromagnetic coupling constants, assuming thatM(t) can only increase if any bond in the chain is strengthened. If the coupling constants have a continuous distribution in which the probability density varies as a power law near some maximum valueJ 0, we find that ln (t) varies as –t 1/3(lnt)2/3 for large times.  相似文献   

14.
Consider a viscous incompressible fluid in the half-plane and letu t be a solution of the Navier-Stokes equation. In this paper we prove that the product formula (E t/n G t/n u) n u 0, whereE t is the Euler flow,G t is the heat flow and is a suitable operator describing the vorticity production due to the boundary, converges uniformly tou t in the limitn .Research supported by Ministero della Pubblica Istruzione, CNR contract No. 84.00016.02 and GNFM  相似文献   

15.
The nonlinear wave equation, tt –+3=0, has many solutions that are periodic in time and localized in space, all with infinte energies. The search for spherically symmetric solutions that are well represented by the simple approximation, (r, t)A(r) sin t, leads to a discrete spectrum of solutions{ N (r, t; )}. The solutions are nonlinear wavepackets, and they can be regarded as particles. The asymptotic theory () of the motion of the guiding center of theNth wavepacket, in the presence of a specified potential, is characterized by an infinite mechanical mass and an infinte interaction mass, and they are compatible. The rest mass in the classical relativistic mechanics of guiding centers ism 0 c 2= N ; i.e. the spectrum { N } determines a spectrum of Planck's constants.On leave (1972–73) Université de Paris VI, Département de Mécanique, 75 Paris 5e, France.  相似文献   

16.
A subalgebraM 0 of a von Neumann algebraM is called weakly sufficient with respect to a pair (,) of states if the relative entropy of and coincides with the relative entropy of their restrictions toM 0. The main result says thatM 0 is weakly sufficient for (,) if and only ifM 0 contains the Radon-Nikodym cocycle [D,D] t . Other conditions are formulated in terms of generalized conditional expectations and the relative Hamiltonian.  相似文献   

17.
In this paper we propose a new theory of a fiber bundle provided with a local metric of internal space. The fibers differ from usual fibers, having an enlarged factor. The enlargement may be procured by a differential mapping(x) from structure groupG to the fiberF x atx M, and(x)R. The torsion presented stems from the local metric of internal space and the local metric stems from a induced mapping *(x) of(x). From the theory we can get the Brans-Dicke theory with torsion. If we assume the spin density of the gauge field determines the enlarged factor of the fiberF x, our theory is an extended Cartan theory.  相似文献   

18.
We consider a boson field (x) under an interaction of the form V( k (x))dx, where k (x) is the momentum cut-off field, andV() is a continuous bounded function. Under a weak regularity condition onV(), we prove that the total energy operator is self adjoint, that the asymptotic fields exist and that the scattering operator exists.  相似文献   

19.
We give a simple proof of Lorentz covariance for theP()2 model without using the higher order estimates: For each Poincaré transformation {a, } and each bounded regionB of Minkowski space there exists a unitary operatorU which correctly transforms the Heisenberg picture field operator:U (f)U*=(f (a,)),f C 0 (B).  相似文献   

20.
mesons have been reconstructed from their decay to positive and negative kaons, using the data obtained from interaction of neutrons at 20–70 GeV with a carbon target collected by EXCHARM experiment at the Serpukhov accelerator. The analysis relies on the use of reconstructing trajectories and particle identification. From about 45 million events (19600 ± 350) mesons were found. The meson mass is measured to be (1019.4 ± 0.1)MeV/c 2; the meson width is measured to be (4.9 ± 0.3)MeV/c 2. The investigation has been performed at the Joint Institute for Nuclear Research at the Laboratory of Super High Energies.  相似文献   

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