Oscillatory behavior in cosmological models

Oscillatory behavior in cosmological models is investigated, motivated, in part, by the apparent periodic distribution of galaxies in deep narrow-cone red-shift surveys. In particular, oscillatory behavior in two cosmological models is studied; a qualitative analysis is performed and approximate solutions are found for a soft inflationary model and for a Friedmann-Robertson-Walker model containing a perfect fluid and a scalar field source. These two models are conformally equivalent to particular models arising from a large class of scalar-tensor theories. It is then argued that such oscillatory behavior is a generic property of scalartensor theories of gravity.