K. Ezawa, SEMICLASSICAL INTERPRETATION OF THE TOPOLOGICAL SOLUTIONS FOR CANONICAL QUANTUM-GRAVITY, Physical review. D. Particles and fields, 53(10), 1996, pp. 5651-5663
Ashtekar's formulation for canonical quantum gravity is known to posse
ss the topological solutions which have their support only on the modu
li space N of flat SL(2,C) connections. We show that each point on the
moduli space N corresponds to a geometric Structure, or more precisel
y the Lorentz group part of a family of Lorentzian structures,on the f
lat (3+1)-dimensional spacetime. A detailed analysis is given in the c
ase where the spacetime is homeomorphic to RxT(3). Most of the points
on the moduli space N yield pathological spacetimes which suffer from
singularities on each spatial hypersurface or which violate the strong
causality condition. There is, however, a subspace of N on which each
point corresponds to a family of regular spacetimes.