Work

Nonperturbative toolkit for quantum gravity

Year: 2026

Type: article

Abstract: We propose a method for demonstrating equivalences beyond the saddle point approximation between quantities in quantum gravity that are defined by the Euclidean path integral, without assumptions about holographic duality. The method involves three ingredients: (1) a way of resolving the identity with an overcomplete basis of microstates that is under semiclassical control, (2) a drastic simplification of the sum over topologies in the limit where the basis is infinitely overcomplete, and (3) a way of cutting and splicing geometries to demonstrate equality between two different gravitational path integrals even if neither can be explicitly computed. We illustrate our methods by giving a general argument that the thermal partition function of quantum gravity with two boundaries factorizes. One implication of our results is that universes containing a horizon can sometimes be understood as superpositions of horizonless geometries entangled with a closed universe.

Source: Physical review. D/Physical review. D.

DOI: 10.1103/nlzj-w34h

Authors: Vijay Balasubramanian, Tom Yildirim

Institutions: Vrije Universiteit Brussel, University of Oxford, International Solvay Institutes, University of Pennsylvania

Language: English

Topic: Black Holes and Theoretical Physics

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funders: U.S. Department of Energy, Balliol College, University of Oxford

Awards: UNIVERSITY OF PENNSYLVANIA THEORETICAL PROGRAM, DISTRIBUTED QUANTUM INFORMATION: THEORY AND APPLICATIONS