a saddle point variational (spv ) method was applied to the dirac equation as an example of a fully relativistic equation with both negative and positive energy solutions. the effect of the negative energy states was mitigated by maximizing the energy with respect to a relevant parameter while at the same time minimizing it with respect to another parameter in the wave function. the cornell pot...

Analytical and numerical studies of secondary electro-osmotic flow (EOF) and its mixing in microchannels with heterogeneous zeta potentials are carried out in the present work. The secondary EOFs are analyzed by solving the Stokes equation with heterogeneous slip velocity boundary conditions. The analytical results obtained are compared with the direct numerical simulation of the Navier-Stokes ...

The nonminimal coupling (NMC) of the scalar field to the Ricci curvature is unavoidable in many cosmological scenarios. Inflation and quintessence models based on nonminimally coupled scalar fields are studied, with particular attention to the balance between the scalar potential and the NMC term ξRφ2/2 in the action. NMC makes acceleration of the universe harder to achieve for the usual potent...

Scalar fields have played a major role in attempts to model the early Universe. In particular, nearly every incarnation of the inflation scenario has relied on scalars to generate vacuum energy and in turn exponential expansion and density fluctuations. Many of these models rely on slow roll potentials, i.e., potentials that are nearly flat where the scalar masses can be very small. Recently, h...

The momentum dependence of the empirical scalar and vector potentials needed for describing relativistic heavy-ion collisions at 1 GeV/nucleon is compared with that derived from self-consistent Dirac-Brueckner calculations using the Bonn-A potential. Our calculated scalar and vector potentials exhibit a weak momentum dependence and their magnitudes decrease with nu-cleon momentum, in close simi...

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, within this framework, we demonstrate that this symmetry may be approximately conserved for realistic scalar and vector potentials. P...

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 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 exits 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...

The dynamics of homogeneous Robertson–Walker cosmological models with a self-interacting scalar field source is examined here in full generality, requiring only the scalar field potential to be bounded from below and divergent when the field diverges. In this way we are able to give a unified treatment of all the already studied cases such as positive potentials which exhibit asymptotically pol...

Nucleon flow in Au+Au collisions at 1 GeV/nucleon region and dilepton spectra in S+Au collisions at SPS energies are analysed in the relativistic transport model. They are shown to be sensitive to the nucleon vector and scalar potentials, respectively, and are thus useful probes of these potentials in dense matter. A recently developed effective Lagrangian with self-interactions of vector as we...