Cosm ologicalScaling Solutions and C ross-couplingExponentialPotential

摘要: We present a phase-space analysis of cosmology containing multiple scalar elds with a positive or negative cross-coupling exponential potential. We show that there exist power law kinetic-potential-scaling solutions for a sciently at positive potential or for a steep negative potential.The former is the unique late-ti e attractor, but it is difficult to yield assisted ination.Thelaterisneverstablein an expanding universe.M oreover,fora steep negative potentialthere existsa kinetic-dom inated regim e in which each solution isa latetime attractor. In the presence ofordinary m atterthese scaling solutionswith a negative cross-coupling potentialare found unstable. W e briey discuss the physicalconsequences of these results.