62,370 research outputs found
Weak gravity conjecture constraints on inflation
We consider the gravitational correction to the coupling of the scalar
fields. Weak gravity conjecture says that the gravitational correction to the
running of scalar coupling should be less than the contribution from scalar
fields. For instance, a new scale sets a UV cutoff
on the validity of the effective theory. Furthermore, this
conjecture implies a possible constraint on the inflation model, e.g. the
chaotic inflation model might be in the swampland.Comment: 11 pages, 3 figs; monor corrections; some clarifying remarks added
and the final version for publication in JHE
Interacting non-minimally coupled canonical, phantom and quintom models of holographic dark energy in non-flat universe
Motivated by our recent work \cite{set1}, we generalize this work to the
interacting non-flat case. Therefore in this paper we deal with canonical,
phantom and quintom models, with the various fields being non-minimally coupled
to gravity, within the framework of interacting holographic dark energy. We
employ the holographic model of interacting dark energy to obtain the equation
of state for the holographic energy density in non-flat (closed) universe
enclosed by the event horizon measured from the sphere of horizon named .Comment: 18 pages, 3 figures. Accepted for publication in IJMPD (2010
Limits from Weak Gravity Conjecture on Dark Energy Models
The weak gravity conjecture has been proposed as a criterion to distinguish
the landscape from the swampland in string theory. As an application in
cosmology of this conjecture, we use it to impose theoretical constraint on
parameters of two types of dark energy models. Our analysis indicates that the
Chaplygin-gas-type models realized in quintessence field are in the swampland,
whereas the power-low decay model of the variable cosmological constant can
be viable but the parameters are tightly constrained by the conjecture.Comment: Revtex4, 8 pages, 5 figures; References, minor corrections in
content, and acknowledgement adde
Agegraphic Chaplygin gas model of dark energy
We establish a connection between the agegraphic models of dark energy and
Chaplygin gas energy density in non-flat universe. We reconstruct the potential
of the agegraphic scalar field as well as the dynamics of the scalar field
according to the evolution of the agegraphic dark energy. We also extend our
study to the interacting agegraphic generalized Chaplygin gas dark energy
model.Comment: 8 page
Gravitational Correction and Weak Gravity Conjecture
We consider the gravitational correction to the running of gauge coupling.
Weak gravity conjecture implies that the gauge theories break down when the
gravitational correction becomes greater than the contribution from gauge
theories. This observation can be generalized to non-Abelian gauge theories in
diverse dimensions and the cases with large extra dimensions.Comment: 8 pages; minor correction and refs adde
Holographic dark energy model with non-minimal coupling
We find that holographic dark energy model with non-minimally coupled scalar
field gives rise to an accelerating universe by choosing Hubble scale as IR
cutoff. We show viable range of a non-minimal coupling parameter in the
framework of this model.Comment: 7 pages, no figure, corrected some typos, to be published in
Europhys. Let
All-organic dielectric-percolative three-component composite materials with high electromechanical response
By combining the high-dielectric copper phthalocyanine oligomer (PolyCuPc) and conductive polyanline (PANI) within polyurethane (PU) matrix an all-organic three-component dielectric-percolative composite with high dielectric constant is demonstrated. In this three-component composite system, the high-dielectric-constant PolyCuPc particulates enhance the dielectric constant of the PU matrix and this combined two-component dielectric matrix in turn serves as the high-dielectric-constant host for the PANI to realize percolative phenomenon and further enhance the dielectric response. As a result, an electromechanical strain of 9.3% and elastic energy density of 0.4 J/cm(3) under an electric field of 20 V/mum can be induced
The Measure for the Multiverse and the Probability for Inflation
We investigate the measure problem in the framework of inflationary
cosmology. The measure of the history space is constructed and applied to
inflation models. Using this measure, it is shown that the probability for the
generalized single field slow roll inflation to last for e-folds is
suppressed by a factor , and the probability for the generalized
-field slow roll inflation is suppressed by a much larger factor
. Some non-inflationary models such as the cyclic model do not
suffer from this difficulty.Comment: 16 page
An Implication of "Gravity as the Weakest Force"
The negative specific heat of a radiating black hole is indicative of a
cataclysmic endpoint to the evaporation process. In this letter, we suggest a
simple mechanism for circumventing such a dramatic outcome. The basis for our
argument is a conjecture that was recently proposed by Arkani-Hamed and
collaborators. To put it another way, we use their notion of ``Gravity as the
Weakest Force'' as a means of inhibiting the process of black hole evaporation.Comment: 7 pages; v2 some discussion clarifie
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