hide
Free keywords:
High Energy Physics - Theory, hep-th,General Relativity and Quantum Cosmology, gr-qc
Abstract:
We study a model for a non-singular cosmic bounce in N=1 supergravity, based
on supergravity versions of the ghost condensate and cubic Galileon scalar
field theories. The bounce is preceded by an ekpyrotic contracting phase which
prevents the growth of anisotropies in the approach to the bounce, and allows
for the generation of scale-invariant density perturbations that carry over
into the expanding phase of the universe. We present the conditions required
for the bounce to be free of ghost excitations, as well as the tunings that are
necessary in order for the model to be in agreement with cosmological
observations. All of these conditions can be met. Our model thus provides a
proof-of-principle that non-singular bounces are viable in supergravity,
despite the fact that during the bounce the null energy condition is violated.
