Microscopic origin of Einstein's field equations and the raison d'être for a positive cosmological constant

  title={Microscopic origin of Einstein's field equations and the raison d'{\^e}tre for a positive cosmological constant},
  author={Thanu Padmanabhan and Sumanta Chakraborty},
  journal={Physics Letters B},

On the cosmological constant of flat flrw spacetime

We consider an exponentiallyexpanding, flat, Friedmann-Lemaˆıtre-Robertson-Walker (FLRW) Universe filled with a free Schroedinger field. The probability fluid of the latter is used to mimic the

Conditions for graviton emission in the recombination of a delocalized mass

We revisit a known gedankenexperiment in which a delocalized mass is recombined while the gravitational field sourced by it is probed by another (distant) particle. This setup has been proposed in the

Information content and minimum-length metric: A drop of light

  • A. Pesci
  • Physics
    General Relativity and Gravitation
  • 2022
In the vast amount of results linking gravity with thermodynamics, statistics, information, a path is described which tries to explore this connection from the point of view of (non)locality of the

Quantum mechanics, statistics, standard model and gravity

Careful considerations concerning the interpretation of quantum mechanics serves not only for a better philosophical understanding of the physical world, but can also be instrumental for model



Eddington gravity with matter: An emergent perspective

We describe an action principle, within the framework of the Eddington gravity, which incorporates the matter fields in a simple manner. Interestingly, the gravitational field equations derived from

Gravity and quantum theory: Domains of conflict and contact

There are two strong clues about the quantum structure of spacetime and the gravitational dynamics, which are almost universally ignored in the conventional approaches to quantize gravity. The first

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

Boundary terms of the Einstein-Hilbert action

The Einstein-Hilbert action for general relativity is not well posed in terms of the metric $g_{ab}$ as a dynamical variable. There have been many proposals to obtain an well posed action principle

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

Thermodynamical interpretation of the geometrical variables associated with null surfaces

The emergent gravity paradigm interprets gravitational field equations as describing the thermodynamic limit of the underlying statistical mechanics of microscopic degrees of freedom of the

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

Variational principle for gravity with null and non-null boundaries: a unified boundary counter-term

It is common knowledge that the Einstein–Hilbert action does not furnish a well-posed variational principle. The usual solution to this problem is to add an extra boundary term to the action, called

Analogue Gravity

The history, aims, results, and future prospects for the various analogue models of gravity are discussed, including a particularly simple example of an analogue model and the rich history and complex tapestry of models discussed in the literature.