The Atoms Of Space, Gravity and the Cosmological Constant

@article{Padmanabhan2016TheAO,
  title={The Atoms Of Space, Gravity and the Cosmological Constant},
  author={Thanu Padmanabhan},
  journal={arXiv: General Relativity and Quantum Cosmology},
  year={2016}
}
  • T. Padmanabhan
  • Published 29 March 2016
  • Physics
  • arXiv: General Relativity and Quantum Cosmology
I describe an approach which connects classical gravity with the quantum microstructure of spacetime. The field equations arise from maximizing the density of states of matter plus geometry. The former is identified using the thermodynamics of null surfaces while the latter arises due to the existence of a zero-point length in the spacetime. The resulting field equations remain invariant when a constant is added to the matter Lagrangian, which is a symmetry of the matter sector. Therefore, the… 
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References

SHOWING 1-10 OF 38 REFERENCES

Atoms of Spacetime and the Nature of Gravity

This principle implies that: (1) the metric cannot be varied in any extremum principle to obtain the field equations; and (2) the stress-tensor of matter should appear in the variational principle through the combination of $T_{ab}n^an^b$ where $n_a$ is an auxiliary null vector field, which could be varied to get the field equation.

Entropy density of spacetime from the zero point length

Exploring the Nature of Gravity

I clarify the differences between various approaches in the literature which attempt to link gravity and thermodynamics. I then describe a new perspective based on the following features: (1) As in…

Cosmological Constant from the Emergent Gravity Perspective

Observations indicate that our universe is characterized by a late-time accelerating phase, possibly driven by a cosmological constant $\Lambda$, with the dimensionless parameter $\Lambda L_P^2…

General relativity from a thermodynamic perspective

I show that the gravitational dynamics in a bulk region of space can be connected to a thermodynamic description in the boundary of that region, thereby providing clear physical interpretations of…

Entropy density of spacetime as a relic from quantum gravity

There is a considerable amount of evidence to suggest that the field equations of gravity have the same status as, say, the equations describing an emergent phenomenon like elasticity. In fact, it is…

Dark Energy and its Implications for Gravity

The cosmological constant is the most economical candidate for dark energy. No other approach really alleviates the difficulties faced by the cosmological constant because, in all other attempts to…

Renormalized spacetime is two-dimensional at the Planck scale

Quantum field theory distinguishes between the bare variables – which we introduce in the Lagrangian – and the renormalized variables which incorporate the effects of interactions. This suggests that…

DUALITY AND ZERO-POINT LENGTH OF SPACETIME

The action for a relativistic free particle of mass m receives a contribution -mds from a path of infinitesimal length ds. Using this action in a path integral, one can obtain the Feynman propagator…

Entropy density of spacetime and the Navier-Stokes fluid dynamics of null surfaces

It has been known for several decades that Einstein's field equations, when projected onto a null surface, exhibit a structure very similar to the nonrelativistic Navier-Stokes equation. I show that…