Designing cyclic universe models.
The phenomenological constraints on the scalar field potential in cyclic models of the Universe are presented. We show that cyclic models require a comparable degree of tuning to that needed for inflationary models. The constraints are reduced to a set of simple design rules including "fast-roll" parameters analogous to the "slow-roll" parameters in inflation.
Khoury
Justin
J
ISCAP, Columbia University, New York, New York 10027, USA.
Steinhardt
Paul J
PJ
Turok
Neil
N