MG15 - Talk detail

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Accepted

Yes

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Abstract

In this article we will discuss a Lorentzian sector calculation of the entropy of a minimally coupled scalar field in the Kerr family of black hole backgrounds. We will use the brick wall model of 't Hooft. In a Kerr black hole, it is possible to calculate the entropy of a thin shell of matter field in the near-horizon region using the brick wall model. The corresponding leading-order entropy of the scalar field is found to be proportional to the area of the horizon and is logarithmically divergent. The entropy is also found to be a decreasing function of the the thickness of the thin shell. The above aspects are also valid in a Schwarzschild black hole. Quantum fields in a curved spacetime is regarded as the semi-classical limit of a quantum theory of gravity. Thus, we obtain a bound on the entropy of matter fields confined in the near-horizon region of the asymptotically flat black holes from the semi-classical theory of quantum gravity.

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Session

Accepted

Yes

Order

Time

Talk

Title

Abstract

In this manuscript, we will discuss the construction of a covariant derivative operator in a quantum theory of gravity. We will find it is more appropriate to use connection coefficients more general than the Levi-Civita connections in a general quantum theory of gravity irrespective of coupling with gauge and matter fields. We will demonstrate this for a canonical quantum theory of gravity. We will also find that quantum fluctuations in geometry can give additional fields besides metric. These are associated with the generalized connections. These additional fields vanish in the classical spacetime manifolds that are solutions of the Einstein equations with connections given by the Levi-Civita connections. These additional fields also arise in a path integral formulation of quantum gravity with the Palatini action. They can be described by the torsion tensor and a symmetric second rank covariant tensor together with its ordinary partial derivatives. The later field is not considered in quantum theories of gravity. This field and torsion can enhance the dynamical degrees of freedom of quantum theory of gravity and become significant in quantum cosmology. We will also find that we may have to extend the strict electric current conservation law when we use connections more general that the Levi-Civita connections.

Pdf file

Session

Accepted

Yes

Order

Time

Talk

Title

Abstract

In this presentation, we will show it is more appropriate to use connection coefficients more general than the Levi-Civita connections in a general quantum theory of gravity irrespective of coupling with gauge and matter fields. We will demonstrate this for a canonical quantum theory of gravity. We will also find that quantum fluctuations in geometry can give additional fields besides metric. These are associated with the generalized connections. These additional fields vanish in the classical spacetime manifolds that are solutions of the Einstein equations with connections given by the Levi-Civita connections. These additional fields also arise in a path integral formulation of quantum gravity with the Palatini action. They can be described by the torsion tensor and a symmetric second rank covariant tensor together with its ordinary partial derivatives. The later field is not considered in the quantum theory of gravity. This field and torsion can enhance the dynamical degrees of freedom of quantum theory of gravity and become significant in quantum cosmology. We will also find that we may have to extend the strict electric current conservation law when we use connections more general that the Levi-Civita connections.

Pdf file

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