In agreement with the most recent observations of the universe, there are twointrinsically different models of the early universe. In the first alternative, the universe wascreated at a big bang singularity, and after a period of exponential expansion, it was drivento a hot state which agrees perfectly with all cosmological observations presently at hand. Incontrast, the second proposal argues, in the beginning, there was a transition from a contractingphase to an expanding one. Using an approach based on a supersymmetric quantum cosmology,we will describe a new formalism to explain the origin and evolution of the universe. Forthis, we study a supersymmetric and flat Friedmann-Robertson-Walker model in the superfieldformulation. The WKB method is then applied, and we show that supersymmetry introducesextra terms in the Einstein-Klein-Gordon equations of motion. We prove that supersymmetry(or indirectly, the gravitinos) fixes a type of matter with a stiff equation of state at early stagesin the evolution of the universe. Finally, we study the solutions of the equations of motion, theirstability properties, and their cosmological consequences.
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