Wormholes and black universes communicated with extra dimensions

Understand

In 6D general relativity with a phantom scalar field as a source of gravity, we present solutions that implement a transition from an effective 4D geometry times small extra dimensions to an effectively 6D space-time where the physical laws are different from ours.

• We consider manifolds with the structure M0 x M1 x M2, where M0 is 2D Lorentzian space-time while each of M1 and M2 can be a 2-sphere or a 2-torus.
• Some solutions describe wormholes with spherical symmetry in our space-time and toroidal extra dimensions.
• Others are of black universe type: at one end there is a 6D asymptotically anti-de Sitter black hole while beyond the horizon the geometry tends to a 4D de Sitter cosmology times a small 2D spherical extra space.