Regular Instantons in the Eddington-inspired-Born-Infeld Gravity: Lorentzian Wormholes from Bubble Nucleations

Understand

The O(4)-symmetric regular instanton solutions are studied within the framework of the Eddington-inspired-Born-Infeld gravity (EiBI).

• We find that the behavior of the solution would deviate from that in Einstein gravity when the kinetic energy of the scalar field is sufficiently large.
• The tunneling probability is calculated numerically in different parameter space.
• We find that the tunneling probability would increase with the Born-Infeld coupling constant, which is assumed to be positive in this paper.