Fate of Wormholes Created by First-Order Phase Transition in the Early Universe

It has been pointed out recently that wormholes and black holes are created by cosmological first-order phase transition of vacuum. In the present paper this creation mechanism is discussed precisely. In particular, we investigate how bubbles nucleated in a trapped false vacuum (a false vacuum region surrounded by true vacuum) change the creation mechanism of wormholes and black holes. As a result, it is found that, due to a bubble nucleated in the trapped false vacuum, a wormhole collapses to a black hole in some case, while neither a wormhole nor a black hole is created in another case.