Properties of effective interactions in neutron-rich matter are reflected in the medium’s equation of state (EOS), which is a relationship among several state variables. Spin and isospin asymmetries play an important role in the energy balance and could alter the stability conditions of the nuclear EOS. The EOS has far-reaching consequences for numerous nuclear processes in both the terrestrial...

In this letter, it is shown that dark energy is contributed by riccion (a particle concept for physical aspect of the Ricci scalar curvature) in a natural way without any input in the theory for it. In contrast to other models, where an idea for dark energy is introduced in the beginning of the theory, here it emerges from the gravitational sector spontaneously. Interestingly, it is found that ...

We show that rapid primordial inflation and slow asymptotic inflation is a natural consequence of Brans-Dicke theory. The ratio of the two inflation parameters is proportional to the square root of the Brans-Dicke parameter ω (ω ≫ 1). We also calculate the Hubble parameter H and the time variation of the time dependent Newtonian gravitational constant G for both regimes. The variation of the Hu...

The dark energy formula derived by Gurzadyan and Xue which leads to a value fitting the SN data, provides a scaling relation between the physical constants and cosmological parameters and defines a set of cosmological models. In previous works we have considered several of those models and derived the cosmological equations for each case. In this letter, we present the phase portrait analysis o...

In this paper, we present the self-similar symmetry (SSS) model that describes the hierarchical structure of the universe. The model is based on the concept of self-similarity, which explains the symmetry of the cosmic microwave background (CMB). The approximate length and time scales of the six hierarchies of the universe—grand unification, electroweak unification, the atom, the pulsar, the so...

Hamilton-Jacobi equation for Brans-Dicke theory is solved by using a longwavelength approximation. We examine the non-linear evolution of the inhomogeneities in the dust fluid case and the cosmological constant case. In the case of dust fluid, it turns out that the inhomogeneities of space-time grow. In the case of cosmological constant, the inhomogeneities decay, which is consistent with the c...

Two phenomenological models of Λ, viz. Λ ∼ (ȧ/a) and Λ ∼ ä/a are studied under the assumption that G is a time-variable parameter. Both models show that G is inversely proportional to time as suggested earlier by others including Dirac. The models considered here can be matched with observational results by properly tuning the parameters of the models. Our analysis shows that Λ ∼ ä/a model corr...

We argue that the Lagrangian for gravity should remain bounded at large curvature, and interpolate between the weak-field tested Einstein-Hilbert LagrangianLEH = R/16πG and a pure cosmological constant for large R with the curvature-saturated ansatz Lcs = LEH/ √ 1+ l4 R2, where l is a length parameter expected to be a few orders of magnitude above the Planck length. The curvature-dependent effe...