Related papers: Hilltop Quintessence
We consider the Wigner equation corresponding to a nonlinear Schroedinger evolution of the Hartree type in the semiclassical limit $\hbar\to 0$. Under appropriate assumptions on the initial data and the interaction potential, we show that…
We examine several dark energy models with a time-varying equation of state parameter, $w(z)$, to determine what information can be derived by fitting the distance modulus in such models to a constant equation of state parameter, $w_*$. We…
We consider a minimal model where the Higgs boson arises as an elementary pseudo-Nambu-Goldstone boson. The model is based on an extended scalar sector with global SO(5)/SO(4) symmetry. To achieve the correct electroweak symmetry breaking…
A new approach to tackle Einstein equations for an isotropic and homogeneous Friedmann--Robertson--Walker Universe in the presence of a quintessence scalar field is devised. It provides a way to get a simple exact solution to these…
We suggest a new type of hill-top inflation originating from the initial conditions in the form of the microcanonical density matrix for the cosmological model with a large number of quantum fields conformally coupled to gravity. Initial…
An analogue of the Oppenheimer-Synder collapsing model is treated analytically, where the matter source is a scalar field with an exponential potential. An exact solution is derived followed by matching to a suitable exterior geometry, and…
In this paper we investigate the quintessence model with a minimally coupled scalar field in the context of recent supernovae observations. By choosing a particular form of the deceleration parameter q, which gives an early deceleration and…
We investigate the possibility that the matter of the universe has a significant component (the quintessence component) determined by the equation of state $p=w\rho$, with $w<0$. Here, we find conditions under which a closed model may look…
We study a model where quintessence potential $e^{-\xi\phi}$ coupled to Higgs potential. We calculate the evolution of the quintessence, and track the running of the effective Higgs self-coupling. We find it slightly larger than that of the…
Using the hierarchical approximation, we discuss the cut-off dependence of the renormalized quantities of a scalar field theory. The naturalness problem and questions related to triviality bounds are briefly discussed. We discuss unphysical…
We show that shape moduli in sub-millimeter extra dimensional scenarios, addressing the gauge hierarchy problem, can dominate the energy density of the universe today. In our scenario, the volume of the extra dimensions is stabilized at a…
We will show that for exponential type potentials, which are used to depict quintessential inflation, the solutions whose initial conditions take place during the slow roll phase in order to describe correctly the inflationary period do not…
We consider local weak large solutions with its blow-up rate near the boundary to certain class of degenerate and/or singular quasilinear elliptic equation\\ ${\rm div}(d^{\alpha}(x,\partial{}B)\Phi_p(\nabla u)) = b(x)f(u)$ in a ball B,…
We introduce a natural model of quintessence in string theory where the light rolling scalar is radiatively stable and couples to Standard Model matter with weaker-than- Planckian strength. The model is embedded in an anisotropic type IIB…
We study the Euler-Korteweg equations with a weak capillarity tensor. It formally converges to the Euler equations in the zero capillarity limit. Our aim is two-fold : first we prove rigorously this limit in R d , d $\ge$ 1, and obtain a…
We investigate the quantum evolution of the universe in the presence of two types of dark energies. First, we consider the phantom class ($\omega<-1$) which would be responsible for a super-accelerated cosmic expansion, and then we apply…
In quintessence scalar field theories, the presence of scaling solutions are important during the radiation and matter epoch due to having their attractor character. Usually, it is assumed that the initial conditions of the quintessence…
We investigate two simplified non-singular cyclic models with a negative time-varying cosmological constant to represent the non-conventional mechanism of negative cosmological constant expected to address the late-time cosmic acceleration.…
We consider non-singular bouncing cosmologies, such as the new ekpyrotic model, in which the universe undergoes a slow contraction phase with equation of state $w \gg 1$, followed by a bounce that occurs at a finite scale factor when…
An extremely light ($m_{\phi} \ll 10^{-33} {\rm eV}$), slowly-varying scalar field $\phi $ (quintessence) with a potential energy density as large as 60% of the critical density has been proposed as the origin of the accelerated expansion…