IS A LAYER PHASE DISSOLVED IN THE EARLY UNIVERSE

The phase structure of a non-isotropic U(1) lattice gauge model at fin ite temperature is investigated with the variational-cumulant expansio n method (VCE). The layer phase proposed by Fu and Nielsen [Nucl. Phys . B 236 (1984) 1671 exists in this model in the case of D = 5, d = 4. We also find the layer phase of d = 3 where D = 4 which is different f rom the result of the non-isotropic U(1) lattice gauge model at zero t emperature. But in the case of D = 3, the layer phase does not exist. From the results we consider that the layer phases exist in all kinds of cases for the non-isotropic U(1) lattice gauge model when the tempe rature approaches infinity (T-->infinity), as particles studied by phy sicists get enough energy to pass through the ''wall'' between two lay ers which is thought as a ''confined'' direction at zero temperature, and all communication among layers is easier. Thus we may also think t hat the layer phase is dissolved in the early universe which is believ ed to be a very hot system.