Search results for "INFLATION"
showing 10 items of 210 documents
Peccei–Quinn field for inflation, baryogenesis, dark matter, and much more
2016
We propose a scenario of brane cosmology in which the Peccei-Quinn field plays the role of the inflaton and solves simultaneously many cosmological and phenomenological issues such as the generation of a heavy Majorana mass for the right-handed neutrinos needed for seesaw mechanism, MSSM $\mu$-parameter, the right amount of baryon number asymmetry and dark matter relic density at the present universe, together with an axion solution to the strong CP problem without the domain wall obstacle. Interestingly, the scales of the soft SUSY-breaking mass parameter and that of the breaking of $U(1)_{\rm PQ}$ symmetry are lower bounded at $\mathcal{O}(10) {\mathrm TeV}$ and $\mathcal{O}(10^{11}) {\ma…
Baryogenesis from a right-handed neutrino condensate
2010
We show that the baryon asymmetry of the Universe can be generated by a strongly coupled right handed neutrino condensate which also drives inflation. The resulting model has only a small number of parameters, which completely determine not only the baryon asymmetry of the Universe and the mass of the right handed neutrino but also the inflationary phase. This feature allows us to make predictions that will be tested by current and planned experiments. As compared to the usual approach our dynamical framework is both economical and predictive.
Eternal hilltop inflation
2016
We consider eternal inflation in hilltop-type inflation models, favored by current data, in which the scalar field in inflation rolls off of a local maximum of the potential. Unlike chaotic or plateau-type inflation models, in hilltop inflation the region of field space which supports eternal inflation is finite, and the expansion rate $H_{EI}$ during eternal inflation is almost exactly the same as the expansion rate $H_*$ during slow roll inflation. Therefore, in any given Hubble volume, there is a finite and calculable expectation value for the lifetime of the "eternal" inflation phase, during which quantum flucutations dominate over classical field evolution. We show that despite this, i…
Transplanckian masses in inflation
2016
AbstractWe explore the possibility that the transplanckian field values needed to accommodate the experimental results in minimally coupled single-field inflation models are only due to our insistence of imposing a minimal coupling of the inflaton field to gravity. A simple conformal transformation can bring the field values below the Planck mass without changing the physics at the expense of having a richer gravitational sector. Transplanckian field values may be the signal that we are (miss)interpreting phenomena due to gravity as being originated exclusively in the scalar sector.
Unduland universe: expansion with alternating eras of acceleration and deceleration
2005
If the equation of state for 'dark energy' varies periodically, the expansion of the Universe may have undergone alternating eras of acceleration and deceleration. We examine a specific form that survives existing observational tests, does not single out the present state of the Universe as exceptional, and suggests a future much like the matter-dominated past: a smooth expansion without a final inflationary epoch.
Phenomenological approaches of inflation and their equivalence
2014
In this work, we analyze two possible alternative and model-independent approaches to describe the inflationary period. The first one assumes a general equation of state during inflation due to Mukhanov, while the second one is based on the slow-roll hierarchy suggested by Hoffman and Turner. We find that, remarkably, the two approaches are equivalent from the observational viewpoint, as they single out the same areas in the parameter space, and agree with the inflationary attractors where successful inflation occurs. Rephrased in terms of the familiar picture of a slowly rolling, canonically normalized scalar field, the resulting inflaton excursions in these two approaches are almost ident…
Partially time invariant panel data regression
2023
When dealing with panel data, considering the variation over time of the variable of interest allows to get rid of potential individual effects. Even though the outcome variable has a continuous distribution, its variation over time can be equal to zero with a strictly positive probability and thus its distribution is a mixture of a mass at zero and a continuous distribution. We introduce a parametric statistical model based on conditional mixtures, build estimators for the parameters related to the conditional probability of no variation and to the conditional expectation related to the continuous part of the distribution and derive their asymptotic consistency and normality under a specif…
Critical study of the quantity theory of money in the history of prices crisis
2014
The Quantity Theory of money which always links the increase in the high-Powered money supply and the general rise in prices is one of the oldest concepts in economics. After to have been the subject of many controversies at different times, it seems nowadays to hold less attention from the economists because the dispute is dissipated in a kind of religious choice to believe or not to believe to quantity theory. This theory officially influences the monetary policy of most of central banks in the world that bind conventional measures to control the money supply to curb inflation process. In many orthodox economics’ textbooks, the quantity theory is still deployed in perpetuum to explain the…
Association between reduced bronchodilatory effect of deep inspiration and loss of alveolar attachments.
2005
Abstract Background We have previously shown that the bronchodilatory effect of deep inspiration is attenuated in individuals with COPD. This study was designed to investigate whether the impairment in this effect is associated with loss of alveolar attachments. Methods We measured deep inspiration (DI)-induced bronchodilation in 15 individuals with and without COPD (67 ± 2.2 yrs of age, mean ± SEM) undergoing lobar resection for peripheral pulmonary nodule. Prior to surgery, we measured TLCO and determined the bronchodilatory effect of deep inspiration after constricting the airways with methacholine. The number of destroyed alveolar attachments, as well as airway wall area and airway smoo…
Why chronic obstructive pulmonary disease patients get so short of breath with limited activity
2013
equivalence despite the simplicity of MPT versus CPET as a surrogate to detect DH in COPD patients, by measuring the decrease in inspiratory capacity to reflect the increase in end-expiratory lung volume [3] . Lahaije et al. [2] have investigated whether DH as measured in the laboratory settings (CPET and MPT) reflects DH that is associated with dyspnea-limiting ADL. The authors conclude that both CPET and MPT can serve as a screening tool to identify patients who are susceptible to develop DH during ADL. In practice, MPT is simpler to obtain and is an inexpensive surrogate. However, sensitivity of MPT may not be optimal. When DH does not occur during CPET, it is unlikely to occur during AD…