English

Gravity without averaging

High Energy Physics - Theory 2022-03-09 v1

Abstract

We present a gravitational theory that interpolates between JT gravity, and a gravity theory with a fixed boundary Hamiltonian. For this, we consider a matrix integral with the insertion of a Gaussian with variance σ2\sigma^2, centered around a matrix H0\textsf{H}_0. Tightening the Gaussian renders the matrix integral less random, and ultimately it collapses the ensemble to one Hamiltonian H0\textsf{H}_0. This model provides a concrete setup to study factorization, and what the gravity dual of a single member of the ensemble is. We find that as σ2\sigma^2 is decreased, the JT gravity dilaton potential gets modified, and ultimately the gravity theory goes through a series of phase transitions, corresponding to a proliferation of extra macroscopic holes in the spacetime. Furthermore, we observe that in the Efetov model approach to random matrices, the non-averaged factorizing theory is described by one simple saddle point.

Keywords

Cite

@article{arxiv.2107.02178,
  title  = {Gravity without averaging},
  author = {Andreas Blommaert and Jorrit Kruthoff},
  journal= {arXiv preprint arXiv:2107.02178},
  year   = {2022}
}

Comments

47 pages, 15 figures and many delta functions

R2 v1 2026-06-24T03:54:28.743Z