Instabilities of wormholes and regular black holes supported by a phantom scalar field

Understand

We test the stability of various wormholes and black holes supported by a scalar field with a negative kinetic term.

• The general axial perturbations and the monopole type of polar perturbations are considered in the linear approximation.
• Two classes of objects are considered: (i) wormholes with flat asymptotic behavior at one end and AdS on the other (M-AdS wormholes) and (ii) regular black holes with asymptotically de Sitter expansion far beyond the horizon (the so-called black universes).
• A difficulty in such stability studies is that the effective potential for perturbations forms an infinite wall at throats, if any.