Quasiparticle picture from the Bekenstein bound

TL;DR

This paper explores how the holographic bound and unitarity imply that classical geometry and quantum fields are emergent phenomena from a fundamental quantum gravity theory, with implications for black hole information loss.

Contribution

It proposes a framework linking low-energy theories to quantum gravity via the holographic bound, emphasizing geometry and fields as emergent from fundamental degrees of freedom.

Findings

Geometry and quantum fields emerge from fundamental degrees of freedom.

Entanglement between geometry and fields affects information retention.

A toy model shows average information loss due to geometry-field entanglement.

Abstract

We provide general arguments regarding the connection between low-energy theories (gravity and quantum field theory) and a hypothetical fundamental theory of quantum gravity, under the assumptions of (i) validity of the holographic bound and (ii) preservation of unitary evolution at the level of the fundamental theory. In particular, the appeal to the holographic bound imposed on generic physical systems by the Bekenstein-Hawking entropy implies that both classical geometry and quantum fields propagating on it should be regarded as phenomena emergent from the dynamics of the fundamental theory. The reshuffling of the fundamental degrees of freedom during the unitary evolution then leads to an entanglement between geometry and quantum fields. The consequences of such scenario are considered in the context of black hole evaporation and the related information-loss issue: we provide a simplistic toy model in which an average loss of information is obtained as a consequence of the geometry-field entanglement.