Is it possible to obtain cosmic accelerated expansion through energy transfer between different energy densities?

TL;DR

This paper investigates whether energy transfer between different densities, such as matter converting to radiation, can lead to cosmic acceleration, finding it requires an intermediate state with negative equation of state.

Contribution

It demonstrates that cosmic acceleration via energy transfer is possible only if an intermediate negative equation of state phase occurs during conversion.

Findings

Cosmic acceleration requires a negative equation of state during energy transfer.

Energy transfer alone does not guarantee acceleration without specific conditions.

Intermediate negative state is crucial for acceleration in this scenario.

Abstract

The equation of state of an energy density may be significantly modified by coupling it to another energy density. In the light of this observation we check the possibility of producing cosmic accelerated expansion in this way. In particular we consider the case where matter is converted to radiation (or vice versa by particle physics processes). We find that cosmic accelerated expansion can be obtained in this way only if an intermediate state with negative equation of state forms during the conversion.