1204.3654 (A. G. S. Landulfo et al.)

Burst of particles from the falling asleep of the vacuum (or Tachyonic instability in relativistic stars)    [PDF]

A. G. S. Landulfo, W. C. C. Lima, G. E. A. Matsas, D. A. T. Vanzella

Dense enough compact objects were recently shown to lead to an exponentially fast increase of the vacuum energy density for free scalar fields properly coupled to the spacetime curvature: the vacuum awakening effect. This exponential increase may be alternatively seen as a sort of tachyonic instability which also plays an important role in inflationary cosmology. After the instability is triggered, the star energy density would be overwhelmed by the vacuum energy in a few milliseconds. This demands that at some point backreaction takes over to bring the vacuum back to a stationary regime. Here we show that the vacuum energy density built up during the unstable epoch when the vacuum is awake leads to a burst of particles in the final stationary state when the vacuum "falls asleep". We emphasize that this phenomenon occurs even in the adiabatic limit, where the spacetime geometry changes arbitrarily slowly. Therefore, the burst of particles at the end of the awaken phase differs drastically from the usual particle creation due to the change in the background geometry.

View original: http://arxiv.org/abs/1204.3654