title: Constructing phantom cosmologies from standard scalar field universes.
abstract: We illustrate how form-invariance transformations can be used for constructing phantom cosmologies from standard scalar field universes. First we discuss how to relate two flat Friedmann-Robertson-Walker cosmologies with different barotropic indexes gamma and gamma;. Then we consider the particular case gamma;=-gamma, and we show that, if the matter content is interpreted in terms of self-interacting scalar fields, then the corresponding transformation provides the link between a standard and a phantom cosmology. After that, we illustrate the method by considering models with exponential potentials. Finally, we also show that the mentioned duality persists even if the typical brane-world modifications to the Friedmann equation are considered.
authors.affiliation: Departamento de Física Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón I, 1428 Buenos Aires, Argentina. chimento@df.uba.ar
authors.forename: Luis P
authors.initials: LP
authors.lastname: Chimento
authors.forename: Ruth
authors.initials: R
authors.lastname: Lazkoz