Emergence of extended Newtonian gravity from thermodynamics

TL;DR

This paper reveals a thermodynamic foundation for extended Newtonian gravity, deriving a nonlinear field equation with a dissipative term that transitions from Newtonian to non-Newtonian behavior across scales.

Contribution

It introduces a thermodynamic approach to gravity, deriving a nonlinear gravitational field equation from entropy considerations, highlighting a scale-dependent transition from Newtonian to extended gravity.

Findings

System relaxes to Newtonian gravity at small scales

Emergence of non-Newtonian gravity at larger scales

Presence of a dissipative term due to irreversibility

Abstract

Discovery of a novel thermodynamic aspect of nonrelativistic gravity is reported. Here, initially, an unspecified scalar field potential is considered and treated not as an externally applied field but as a thermodynamic variable on an equal footing with the fluid variables. It is shown that the second law of thermodynamics imposes a stringent constraint on the field, and, quite remarkably, the allowable field turns out to be only of gravity. The resulting field equation for the gravitational potential derived from the analysis of the entropy production rate contains a dissipative term due to irreversibility. It is found that the system relaxes to the conventional theory of Newtonian gravity up to a certain spatial scale, whereas on the larger scale there emerges non-Newtonian gravity described by a nonlinear field equation containing a single coefficient. A comment is made on an estimation of the coefficient that has its origin in the thermodynamic property of the system.