Wormhole solution free of ghosts in Einstein’s gravity with two scalar fields

Abstract

In this paper, we construct models that admit the traversable wormhole geometries in the framework of Einstein's gravity with two scalar fields. As is well known, the energy conditions are broken, and we show that a ghost appears. The ghost can be, however, eliminated by imposing a constraint on the ghost field, which is a scalar. The constraint is similar to the mimetic one proposed by Chamseddine and Mukhanov to construct an alternative description of cold dark matter. We explicitly show that there does not appear to be any unstable mode although the energy conditions are broken. Therefore, we obtain a model that realizes the traversable and stable wormhole.