Ghosts and Tachyons in the Fifth Dimension

Abstract

We present several solutions for the five dimensional gravity models in the presence of bulk ghosts and tachyons to argue that these "troublesome" fields can be a useful model-building tool. The ghost-like signature of the kinetic term for a bulk scalar creates a minimum in the scale factor, removing the necessity for a negative tension brane in models with the compactified fifth dimension. It is shown that the model with the positive tension branes and a ghost field in the bulk leads to the radion stabilization. The bulk scalar with the variable sign kinetic term can be used to model both positive and negative tension branes of a finite width in the compact dimension. Finally, we present several ghost and tachyon field configurations in the bulk that lead to the localization of gravity in four dimensions, including one solution with the Gaussian profile for the metric, g_{μν}(y)=η_{μν}\exp{-αy^2}, which leads to a stronger localization of gravity than the Randall-Sundrum model.

New references added

Cited by in corpus (8)

• Anti-de-Sitter Island-Universes from 5D Standing Waves
• An anisotropic standing wave braneworld and associated Sturm-Liouville problem
• Localization of scalar and tensor fields in the standing wave braneworld with increasing warp factor
• Localization Problem in the 5D Standing Wave Braneworld
• Localization of Matter Fields in the 5D Standing Wave Braneworld
• General self-tuning solutions and no-go theorem
• Smoothing out Negative Tension Brane
• Tuning the Cosmological Constant, Broken Scale Invariance, Unitarity