Commutative Evolution Laws in Holographic Cellular Automata: AdS/CFT, Near-Extremal D3-Branes, and a Deep Learning Approach
Hyunju Go
TL;DR
Problem: realize commutative evolution laws in a holographic CA consistent with AdS/CFT and capture bulk curvature effects while preserving information. Approach: combine near-extremal D3-brane geometry yielding two Minkowski patches with a Z operator connecting horizon and boundary, and enforce commutativity $[T,Z]=0$; apply torus compactification to render finite degrees of freedom and train a CNN-based deep learning model to learn Z from T. Outcome: the trained DL model discovers nontrivial Z operators that satisfy $TZ=ZT$ for test inputs, indicating curvature information is encoded in the holographic map. Significance: demonstrates a concrete computational pathway to infer bulk curvature from boundary dynamics in a holographic setting and highlights DL's potential to uncover evolution laws subject to commutativity, with prospects to enforce covariance and unitarity in future work.
Abstract
According to 't Hooft, restoring Poincaré invariance in a holographic cellular automaton (CA) requires two distinct evolution laws that commute. We explore how this is realized in the AdS/CFT framework, assuming commutativity as a fundamental principle--much like general covariance once did--for encoding curvature. In our setup, physical processes in a given spacetime are encoded in a CA; to preserve Poincaré symmetry, the spacetime curvature must effectively vanish, so we consider a near-extremal black D3-brane solution, in which both the stretched horizon and the conformal boundary are approximated by Minkowski space. AdS/CFT implies a spatial evolution law connecting these hypersurfaces. Commutativity means the final state does not depend on the order of time evolution on each hypersurface and spatial evolution between them, forcing the time evolution law on the horizon and boundary to coincide. To satisfy all these conditions, we aim to demonstrate that the spatial evolution law inevitably encapsulates the curvature of the bulk, including quantum effects. For a computational model, we compactify the hyperplanes to tori, reducing the degrees of freedom to a finite number; taking these tori to infinite size then restores Poincaré symmetry. We propose a deep learning algorithm that, given a known time evolution law and commutativity, deduces the corresponding spatial evolution law.
