Existence of Spinorial States in Pure Loop Quantum Gravity

TL;DR

This paper shows that pure loop quantum gravity admits spinorial states, indicating the potential for particle-like bound states arising from non-trivial spatial topology in a matter-free quantum gravity framework.

Contribution

It provides the first demonstration of spinorial states in pure loop quantum gravity, linking topological features to particle-like quantum states without matter fields.

Findings

Existence of states transforming non-trivially under 2π rotations.

Evidence for bound states with particle properties in topology-rich regions.

Connection between diffeomorphism group actions and fractional spin states.

Abstract

We demonstrate the existence of spinorial states in a theory of canonical quantum gravity without matter. This should be regarded as evidence towards the conjecture that bound states with particle properties appear in association with spatial regions of non-trivial topology. In asymptotically trivial general relativity the momentum constraint generates only a subgroup of the spatial diffeomorphisms. The remaining diffeomorphisms give rise to the mapping class group, which acts as a symmetry group on the phase space. This action induces a unitary representation on the loop state space of the Ashtekar formalism. Certain elements of the diffeomorphism group can be regarded as asymptotic rotations of space relative to its surroundings. We construct states that transform non-trivially under a $2\pi$-rotation: gravitational quantum states with fractional spin.