Non-local dilaton coupling to dark matter: cosmic acceleration and pressure backreaction

TL;DR

This paper explores a non-local dilaton interaction model inspired by string theory, demonstrating how strong coupling can counteract cosmic acceleration caused by dark energy, restoring a decelerated universe.

Contribution

It introduces a novel non-local dilaton coupling framework that influences dark matter interactions and cosmic acceleration, with analytical and numerical validation.

Findings

Non-local effects can induce backreaction that offsets acceleration.

Strong coupling leads to a return to dust-dominated deceleration.

Analytical and numerical results support the model's predictions.

Abstract

A model of non-local dilaton interactions, motivated by string duality symmetries, is applied to a scenario of "coupled quintessence" in which the dilaton dark energy is non-locally coupled to the dark-matter sources. It is shown that the non-local effects tend to generate a backreaction which -- for strong enough coupling -- can automatically compensate the acceleration due to the negative pressure of the dilaton potential, thus asymptotically restoring the standard (dust-dominated) decelerated regime. This result is illustrated by analytical computations and numerical examples.