Speaker
Description
This study investigates the decay of the Kaluza-Klein vacuum mediated by instanton solutions with singularities. For the Kaluza-Klein vacuum, there exists a non-perturbative decay channel where spacetime is overwhelmed by the bubble of nothing (BoN), which has no degrees of freedom therein. The instanton solution mediating this decay is the BoN instanton, which is the Euclideanized 5D Schwarzschild black hole solution. In general discussions, the periodicity of imaginary time is fixed to appropriate values at the position of the event horizon to avoid singularities. However, we relax this smoothness condition and calculate the contribution of the conical singularity to the Euclidean action based on the conical deficit regularization. These contributions are always negative and tend to decrease the Euclidean action. Thus, if correct, decay via singular instanton solutions may be a more dominant process. Additionally, we reconstruct the bounce action using thermodynamic functions and attempt a thermodynamic interpretation of the catalytic effect mentioned above.
