Aims. To study cosmological models in scalar tensor theories of gravity with power law potentials as models of an accelerating universe. Methods. We consider cosmological models in scalar tensor theories of gravity that describe an accelerating universe, and we study a family of inverse power law potentials, for which exact solutions of the Einstein equations are known. We also compare theoreti...

We construct Komar-type integrals for theories of gravity higher order in the Riemann curvature coupled to simple kinds matter (scalar and vector fields) we use them compute Smarr formulae black-hole solutions those theories. The equivalence between f(R) Brans-Dicke is used argue that dimensionful parameters appear scalar potentials must be interpreted as thermodynamical variables ("pressures")...

We propose an alternative framework for designing genuinely multi-dimensional (GMD) finite volume schemes for systems of conservation laws in two space dimensions. The approach is based on reformulating edge centered numerical fluxes in terms of vertex centered potentials. Any consistent numerical flux can be used to define the potentials. Suitable choices of potentials result in schemes that p...

Using the quark-meson coupling (QMC) model we study nuclear matter from the point of view of quark degrees of freedom. As the nucleon model we adopt the MIT bag model and the relativistic constituent quark model, where a square well and harmonic oscillator potentials are used to confine the quarks. We introduce the Lorentz-vector type confining potential as well as the Lorentz-scalar type one i...

The low energy effective action of gravity in any even dimension generally acquires non-local terms associated with the trace anomaly, generated by the quantum fluctuations of massless fields. The local auxiliary field description of this effective action in four dimensions requires two additional scalar fields, not contained in classical general relativity, which remain relevant at macroscopic...

We study the low-energy effective field equations that couple gravity, the dilaton, and the bulk closed string tachyon of bosonic closed string theory. We establish that whenever the tachyon induces the rolling process, the string metric remains fixed while the dilaton rolls to strong coupling. For negative definite potentials we show that this results in an Einstein metric that crunches the un...

We consider the ground state in a model with scalar nucleons and a meson using the formalism of light-front dynamics. Light-front potentials for twonucleon bound states are calculated using two approaches. First, light-front time-ordered perturbation theory is used to calculate oneand two-mesonexchange potentials. These potentials give results that agree well with the ladder and ladder plus cro...

We consider the ground state in a model with scalar nucleons and a meson using the formalism of light-front dynamics. Light-front potentials for twonucleon bound states are calculated using two approaches. First, light-front time-ordered perturbation theory is used to calculate oneand two-mesonexchange potentials. These potentials give results that agree well with the ladder and ladder plus cro...

Two results support the idea that the scalar and vector potentials in the Lorenz gauge can be considered to be physical quantities: (i) they separately satisfy the properties of causality and propagation at the speed of light and do not imply spurious terms and (ii) they can naturally be written in a manifestly covariant form. In this paper we introduce expressions for the Lorenz-gauge potentia...

We derive an extended version of the well-known Lyth Bound on the total variation of the inflaton field, incorporating higher order corrections in slow roll. We connect the field variation ∆φ to both the spectral index of scalar perturbations and the amplitude of tensor modes. We then investigate the implications of this bound for “small field” potentials, where the field rolls off a local maxi...