Emergent gravity from a mass deformation in warped spacetime

Abstract

We consider a deformation of five-dimensional warped gravity with bulk and boundary mass terms to quadratic order in the action. We show that massless zero modes occur for special choices of the masses. The tensor zero mode is a smooth deformation of the Randall-Sundrum graviton wavefunction and can be localized anywhere in the bulk. There is also a vector zero mode with similar localization properties, which is decoupled from conserved sources at tree level. Interestingly, there are no scalar modes, and the model is ghostfree at the linearized level. When the tensor zero mode is localized near the IR brane, the dual interpretation is a composite graviton describing an emergent (induced) theory of gravity at the IR scale. In this case Newton's law of gravity changes to a new power law below the millimeter scale, with an exponent that can even be irrational.

Massless gravitons on a brane from massive gravity in five-dimensional Minkowski space

“…A similar analysis has been performed, in the limit of a δ-like mass profile and in the context of a compact and curved extra dimension, in [7]. The focus of our work is different from that of [7], as the main question we are asking concerns the possibility of localizing gravity in non compact five-dimensional Minkowski space. Our results agree with those of [7], where applicable.…”

“…The focus of our work is different from that of [7], as the main question we are asking concerns the possibility of localizing gravity in non compact five-dimensional Minkowski space. Our results agree with those of [7], where applicable.…”

Probing composite gravity in colliders

“…Hence, this is a shortdistance test of GR, which in turn places a lower bound on Λ g . On the other hand, the relation (13) implies that if we find composite gravity first at some Λ g , then we will not discover a gravitino above the scale Λ g -at best we may just see a pseudo-gravitino which is nothing but a random spin-3/2 state.…”

“…In the AdS composite graviton model of Ref. [13], the graviton wavefunction is highly peaked toward the IR brane, but there is an exponentially suppressed tail overlapping the UV brane where the SM fields live, which can be thought of as an explanation for the weakness of gravity. Adding supersymmetry to their setup to study the gravitino properties is saved for future work.…”

“…To this goal, Gherghetta, Peloso and Poppitz recently presented a theory in a 5-dimensional Anti-deSitter (AdS) space which is dual to a 4-dimensional conformal field theory in which the conformal symmetry is dynamically broken in the IR yielding a spectrum containing a massless spin-2 resonance [13]. To complete their picture, analyses beyond the quadratic order in action must be performed, especially concerning effects of the stabilization of the AdS space, and if the delicate existence of the massless spin-2 state persists, this will be a solid, concrete example of a theory of a composite graviton.…”