Quantum gravity tomography

TL;DR

This paper introduces a model for holographic reconstruction in flat spacetime quantum gravity, demonstrating how boundary measurements can fully recover quantum states, with implications for black hole information paradox.

Contribution

It presents a method to reconstruct quantum states from boundary metric data in flat spacetime quantum gravity, extending holographic principles beyond AdS models.

Findings

Complete quantum state reconstruction from boundary measurements.

Use of a relativistic Wigner function for holographic encoding.

Implications for recovering information in black hole scenarios.

Abstract

The holographic principle posits that all quantum information in a region of spacetime is encoded on its boundary. While there is strong evidence for this principle in certain models of quantum gravity in asymptotically anti-de Sitter spacetime, it is yet to be established whether holography is a generic feature of quantum gravity, or a peculiar property of these models. The goal of the present work is to present a model of holographic reconstruction in the framework of perturbative quantum gravity in flat spacetime. Specifically, we consider a state in the single-particle sector of a quantum field theory and give a method to completely reconstruct the quantum state from measurement of the metric at spatial infinity. Our argument uses a relativistic generalization of the quantum-mechanical Wigner function, and gives an explicit mechanism by which the gravitational constraints encode quantum information holographically on the boundary. Moreover, it suggests how information about more general states might be recovered from soft charges at null infinity, with applications to the black hole information loss paradox.