Extension of covariant derivative (II): From flat space to curved space

2015 ◽  
Vol 31 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Ya-Jun Yin
2016 ◽  
Vol 13 (06) ◽  
pp. 1650076 ◽  
Author(s):  
Zi-Hua Weng

The paper aims to extend major equations in the electromagnetic and gravitational theories from the flat space into the complex octonion curved space. Maxwell applied simultaneously the quaternion analysis and vector terminology to describe the electromagnetic theory. It inspires subsequent scholars to study the electromagnetic and gravitational theories with the complex quaternions/octonions. Furthermore Einstein was the first to depict the gravitational theory by means of tensor analysis and curved four-space–time. Nowadays some scholars investigate the electromagnetic and gravitational properties making use of the complex quaternion/octonion curved space. From the orthogonality of two complex quaternions, it is possible to define the covariant derivative of the complex quaternion curved space, describing the gravitational properties in the complex quaternion curved space. Further it is possible to define the covariant derivative of the complex octonion curved space by means of the orthogonality of two complex octonions, depicting simultaneously the electromagnetic and gravitational properties in the complex octonion curved space. The result reveals that the connection coefficient and curvature of the complex octonion curved space will exert an influence on the field strength and field source of the electromagnetic and gravitational fields, impacting the linear momentum, angular momentum, torque, energy, and force and so forth.


1967 ◽  
Vol 22 (9) ◽  
pp. 1328-1332 ◽  
Author(s):  
Jürgen Ehlers

The transition from the (covariantly generalized) MAXWELL equations to the geometrical optics limit is discussed in the context of general relativity, by adapting the classical series expansion method to the case of curved space time. An arbitrarily moving ideal medium is also taken into account, and a close formal similarity between wave propagation in a moving medium in flat space time and in an empty, gravitationally curved space-time is established by means of a normal hyperbolic optical metric.


Author(s):  
Jean‐Pierre Luminet

This chapter notes that the twin paradox is the best-known thought experiment associated with Einstein's theory of relativity. An astronaut who makes a journey into space in a high-speed rocket will return home to find he has aged less than his twin who stayed on Earth. This result appears puzzling, as the homebody twin can be considered to have done the travelling with respect to the traveller. Hence, it is called a “paradox”. In fact, there is no contradiction, and the apparent paradox has a simple resolution in special relativity with infinite flat space. In general relativity (dealing with gravitational fields and curved space-time), or in a compact space such as the hypersphere or a multiply connected finite space, the paradox is more complicated, but its resolution provides new insights about the structure of space–time and the limitations of the equivalence between inertial reference frames.


1990 ◽  
Vol 05 (20) ◽  
pp. 1599-1604 ◽  
Author(s):  
I.L. BUCHBINDER ◽  
I.L. SHAPIRO ◽  
E.G. YAGUNOV

GUT’s in curved space-time is considered. The set of asymptotically free and asymptotically conformally invariant models based on the SU (N) gauge group is constructed. The general solutions of renormalization group equations are considered as the special ones. Several SU (2N) models, which are finite in flat space-time (on the one-loop level) and asymptotically conformally invariant in external gravitational field are also presented.


1986 ◽  
Vol 181 (1-2) ◽  
pp. 137-140 ◽  
Author(s):  
N.S. Manton ◽  
P.J. Ruback
Keyword(s):  

1989 ◽  
Vol 39 (6) ◽  
pp. 1567-1578 ◽  
Author(s):  
A. Ceresole ◽  
P. Pizzochero ◽  
P. van Nieuwenhuizen

1974 ◽  
Vol 29 (11) ◽  
pp. 1527-1530 ◽  
Author(s):  
H. Goenner

In Einstein's theory, the physics of gravitational fields is reflected by the geometry of the curved space-time manifold. One of the methods for a study of the geometrical properties of space-time consists in regarding it, locally, as embedded in a higher-dimensional flat space. In this paper, metrics admitting a 3-parameter group of motion are considered which form a generalization of spherically symmetric gravitational fields. A subclass of such metrics can be embedded into a five- dimensional flat space. It is shown that the second fundamental form governing the embedding can be expressed entirely by the energy-momentum tensor of matter and the cosmological constant. Such gravitational fields are called energetically rigid. As an application gravitating perfect fluids are discussed.


1996 ◽  
Vol 74 (9-10) ◽  
pp. 626-633
Author(s):  
Anjana Sinha ◽  
Rajkumar Roychoudhury

The effective potential for the sine-Gordon model in a curved space-time, given by [Formula: see text], has been calculated using the Schrödinger picture formalism. It has been shown that when α(x) → 1 our method reproduces the flat-space results. To show the effect of the curvature term, the effective potential Veff has been calculated numerically for several values of the parameter M, where α(x) has been taken to be of the form [Formula: see text].


1988 ◽  
Vol 03 (05) ◽  
pp. 1123-1146
Author(s):  
N. SANCHEZ

We generalize the approach to Q.F.T. in accelerated frames based on analytic mappings in a way which stresses further the comparison between the flat and curved space-time situations. Combined linear acceleration with uniform and nonuniform translations or rotations, and nonanalytic but asymptotically analytic mappings are included. A density matrix formulation is given for quantum states at global and asymptotic thermal equilibrium, and the role of the PCT symmetry is discussed. Flat space models of rotating and charged black holes are investigated, together with their surface gravity, chemical potentials, Hawking radiation and superradiance properties.


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