Related papers: Aether, Dark Energy, and String Compactifications
The main goal of string phenomenology is to find realistic models of particle physics and cosmology within string theory. Dark bubble cosmology is an alternative to string compactifications, where our universe lives on a bubble expanding in…
The string tensions can be dynamical in the modified measure formalism and appear as an additional dynamical degrees of freedom . These tensions may not be universal, instead, each string generates its own tension. We then consider a new…
Dark energy is an elusive concept, which has been introduced two decades ago in order to make the acceleration of the universe a comprehensible phenomenon. However, the nature of this energy is far from being understood, both from a…
A unification of dark matter and dark energy based on a dynamical space time theory is suggested. By introducing a dynamical space time vector field $\chi_\mu$ as a Lagrange multiplier, a conservation of an energy momentum tensor…
We revisit a non-perturbative formulation leading to a vacuum created gravitational pair of (33)-brane by a Poincare dual higher form U (1) gauge theory on a D4 -brane. In particular, the analysis has revealed a dynamical geometric torsion…
It is argued that fluctuations of quantum fields in four-dimensional space do not give rise to dark energy, but are rather a negligible contribution to dark matter. By (relativistic) dark matter we mean that the relation between pressure…
We build a novel realization of dark bubble cosmology in non-supersymmetric string theory. Among the simplest models in ten dimensions, the type 0'B orientifold is the unique option which yields a scale-separated construction. The resulting…
Dark energy is one of the mysteries of modern science. It is unlike any known form of matter or energy and has been detected so far only by its gravitational effect of repulsion. Owing to its effects being discernible only at very very…
We describe cosmic D--term strings as D3 branes wrapped on a resolved conifold. The matter content that gives rise to D--term strings is shown to describe the world--volume theory of a space--filling D3 brane transverse to the conifold…
The smallness of the cosmological constant is one of the basic problems in particle physics and cosmology. Various attempts have been made to explain this mystery, but no satisfactory solution has been found yet. The appearance of extra…
It is shown that dark energy can be obtained from the interplay of the Higgs boson and the inflaton. A key element is the realization that electroweak symmetry breaking can trigger a second phase of rolling of the inflaton, which, when…
Cosmic strings are one-dimensional topological defects which could have been formed in the early stages of our Universe. They triggered a lot of interest, mainly for their cosmological implications: they could offer an alternative to…
We argue that dark matter and dark energy phenomena associated with galactic rotation curves, X-ray cluster mass profiles, and type Ia supernova data can be accounted for via small corrections to idealized general relativistic spacetime…
Since there are dark matter particles (neutrino) with mass about 10^(-1)eV in the universe, the superstructures with a scale of 10^(19) solar mass [large number A is about 10^(19)] appeared around the era of the hydrogen recombination. The…
We consider the generalized particle dynamics, proposed by us, in brane world formalisms for an asymptotically anti de Sitter background. The present framework results in a new model that accounts for the late acceleration of the universe.…
It is proposed that an ultra-light fermionic species, dubbed cosmic magnino has condensed into a ferromagnetic state in the Universe. The extended structure of domain walls associated with this ferromagnetism accounts for the observed Dark…
Brane-world models offer the possibility of explaining the late acceleration of the universe via infra-red modifications to General Relativity, rather than a dark energy field. However, one also expects ultra-violet modifications to General…
We discuss the exact solutions of brane universes and the results indicate the Friedmann equations on the branes are modified with a new density term. Then, we assume the new term as the density of dark energy. Using Wetterich's…
Warped string compactifications are central to many attempts to stabilize moduli and connect string theory with cosmology and particle phenomenology. We present a first-principles derivation of the low-energy 4D effective theory from…
Cosmological observations strongly suggest the presence of dark energy which comprises the majority of the current energy density of the universe. The equation of state relating the pressure and energy density of this dark energy, p = w…