Effective equation of state and energy conditions in phantom/tachyon inflationary cosmology perturbed by quantum effects

We discuss the model consisting of tachyon which may have the negative kinetic energy plus scalar phantom and plus conformal quantum matter. It is demonstrated that such a model naturally admits two de Sitter phases where the early universe inflation is produced by quantum effects and the late time accelerating universe is caused by phantom/tachyon. The energy conditions bounds for such cosmology are derived. It is interesting that effective equation of state may change its sign what depends from the proper choice of the combination of phantom/tachyon and quantum effects. (C) 2003 Elsevier B.V. All rights reserved.