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Item The bending of light by gravity(Physics News, 2015-04-10) Narlikar, J. V.Item Structural Aspects Of Gravitational Dynamics And The Emergent Perspective Of Gravity(2013-08-06) Padmanabhan, T.I describe several conceptual aspects of a particular paradigm which treats the field equations of gravity as emergent. These aspects are related to the features of classical gravitational theories which defy explanation within the conventional perspective. The alternative interpretation throws light on these features and could provide better insights into possible description of quantum structure of spacetime. This review complements arXiv:1207.0505, which describes space itself as emergent in the cosmological context.Item Gravity can create illusion(Financial chronicle, 2008-10-01) Naralikar, J.V.Item Emergent perspective of Gravity and Dark Energy(2012-07-02) Padmanabhan, T.There is sufficient amount of internal evidence in the nature of gravitational theories to indicate that gravity is an emergent phenomenon like, e.g, elasticity. Such an emergent nature is most apparent in the structure of gravitational dynamics. It is, however, possible to go beyond the field equations and study the space itself as emer-gent in a well-defined manner in (and possibly only in) the context of cosmology. In the first part of this review, I describe various pieces of evidence which show that gravitational field equations are emergent. In the second part, I describe a novel way of studying cosmology in which I interpret the expansion of the universe as equivalent to the emergence of space itself. In such an approach, the dynamics evolves towards a state of holographic equipartition, characterized by an equality in the number of bulk and surface degrees of freedom in a region bounded by the Hubble radius. This prin-ciple correctly reproduces the standard evolution of a Friedmann universe. Further, (a) it demands the existence of an early inflationary phase as well as late time accelera-tion for its successful implementation and (b) allows us to link the value of late time cosmological constant to the e-folding factor during inflation.Item Two Aspects of Black hole entropy in Lanczos-Lovelock models of gravity(American physical society, 2012-03-06) Padmanabhan, T.; Kothawala, Dawood; Kolekar, SanvedWe consider two specific approaches to evaluate the black hole entropy which are known to produce correct results in the case of Einstein’s theory and generalize them to Lanczos- Lovelock models. In the first approach (which could be called extrinsic) we use a procedure motivated by earlier work by Pretorius, Vollick and Israel, and by Oppenheim, and evaluate the entropy of a configuration of densely packed gravitating shells on the verge of forming a black hole in Lanczos-Lovelock theories of gravity. We find that this matter entropy is not equal to (it is less than) Wald entropy, except in the case of Einstein theory, where they are equal. The matter entropy is proportional to the Wald entropy if we consider a specific m-th order Lanczos-Lovelock model, with the proportionality constant depending on the spacetime dimensions D and the order m of the Lanczos-Lovelock theory as (D−2m)/(D−2). Since the proportionality constant depends on m, the proportionality between matter entropy and Wald entropy breaks down when we consider a sum of Lanczos-Lovelock actions involving different m. In the second approach (which could be called intrinsic) we generalize a procedure, previ- ously introduced by Padmanabhan in the context of GR, to study off-shell entropy of a classof metrics with horizon using a path integral method. We consider the Euclidean action of Lanczos-Lovelock models for a class of metrics off-shell and interpret it as a partition function. We show that in the case of spherically symmetric metrics, one can interpret the Euclidean action as the free energy and read off both the entropy and energy of a black hole spacetime. Surprisingly enough, this leads to exactly the Wald entropy and the energy of the spacetime in Lanczos-Lovelock models obtained by other methods. We comment on possible implications of the result.Item A matter of gravity(Bulletin of the astronomical society of india, 1993-02-01) Naralikar, J.V.Item If there were no gravity(Science Today, 1980-02-02) Naralikar, J.V.Item Scale invariance and gravity(Nature, 1971-07-01) Naralikar, J.V.Item Some aspects of field equations in generalised theories of gravity(American Astronomical Society, 2011-12-19) Padmanabhan, T.Item Lighter side of gravity(Proceedings of the GIREP Conference in Copenhagen, 1986-04-15) Narlikar, J. V.This talk presents a light-hearted look at the phenomenon of gravity, the most enigmatic of all known natural interactions. The fact that a major international society is wholly devoted towards understanding this basic interaction of nature is ample testimony to its intellectual challenges. The GR-meetings are held once every three years to bring together workers in the field to share their ignorance as well as expertise in the field of gravity. It would be presumptuous on my part to attempt to tell anything new to the experts gathered here. This evening I will stay away from the complexities and take a light hearted look at some ideas and phenomena that make gravity so peculiar.