scholarly journals Standard general relativity from Chern–Simons gravity

2009 ◽  
Vol 678 (2) ◽  
pp. 213-217 ◽  
Author(s):  
F. Izaurieta ◽  
P. Minning ◽  
A. Perez ◽  
E. Rodriguez ◽  
P. Salgado
Symmetry ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1130 ◽  
Author(s):  
Stephon Alexander ◽  
Joao Magueijo ◽  
Lee Smolin

We present an extension of general relativity in which the cosmological constant becomes dynamical and turns out to be conjugate to the Chern–Simons invariant of the Ashtekar connection on a spatial slicing. The latter has been proposed Soo and Smolin as a time variable for quantum gravity: the Chern–Simons time. In the quantum theory, the inverse cosmological constant and Chern–Simons time will then become conjugate operators. The “Kodama state” gets a new interpretation as a family of transition functions. These results imply an uncertainty relation between Λ and Chern–Simons time; the consequences of which will be discussed elsewhere.


Proceedings ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 14
Author(s):  
Alejandro Cárdenas-Avendaño

The continuous X-ray flux of stellar-mass black holes provides an excellent source of data to learn about the astrophysics of accretion disks and about the spacetime itself. The extraction of information, however, depends heavily on our ability to correctly model the astrophysics and the theory of gravity, and the quality of the data. By combining a relativistic ray-tracing and Markov-Chain Monte-Carlo sampling technique, I show that the incorporation of the spin parameter through a slowly-rotating approximation, is not able to break the complex degeneracies of the model and therefore, when introducing modifications beyond general relativity it is very challenging to perform tests of general relativity with this type of observations. As a particular case, I show that it not possible to distinguish the small-coupling, slow-rotation black hole solution of dynamical Chern–Simons gravity from the Kerr solution with current instruments.


2010 ◽  
Vol 19 (08n10) ◽  
pp. 1323-1327 ◽  
Author(s):  
L. A. CABRAL

We consider a theory which involves an extension of general relativity known as Chern–Simons modified gravity (CSMG). In this theory the standard Einstein–Hilbert action is extended with a gravitational Pontryagin density that is obtained from a divergence of a Chern–Simons topological current. The extended theory has the standard Schwarzchild metric as solution, however, only a perturbed Kerr metric holds solution. From the exact Kerr metric we construct dual metrics to search for rotating black hole solutions. The conditions on the Killing tensors associated with dual metrics entail nontrivial solutions to CSMG.


2004 ◽  
Vol 70 (2) ◽  
Author(s):  
T. Mariz ◽  
J. R. Nascimento ◽  
E. Passos ◽  
R. F. Ribeiro

2009 ◽  
Vol 480 (1-2) ◽  
pp. 1-55 ◽  
Author(s):  
Stephon Alexander ◽  
Nicolás Yunes

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