Structured objects in quantum gravity. The external field approximation.

The external field approximation (EFA) provides a mechanism whereby classical gravity and inertia emerge from a quantum background. The two-point vector, that in EFA represents gravity, is the byproduct of symmetry breaking and is accompanied by classical, vortical structures. Its interaction range is, in general, that of the metric tensor, but, in the context of a simple symmetry-breaking model, the range can be made finite by the presence of massive scalar particles. Vortices that conceal matter can then be produced, making it effectively 'dark'. In EFA, fermion relativistic vortices can be induced, in particular, by rotation. [ABSTRACT FROM AUTHOR]