Quantum Information and Gravity Cutoff in Theories with Species

TL;DR

The paper argues that the gravitational cutoff in theories with $N$ species, $\Lambda = \frac{M_{Pl}}{\sqrt{N}}$, can be derived from quantum information principles, not solely black-hole arguments. By relating entanglement entropy to holographic bounds, invoking quantum cloning, and analyzing scrambling dynamics, the authors show that the minimal information-processing scale $l_N$ naturally enforces the bound and explains the equality of entanglement and Bekenstein-Hawking entropies. They then connect this UV/IR structure to gravity dualities, recovering AdS/CFT in the appropriate limit and proposing a broader holographic framework beyond AdS spaces, including Barvinski-type dualities. The work thus unifies information-theoretic limits with gravitational holography and suggests a generalized correspondence between four-dimensional theories with many species and higher-dimensional gravity.

Abstract

We show that lowering of the gravitational cutoff relative to the Planck mass, imposed by black hole physics in theories with N species, has an independent justification from quantum information theory. First, this scale marks the limiting capacity of any information processor. Secondly, by taking into the account the limitations of the quantum information storage in any system with species, the bound on the gravity cutoff becomes equivalent to the holographic bound, and this equivalence automatically implies the equality of entanglement and Bekenstein-Hawking entropies. Next, the same bound follows from quantum cloning theorem. Finally, we point out that by identifying the UV and IR threshold scales of the black hole quasi-classicality in four-dimensional field and high-dimensional gravity theories, the bound translates as the correspondence between the two theories. In case when the high-dimensional background is AdS, this reproduces the well-known AdS/CFT relation, but also suggests a generalization of the correspondence beyond AdS spaces. In particular, it reproduces a recently suggested duality between a four-dimensional CFT and a flat five dimensional theory, in which gravity crosses over from four to five dimensional regime in far infrared.