Induced gravity in Z_N orientifold models

TL;DR

This paper studies how four-dimensional gravity can emerge from quantum effects in certain string theory models, specifically Z_N orientifolds, with a focus on one-loop contributions and large N limits.

Contribution

It demonstrates that in odd N Z_N orientifold models, the one-loop renormalization of the Planck mass is dominated by the torus contribution, supporting the induced gravity scenario.

Findings

One-loop Planck mass renormalization is O(N) for odd N.

Annulus, Moebius strip, Klein bottle contributions cancel out.

Large N enhances quantum-induced gravity effects.

Abstract

We consider non-compact Z_N orientifold models of type IIB superstring theory with four-dimensional gravity induced on a set of coincident D3-branes. For the models with odd N the contribution to the one-loop renormalization of the Planck mass is shown to come only from the torus and to be O(N) as the contributions from annulus, Moebius strip and Klein bottle cancel. One can therefore realize the Dvali-Gabadadze-Porrati idea that four-dimensional gravity is induced by quantum effects at the one-loop level by considering large N.