The dynamics of closed scalar field FRW cosmological models is studied for several types of exponentially and more than exponentially steep potentials. The parameters of scalar field potentials which allow a chaotic behaviour are found from numerical investigations. It is argued that analytical studies of equation of motion at the Euclidean boundary can provide an important information about th...

We show that the generators of pseudospin symmetry are the non relativistic limit of the generators of an SU(2) symmetry which leaves invariant the Dirac Hamiltonian with scalar and vector potentials equal in magnitude but opposite in sign, VV = −VS. Furthermore, we demonstrate that this symmetry may be approximately conserved for realistic scalar and vector potentials. PACS: 24.10.Jv, 21.60.Cs...

We present a phase-space analysis of cosmology containing multiple scalar fields with positive and negative exponential potentials. In addition to the well-known assisted inflationary solutions, there exist power-law multi-kinetic-potential scaling solutions for sufficiently flat positive potentials or steep negative potentials, which are the unique late-time attractor whenever they exist. We b...

We investigate the range of inflationary universe models driven by scalar fields possessing a general interaction potential of the form V (φ) = V0φ n exp(−λφm). Power-law, de Sitter and intermediate inflationary universes emerge as special cases together with several new varieties of inflation. Analysing the behaviour of these models at the extrema of φ we derive sufficient constraints on the m...