Quantum gravity and the standard model

TL;DR

This paper demonstrates that certain background independent quantum gravity models inherently contain local excitations that correspond to standard model fermions, providing a potential quantum gravitational foundation for particle physics.

Contribution

It shows that specific quantum spacetime models include matter-like excitations as noiseless subsystems, linking quantum gravity with the standard model through topological graph braiding patterns.

Findings

Local excitations map to first-generation fermions

Matter states are noiseless subsystems of quantum dynamics

Topological braiding patterns encode matter properties

Abstract

We show that a class of background independent models of quantum spacetime have local excitations that can be mapped to the first generation fermions of the standard model of particle physics. These states propagate coherently as they can be shown to be noiseless subsystems of the microscopic quantum dynamics. These are identified in terms of certain patterns of braiding of graphs, thus giving a quantum gravitational foundation for the topological preon model proposed by one of us. These results apply to a large class of theories in which the Hilbert space has a basis of states given by ribbon graphs embedded in a three-dimensional manifold up to diffeomorphisms, and the dynamics is given by local moves on the graphs, such as arise in the representation theory of quantum groups. For such models, matter appears to be already included in the microscopic kinematics and dynamics.