共查询到20条相似文献,搜索用时 546 毫秒
1.
Eric A Lord 《Pramana》1975,4(4):164-170
A new generalisation of Einstein’s theory is proposed which is invariant under conformal mappings. Two scalar fields are introduced
in addition to the metric tensor field, so that two special choices of gauge are available for physical interpretation, the
‘Einstein gauge’ and the ‘atomic gauge’. The theory is not unique but contains two adjustable parameters ζ anda. Witha=1 the theory viewed from the atomic gauge is Brans-Dicke theory (ω=−3/2+ζ/4). Any other choice ofa leads to a creation-field theory. In particular the theory given by the choicea=−3 possesses a cosmological solution satisfying Dirac’s ‘large numbers’ hypothesis. 相似文献
2.
K. S. Adhav M. V. Dawande V. B. Raut 《International Journal of Theoretical Physics》2009,48(3):700-705
Bianchi type III space time is considered in the presence of cosmic strings in Einstein’s general theory of relativity. Exact
cosmological models are presented with the help of relation C=B
n
between metric coefficients C and B. Some physical properties of the model in each cases are discussed. 相似文献
3.
Einstein’s relation E = Mc 2 between the energy E and the mass M is the cornerstone of the relativity theory. This relation is often derived in a context of the relativistic theory for closed systems which do not accelerate. By contrast, the Newtonian approach to the mass is based on an accelerated motion. We study here a particular neoclassical field model of a particle governed by a nonlinear Klein-Gordon (KG) field equation. We prove that if a solution to the nonlinear KG equation and its energy density concentrate at a trajectory, then this trajectory and the energy must satisfy the relativistic version of Newton’s law with the mass satisfying Einstein’s relation. Therefore the internal energy of a localized wave affects its acceleration in an external field as the inertial mass does in Newtonian mechanics. We demonstrate that the “concentration” assumptions hold for a wide class of rectilinear accelerating motions. 相似文献
4.
The action of the bosonic sector of the effective field theory induced by heterotic strings in four dimensions, which is relevant
(for instance) to the study of dyons (Shapere et al. in Mod Phys Lett A6: 2677, 1991), is re-interpreted geometrically by
using the new concept of ‘D-Differentiation’. This extends the authors’ geometrical unification of the Einstein–Maxwell theory. 相似文献
5.
Alberto Escalante 《International Journal of Theoretical Physics》2009,48(9):2486-2498
The Hamiltonian analysis for the Einstein’s action in G→0 limit is performed. Considering the original configuration space without involve the usual ADM variables we show that the version G→0 for Einstein’s action is devoid of physical degrees of freedom. In addition, we will identify the relevant symmetries of
the theory such as the extended action, the extended Hamiltonian, the gauge transformations and the algebra of the constraints.
As complement part of this work, we develop the covariant canonical formalism where will be constructed a closed and gauge
invariant symplectic form. In particular, using the geometric form we will obtain by means of other way the same symmetries
that we found using the Hamiltonian analysis. 相似文献
6.
The superdense stars with mass-to-size ratio exceeding 0.3 are expected to be made of strange matter. Assuming that the 3-space
of the interior space-time of a strange star is that of a three-paraboloid immersed in a four-dimensional Euclidean space,
we obtain a two-parameter family of their physically viable relativistic models. This ansatz determines density distribution of the interior self-gravitating matter up to one unknown parameter. The Einstein’s field
equations determine the fluid pressure and the remaining geometrical variables. The information about mass-to-size ratio together
with the conventional boundary conditions lead to the determination of total mass, radius and other parameters of the stellar
configuration.
相似文献
7.
Detlev Buchholz Gandalf Lechner Stephen J. Summers 《Communications in Mathematical Physics》2011,304(1):95-123
Warped convolutions of operators were recently introduced in the algebraic framework of quantum physics as a new constructive
tool. It is shown here that these convolutions provide isometric representations of Rieffel’s strict deformations of C
*–dynamical systems with automorphic actions of
\mathbb Rn{\mathbb R^n} , whenever the latter are presented in a covariant representation. Moreover, the device can be used for the deformation of
relativistic quantum field theories by adjusting the convolutions to the geometry of Minkowski space. The resulting deformed
theories still comply with pertinent physical principles and their Tomita–Takesaki modular data coincide with those of the
undeformed theory; but they are in general inequivalent to the undeformed theory and exhibit different physical interpretations. 相似文献
8.
Based on the geodesic equation in a static spherically symmetric metric we discuss the rotation curve and gravitational lensing.
The rotation curve determines one function in the metric without assuming Einstein’s equations. Then lensing is considered
in the weak field approximation of general relativity. From the null geodesics we derive the lensing equation. The gravitational
potential U(r) which determines the lensing is directly give by the rotation curve U(r) = −v
2(r). This allows to test general relativity on the scale of galaxies where dark matter is relevant. 相似文献
9.
N. Yongram 《International Journal of Theoretical Physics》2011,50(3):838-849
Spin correlations of e
+
e
− pair productions of two colliding photons are investigated and explicit expressions for their corresponding probabilities
are derived and found to be energy (speed) dependent, for initially linearly and circularly polarized photons, different from those obtained by simply combining the spins of the relevant particles, for initially polarized photons. These expressions also depend on the angles of spin of e
+ (and/or of e
−), for initially linearly polarized photons, but not for circularly polarized photons, as a function of the energy. It is remarkable that these explicit results obtained from quantum field theory show
a clear violation of Bell’s inequality of Local Hidden Variables theories at all energies beyond that of the threshold one for particle production, in support of quantum field theory in the relativistic regime.
We hope that our explicit expression will lead to experiments, of the type described in the bulk of this paper, which can
monitor energy (and speed) in polarization correlation experiments. 相似文献
10.
Bianchi type-V string cosmological models in general relativity are investigated. To get the exact solution of Einstein’s
field equations, we have taken some scale transformations used by Camci et al [Astrophys. Space Sci.
275, 391 (2001)]. It is shown that Einstein’s field equations are solvable for any arbitrary cosmic scale function. Solutions
for particular forms of cosmic scale functions are also obtained. Some physical and geometrical aspects of the models are
discussed. 相似文献
11.
12.
As the whole physical community is celebrating 30 years of supersymmetry, the aim of the present paper is to analyse an 50(3,1)
×SU(N)— gauge invariant supersymmetric model on the Einstein’s universe. Thus, by exploiting the maximalS
3 symmetry, which allows the use of group theoretical techniques, we deal with a (1/2, 1, 3/2)—spin particle system on theS
3 ×R manifold. After we derive the Dirac-Rarita-Schwinger-Yang-Mills-type field equations, we focus on the additional terms that
come into theory as a result of the compactness of space and spin coupling to gravity. 相似文献
13.
S. G. Turyshev 《The European physical journal. Special topics》2008,163(1):227-253
We review the foundations of Einstein’s general theory of relativity, discuss recent progress in the tests of relativistic
gravity, and present motivations for new generation of high-accuracy gravitational experiments. We discuss the advances in
our understanding of fundamental physics anticipated in the near future and evaluate discovery potential of the recently proposed
gravitational experiments. 相似文献
14.
The scattering theory for the Klein Gordon equation, with time-dependent potential and in a non-static space-time, is considered.
Using the Klein Gordon equation formulated in the Hubert spaceL
2(R
3) and the Einstein’s relativistic equation in the spaceL
2(R
3, dx) and establishing the equivalence of the vacuum states of their linearized forms in the Hubert spaceL
2(R
3) with the help of unique symmetric symplectic operator, the time evolution unitary operatorU(t) has been fixed for the Klein Gordon equation, incorporating either the positive or negative frequencies, in the infinite
dimensional Hubert spaceL
2(R
3). 相似文献
15.
Marcelo Samuel Berman 《International Journal of Theoretical Physics》2009,48(7):1933-1936
After a discussion on several limiting cases where General Relativity turns into less sophisticated theories, we find that
in the correct thermodynamical and cosmological weak field limit of Einstein’s field equations the entropy of the Universe
is R
3/2-dependent, where R stands for the radius of the causally related Universe. Thus, entropy grows in the Universe, contrary to Standard Cosmology
prediction. 相似文献
16.
M. Faber 《Few-Body Systems》2001,30(3):149-186
We introduce a model designed to describe charged particles as stable topological solitons of a field with values on the
internal space S
3. These solitons behave like particles with relativistic properties like Lorentz contraction and velocity dependence of mass.
This mass is defined by the energy of the soliton. In this sense this model is a generalization of the Sine-Gordon model1(We do not chase the aim to give a four-dimensional generalization of Coleman’s isomorphism between the Sine-Gordon model
and the Thirring model which was shown in 2-dimensional space-time) from 1 + 1-dimensions to 3 + 1-dimensions, from S
1 to S
3. For large distances from the centre of solitons this model tends to a dual U(1)-theory with freely propagating electromagnetic waves. Already at the classical level it describes important effects, which
usually have to be explained by quantum field theory, like particle-antiparticle annihilation and the running of the coupling.
Received November 30, 1999; revised June 20, 2000; accepted for publication October 2, 2000 相似文献
17.
18.
Relativistic constraint mechanics yields consistent systems of coupled Dirac equations for pairs of spinning particles. We
explicitly connect these equations to the Bethe-Salpeter equation of quantum field theory and to the interactions of classical
Fokker-Tetrode dynamics (and hence to classical relativistic field theory) to obtain versions of these equations governed
by systems of (possibly noncoulombic) relativistic potentials whose detailed structures contain important relativistic effects
like correct Darwin interactions. We recast the defining pair of Dirac equations in a number of equivalent but important forms—“external
potential,” Sazdjian, hyperbolic, and Breit— and examine their interconnection. Since the potentials in these equations are
no more singular than — 1/4r2 we are able to solve appropriate versions of them nonperturbatively for the qˉq system to obtain a very good fit to the entire
meson spectrum and for the e
+
e
−
system to calculate the positronium spectrum of QED correct through order α
4
. 相似文献
19.
I. V. Sokolov 《Journal of Experimental and Theoretical Physics》2009,109(2):207-212
Dirac’s analysis of radiation reaction force in classical electrodynamics suggested that a 4-momentum not collinear with 4-velocity
could be introduced for a radiating electron. This would be equivalent to renormalization of the electron mass as an operator
relating these 4-vectors. Dirac also pointed to an arbitrary choice made in deriving the Lorentz-Abraham-Dirac (LAD) equation.
It was shown that renormalization substantially modifies the LAD equation under the additional requirement that the standard
relativistic relation ℰ2 = p
2
c
2 + m
2
c
4 holds for the renormalized energy and momentum. The renormalized LAD equation is more rigorous than the LAD equation, because
the drawbacks of the latter are eliminated, and is simpler than a well-known approximation of the LAD equation. The renormalized
LAD equation appears to be better suited for numerical simulations of processes in ultrahigh-intensity laser-pulse fields. 相似文献
20.
Recently, a non-relativistic renormalizable theory of gravity has been proposed by Hořava. This theory is essentially a field theoretic model for a UV complete theory of gravity and it reduces to Einstein’s general
relativity at large distances. Subsequently, Cai and his collaborators have obtained black hole solution in this gravity theory
and studied the thermodynamic properties of the black hole solutions. In present work, we investigate the geometric thermodynamics
of the above black hole solutions and examine the possibilities of any phase transition. 相似文献