This project deals with a novel emergent theory of gravity that arises from the IKKT matrix model and proposes to study this thoroughly. Interestingly, this matrix model can be viewed as a constructive definition of IIB (super-) string theory, thus bypassing the notorious landscape problem of string theory and admitting various brane-like solutions. This model can also resolve the notorious UV/IR mixing issue of string theory. The main questions to be addressed through this project is:
Is the origin of “dark matter” related to the torsion of the Weitzenböck connection?
So far, this emergent gravity model has shown some promising results like possible explanation of dark matter in terms of this modified non-linear theory and therefore, it is timely that we understand this in full detail. More explicitly, it has been shown to produce a Schwarzschild-like metric structure for the IR (or large r) limit that deviates from the Ricci-flat configuration in the non-linear regime. These solutions are actually that of pre-gravity theory associated with classical brane configurations. I will study these solutions in more detail from a physics perspective and compare them with the standard picture of dark matter. Indeed, some deviations from general relativity are expected, due to the underlying matrix model action. On scales shorter than the cosmological scales one would expect this to be reconciled with GR due to the induced Einstein–Hilbert action. I will, therefore, also investigate the cross-over regime by taking this quantum feature into account. I am also interested in exploring other possible solutions of this semi-classical matrix model beyond the static configurations already obtained; the latter yielded hyperbolic FLRW spacetime structure! This endeavour could shed some light on the notion of time in matrix model and cosmology and might pave the way to understanding similar numerical results obtained earlier.
Duration of stay: 5th March - 14th May 2023
|Kaushlendra Kumar||University of Hannover|