Instability of a non-minimally coupled scalar field in cylindrical spacetimes.

RUBÍN DE CELIS, EMILIO; SIMEONE, CLAUDIO; TOMASINI, CECILIA

Conferencia; 15th International Conference: Dark Side of the Universe; 2019

A stable spacetime in General Relativity can become unstable with the inclusion of a scalar field non-minimally coupled to gravity. In this work we investigate the stability in the spacetime of a cylindrical shell of matter coupled to a massive scalar field. Resonant or stable Green's functions for the field are characterized in terms of the coupling ξ {[1]}. The classical instability under linear perturbations determine that the vacuum energy density fluctuations of the scalar field can have an exponential enhancement in some unfavored resonant configurations. These mechanisms can be adapted to probe the nature of vacuum energy through astrophysical observations in some specific models {[2]}. We found the critical couplings which produce resonant configurations in the studied backgrounds. On the other hand we establish a safety domain for the configuration parameters corresponding to stable couplings values.