scholarly journals THE BICONNECTION VARIATIONAL PRINCIPLE FOR GENERAL RELATIVITY

Author(s):  
NICOLA TAMANINI
Author(s):  
R. H. Boyer

AbstractWe describe some properties of a stationary, isolated, axially symmetric, rotating body of perfect fluid, according to general relativity. We first specialize to the case of constant specific entropy and constant angular velocity. The latter condition is equivalent to rigidity in the Born sense; both conditions are consequences of a simple variational principle. The hydrodynamic equations can then be integrated completely. Analogous first integrals are given also for the case of differential rotation. No use is made of the full field equations.


Author(s):  
Yuhua Fu

Generalized and hybrid set can be created with neutrosophy and quad-stage method. Firstly the generalized and hybrid neutrosophic set is discussed. Secondly the combination or synthetical body of generalized and hybrid sets is named as “library” (various generalized and hybrid sets can be put into the related “library”); such as “mathematics library”, “physics library”, and the like. As for the constitution of “library”, the concept and methodology of a special “Four-library” are proposed. Neutrosophy and quad-stage method can also be used to solve many actual problems within the framework of “set” and “library”; for example, based on the analyses of one “Four-library”, jointly solving problem of advance of planet's perihelion with partial results of law of gravity and general relativity; and jointly expanding “uncertainty principle” to “certainty-uncertainty principle set”. Finally, we introduce the concepts of “variational principle of set” and “variational principle of library”, and establish a kind of “partial and temporary unified theory of mathematics so far”.


2012 ◽  
Vol 86 (8) ◽  
Author(s):  
Jose Beltrán Jiménez ◽  
Alexey Golovnev ◽  
Mindaugas Karčiauskas ◽  
Tomi S. Koivisto

1955 ◽  
Vol 33 (12) ◽  
pp. 824-827
Author(s):  
G. E. Tauber

It has been shown that both the equations of motion of a charged particle in a gravitational field and the field equations can be obtained from one variational principle by suitably generalizing Dirac's classical theory of electrons.


2014 ◽  
Vol 755 ◽  
Author(s):  
G. Haller ◽  
F. J. Beron-Vera

AbstractIn Haller & Beron-Vera (J. Fluid Mech., vol. 731, 2013, R4) we developed a variational principle for the detection of coherent Lagrangian vortex boundaries. The solutions of this variational principle turn out to be closed null geodesics of the Lorentzian metric induced by a generalized Green–Lagrange strain tensor family. This metric interpretation implies a mathematical analogy between coherent Lagrangian vortex boundaries and photon spheres in general relativity. Here, we give an improved discussion of this analogy.


2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Venkatesa Chandrasekaran ◽  
Éanna É. Flanagan ◽  
Ibrahim Shehzad ◽  
Antony J. Speranza

Abstract The Brown-York stress tensor provides a means for defining quasilocal gravitational charges in subregions bounded by a timelike hypersurface. We consider the generalization of this stress tensor to null hypersurfaces. Such a stress tensor can be derived from the on-shell subregion action of general relativity associated with a Dirichlet variational principle, which fixes an induced Carroll structure on the null boundary. The formula for the mixed-index tensor Tij takes a remarkably simple form that is manifestly independent of the choice of auxiliary null vector at the null surface, and we compare this expression to previous proposals for null Brown-York stress tensors. The stress tensor we obtain satisfies a covariant conservation equation with respect to any connection induced from a rigging vector at the hypersurface, as a result of the null constraint equations. For transformations that act covariantly on the boundary structures, the Brown-York charges coincide with canonical charges constructed from a version of the Wald-Zoupas procedure. For anomalous transformations, the charges differ by an intrinsic functional of the boundary geometry, which we explicity verify for a set of symmetries associated with finite null hyper-surfaces. Applications of the null Brown-York stress tensor to symmetries of asymptotically flat spacetimes and celestial holography are discussed.


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