Research Papers (JVN)
Permanent URI for this collectionhttp://localhost:4000/handle/11007/400
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Item Stationary states in a quantum gravity model(Elsevier Science Publishers, 1981-05-05) Padmanabhan, T.; Narlikar, J. V.A model theory for quantized gravity is discussed whereonly selected degrees of freedomare quantized. The concept of stationary states is introduced. It is shown that the Planck length arises as a lower bound to the space—time length scale in a natural way.Item Quantum fluctuations in the Schwarzschild spacetime(-, 1980-01-01) Narlikar, J. V.; Padmanabhan, T.Item Quantum fluctuations near the classical space-time singularity(Springer, 1979-01-03) Narlikar, J. V.The method of path integration is used to study the effects of quantum fluctuations in the space-time geometry near the classical singularity of general relativity. It is shown that in certain special cases explicit Feynman propagators can be constructed which enable us to evaluate these fluctuations quantitatively. The cases discussed are (i) the gravitational col- lapse of a uniform dust ball, (ii) the Friedmann cosmologies, (iii) the axisymmetric Bianchi type I cosmological model, and (iv) the general anisotropic Bianchi type I cosmological model. In all cases discussed here the quantum uncertainty grows to infinity as the classical space-time singularity is approached. In this wider regime of quantum gravitation non- singular solutions can occur with finite probabilities.Item Quantum fluctuations near the classical space-time singularity(Springer, 1978-04-03) Narlikar, J. V.The method of path integration is used to study the effects of quantum fluctuations in the space-time geometry near the classical singularity of general relativity. It is shown that in certain special cases explicit Feynman propagators can be constructed which enable us to evaluate these fluctuations quantitatively. The cases discussed are (i) the gravitational col- lapse of a uniform dust ball, (ii) the Friedmann cosmologies, (iii) the axisymmetric Bianchi type I cosmological model, and (iv) the general anisotropic Bianchi type I cosmological model. In all cases discussed here the quantum uncertainty grows to infinity as the classical space-time singularity is approached. In this wider regime of quantum gravitation non- singular solutions can occur with finite probabilities.Item On the general correspondence between field theories and the theories of direct interparticle action(Cambridge University Press, 1968-01-10) Narlikar, J. V.It is well known that classical electrodynamics can be described both as a field theory and as a theory of direct interparticle action. In the present paper it is shown that, provided certain general conditions are satisfied, fields of arbitrary spin have their counterparts in 'direct particle fields'. This correspondence between the two formalisms is established in the Riemannian space-time used for general relativity.Item Schwarzschild solution: some conceptual difficulties(Springer, 1987-04-27) Narlikar, J. V.; Padmanabhan, T.It is shown that inconsistencies arise when we look upon the Schwarzschild solution as the space-time arising from a localized point singularity. The notion of black holes is critically examined, and it is argued that, since black hole formation never takes place within the past light cone of a typical external observer, the discussion of physical behavior of black holes, classical or quantum, is only of academic interest. It is suggested that problems related to the source could be avoided if the event horizon did not form and that the universe only contained quasi-black holes.