Dynamical back-reaction of relic gravitons

The dynamical effects of the tensor modes of the geometry are investigated in the context of curvature bounces. Since the bouncing behaviour implies sharp deviations from a radiationdominated evolution, significant back-reaction effects of relic gravitons may be expected at short wavelengths. After developing a general iterative framework for the calculation of dynamical back-reaction effects, explicit analytical and numerical examples are investigated for different parametrizations of the energy-momentum pseudo-tensor(s) of the produced gravitons. The reported results suggest that dynamical back-reaction effects are a necessary ingredient for a consistent description of bouncing models at late times. e-mail address: [email protected]