Spacetime and dark matter from spontaneous breaking of Lorentz symmetry

It is shown that a spontaneously-broken gauge theory of the Lorentz group contains Ashtekar's chiral formulation of general relativity accompanied by dust. From this perspective, gravity is described entirely by a connection ω valued in the Lie algebra of the complexified Lorentz group and a Lorentz-charged scalar field t. The model is 'pre-geometric' in the sense that the spacetime metric may be constructed only in the symmetry-broken regime. We speculate on the extent to which this dust may account for dark matter and on the behaviour of the theory in regimes where the symmetry is not broken. (paper)