Generic predictions of quantum theories of gravity

TL;DR

This paper explores generic predictions of background independent quantum gravity theories, such as loop quantum gravity, including discreteness of geometry, black hole entropy, and potential experimental signals.

Contribution

It identifies three new generic consequences of causal spin network theories: deformed special relativity, particles as excitations of quantum geometry, and disordered locality.

Findings

Discreteness of quantum geometry confirmed

Black hole and cosmological horizon entropy derived

Possible experimental signals of quantum gravity effects

Abstract

I discuss generic consequences (sometimes called "soft predictions") of a class of background independent quantum theories of spacetime called causal spin network theories. These are theories whose kinematics and dynamics is based on the evolution of labeled graphs, by local moves, such as in loop quantum gravity and spin foam models. Some generic consequences are well known, including the discreteness of quantum geometry, the elimination of spacetime singularities, the entropy of black hole and cosmological horizons and the fact that positive cosmological constant spacetimes are hot. Within the last few years three possible generic consequences have come to light. These are 1) Deformed special relativity as the symmetry of the ground state, 2) Elementary particles as coherent excitations of quantum geometry, 3) Locality is disordered. I discuss some possible experimental consequences of each.