scholarly journals Inflation via gravitino condensation in dynamically broken supergravity

2015 ◽  
Vol 24 (04) ◽  
pp. 1541004 ◽  
Author(s):  
Jean Alexandre ◽  
Nick Houston ◽  
Nick E. Mavromatos
Keyword(s):  
Conformal Symmetry ◽  
Particle Spectrum ◽  
Wave Function Renormalization ◽  
Slow Roll ◽  
Inflationary Phase ◽  
Global Supersymmetry ◽  
Added Benefit ◽  
Higgs Effect ◽  
Planck Satellite

Gravitino-condensate-induced inflation via the super-Higgs effect is a UV-motivated scenario for both inflating the early universe and breaking local supersymmetry dynamically, entirely independent of any coupling to external matter. As an added benefit, this also removes the (as of yet unobserved) massless Goldstino associated to global supersymmetry breaking from the particle spectrum. In this review, we detail the pertinent properties and outline previously hidden details of the various steps required in this context in order to make contact with current inflationary phenomenology. The class of models of SUGRA we use to exemplify our approach are minimal four-dimensional N = 1 supergravity and extensions thereof with broken conformal symmetry. Therein, the gravitino condensate itself can play the role of the inflation, however the requirement of slow-roll necessitates unnaturally large values of the wave function renormalization. Nevertheless, there is an alternative scenario that may provide Starobinsky-type inflation, occurring in the broken-SUGRA phase around the nontrivial minima of the gravitino-condensate effective potential. In this scenario higher curvature corrections to the effective action, crucial for the onset of an inflationary phase, arise as a result of integrating out massive quantum gravitino fields in the path integral. The latter scenario is compatible with Planck satellite phenomenology but not with BICEP2 data.

scholarly journals Inflationary universe in terms of a van der Waals viscous fluid

2017 ◽  
Vol 14 (12) ◽  
pp. 1750185 ◽  
Author(s):  
I. Brevik ◽  
E. Elizalde ◽  
S. D. Odintsov ◽  
A. V. Timoshkin
Keyword(s):  
Van Der Waals ◽  
Early Time ◽  
Accelerated Expansion ◽  
Inflationary Universe ◽  
Van Der Waals Equation ◽  
Slow Roll ◽  
Viscosity Term ◽  
Gravitational Equations ◽  
Planck Satellite

The inflationary expansion of our early-time universe is considered in terms of the van der Waals equation, as equation of state for the cosmic fluid, where a bulk viscosity contribution is assumed to be present. The corresponding gravitational equations for the energy density in a homogeneous and isotropic Friedmann–Lemaître–Robertson–Walker universe are solved, and an analytic expression for the scale factor is obtained. Attention is paid, specifically, to the role of the viscosity term in the accelerated expansion; the values of the slow-roll parameters, the spectral index, and the tensor-to-scalar ratio for the van der Waals model are calculated and compared with the most recent astronomical data from the Planck satellite. By imposing reasonable restrictions on the parameters of the van der Waals equation, in the presence of viscosity, it is shown to be possible for this model to comply quite precisely with the observational data. One can therefore conclude that the inclusion of viscosity in the theory of the inflationary epoch may definitely improve the cosmological models.

scholarly journals Domestic corpuscular inflaton

2019 ◽  
Vol 16 (07) ◽  
pp. 1950108 ◽  
Author(s):  
Andrea Giugno ◽  
Andrea Giusti
Keyword(s):  
Degrees Of Freedom ◽  
Oscillatory Behavior ◽  
Particle Spectrum ◽  
De Sitter ◽  
Precise Description ◽  
Slow Roll ◽  
Inflationary Phase ◽  
Free Mode ◽  
Scalar Mode ◽  
Slow Roll Inflation

The aim of this paper is to provide a more precise description of the paradigm of corpuscular slow-roll inflation, which was previously introduced by Casadio et al. in [Corpuscular slow-roll inflation, Phys. Rev. D 97 (2018) 024041]. Specifically, we start by expanding the Starobinsky theory on a curved background and then infer the number and nature of the propagating degrees of freedom, both in the true inflationary phase and in a quasi-de Sitter approximation. We correctly find that the particle spectrum contains a transverse trace-free mode and a scalar one. The scalar mode displays a tachyonic nature during the slow-roll phase, due to the instability of the system, whereas it acquires the appropriate oscillatory behavior as the background approaches a critical value of the curvature. These results confirm the fact that the Einstein–Hilbert term acts as a perturbation to the quadratic one, and is responsible for driving the early Universe out of the inflationary phase, thus realizing the inflaton field in terms of pure (corpuscular) gravity.

Corticoids and Respiratory Distress

PEDIATRICS ◽  
1973 ◽  
Vol 51 (5) ◽  
pp. 955-956
Author(s):  
William W. Holm
Keyword(s):  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Pulmonary Arteries ◽  
In Utero ◽  
Target Organ ◽  
Primary Target ◽  
Bronchial Arteries ◽  
Added Benefit

Liggins and Howie1 have demonstrated the effect of antepartum dexamethasone in the prevention of the respiratory distress syndrome (RDS). Contrary to the current concept2 that this prevention results from maturation of the lung, though this may be an added benefit, the writer proposes that the adrenal is the primary target organ. In a previous letter3 regarding the role of catecholamines in the etiology of RDS he advised that whereas the lung of the mature infant is perfused by the pulmonary arteries (inducing alveolar expansion),4 the lung of the infant in utero is perfused by the bronchial arteries (inducing atelectasis).4

scholarly journals Viability of slow-roll inflation in light of the non-zero k min measured in the cosmic microwave background power spectrum

2020 ◽  
Vol 476 (2239) ◽  
pp. 20200364
Author(s):  
Jingwei Liu ◽  
Fulvio Melia
Keyword(s):  
Spectral Indices ◽  
Fluctuation Spectrum ◽  
Microwave Background ◽  
Scale Free ◽  
Horizon Problem ◽  
Slow Roll ◽  
Inflationary Phase ◽  
Joint Resolution ◽  
Conventional Picture ◽  
Slow Roll Inflation

Slow-roll inflation may simultaneously solve the horizon problem and generate a near scale-free fluctuation spectrum P ( k ). These two processes are intimately connected via the initiation and duration of the inflationary phase. But a recent study based on the latest Planck release suggests that P ( k ) has a hard cut-off, k min ≠ 0 , inconsistent with this conventional picture. Here, we demonstrate quantitatively that most—perhaps all—slow-roll inflationary models fail to accommodate this minimum cut-off. We show that the small parameter ϵ must be ≳ 0.9 throughout the inflationary period to comply with the data, seriously violating the slow-roll approximation. Models with such an ϵ predict extremely red spectral indices, at odds with the measured value. We also consider extensions to the basic picture (suggested by several earlier workers) by adding a kinetic-dominated or radiation-dominated phase preceding the slow-roll expansion. Our approach differs from previously published treatments principally because we require these modifications not only to fit the measured fluctuation spectrum but also simultaneously to fix the horizon problem. We show, however, that even such measures preclude a joint resolution of the horizon problem and the missing correlations at large angles.

scholarly journals General Slow-Roll Inflation in f(R) Gravity under the Palatini Approach

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1958
Author(s):  
Sabit Bekov ◽  
Kairat Myrzakulov ◽  
Ratbay Myrzakulov ◽  
Diego Sáez-Chillón Gómez
Keyword(s):  
Scalar Field ◽  
Simple Model ◽  
Spectral Index ◽  
Effective Potential ◽  
Modified Gravity ◽  
Palatini Formalism ◽  
Slow Roll ◽  
Slow Roll Inflation

Slow-roll inflation is analyzed in the context of modified gravity within the Palatini formalism. As shown in the literature, inflation in this framework requires the presence of non-traceless matter; otherwise, it does not occur just as a consequence of the nonlinear gravitational terms of the action. Nevertheless, by including a single scalar field that plays the role of the inflaton, slow-roll inflation can be performed in these theories, where the equations lead to an effective potential that modifies the dynamics. We obtain the general slow-roll parameters and analyze a simple model to illustrate the differences introduced by the gravitational terms under the Palatini approach, and the modifications on the spectral index and the tensor to scalar ratio predicted by the model.

Investigating inflation driven by DBI-essence scalar field

2020 ◽  
Vol 29 (12) ◽  
pp. 2050087
Author(s):  
Gargee Chakraborty ◽  
Surajit Chattopadhyay
Keyword(s):  
Scalar Field ◽  
Early Universe ◽  
Inflationary Model ◽  
Type Iii ◽  
Ultraviolet Cutoff ◽  
Big Rip ◽  
Slow Roll ◽  
Limiting Case

Motivated by the work of Nojiri et al., Phys. Lett. B 797, 134829 (2019), the present study demonstrates inflation driven by holographic DBI-essence scalar field. Considering a simple correction due to the Ultraviolet cutoff, we have studied the slow-roll parameters. It has been observed that the role of the UV-cutoff is not negligible and in the limiting case of [Formula: see text] the inflationary model is characterized by Type-III singularity but can avoid Big-Rip singularity. Finally, it has been observed that the trajectories in [Formula: see text] are compatible with the observational bound found by Planck. It has been concluded that the tensor to scalar ratio for this model can explain the primordial fluctuation in the early universe as well. However, under the purview of [Formula: see text] inflation, although the DBI-essence scalar field can explain primordial fluctuation, the holographic DBI-essence scalar field does not lead to [Formula: see text] trajectory satisfying the Planck’s observational bound.

scholarly journals Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 10: Lumbar fusion for stenosis without spondylolisthesis

2014 ◽  
Vol 21 (1) ◽  
pp. 62-66 ◽  
Author(s):  
Daniel K. Resnick ◽  
William C. Watters ◽  
Praveen V. Mummaneni ◽  
Andrew T. Dailey ◽  
Tanvir F. Choudhri ◽  
...  
Keyword(s):  
Spinal Canal ◽  
Lumbar Fusion ◽  
Primary Objective ◽  
Neurogenic Claudication ◽  
Spinal Instability ◽  
Surgical Interventions ◽  
Appropriate Treatment ◽  
Added Benefit ◽  
Care Surgery

Lumbar stenosis is one of the more common radiographic manifestations of the aging process, leading to narrowing of the spinal canal and foramen. When stenosis is clinically relevant, patients often describe activity-related low-back or lower-extremity pain, known as neurogenic claudication. For those patients who do not improve with conservative care, surgery is considered an appropriate treatment alternative. The primary objective of surgery is to reconstitute the spinal canal. The role of fusion, in the absence of a degenerative deformity, is uncertain. The previous guideline recommended against the inclusion of lumbar fusion in the absence of spinal instability or a likelihood of iatrogenic instability. Since the publication of the original guidelines, numerous studies have demonstrated the role of surgical decompression in this patient population; however, few have investigated the utility of fusion in patients without underlying instability. The majority of studies contain a heterogeneous cohort of subjects, often combining patients with and without spondylolisthesis who received various surgical interventions, limiting fusions to those patients with instability. It is difficult if not impossible, therefore, to formulate valid conclusions regarding the utility of fusion for patients with uncomplicated stenosis. Lower-level evidence exists, however, that does not demonstrate an added benefit of fusion for these patients; therefore, in the absence of deformity or instability, the inclusion of a fusion is not recommended.

THE ROLE OF A CHAMELEON FIELD IN AN ANISOTROPIC UNIVERSE WITH LOGAMEDIATE AND INTERMEDIATE SCENARIOS

2010 ◽  
Vol 25 (24) ◽  
pp. 4691-4701 ◽  
Author(s):  
SHUVENDU CHAKRABORTY ◽  
UJJAL DEBNATH
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Anisotropic Universe ◽  
Anisotropic Model ◽  
Scale Factors ◽  
Slow Roll ◽  
Energy Scalar ◽  
The Universe

In this work, we consider the Universe is being filled with matter composed of a chameleon-type dark energy scalar field. Employing a particular form of potential, we discuss the field's role in the accelerating phase of the Universe for an anisotropic model using the logamediate and intermediate forms of scale factors. The natures of statefinder and slow-roll parameters are discussed diagrammatically.

scholarly journals Higgs Portal Inflation with Fermionic Dark Matter

2018 ◽  
Vol 168 ◽  
pp. 06002
Author(s):  
Aditya Aravind ◽  
Minglei Xiao ◽  
Jiang-Hao Yu
Keyword(s):  
Dark Matter ◽  
Scalar Potential ◽  
Scalar Fields ◽  
Fermionic Field ◽  
Planck Data ◽  
Slow Roll ◽  
The Standard Model ◽  
The Masses ◽  
Higgs Portal

We discuss the inflationary model presented in [1], involving a gauge singlet scalar field and fermionic dark matter added to the standard model. Either the Higgs or the singlet scalar could play the role of the inflaton, and slow roll is realized through its non-minimal coupling to gravity. The effective scalar potential is stabilized by the mixing between the scalars as well as the coupling with the fermionic field. Mixing of the two scalars also provides a portal to dark matter. Constraints on the model come from perturbativity and stability, collider searches and dark matter constraints and impose a constraining relationship on the masses of dark matter and scalar fields. Inflationary predictions are generically consistent with current Planck data.

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