Quantum Compositeness of Gravity: Black Holes, AdS and Inflation

TL;DR

This work reimagines gravity as a quantum-composite system of N soft gravitons, placing gravitational backgrounds at a quantum-critical point and deriving classical curved spacetimes as the large-N limit of graviton scattering. By coupling this picture to inflation and de Sitter spaces (via a gravitons-inflaton condensate), the authors reproduce standard inflationary predictions while revealing cumulative, finite-N quantum corrections that bound the duration of inflation and encode the entire history of the Hubble patch. A key insight is that particle creation is not a vacuum process but results from depletion of real background quanta, yielding new clocks (depletion and entanglement) that can affect observables and potentially address the cosmological constant problem. The framework also extends to AdS, where AdS holography emerges as the criticality of a graviton condensate and large AdS black holes are described via a graviton-entropy correspondence, offering a unified microscopic foundation for holography and quantum gravity phenomena. Overall, the paper provides a microscopic, many-body perspective on gravity that connects black hole physics, inflationary cosmology, and AdS/CFT through graviton condensates and quantum-critical dynamics, predicting measurable quantum corrections beyond standard semiclassical gravity.

Abstract

Gravitational backgrounds, such as black holes, AdS, de Sitter and inflationary universes, should be viewed as composite of N soft constituent gravitons. It then follows that such systems are close to quantum criticality of graviton Bose-gas to Bose-liquid transition. Generic properties of the ordinary metric description, including geodesic motion or particle-creation in the background metric, emerge as the large-N limit of quantum scattering of constituent longitudinal gravitons. We show that this picture correctly accounts for physics of large and small black holes in AdS, as well as reproduces well-known inflationary predictions for cosmological parameters. However, it anticipates new effects not captured by the standard semi-classical treatment. In particular, we predict observable corrections that are sensitive to the inflationary history way beyond last 60 e-foldings. We derive an absolute upper bound on the number of e-foldings, beyond which neither de Sitter nor inflationary Universe can be approximated by a semi-classical metric. However, they could in principle persist in a new type of it quantum eternity state. We discuss implications of this phenomenon for the cosmological constant problem.

Figures (2)

• Figure 1: Quantum scattering of a probe particle $\phi$ at the constituent gravitons.
• Figure 2: Leading order process responsible for the particle creation.