Modified gravity at large scales on quantum spacetime in the IKKT model

TL;DR

This paper investigates how quantum spacetime in the IKKT matrix model modifies gravitational dynamics at large scales, revealing potential explanations for dark matter phenomena through extra geometric modes.

Contribution

It introduces a combined action in the IKKT model that leads to modified Einstein equations with novel geometric modes resembling dark matter.

Findings

Discovery of non-Ricci flat geometric modes with non-standard dispersion relations

Modified Einstein equations include an extra geometrical tensor interpreted as 'mirage matter'

Potential implications for understanding dark matter phenomena

Abstract

The gravitational dynamics of 3+1 dimensional covariant quantum spacetime in the IKKT or IIB matrix model is studied at one loop, combining the Yang-Mills-type matrix action with the induced Einstein-Hilbert action. This combined action leads to interesting modifications of the gravitational dynamics at long distances, governed by modified Einstein equations including an extra geometrical tensor interpreted as ''mirage matter''. In particular we find extra non-Ricci flat geometric modes with a non-standard dispersion relation, with features reminiscent of dark matter.