PARTITION FUNCTION AND ENERGY DENSITY OF A SCALAR FIELD AT FINITE TEMPERATURE IN ROBERTSON-WALKER SPACETIME

<正> The path integral method of partition functional in static Spacetimes is extended to a dynamic R-W spacetime with space curvature k=+1. In terms of the conformal transformation between R-W spacetime and the static Einstein spacetime, the total energy density of a conformal invariant scalar field is obtained. In the case of a massive field we have calculated the correction of the energy density at finite temperature up to the order of μ2. It will be useful for Studying the evolution of the universe at its early stage.