Related papers: Natural Quintessence and Large Extra Dimensions
We present a systematic treatment of the initial conditions and evolution of cosmological perturbations in a universe containing photons, baryons, neutrinos, cold dark matter, and a scalar quintessence field. By formulating the evolution in…
It has recently been argued that non--BPS brane world scenarios can reproduce the small value of the cosmological constant that seems to have been measured. Objections against this proposal are discussed and necessary (but not sufficient)…
We propose a new quintessence scenario in the brane cosmology, assuming that a quintessence field $Q$ is confined in our 3-dimensional brane world. With a potential $V(Q)= \mu^{\alpha+4} Q^{-\alpha}~(\alpha\geq 2)$, we find that the density…
We present a systematic treatment of the initial conditions and evolution of cosmological perturbations in a universe containing photons, baryons, neutrinos, cold dark matter, and a scalar quintessence field. By formulating the evolution in…
The higher dimensional cosmology provides a natural setting to treat, at a classical level, the cosmological effects of vacuum energy. Here we discuss two situations where starting with an ordinary matter field without any equation of state…
We consider ``brane universe'' with nonzero tension in the models with large extra dimensions. We find exact solutions of higher-dimensional Einstein equations with single flat Minkowsky brane of arbitrary large tension (or brane…
We propose a framework for the low-energy realization of supersymmetry which is very predictive, but differs radically in its phenomenological implications from the supersymmetric Standard Model (minimal or otherwise). The proposal consists…
In models with Large Extra Dimensions the smallness of neutrino masses can be naturally explained by introducing gauge singlet fermions which propagate in the bulk. The Kaluza-Klein modes of these fermions appear as towers of sterile…
A substantial fraction of the energy density of the universe may consist of quintessence in the form of a slowly-rolling scalar field. Since the energy density of the scalar field generally decreases more slowly than the matter energy…
The tired-light cosmology is considered in the framework of Kaluza-Klein theory in 5D. The solution of the five-dimensional semi-classical Einstein equations with nonzero five-dimensional energy-momentum tensor gives density of matter in…
Evolution of a universe with homogeneous extra dimensions is studied with the benefit of a well-chosen parameter space that provides a systematic, useful, and convenient way for analysis. In this model we find a natural evolution pattern…
A quintessence scalar field or cosmon interacting with neutrinos can have important effects on cosmological structure formation. Within growing neutrino models the coupling becomes effective only in recent times, when neutrinos become…
In brane-world models with low tension, the fluctuations of the brane along the extra dimensions (branons) are the only relevant new low-energy modes. Such branon fields are in general massive, stable and weakly interacting, and accordingly…
We consider theories in which the Standard Model gauge fields propagate in extra dimensions whose size is around the electroweak scale. The Standard Model quarks and leptons may either be localized to a brane or propagate in the bulk. This…
We consider ``brane-universes'', where matter is confined to four-dimensional hypersurfaces (three-branes) whereas one extra compact dimension is felt by gravity only. We show that the cosmology of such branes is definitely different from…
If an ultraviolet fixed point renders quantum gravity renormalizable, the effective potential for a singlet scalar field -- the cosmon -- can be computed according to the corresponding scaling solution of the renormalization group…
We address the issue of whether extra dimensions could have an infinite volume and yet reproduce the effects of observable four-dimensional gravity on a brane. There is no normalizable zero-mode graviton in this case, nevertheless correct…
There appears to be no natural explanation for the cosmological constant's small size within the framework of local relativistic field theories. We argue that the recently-discussed framework for which the observable universe is identified…
A generic feature of cosmic quintessence models is the possibility of significant energy density in the scalar field during the radiation dominated epoch. This possibility is even greater if the quintessence field begins in a…
We review recent attempts to address the cosmological constant problem and the late-time acceleration of the Universe based on braneworld models. In braneworld models, the way in which the vacuum energy gravitates in the 4D spacetime is…