Interacting String Multi-verses and Holographic Instabilities of Massive Gravity

TL;DR

This paper explores quantum multi-gravity theories derived from large-N conformal field theories, analyzing their stability and strong coupling issues through holographic principles and boundary condition tuning.

Contribution

It introduces stable multi-graviton models with suppressed strong coupling effects by fine-tuning boundary conditions in AdS space.

Findings

Identified stable multi-graviton configurations with reduced scalar mode instabilities

Demonstrated the necessity of fine-tuning boundary conditions to prevent background backreaction

Provided insights into holographic approaches to massive gravity problems

Abstract

Products of large-N conformal field theories coupled by multi-trace interactions in diverse dimensions are used to define quantum multi-gravity (multi-string theory) on a union of (asymptotically) AdS spaces. One-loop effects generate a small O(1/N) mass for some of the gravitons. The boundary gauge theory and the AdS/CFT correspondence are used as guiding principles to study and draw conclusions on some of the well known problems of massive gravity - classical instabilities and strong coupling effects. We find examples of stable multi-graviton theories where the usual strong coupling effects of the scalar mode of the graviton are suppressed. Our examples require a fine tuning of the boundary conditions in AdS. Without it, the spacetime background backreacts in order to erase the effects of the graviton mass.