关于有挠时空理论中的宇宙模型

本文阐明了引力规范理论的自治性.以简单的R+Q~2理论为例讨论了宇宙模型.挠率的存在并不改变标准宇宙模型的结果.     

On CCGG,the De Donder-Weyl Hamiltonian formulation of canonical gauge gravity

This short paper gives a brief overview of the manifestly covariant canonical gauge gravity (CCGG) that is rooted in the De Donder-Weyl Hamiltonian formulation of relativistic field theories, and the proven methodology of the canonical transformation theory. That framework derives, from a few basic physical and mathematical assumptions, equations describing generic matter and gravity dynamics with the spin connection emerging as a Yang Mills-type gauge field. While the interaction of any matter field with spacetime is fixed just by the transformation property of that field, a concrete gravity ansatz is introduced by the choice of the free (kinetic) gravity Hamiltonian. The key elements of this approach are discussed and its implications for particle dynamics and cosmology are presented. New insights: Anomalous Pauli coupling of spinors to curvature and torsion of spacetime, spacetime with (A)dS ground state, inertia, torsion and geometrical vacuum energy, Zero-energy balance of the Universe leading to a vanishing cosmological constant and torsional dark energy.     

Correlation between the physical parameters and morphological type of spiral galaxies

Static Friedmann-Robertson-Walker vacuum models are derived in the scale-covariant theory. Specific functional forms are obtained for the gauge function which occurs in the theory. This is in contrast to the nonstatic vacuum solutions where the gauge function is arbitrary.     

Torsion,minimum time,string tension and its physical implications in cosmology

We show that introducing torsion in general relativity, that is, physically, considering the effect of the spin, and linking the torsion to defects in the space-time topology we can have a minimum unit of time. In this context we have the possibility of identifying the defects in space-time topology induced by torsion as behaving like a string so that the minimum length, derived by treating the spin as an extra dimension, is related with string tension. Physical implications are considered for field theory (we can eliminate the divergence of self-energy integral without introducing anyad hoc cut-off), particle decay, evaporation of black holes, and information theory.     

Bianchi type I cosmological perfect fluid model in scale invariant theory

The intention of this paper is to study the perfect fluid distribution in scale invariant theory of gravity when the space-time is described by Bianchi type I metric with a time dependent gauge function. The cosmological equations for this space-time with gauge function are solved and some physical properties of the model are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Physical consequences of intrinsic dilation currents

In the Einstein-Carten theory only the traceless part of the torsion field can be related spin. Here we generalize the Einstein-Cartan theory by allowing iutrinsic dilation currents, which couple algebraically to the torsion trace. This implies implies a variable gravitational coupling, G.     

The General Method for Fixing the Gauges of Relativistic Astronomical Reference Systems

This article applies a new scheme of the first post-Newtonian theory (Damour et al., 1991–1994) to the problem of gauge in relativistic reference systems. Choosing and fixing gauge are necessary when the precision of time measurement and application needs to reach the 2PN level (10⁻¹⁶ or better). We present a general method for fixing the gauges of both the global and local coordinate systems, and for determining the expressions of gravitational potentials and coordinate transformations. The results relevant are consistent with the newest IAU resolutions, therefore they can be applied to astronomical practice.     

Bianchi type VI1 cosmological model with wet dark fluid in scale invariant theory of gravitation

In this paper, we have investigated Bianchi type VI _h , II and III cosmological model with wet dark fluid in scale invariant theory of gravity, where the matter field is in the form of perfect fluid and with a time dependent gauge function (Dirac gauge). A non-singular model for the universe filled with disorder radiation is constructed and some physical behaviors of the model are studied for the feasible VI _h (h=1) space-time.     

An exact spherically symmetric space–time in Einstein–Cartan theory

By adopting the Newman–Penrose–Jogia–Griffith formalism, the field equations in Einstein–Cartan theory for matter with spin creating torsion in space–time are solved in a spherically symmetric space–time by assuming only one non-vanishing component of spin. The exact solution might be the prototype for more realistic models.     

New exact solutions of Bianchi I,Bianchi III and Kantowski–Sachs spacetimes in scalar-coupled gravity theories via Noether gauge symmetries

The Noether symmetry approach is useful tool to restrict the arbitrariness in a gravity theory when the equations of motion are underdetermined due to the high number of functions to be determined in the ansatz. We consider two scalar-coupled theories of gravity, one motivated by induced gravity, the other more standard; in Bianchi I, Bianchi III and Kantowski–Sachs cosmological models. For these models, we present a full set of Noether gauge symmetries, which are more general than those obtained by the strict Noether symmetry approach in our recent work. Some exact solutions are derived using the first integrals corresponding to the obtained Noether gauge symmetries.     

Birkhoff-type theorem in the scale-covariant theory of gravitation

It is shown that an analog of Birkhoff's theorem of general relativity exists in the scale-covariant theory of gravitation when the gauge function which occurs in the theory is independent of time.     

Cylindrically symmetric cosmologies in Lyra geometry

A class of new exact solutions of the Einstein field equations have been investigated for stationary cylindrically symmetric space-time around a local cosmic string in the theory based on Lyra’s geometry in normal gauge in the presence and absence of an electromagnetic field. The cosmological solutions have been analyzed through various physical and geometrical parameters. It has also been shown that the solutions are space-time inhomogeneous and filled with charged dust.     

挠率和宇宙临界密度的修正

本文指出,应用Poincare's引力规范理论,考虑时空挠率对宇宙临界密度的修正,能使我们从另一途径、寻找失踪的质量。     

Tachyonic teleparallel dark energy

Teleparallel gravity is an equivalent formulation of general relativity in which instead of the Ricci scalar R, one uses the torsion scalar T for the Lagrangian density. Recently teleparallel dark energy has been proposed by Geng et al. (in Phys. Lett. B 704, 384, 2011). They have added quintessence scalar field, allowing also a non-minimal coupling with gravity in the Lagrangian of teleparallel gravity and found that such a non-minimally coupled quintessence theory has a richer structure than the same one in the frame work of general relativity. In the present work we are interested in tachyonic teleparallel dark energy in which scalar field is responsible for dark energy in the frame work of torsion gravity. We find that such a non-minimally coupled tachyon gravity can realize the crossing of the phantom divide line for the effective equation of state. Using the numerical calculations we display such a behavior of the model explicitly.     

Static Spherically Symmetric Electromagnetic Mass Models with Charged Dust Sources in Einstein-Cartan Theory: Lane-Emden Models

Static spherically symmetric charged dust models, known as Lane-Emden electromagnetic mass models, having their seed in the well-known Lane-Emden equations of classical astrophysics, have been derived for Einstein-Cartan theory. The models are of purely electromagnetic origin. The physical significance of these solutions can be understood from the very fact (i) that they are generated from the well-known Lane-Emden equations of classical astrophysics having a proven physical foundation and (ii) that, being the solution of Einstein-Cartan theory, they involve spin and torsion, characteristics which a material system must possess for its subtle and finer details. PACS number(s): 04.90.+e, 04.20.jb. This revised version was published online in July 2006 with corrections to the Cover Date.     

Torsion,massive electrodynamics and gravitation induced by scalar fields

The equivalence of Lagrangian containing gravitational, electromagnetic, scalar, and torsion fields is discussed. It is shown that the equation for the variation of the scalar field leads to a torsion wave equation generated by electromagnetic field leads to a torsion wave equation generated by electromagnetic fields. The system is proved to be equivalent to a Proca field coupling torsion non-minimally to a massive photon and having the scalar Higgs field as a strength of this photon-torsion coupling. The generalized Maxwell equations containing the scalar fields are obtained. The torsion potential around the Sun or a more massive collapsing star in the weak field limit is estimated.     

Shear and vorticity in an accelerating Brans-Dicke lambda-Universe with torsion

We study accelerating Universes with power-law scale-factors. We include shear and vorticity, a cosmological “constant” term, and spin from torsion, as in Einstein-Cartan’s theory when a scalar-field of Brans-Dicke type acts in the model. We find a “no-hair” result, for shear and vorticity; we also make contact with the alternative Machian picture of the Universe.     

Revisiting Noether gauge symmetry for F(R) theory of gravity

Noether gauge symmetry for F(R) theory of gravity has been explored recently. The fallacy is that, even after setting gauge to vanish, the form of F(R)∝R ⁿ (where n≠1 is arbitrary) obtained in the process, has been claimed to be an outcome of gauge Noether symmetry. On the contrary, earlier works proved that any nonlinear form other than $F(R) \propto R^{\frac{3}{2}}$ is obscure. Here, we show that, setting gauge term zero, Noether equations are satisfied only for n=2, which again does not satisfy the field equations. Thus, as noticed earlier, the only form that Noether symmetry admits is $F(R) \propto R^{\frac{3}{2}}$ . Noether symmetry with non-zero gauge has also been studied explicitly here, to show that it does not produce anything new.     

The superconnection,a different local supersymmetry mode

After an introduction relating to the late Dennis Sciama, I review the interlocked quantization programs of Gravity and Weyl Yang-Mills gauge theory, including the independent emergence of two superalgebraic systems: (a) Supersymmetry with supermultiplets relating multiplets of different Quantum Statistics: (b) superalgebraic extensions of the calculus of differential forms. The latter include the BRST unitarity-inducing constrains and a new tool, the Quillen Superconnection, with contributions from noncommutative geometry. Two examples are reviewed, one predicting the mass of the Higgs meson in Electroweak theory and the other relating to Riemannian Gravity emerging through a similar mechanism.     

Operator manifold approach to geometry and particle physics

The question that guides our discussion ishow did the geometry and particles come into being? To explore this query the present theory reveals primordial deeper structures underlying fundamental concepts of contemporary physics. We begin with a drastic revision of a role of local internal symmetries in phys ical concept of curved geometry. Under the reflection of fields and their dynamics from Minkowski space to Riemannian a standard gauge principle of local internal symmetries was generalized. The gravitation gauge group is proposed, which was generated by hidden local internal symmetries. In all circumstances, it seemed to be of the most importance for understanding of physical nature of gravity. Last two parts of this paper address to the question of physical origin of geometry and basic concepts of particle physics such as the fundamental fields of quarks with the spins and various quantum numbers, internal symmetries and so forth; also four basic principles of Relativity, Quantum, Gauge and Color Confinement, which are, as it was proven, all derivative and come into being simultaneously. The substance out of which the geometry and particles are made is a set of new physical structures —the goyaks, which are involved into reciprocal linkage establishing processes. The most promising aspect of our approach so far is the fact that many of the important anticipated properties, basic concepts and principles of particle physics are appeared quite naturally in the framework of suggested theory.