43,565 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
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
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
Extended Holographic dark energy
The idea of relating the infrared and ultraviolet cutoffs is applied to
Brans-Dicke theory of gravitation. We find that extended holographic dark
energy from the Hubble scale or the particle horizon as the infrared cutoff
will not give accelerating expansion. The dynamical cosmological constant with
the event horizon as the infrared cutoff is a viable dark energy model.Comment: one reference is corrected, 3 pages, no figure,V3: minor correction
Electronic structure and superconductivity of BiS2-based compounds LaO1-xFxBiS2
Using the density-functional perturbation theory with structural
optimization, we investigate the electronic structure, phonon spectra, and
superconductivity of BiS2-based layered compounds LaO1-xFxBiS2. For
LaO0.5F0.5BiS2, the calculated electron-phonon coupling constant is equal to
lambda = 0.8, and obtained Tc = 9.1 K is very close to its experimental value,
indicating that it is a conventional electron-phonon superconductor
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
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