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1.
Anderson W. Mol 《Central European Journal of Physics》2011,9(5):1151-1164
In the present work we propose a generalization of Newton’s gravitational theory from the original works of Heaviside and
Sciama, that takes into account both approaches, and accomplishes the same result in a simpler way than the standard cosmological
approach. The established formulation describes the local gravitational field related to the observables and effectively implements
the Mach’s principle in a quantitative form that retakes Dirac’s large number hypothesis. As a consequence of the equivalence
principle and the application of this formulation to the observable universe, we obtain, as an immediate result, a value of
Ω = 2. We construct a dynamic model for a galaxy without dark matter, which fits well with recent observational data, in terms
of a variable effective inertial mass that reflects the present dynamic state of the universe and that replicates from first
principles, the phenomenology proposed in MOND. The remarkable aspect of these results is the connection of the effect dubbed
dark matter with the dark energy field, which makes it possible for us to interpret it as longitudinal gravitational waves. 相似文献
2.
D. F. Roscoe 《General Relativity and Gravitation》2002,34(5):577-603
This paper is essentially a speculation on the realization of Mach's Principle, and we came to the details of the present analysis via the formulation of two questions: (a) Can a globally inertial space &; time be associated with a non-trivial global matter distribution? (b) If so, what are the general properties of such a global distribution? These questions are addressed within the context of an extremely simple model universe consisting of particles possessing only the property of enumerability existing in a formless continuum.Since there are no pre-specified ideas of clocks and rods in this model universe, we are forced into two fundamental considerations, these being: What invariant meanings can be given to the concepts of spatial displacement and elapsed time in this model universe? Briefly, these questions are answered as follows: the spatial displacement of a particle is defined in terms of its changed relationship with the particle ensemble as a whole—this is similar to the man walking down a street who can estimate the length of his walk by reference to his changed view of the street. Once the concept of invariant spatial displacement is established, a corresponding concept of elapsed time then emerges in a natural way as ‘process’ within the system. Thus, unlike for example, general relativity, which can be considered as a theory describing the behaviour of specified clocks and rods in the presence of matter, the present analysis can be considered as a rudimentary—but fundamental—theory of what underlies the concepts of clocks and rods in a material universe. In answer to the original two questions, this theory tells us that a globally inertial space &; time can be associated with a non-trivial global matter distribution, and that this distribution is necessarily fractal with D = 2. This latter result is compared with the results of modern surveys of galaxy distributions which find that such distributions are quasi-fractal with D ? 2 on the small-to-medium scales, with the situation on the medium-to-large scales being a topic of considerable debate. Accordingly, and bearing in mind the extreme simplicity of the model considered, the observational evidence is consistent with the interpretation that the analysed point-of-view captures the cosmic reality to a good first-order approximation. We consider the implications of these results. 相似文献
3.
To test modified Newtonian dynamics (MOND) on galactic scales, we study six strong gravitational lensing early-type galaxies from the CASTLES sample. Comparing the total mass (from lensing) with the stellar mass content (from a comparison of photometry and stellar population synthesis), we conclude that strong gravitational lensing on galactic scales requires a significant amount of dark matter, even within MOND. On such scales a 2 eV neutrino cannot explain the excess of matter in contrast with recent claims to explain the lensing data of the bullet cluster. The presence of dark matter is detected in regions with a higher acceleration than the characteristic MOND scale of approximately 10(-10) m/s(2). This is a serious challenge to MOND unless lensing is qualitatively different [possibly to be developed within a covariant, such as Tensor-Vector-Scalar (TeVeS), theory]. 相似文献
4.
Subhash Kak 《International Journal of Theoretical Physics》2007,46(5):1424-1430
This paper considers how the motion of an observer in an isotropic universe may be determined by measurements. This provides
a means to identify inertial frames, yielding a simple resolution to the twins paradox of relativity theory in such a universe.
We propose that isotropy is a requirement for a frame to be inertial; this makes it possible to relate motion to the large
scale structure of the universe. 相似文献
5.
Hans J. Fahr 《Foundations of Physics Letters》2006,19(5):423-440
According to ideas of Mach, Whitrow, Dirac, or Hoyle, inertial masses of particles should not be a genuine, predetermined
quantity; rather they should represent a relational quantity which by its value somehow reflects the deposition and constellation
of all other objects in their cosmic environment. In this paper we want to pick up suggestions given by Thirring and by Hoyle
of how, due to requirements of the equivalence of rotations and of general relativistic conformal scale invariance, the particle
masses of cosmic objects should vary with the cosmic length scale. We study cosmological consequences of comoving cosmic masses
which co-evolve by mass with the expansion of the universe. The vanishing of the covariant divergence of the cosmic energy-momentum
tensor under the new prerequisite that matter density only falls off with the reciproke of the squared cosmic scale S(t) then leads to the astonishing result that cosmic pressuredoes not fall off adiabatically but rather falls off in a quasi-isothermal
behaviour, varying with S(t) as matter density does. Hence, as a new cosmological fact, it arises that, even in the late phases of cosmic expansion,
pressure cannot be neglected what concerns its gravitational action on the cosmic dynamics. We then show that under these
conditions the cosmological equations can, however, only be solved if, in addition to matter, also pressure and energy density
of the cosmic vacuum are included in the calculation. An unaccelerated expansion with a Hubble parameter falling off with
S(t)−1 is obtained for a vacuum energy density decay according to S(t)−2 with a well-tuned proportion of matter and vacuum pressures. As it appears from these results, a universe with particle masses
increasing with the cosmic sale S(t) is in fact physically conceivable in an energetically consistent manner, if vacuum energy at the expansion of the universe
is converted into mass density of real matter with no net energy loss occuring. This universe in addition also happens to
be an economical one which has and keeps a vanishing total energy. 相似文献
6.
Summary We analyse the scaling properties of the matter distribution generated by the truncated Zel'dovich approximation (TZA) for
a universe dominated by a mixture of cold+hot non-baryonic dark matter. At the present epoch, the dark-matter distribution
generated by TZA displays an intermediate scaling behaviour between about 4 and 60h
−1 Mpc with a correlation dimensionD
q∼2 forq≥2. The possible implications of these results are considered. 相似文献
7.
Takao Fukui 《General Relativity and Gravitation》1992,24(4):389-395
A simple vacuum cosmological solution that is a function ofct, Gm/c
2 andeG
1/2/C2 is obtained in the 6D space-time-mass-charge universe which is proposed by Wesson [1] with the introduction of the sixth coordinate of charge in order to obtain a unified theory of gravity and electromagnetism along the line of his original 5D space-time-mass universe [2]. It reduces to a similar solution to that of the radiation era in the 4D FRW universe through the compactifications of the extra dimensions. The trajectory of a test particle in the 6D universe is also studied by using the solution. 相似文献
8.
Mendel Sachs 《Foundations of Physics Letters》1988,1(2):163-169
Inertial mass in relativity theory is discussed from a conceptual view. It is shown that though relativistic dynamics implies a particular dependence of the momentum of a free particle on its velocityin special relativity, which diverges as v approaches c, the inertial mass itself of a moving body remains constant, from any frame of observation. However, extension to general relativity does conceptually introduce variability of the inertial mass of a body, through a necessarily generally covariant field theory of inertia, when the Mach principle is incorporated into the theory of general relativity, as a theory of matter. 相似文献
9.
Surajit Chattopadhyay Ujjal Debnath Samarpita Bhattacharya 《International Journal of Theoretical Physics》2012,51(10):3168-3185
In this work, we have studied the thermodynamic quantities like temperature of the universe, heat capacity and squared speed of sound in generalized gravity theories like Brans-Dicke, Hořava-Lifshitz and f(R) gravities. We have considered the universe filled with dark matter and dark energy. Also we have considered the equation of state parameters for open, closed and flat models. We have observed that in all cases the equation of state behaves like quintessence. The temperature and heat capacity of the universe are found to decrease with the expansion of the universe in all cases. In Brans-Dicke and f(R) gravity theories the squared speed of sound is found to exhibit increasing behavior for open, closed and flat models and in Hořava-Lifshitz gravity theory it is found to exhibit decreasing behavior for open and closed models with the evolution of the universe. However, for flat universe, the squared speed of sound remains constant in Hořava-Lifshitz gravity. 相似文献
10.
A new dark energy model called “ghost dark energy” was recently suggested to explain the observed accelerating expansion of
the universe. This model originates from the Veneziano ghost of QCD. The dark energy density is proportional to Hubble parameter,
ρ
D
= α H, where α is a constant of order LQCD3{\Lambda_{\rm QCD}^3} and ΛQCD ~ 100 MeV is QCD mass scale. In this Letter, we extend the ghost dark energy model to the universe with spatial curvature
in the presence of interaction between dark matter and dark energy. We study cosmological implications of this model in detail.
In the absence of interaction the equation of state parameter of ghost dark energy is always w
D
> −1 and mimics a cosmological constant in the late time, while it is possible to have w
D
< −1 provided the interaction is taken into account. When k = 0, all previous results of ghost dark energy in flat universe are recovered. For the observational test, we use Supernova
type Ia Gold sample, shift parameter of cosmic microwave background radiation and the correlation of acoustic oscillation
on the last scattering surface and the baryonic acoustic peak from Sloan Digital Sky Survey are used to confine the value
of free parameter of mentioned model. 相似文献
11.
John G Hartnett 《International Journal of Theoretical Physics》2006,45(11):2118-2136
Equations of motion, in cylindrical co-ordinates, for the observed rotation of gases within the gravitational potential of spiral galaxies have been derived from Carmeli's Cosmological General Relativity theory. A Tully-Fisher type relation results and rotation curves are reproduced without the need for non-baryonic halo dark matter. Two acceleration regimes are discovered that are separated by a critical acceleration m s−2. For accelerations larger than the critical value the Newtonian force law applies, but for accelerations less than the critical value the Carmelian regime applies. In the Newtonian regime the accelerations fall off as r
−2, but in the Carmelian regime the accelerations fall off as r
−1. This is new physics but is exactly what is suggested by Milgrom's phenomenological MOND theory. 相似文献
12.
We study the properties of D and [`(D)] \bar{{D}} mesons in hot isospin asymmetric strange hadronic matter, arising due to their interactions with the hadrons in the hyperonic
medium. The interactions of D and [`(D)] \bar{{D}} mesons with these light hadrons are derived by generalizing the chiral SU(3) model used for the study of hyperonic matter to SU(4). The nucleons, hyperons, the scalar isoscalar meson, σ and the scalar-isovector meson, d \delta as modified in the strange hadronic matter, modify the masses of D and [`(D)] \bar{{D}} mesons. It is found that, as compared to the [`(D)] \bar{{D}} mesons ([`(D0)] \bar{{D^0}}, D
−), the properties of the D mesons (D
0, D
+) are more sensitive to the isospin asymmetry at high densities. On the other hand, the effects of strangeness fraction are
found to be more dominant for the [`(D)] \bar{{D}} mesons as compared to the D mesons and these modifications are observed to be particularly appreciable at high densities. We also study the mass modifications
of the charmonium states J/ψ, ψ(3686) and ψ(3770) in the isospin asymmetric strange hadronic matter at finite temperatures and investigate the possibility of the decay
of the charmonium states into D
[`(D)] \bar{{D}} pairs in the hot hadronic medium. The mass modifications of these charmonium states arise due to their interaction with the
gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD
within the effective chiral model. The effects of finite quark masses are taken into account in the trace of the energy momentum
tensor in QCD, while investigating the medium modification of the charmonium masses through the modification of the gluon
condensate in the medium. We also compute the partial decay widths of the charmonium states to the D
[`(D)] \bar{{D}} pairs in the hadronic medium. The strong dependence on density of the in-medium properties of the D, [`(D)] \bar{{D}} and the charmonium states, as well as the partial decay widths of charmonium states to D
[`(D)] \bar{{D}} pairs, found in the present investigation, will be of direct relevance in observables like open charm enhancement as well
as J/ψ suppression in the compressed baryonic matter (CBM) experiments at the future Facility for Antiproton and Ion Research, GSI,
where the baryonic matter at high densities is planned to be produced. 相似文献
13.
Martin Markl 《Communications in Mathematical Physics》2001,221(2):367-384
Barton Zwiebach constructed [20] “string products” on the Hilbert space of a combined conformal field theory of matter and
ghosts, satisfying the “main identity”. It has been well known that the “tree level” of the theory gives an example of a strongly
homotopy Lie algebra (though, as we will see later, this is not the whole truth).
Strongly homotopy Lie algebras are now well-understood objects. On the one hand, strongly homotopy Lie algebra is given by
a square zero coderivation on the cofree cocommutative connected coalgebra [13, 14]; on the other hand, strongly homotopy
Lie algebras are algebras over the cobar dual of the operad &?om for commutative algebras [9].
As far as we know, no such characterization of the structure of string products for arbitrary genera has been available, though
there are two series of papers directly pointing towards the requisite characterization.
As far as the characterization in terms of (co)derivations is concerned, we need the concept of higher order (co)derivations, which has been developed, for example, in[2, 3]. These higher order derivations were used in the analysis of the ”master
identity“. For our characterization we need to understand the behavior of these higher (co)derivations on (co)free (co)algebras.
The necessary machinery for the operadic approach is that of modular operads, anticipated in [5] and introduced in [8]. We believe that the modular operad structure on the compactified moduli space
of Riemann surfaces of arbitrary genera implies the existence of the structure we are interested in the same manner as was
explained for the tree level in [11].
We also indicate how to adapt the loop homotopy structure to the case of open string field theory [19].
Received: 10 November 1999 / Accepted: 29 March 2001 相似文献
14.
We develop hydrodynamics in a new geometrical gravitational theory, calledO
4 gravity, which we recently proposed. According to this formulation, matter is not necessarily conserved. The nonconservation of matter might have been considerable in an early era of cosmological evolution. 相似文献
15.
We review the main arguments against antigravity, a different acceleration of antimatter relative to matter in a gravitational field, discussing and challenging Morrison’s, Good’s and Schiff’s arguments. Following Price, we show that, very surprisingly, the usual expression of the Equivalence Principle is violated by General Relativity when particles of negative mass are supposed to exist, which may provide a fundamental explanation of MOND phenomenology, obviating the need for Dark Matter. Motivated by the observation of repulsive gravity under the form of Dark Energy, and by the fact that our universe looks very similar to a coasting (neither decelerating nor accelerating) universe, we study the Dirac-Milne cosmology, a symmetric matter-antimatter cosmology where antiparticles have the same gravitational properties as holes in a semiconductor. Noting the similarities with our universe (age, SN1a luminosity distance, nucleosynthesis, CMB angular scale), we focus our attention on structure formation mechanisms, finding strong similarities with our universe. Additional tests of the Dirac-Milne cosmology are briefly reviewed, and we finally note that a crucial test of the Dirac-Milne cosmology will be soon realized at CERN next to the ELENA antiproton decelerator, possibly as early as fall 2018, with the AEgIS, ALPHA-g and Gbar antihydrogen gravity experiments. 相似文献
16.
U. Kasper 《Annalen der Physik》1979,491(2):135-147
Subject is considered on the level of classical field theory. We start from some aspects of the theory of ferromagnets. Their counterpart in classical field theory is pointed out using the over simplified model of a selfinteracting scalar field. The ground state (“vacuum expection value”) of the scalar field is interpreted as cosmic background field, which can be considered as constant for local physical phenomena. In practice, however, it is a function of the age of universe. Which kind of function it could be is suggested by a discussion of the cosmic variability of Eddington's number γ = 1040, which refers to Dirac's consideration of this problem. But contrary to Dirac's assumption that atomic quantities are constant, we suppose that the inertial mass of elementary particles is a function of the age of universe. The cosmic gravitational field is described by other equations than the gravitational field created by local matter distributions. The field equations for the local gravitational field we start from reduce to Einstein's equations, if we neglect the possible influence of the universe on local phenomena. In case that the cosmic matter is homogeneously and isotropically distributed, the field equations for the cosmic gravitational field permit only such a time dependent solution the three-spaces of which are linearly expanding and spherically closed. The different field equations for cosmic and local gravitational fields are considered approximations of more fundamental field equations which approximately split into two sets of equations, if it is possible to contrast local physical systems with the universe. The described cosmological model taken as a basis, the inertial mass of elementary particles becomes a function of the matter density creating the cosmic gravitational field. This could be considered as, at least, partly realisation of Mach's idea concerning the origin of inertia. Starting from the interpretation of the ground state (vacuum expection value) as a function of a certain cosmic background field, more realistic gage field models could give the following picture of cosmic development: In the far past there was a state of the universe characterized by enormous contraction of matter. In this stage of development, it was impossible to contrast particles with the universe. Matter expands and it becomes possible to contrast certain physical systems with the universe. But the ground state is such a symmetric one that only fields with vanishing rest mass can be contrasted with the universe (ferromagnet above Curie temperature). With further expansion of the universe the ground state will lose certain symmetry properties. By this it becomes possible that you get the impression there are particles with nonvanishing rest mass (ferromagnet below Curie temperature). Finally, the influence of the universe on local physical systems goes to zero with further expansion. Especially, this means the inertial mass of elementary particles goes to zero, too (Curie temperature of ferromagnetic material goes to zero with cosmic expansion). 相似文献
17.
Using a D = 1 supergravity framework I construct a super-Friedmann equation for an isotropic and homogenous universe including dynamical scalar fields. In the context of quantum theory this becomes an equation for a wave function of the universe of spinorial type, the Wheeler–DeWitt–Dirac equation. It is argued that a cosmological constant breaks a certain chiral symmetry of this equation, a symmetry in the Hilbert space of universe states, which could protect a small cosmological constant from being affected by large quantum corrections.
相似文献18.
19.
It has been shown that the orbits of motion for a wide class of non-relativistic Hamiltonian systems can be described as geodesic
flows on a manifold and an associated dual by means of a conformal map. This method can be applied to a four dimensional manifold
of orbits in spacetime associated with a relativistic system. We show that a relativistic Hamiltonian which generates Einstein
geodesics, with the addition of a world scalar field, can be put into correspondence in this way with another Hamiltonian
with conformally modified metric. Such a construction could account for part of the requirements of Bekenstein for achieving
the MOND theory of Milgrom in the post-Newtonian limit. The constraints on the MOND theory imposed by the galactic rotation
curves, through this correspondence, would then imply constraints on the structure of the world scalar field. We then use
the fact that a Hamiltonian with vector gauge fields results, through such a conformal map, in a Kaluza-Klein type theory,
and indicate how the TeVeS structure of Bekenstein and Saunders can be put into this framework. We exhibit a class of infinitesimal gauge transformations
on the gauge fields Um(x){\mathcal{U}}_{\mu}(x) which preserve the Bekenstein-Sanders condition UmUm=-1{\mathcal{U}}_{\mu}{\mathcal{U}}^{\mu}=-1. The underlying quantum structure giving rise to these gauge fields is a Hilbert bundle, and the gauge transformations induce
a non-commutative behavior to the fields, i.e. they become of Yang-Mills type. Working in the infinitesimal gauge neighborhood
of the initial Abelian theory we show that in the Abelian limit the Yang-Mills field equations provide residual nonlinear
terms which may avoid the caustic singularity found by Contaldi et al. 相似文献
20.
The photocurrent in n-InSb at 85K was measured as function of the applied longitudinal voltage and an additionally applied
transverse magnetic field. In the driftconfiguration the photoionized electron-hole plasma was driven into the sample volume,
and negative photocurrents resulted from the negative feedback of this motion. With the magnetic field being reversed, in
the Suhl configuration, only positive photocurrents were measured. All results are in agreement with the theory in [1]. They
were used to determine recombination coefficients in n-InSb, and, principally, the transverse diffusion coefficientD
⊥. As first observed in [13],D
⊥ proved to be anomalously enhanced above classical values if plasma instabilities were generated in the samples. 相似文献