Emergent perspective of gravity and dark energy

@article{Padmanabhan2012EmergentPO,
  title={Emergent perspective of gravity and dark energy},
  author={Thanu Padmanabhan},
  journal={Research in Astronomy and Astrophysics},
  year={2012},
  volume={12},
  pages={891-916}
}
  • T. Padmanabhan
  • Published 2 July 2012
  • Physics
  • Research in Astronomy and Astrophysics
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 emergent 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… 

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References

SHOWING 1-10 OF 46 REFERENCES
Equipartition of energy in the horizon degrees of freedom and the emergence of gravity
It is possible to provide a physical interpretation for the field equations of gravity based on a thermodynamical perspective. The virtual degrees of freedom associated with the horizons, as
Emergence and Expansion of Cosmic Space as due to the Quest for Holographic Equipartition
One possible interpretation of the holographic principle is the equality of the number of degrees of freedom in a bulk region of space and the number of degrees of freedom on the boundary surface. It
Dark energy and gravity
I review the problem of dark energy focussing on cosmological constant as the candidate and discuss what it tells us regarding the nature of gravity. Section 1 briefly overviews the currently popular
Action principle for the fluid-gravity correspondence and emergent gravity
It has been known for a long time that Einstein’s field equations when projected onto a black hole horizon look very similar to a Navier-Stokes equation in suitable variables. More recently, it was
The Classification of Universes
We define a universe as the contents of a spacetime box with comoving walls, large enough to contain measurable phenomena, but not much larger. This allows the construction of a local ensemble of
Cosmological Event Horizons, Thermodynamics, and Particle Creation
It is shown that the close connection between event horizons and thermodynamics which has been found in the case of black holes can be extended to cosmological models with a repulsive cosmological
Lessons from Classical Gravity about the Quantum Structure of Spacetime
I present the theoretical evidence which suggests that gravity is an emergent phenomenon like gas dynamics or elasticity with the gravitational field equations having the same status as, say, the
Entropy of static spacetimes and microscopic density of states
A general ansatz for gravitational entropy can be provided using the criterion that any patch of area which acts as a horizon for a suitably defined accelerated observer must have an entropy
Thermodynamical aspects of gravity: new insights
The fact that one can associate thermodynamic properties with horizons brings together principles of quantum theory, gravitation and thermodynamics and possibly offers a window to the nature of
On the origin of gravity and the laws of Newton
Starting from first principles and general assumptions we present a heuristic argument that shows that Newton’s law of gravitation naturally arises in a theory in which space emerges through a
...
1
2
3
4
5
...