We present a new type of inflationary scenario based on metric formulations of gravity different from that of Einstein, e.g., a Brans-Dicke theory of gravity. Unlike previous inflation models, the inflationary phase transition can be completed via bubble nucleation. Hence, the fine tuning of an effective potential to obtain a slow-rollover transition is not required.

• Received 11 October 1988

DOI:https://doi.org/10.1103/PhysRevLett.62.376