20 research outputs found
Induced-Gravity GUT-Scale Higgs Inflation in Supergravity
Models of induced-gravity inflation are formulated within Supergravity
employing as inflaton the Higgs field which leads to a spontaneous breaking of
a U(1)B-L symmetry at Mgut=2x10^16 GeV. We use a renormalizable superpotential,
fixed by a U(1) R symmetry, and Kahler potentials which exhibit a quadratic
non-minimal coupling to gravity with or without an independent kinetic mixing
in the inflaton sector. In both cases we find inflationary solutions of
Starobinsky type whereas in the latter case, others (more marginal) which
resemble those of linear inflation arise too. In all cases the inflaton mass is
predicted to be of the order of 10^13~GeV. Extending the superpotential of the
model with suitable terms, we show how the MSSM mu parameter can be generated.
Also, non-thermal leptogenesis can be successfully realized, provided that the
gravitino is heavier than about 10 TeV.Comment: arXiv admin note: text overlap with arXiv:1710.05759; Final versio
From Hybrid to Quadratic Inflation With High-Scale Supersymmetry Breaking
Motivated by the reported discovery of inflationary gravity waves by the
BICEP2 experiment, we propose an inflationary scenario in supergravity, based
on the standard superpotential used in hybrid inflation. The new model yields a
tensor-to-scalar ratio r ~ 0.14 and scalar spectral index ns ~ 0.964,
corresponding to quadratic (chaotic) inflation. The important new ingredients
are the high-scale, (1.6-10) x 10^13 GeV, soft supersymmetry breaking mass for
the gauge singlet inflaton field and a shift symmetry imposed on the K\"ahler
potential. The end of inflation is accompanied, as in the earlier hybrid
inflation models, by the breaking of a gauge symmetry at (1.2-7.1) x 10^16 GeV,
comparable to the grand-unification scale.Comment: Version with minor corrections to appear in PL
Upper Bound on the Tensor-to-Scalar Ratio in GUT-Scale Supersymmetric Hybrid Inflation
We explore the upper bound on the tensor-to-scalar ratio in
supersymmetric (F-term) hybrid inflation models with the gauge symmetry
breaking scale set equal to the value , as dictated
by the unification of the MSSM gauge couplings. We employ a unique
renormalizable superpotential and a quasi-canonical K\"ahler potential, and the
scalar spectral index is required to lie within the two-sigma interval
from the central value found by the Planck satellite. In a sizable region of
the parameter space the potential along the inflationary trajectory is a
monotonically increasing function of the inflaton, and for this case,
, while the spectral index running, , can be as large as . Ignoring higher order terms which ensure the
boundedness of the potential for large values of the inflaton, the upper bound
on is significantly larger, of order , for subplanckian values of the
inflaton, and .Comment: To appear in PL
Non-Minimal Chaotic Inflation, Peccei-Quinn Phase Transition and non-Thermal Leptogenesis
We consider a phenomenological extension of the minimal supersymmetric
standard model (MSSM) which incorporates non-minimal chaotic inflation, driven
by a quadratic potential in conjunction with a linear term in the frame
function. Inflation is followed by a Peccei-Quinn phase transition, based on
renormalizable superpotential terms, which resolves the strong CP and mu
problems of MSSM and provide masses lower than about 10^12 GeV for the
right-handed (RH) (s)neutrinos. Baryogenesis occurs via non-thermal
leptogenesis, realized by the out-of-equilibrium decay of the RH sneutrinos
which are produced by the inflaton's decay. Confronting our scenario with the
current observational data on the inflationary observables, the light neutrino
masses, the baryon asymmetry of the universe and the gravitino limit on the
reheat temperature, we constrain the strength of the gravitational coupling to
rather large values (~45-2950) and the Dirac neutrino masses to values between
about 1 and 10 GeV.Comment: Final versio
Crowdcloud: A Crowdsourced System for Cloud Infrastructure
The widespread adoption of truly portable,
smart devices and Do-It-Yourself computing platforms
by the general public has enabled the rise of new network
and system paradigms. This abundance of wellconnected,
well-equipped, affordable devices, when combined
with crowdsourcing methods, enables the development
of systems with the aid of the crowd. In this
work, we introduce the paradigm of Crowdsourced Systems,
systems whose constituent infrastructure, or a significant
part of it, is pooled from the general public by
following crowdsourcing methodologies. We discuss the
particular distinctive characteristics they carry and also
provide their “canonical” architecture. We exemplify
the paradigm by also introducing Crowdcloud, a crowdsourced
cloud infrastructure where crowd members can
act both as cloud service providers and cloud service
clients. We discuss its characteristic properties and also
provide its functional architecture. The concepts introduced
in this work underpin recent advances in the areas
of mobile edge/fog computing and co-designed/cocreated
systems