How Emergent is Gravity?

TL;DR

This paper argues that gravity is an emergent phenomenon by demonstrating that the horizon-fluid's energy transport equation resembles the Raychaudhuri equation, linking gravitational dynamics to fluid fluctuations.

Contribution

It provides a statistical mechanical derivation showing how static configurations evolve into dynamic ones, supporting the emergent gravity paradigm.

Findings

Energy transport in horizon-fluid parallels Raychaudhuri equation

Gravity can be derived from horizon-fluid fluctuations

Supports emergent gravity hypothesis

Abstract

General theory of relativity (or Lovelock extensions) is a dynamical theory; given an initial configuration on a space-like hypersurface, it makes a definite prediction of the final configuration. Recent developments suggest that gravity may be described in terms of macroscopic parameters. It finds a concrete manifestation in the fluid-gravity correspondence. Most of the efforts till date has been to relate equilibrium configurations in gravity with fluid variables. In order for the emergent paradigm to be truly successful, it has to provide a statistical mechanical derivation of how a given initial static configuration evolves into another. In this essay, we show that the energy transport equation governed by the fluctuations of the horizon-fluid is similar to Raychaudhuri equation and, hence gravity is truly emergent.