Creation of wormholes by quantum tunnelling in modified gravity theories

Abstract

We study the process of quantum tunnelling in scalar-tensor theories in which the scalar field is non-minimally coupled to gravity. In these theories gravitational instantons can deviate substantially from sphericity and can in fact develop a neck - a feature prohibited in theories with minimal coupling. Such instantons with necks lead to the materialisation of bubble geometries containing a wormhole region. We clarify the relationship of neck geometries to violations of the null energy condition, and also derive a bound on the size of the neck relative to that of the instanton

Regular instantons in the Eddington-inspired-Born-Infeld gravity: Lorentzian wormholes from bubble nucleations

“…Furthermore, we find it attractive that a Lorentzian wormhole can be formed via quantum tunneling effects in the EiBI gravity. Similar wormhole creations can be realized in other modified gravity models [60,61]. The properties of these Lorentzian wormhole solutions deserve more scrutinies.…”

“…[43]) and it actually corresponds to a Lorentzian time-like wormhole after analytically continuing to the Lorentzian spacetime 1 . Similar creations of Lorentzian wormholes via quantum tunneling effects have also been studied in the context of the Gauss-Bonnet-dilaton gravity [60] and scalar-tensor theories in which the scalar field is non-minimally coupled to gravity [61].…”

Wormhole creation by quantum tunnelling

“…After bubble materialisation, such neck geometries lead to two regions of the universe that are separated by a wormhole. However, in contrast to the wormholes beloved by science fiction authors and as discussed in more detail in 15 , these wormholes typically possess a wide cross-section. It is important to stress that, while Jordan and Einstein frames are physically equivalent since they are simply related by a field redefinition, the choice of frame determines whether or not necks in the geometry exist.…”

From the Flamm–Einstein–Rosen bridge to the modern renaissance of traversable wormholes

“…The process of quantum tunneling was studied in a self-interacting scalar field theory with non-minimal coupling to gravity. 64,65 It was demonstrated that in these theories gravitational instantons can develop a neck, which is a feature prohibited in theories with minimal coupling. Furthermore, it was show that such instantons with necks lead to the materialization of bubble geometries containing a wormhole region.…”