共查询到20条相似文献,搜索用时 0 毫秒
1.
A new representation is found for the action of the recently suggested ghost-free nonlocal gravity models generating de Sitter or Anti-de Sitter background with an arbitrary value of the effective cosmological constant. This representation allows one to extend applications of these models from maximally symmetric to generic Einstein spaces and black hole solutions, but clearly indicates violation of the general relativistic limit in this class of theories, induced by their infrared behavior. It is shown that this limit can be recovered in a special conformal frame of these theories, and their relation to critical gravity models is also briefly discussed. 相似文献
2.
We suggest a class of generally covariant ghost-free nonlocal gravity models generating de Sitter or anti-de Sitter background with an arbitrary value of the effective cosmological constant and featuring a mechanism of dark matter simulation. These models interpolate between the general relativistic phase on a flat spacetime background and their strongly coupled infrared (anti-)de Sitter phase with two propagating massless graviton modes. 相似文献
3.
Adrian Wüthrich 《Foundations of Physics》2014,44(6):594-609
A fair amount of recent scholarship has been concerned with correcting a supposedly wrong, but wide-spread, assessment of the consequences of the empirical falsification of Bell-type inequalities. In particular, it has been claimed that Bell-type inequalities follow from “locality tout court” without additional assumptions such as “realism” or “hidden variables”. However, this line of reasoning conflates restrictions on the spatio-temporal relation between causes and their effects (“locality”) and the assumption of a cause for every event (“causality”). It thus fails to recognize a substantial restriction of the class of theories that is falsified through Bell-type inequalities. 相似文献
4.
Hernando Quevedo 《General Relativity and Gravitation》2006,38(4):599-606
We present a parametrization of T
3 and S
1 × S
2 Gowdy cosmological models which allows us to study both types of topologies simultaneously. We show that there exists a coordinate system in which the general solution of the linear polarized special case (with both topologies) has exactly the same functional dependence. This unified parametrization is used to investigate the existence of Cauchy horizons at the cosmological singularities, leading to a violation of the strong cosmic censorship conjecture. Our results indicate that the only acausal spacetimes are described by the Kantowski-Sachs and the Kerr-Gowdy metrics. 相似文献
5.
In the framework of quantum electrodynamics with the nonlocal interaction it is shown that the correspondence principle holds in the problem on the self-mass of an electron and a particle with arbitrary spin. It appears that the second order of perturbation theory in the limit ? → 0 gives just the classical expression for the electron self-energy, and all higher order corrections are zero. 相似文献
6.
Moffat JW 《Physical review D: Particles and fields》1990,41(4):1177-1184
7.
The gauge dependence of the effective action in two-dimensional induced quantum gravity is investigated. A unique effective action is found, and its dependence on the metric of the configuration space is studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 97–100, January, 1992. 相似文献
8.
We propose a string realization of the AdS4 brane in AdS5 that is known to localize gravity. Our theory is M D5 branes in the near horizon geometry of N D3 branes, where M and N are appropriately tuned. 相似文献
9.
Ovesson S 《Physical review letters》2002,88(11):116102
Mean-field nucleation theory has for a long time been successfully used to extract microscopic parameters from island density data in growth experiments. However, it produces grossly incorrect results when used to analyze weakly corrugated systems, where adsorbate interactions cannot be neglected. Here, a mean-field theory that includes nonlocal adsorbate interactions is developed and successfully tested against kinetic Monte Carlo growth simulations for a realistic adsorbate system. 相似文献
10.
Takeshi Fukuyama 《Zeitschrift fur Physik C Particles and Fields》1981,10(1):9-15
General relativity is formulated in the framework of Yang-Mills theory whose gauge group isO(3, 2). This theory allows the global topological charge of spin without breaking Bianchi identity. β function in the renormalization group equation is negative and the confinement of gravity is expected. The confinement radius is, however, actually infinite and we can read off the relation that the average mass density of the present universe is exactly equal to the critical value ρ c (t)=6H 2(t)/K 2. 相似文献
11.
It is pointed out that string-loop effects may generate matter couplings for the dilaton allowing this scalar partner of the tensorial graviton to stay massless while contributing to macroscopic gravity in a way naturally compatible with existing experimental data. Under a certain assumption of universality of the dilaton coupling functions, the cosmological evolution drives the dilaton towards values where it decouples from matter. At the present cosmological epoch, the coupling to matter of the dilaton should be very small, but non zero. This provides a new motivation for improving the experimental tests of Einstein's Equivalence Principle.This essay received the first award from the Gravity Research Foundation, 1994-Ed. 相似文献
12.
The model of quarks in the frame of nonlocal quantum field theory is demonstrated. Here all basic principles of quantum theory are conserved, quarks are automatically confined and the scaling behaviour of the amplitude of an inclusive process is manifested explicitly in lower orders of perturbation theory.On leave of absence from theDept. of Theoretical Physics, Comenius University, Bratislava, Czechoslovakia. 相似文献
13.
It is proved that theS-matrix satisfies the Bogolubov microcausality condition in each order in perturbation theory in a quantum field theory with nonlocal interaction, where the nonlocality is introduced with the help of form factors being entire analytical functions of the order 1/2. 相似文献
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17.
Ramesh Chandra 《General Relativity and Gravitation》1988,20(5):437-450
Quantum effects at the beginning of the universe suggest the variability of the cosmical constant and the effective gravitational constant. These variations may be incorporated into the theory of gravity in a natural way by proposing a longrange complex scalar field similar to the massless Higgs scalar field. On this basis a broken-symmetry theory of gravity has been proposed. The WKB expansion of the complex scalar field helps us to relate the effective gravitational constant to the usual gravitational constant. The proposed theory of gravity has been applied to a homogeneous and isotropic cosmological model to study the quantum effects near the beginning of the universe. 相似文献
18.
J. D. Gegenberg 《General Relativity and Gravitation》1989,21(2):155-169
The route from string theory to a ten-dimensional supergravity/super-Yang-Mills field theory is briefly illumined. The process of extracting a classical four-dimensional gravity theory from the ten-dimensional theory is discussed and a simple model containing gravity, electromagnetism, a dilaton field, and a Kalb-Ramond field is proposed. The equations of motion of a test particle in a background of gravity, dilation, and Kalb-Ramond fields are displayed. Some static spherically symmetric vacuum solutions are derived, and some astrophysical implications are discussed. 相似文献
19.
We perform the dual transformation of theYang-Mills theory in three dimensions using the Wilson action on the cubic lattice. The dual lattice is made of tetrahedra triangulating a 3-dimensional curved manifold but which is embedded into a flat 6-dimensional space [for the SU(2) gauge group]. In the continuum limit, the theory can be reformulated in terms of 6-component gauge-invariant scalar fields having the meaning of the external coordinates of the dual lattice sites. These 6-component fields induce a metric and a curvature of the 3-dimensional dual-color space. The Yang-Mills theory can also be rewritten as a quantum gravity theory with the Einstein-Hilbert action but with a purely imaginary Newton constant plus a homogeneous “ether” term. The theory can be formulated in a gauge-invariant and local form without explicit color degrees of freedom. 相似文献
20.
H R Fazlollahi 《理论物理通讯》2024,(4):128-135
Recently, reconsidering the Rastall idea Tμ;νν=α,μ through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. Hence, in this study we have reinvestigated holographic dark energy ΡX~H2 in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model. 相似文献