Diamonds in the Bulk and Large-$N$ Scaling in AdS/CFT

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: A, Sidan, Banks, Tom
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866913164962037760
author A, Sidan
Banks, Tom
author_facet A, Sidan
Banks, Tom
contents Quantum Field Theory introduced us to the notion that a causal diamond in space-time corresponded to a subsystem of a quantum mechanical system defined on the global space-time. Work by Jacobson, Fischler and Susskind, and particularly Bousso suggested that, in the quantum theory of gravity, this subsystem should have a density matrix of finite entropy. These authors formalized older intuitive arguments based on black hole physics. Although mathematically, Type II von Neumann algebras admit finite entropy density matrices, the black hole arguments suggest that the number of physical states in these subsystems is finite. The conjecture that de Sitter (dS) space has a finite number of physical states was first made by Fischler and one of the present authors. Leutheusser and Liu showed that, in the $N = \infty$ limit, causal diamonds with finite area in AdS radius units had Type $III_1$ von Neumann sub-algebras of the full operator algebra. They claimed that this was true for finite values of the UV cutoff, and that the algebra was the algebra of bulk local fields in the diamond. We will argue that the second part of this conjecture is incorrect and that the bulk field algebra emerges only in a double scaled limit, where the boundary UV cutoff is taken to infinity as $N$ is taken to infinity. There is never a bulk field theory description that resolves distances smaller than the AdS radius.
format Preprint
id arxiv_https___arxiv_org_abs_2601_09621
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Diamonds in the Bulk and Large-$N$ Scaling in AdS/CFT
A, Sidan
Banks, Tom
High Energy Physics - Theory
General Relativity and Quantum Cosmology
Quantum Field Theory introduced us to the notion that a causal diamond in space-time corresponded to a subsystem of a quantum mechanical system defined on the global space-time. Work by Jacobson, Fischler and Susskind, and particularly Bousso suggested that, in the quantum theory of gravity, this subsystem should have a density matrix of finite entropy. These authors formalized older intuitive arguments based on black hole physics. Although mathematically, Type II von Neumann algebras admit finite entropy density matrices, the black hole arguments suggest that the number of physical states in these subsystems is finite. The conjecture that de Sitter (dS) space has a finite number of physical states was first made by Fischler and one of the present authors. Leutheusser and Liu showed that, in the $N = \infty$ limit, causal diamonds with finite area in AdS radius units had Type $III_1$ von Neumann sub-algebras of the full operator algebra. They claimed that this was true for finite values of the UV cutoff, and that the algebra was the algebra of bulk local fields in the diamond. We will argue that the second part of this conjecture is incorrect and that the bulk field algebra emerges only in a double scaled limit, where the boundary UV cutoff is taken to infinity as $N$ is taken to infinity. There is never a bulk field theory description that resolves distances smaller than the AdS radius.
title Diamonds in the Bulk and Large-$N$ Scaling in AdS/CFT
topic High Energy Physics - Theory
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2601.09621