Observables in classical canonical gravity: folklore demystified

被引:38
|
作者
Pons, J. M. [1 ]
Salisbury, D. C. [2 ,3 ]
Sundermeyer, K. A. [4 ]
机构
[1] Univ Barcelona, Dept Estructura & Constituents Mat, Diagonal 647, E-08028 Barcelona, Catalonia, Spain
[2] Austin Coll, Dept Phys, Sherman, TX 75090 USA
[3] Max Planck Inst Wissensch Gesichte, D-14195 Berlin, Germany
[4] Free Univ Berlin, Fachbereich Phys, Inst Theoret Phys, D-14195 Berlin, Germany
关键词
GRAVITATIONAL OBSERVABLES; GAUGE TRANSFORMATIONS; GENERAL-RELATIVITY; PHASE-SPACE; MECHANICS; TIME;
D O I
10.1088/1742-6596/222/1/012018
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We give an overview of some conceptual difficulties, sometimes called paradoxes, that have puzzled for years the physical interpetation of classical canonical gravity and, by extension, the canonical formulation of generally covariant theories. We identify these difficulties as stemming form some terminological misunderstandings as to what is meant by "gauge invariance", or what is understood classically by a "physical state". We make a thorough analysis of the issue and show that all purported paradoxes disappear when the right terminology is in place. Since this issue is connected with the search of observables - gauge invariant quantities - for these theories, we formally show that time evolving observables can be constructed for every observer. This construction relies on the fixation of the gauge freedom of diffeomorphism invariance by means of a scalar coordinatization. We stress the condition that the coordinatization must be made with scalars. As an example of our method for obtaining observables we discuss the case of the massive particle in AdS spacetime.
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页数:15
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