Snowmass white paper: Quantum information in quantum field theory and quantum gravity

TL;DR

This white paper surveys the burgeoning interface between quantum information and quantum field theory (QFT) and quantum gravity, arguing that information-theoretic quantities such as entanglement entropy and complexity reveal universal structure in QFTs, RG flows, and holographic dualities. It reviews foundational definitions and methods for quantifying information in QFT, outlines how holography geometrizes information via the RT/HRT prescriptions, and discusses mixed-state entanglement, scrambling, and complexity as central themes for dynamics and simulation. The authors highlight how SSA-based monotones constrain RG flows, classify phases, and illuminate edge modes and topological order, while emphasizing the practical and conceptual benefits of classical and quantum simulations for strongly coupled field theories and potential quantum-gravity insights. Overall, the work argues that an information-theoretic perspective not only clarifies deep questions about spacetime emergence and black holes but also guides practical computational approaches and experimental avenues for probing QFT and quantum gravity.

Abstract

We present a summary of recent progress and remaining challenges in applying the methods and ideas of quantum information theory to the study of quantum field theory and quantum gravity. Important topics and themes include: entanglement entropy in QFTs and what it reveals about RG flows, symmetries, and phases; scrambling, information spreading, and chaos; state preparation and complexity; classical and quantum simulation of QFTs; and the role of information in holographic dualities. We also highlight the ways in which quantum information science benefits from the synergy between the fields.