primordial non-Gaussianity and inflation

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Planck 2015 results  XVII  Constraints on primordial non Gaussianity

Planck 2015 results XVII Constraints on primordial non Gaussianity

This class of models is characterized by the presence of addi- tional light scalar degrees of freedom besides the inflaton, whose fluctuations give rise, or contribute, to the final primordial cur- vature perturbation at the end of inflation. This includes the case of “multiple-field inflation”, where inflation is driven by more than one scalar field, as well as scenarios in which additional scalar fields remain subdominant during the inflationary expan- sion. From the point of view of primordial NG, the element in common to all these models is that a potentially detectable level of NG in the curvature perturbation is generated via a transfer of super-horizon non-Gaussian isocurvature perturbations in the second field (not necessarily the inflaton) to the adiabatic (cur- vature) density perturbations, accompanied by nonlinearities in the transfer mechanism. This process typically takes place on super-horizon scales, thus implying a local form of NG in real space. When going to Fourier space, this leads to a correlation between large and small scale modes. The bispectrum for this class of models is indeed largest on so-called “squeezed” trian- gles (k 1 k 2 ' k 3 ). The local bispectrum is (Falk et al. 1993;
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Elsner, Franz
  

(2010):


	Search for non-Gaussian Signatures in the Cosmic Microwave Background Radiation.


Dissertation, LMU München: Fakultät für Physik

Elsner, Franz (2010): Search for non-Gaussian Signatures in the Cosmic Microwave Background Radiation. Dissertation, LMU München: Fakultät für Physik

The analysis of cosmic microwave background (CMB) radiation data has considerably improved our understanding of cosmology and played a crucial role in constraining the set of fundamental cosmological parameters of the universe (Spergel et al. 2007; Hinshaw et al. 2009). This success is based on the intimate link between the temperature fluctuations we observe today and the physical processes taking place in the very early universe. Inflation is currently the favored theory predicting the shape of primordial perturba- tions (Guth 1981; Linde 1982), which in its canonical form leads to very small non-Gaussianities that are far from being detectable by means of present-day experiments (Acquaviva et al. 2003; Maldacena 2003). However, inflation scenarios producing larger amounts of non-Gaussianity can naturally be con- structed by breaking one or more of the following properties of canonical inflation: slow-roll, single-field, Bunch-Davies vacuum, or a canonical kinetic term (Bartolo et al. 2004). Thus, a positive detection of primordial non- Gaussianity would allow us to rule out the simplest models. Combined with improving constraints on the scalar spectral index n s , the test for non-Gaus-
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Revisiting non-Gaussianity from non-attractor inflation models

Revisiting non-Gaussianity from non-attractor inflation models

Inflationary cosmology is the leading paradigm of the very early universe [1–7], in which the universe has experienced a primordial phase of quasi-de Sitter expansion. The simplest inflation model is realized by a canonical scalar field slowly rolling along a sufficiently flat potential. The associated perturbation theory successfully predicted a nearly scale-invariant power spectrum of primordial curvature perturbation, which is favoured by the latest cosmic microwave background (CMB) observations [8, 9]. Moreover, it is widely acknowledged that the primordial non-Gaussianity, which encodes information about the very early universe, could be a powerful tool to discriminate different inflation models or alternative scenarios [10–13]. Remarkably, there is a consistency relation for non-Gaussianity in single-field slow-roll inflation models pointed out by Maldacena [14, 15]. The consistency relation states that the amplitude of the primordial non-Gaussianity in squeezed configuration - where the wavelength of one mode is much larger than the other two in the three point correlation fucntion - is proportional to the spectral index of the power spectrum of scalar perturbations, i.e. f NL = 5(1 − n s )/12.
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Agrawal, Aniket
  

(2018):


	Non Gaussianity of primordial gravitational waves and cosmic density and velocity fields.


Dissertation, LMU München: Fakultät für Physik

Agrawal, Aniket (2018): Non Gaussianity of primordial gravitational waves and cosmic density and velocity fields. Dissertation, LMU München: Fakultät für Physik

Diese Dissertation befasst sich mit nicht-Gaussf¨ ormigen Signaturen in Gravitationswellen (GW), die w¨ ahrend der Phase der Inflation erzeugt wurden, sowie in den gegenw¨ artigen Materie-, Galaxiendichte- und Geschwindigkeitsfeldern im Universum. Wir zeigen, dass die nicht-Gaussianit¨ at primordialer GW wichtige Hinweise auf ihre Entstehung liefert und dazu verwendet werden kann, den Energiedichteanteil von “spectator” Eichfeldern zu bes- timmen, falls die GW durch solche erzeugt worden sind. Als Beispiel betrachten wir ein Inflationsmodell, das aus einem skalaren Inflaton, einem “spectator” Axion und SU(2) Eichfeldern besteht. Axion und Eichfelder sind durch eine Chern-Simons-¨ ahnliche Wech- selwirkung gekoppelt. Dieser Kopplung induziert eine tachyonische Instabilit¨ at der Eich- felder w¨ ahrend der Inflation und bewirkt deren Verst¨ arkung. Die SU(2) Eichfelder be- sitzen einen Tensor-Freiheitsgrad der als Quelle von helikalen GW agiert, die eine starke Skalenabh¨ angigkeit aufweisen k¨ onnen. Ihre Amplitude kann die der Vakuumfluktuatio- nen der Metrik deutlich ¨ ubersteigen. In der vorliegenden Arbeit beschr¨ anken wir uns auf von diesem Modell beschriebene skalenunabh¨ angige GW. Wir untersuchen ihr Bis- pektrum und stellen fest, dass sie in erster Linie durch eine Selbstinteraktion der Eich- felder produziert werden. F¨ ur 3 . m Q . 4 wird das Tensor Bispektrum durch Beitr¨ age
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An Estimation of Inflation Threshold for Africa  

					                
                                    Kelikume
                                   	


                                    DOI: 10.32327/IJMESS/7.4.2018.18

An Estimation of Inflation Threshold for Africa Kelikume DOI: 10.32327/IJMESS/7.4.2018.18

While the monetarists’ quantity theory has suggested that inflation is a monetary phenomenon and much of the literature has suggested a growth-stifling effect of high inflation beyond a particular threshold (e.g., Khan and Senhadji, 2001; Pollin and Zhu, 2005; Espinoza et al, 2010; Frimpong and Oteng-Abayie, 2010; Rutayisire, 2013), this study has expanded the literature on the relationship between inflation and economic growth in Africa and has provided new insights into the relations between the two variables in the long term. This study finds that the estimated inflation threshold for Africa is 11.1 percent. Inflation below this threshold may have some growth-augmenting effects, while beyond this threshold, inflation may have growth-stifling effects. The inflation threshold of 11.1 percent as well as the marginal effects of inflation on growth strongly suggests that there is a strong need for intensified efforts in terms of inflation targeting in many African countries such as Ghana, Nigeria and Zimbabwe where the current inflation rates are far above this threshold.
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Volume 03  Issue 05: (2014) Sep.-October 2014

Volume 03 Issue 05: (2014) Sep.-October 2014

Since the 1990s inflation targeting (IT) has been adopted by several central banks as a strategy for monetary policy. It is expected that the adoption of this monetary regime can reduce inflation and inflation volatility. His practice was marked by a large observed at the beginning of the 90s and 2000 stability a debate emerges on efficiency and economic performance of the scheme. Many studies have focused on this question has no authority to reach a final consensus. The objective of this paper is to analysis of two macroeconomic aggregates: inflation and economic growth under different samples. Initially, we assess the evolution of these two quantities, in all countries targeting inflation, from before his adoption and post-adoption. The results of this first comparison show without exception that all inflation targeting countries had a lower and less volatile inflation. From these results we conclude that the efficiency and economic performance of this monetary policy in both the industrialized and emerging countries. Keywords: Inflation targeting, Performance, Efficiency and stability.
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Lavallee, Yan
  

(2008):


	Understanding Dome-Building Eruptions: a Rheological and Acoustic Study.


Dissertation, LMU München: Fakultät für Geowissenschaften

Lavallee, Yan (2008): Understanding Dome-Building Eruptions: a Rheological and Acoustic Study. Dissertation, LMU München: Fakultät für Geowissenschaften

60 Suspension rheology involves cracking throughout the spectrum. In general, the rates of AE output increases non-linearly with increasing strain rate and accelerates exponentially as failure is approached (Figure 4-4). The deformation is essentially aseismic at strain rates below 10 -4 s -1 (a few minor AE are generated by internal rearrangement). The presence of crystals within a melt apparently significantly lowers the strain rate corresponding to the onset of the ductile-brittle transition in these multiphase magmas. Textural analysis of deformed samples indicates that cracking generally develops in plagioclase crystals; presumably because they are commonly twinned and zoned, and possesses important cleavage planes along {001}, {010} and {110}. Textural analysis also reveals the alignment of crystals during deformation and the development of large-scale cracks at high strain rates (also reflected in the decrease of seismic b-value). Complementary quantitative analyses of fabrics developed in Colima and Bezymianny samples using the automated pattern analysis software AMOCADO (Gerik and Kruhl, submitted) revealed an increase in the overall anisotropy of the suspension by ~29 % upon 33 % strain (Figure 4-5). The anisotropy of the crystal phase however decreased by 19 %. These observations suggest that during deformation, elongated crystals become broken into more equant fragments (lowering the crystal anisotropy) while the fragments from the original crystals align themselves perpendicularly to the applied stress to ease flow migration of the interstitial melt (increasing the overall anistropy).
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Primordial Spirituality

Primordial Spirituality

After one’s inner life has been unsettled by death, it is restructured by the mourning ritual. That is consolation or comfort. After he had grieved over Sarah, weeping and lamenting, ‘Abraham rose up from the face of his dead’ (Gn 23:3). Rising up ‘from the face of the dead’ is a dialogic occurrence: Abraham permits his beloved dead to depart into the land of the dead and he himself returns to the land of the living. The dead person and the surviving person release each other from the intimacy of the vis-à-vis relationship which is characteristic for primordial spirituality and specifically for marriage spirituality. We are told three times that Abraham and his dead removed themselves from each other’s face: ‘Abraham rose from the face of the dead […], from the face of the dead […], so that I may bury my dead out of my face’ (Gn 23:3, 4, 8). This farewell ritual makes visible the fact that death is an event which touches the depths of intimacy. After purchasing a burial place in the field of Machpela in Hebron (Gn 23:4–18), he buried his wife Sarah (Gn 23:19). The words ‘to bury’ and ‘burial place’ serve as key words in this chapter (12 times). Solemnly with loud lamentation, the dead woman was carried to her grave. Relatives, friends and acquaintances accompanied the dead as they performed the rituals of self-abasement – striking their breasts, sprinkling dust on their heads (Koch 1989:1153). To bury a person is to bring a person to her grave, an event accomplished in the circle of the family. This act is performed at the burial place, also called one’s ‘eternal home’ (Ec 12:5; cf. Ps 49:11). Being buried meant to come home, to be gathered to one’s ancestors (Gn 25:8, 17; 35:29), to be gathered to one’s place of origin (Koch 1989:1151). A burial was primarily a return to the community of origin. Abraham, Isaac, Rebekah, Leah and Jacob were also to be buried in Sarah’s grave (Gn 49:30 ff; 50:13).
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Inflation persistence and the rationality of inflation expectations

Inflation persistence and the rationality of inflation expectations

The rational expectations hypothesis for survey and model-based inflation forecasts − from the Survey of Professional Forecasters and the Greenbook respectively − is examined by properly taking into account the persistence characteristics of the data. The finding of near-unit-root effects in the inflation and inflation expectations series motivates the use of a local-to-unity specification of the inflation process that enables us to test whether the data are generated by locally non-stationary or stationary processes. Thus, we test, rather than assume, stationarity of near-unit-root processes. In addition, we set out an empirical framework for assessing relationships between locally non-stationary series. In this context, we test the rational expectations hypothesis by allowing the co-existence of a long-run relationship obtained under the rational expectations restrictions with short-run "learning" effects. Our empirical results indicate that the rational expectations hypothesis holds in the long run, while forecasters adjust their expectations slowly in the short run. This finding lends support to the hypothesis that the persistence of inflation comes from the dynamics of expectations.
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Hunting for new physics in the primordial Universe

Hunting for new physics in the primordial Universe

There is another way to suppress the tensor-to-scalar ratio if the sound speed of the perturbations can be smaller than the speed of light during the matter-dominated contracting phase. For example, in the ΛCDM bounce scenario [230] (and its extension [234]; see the review [215]), if there ex- ists a form of dark matter with a small sound speed that dominates the contracting phase when the scale-invariant power spectra are generated, then the tensor-to-scalar ratio is already suppressed proportionally to the sound speed. Therefore, this provides another motivation to study non- Gaussianities when the sound speed is small during the matter-dominated contracting phase. An immediate question is whether the no-go theorem still holds true in this case or whether it can be circumvented. In this work, we want to explore this possibility of having a k-essence scalar field that would mimic dust-like matter with a small sound speed at low energies and that could play the role of the NEC violating scalar field during the bounce. In this paper, we will evaluate the bispectrum produced by a k-essence scalar field in a matter-dominated contracting universe. This more general setup will yield richer features, which have the potential to be detected by future non-Gaussianity observations. In particular, the shapes, amplitudes, and scaling behaviors will be studied systematically. We will show that a small sound speed implies a large amplitude associated with the three-point function. Accordingly, we will claim that the no-go theorem is not circum- vented but rather extended: in single field matter bounce cosmology, one cannot suppress the tensor-to-scalar ratio, either from the onset of the ini- tial conditions in the matter contracting phase or from the amplification of the curvature perturbations during the bouncing phase, without producing large non-Gaussianities.
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Statistical Analysis of Domestic Price Volatility of Sugar in Ethiopia

Statistical Analysis of Domestic Price Volatility of Sugar in Ethiopia

Abstract: The aim of this study was to model and identify determinants of monthly domestic price volatility of sugar in Ethiopia over the study period from December 2001 to December 2011 GC. The volatility in the domestic price of Sugar has been found to vary over months suggesting the use of GARCH family approach. Thus, family of special characteristics of time series models, namely ARCH, GARCH, TGARCH and EGARCH models with ARIMA mean equations were fitted to the data. The best fitting model among each family of models was selected based on how well the model captures the variation in the data and the optimal lag specification accessed via AIC and SBIC. Comparisons of the symmetric and asymmetric model were carried out based on the significance of asymmetric term in TGARCH and EGARCH models. The analysis showed that: statistically significance asymmetric term and least forecast error from the model established that EGARCH model with Student-t distributional assumptions for residual were superior to the GARCH and TGARCH models. Therefore, ARIMA (0,0,2)-EGARCH(1,3) with Student-t were chosen to be the best fitting models for monthly domestic price volatility of Sugar. Moreover, it was found that from candidate explanatory variables, import price for sugar, fuel oil price, exchange rate (dollar-birr), general inflation, inflation for non food items, inflation for food items, past shock, and volatility on monthly domestic price had statistically significant effect on the current month domestic price volatility on sugar.
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Inflation persistence in African countries: Does inflation targeting matter?

Inflation persistence in African countries: Does inflation targeting matter?

The data used in the empirical part of the study consists of the annual rate ofchange in the total consumer price index (CPI) for a panel 46 African countries and has been collected from the Federal Reserve Economic Data (FRED) database for the period of 1994-2014. A comprehensive list of all 46 countries used in the study include: Algeria, Angola, Benin, Botswana, Burkino Faso, Burundi, Cameroon, Cape Verde, Central African Republic (CAR), Chad, Democratic Republic of Congo (DRC), Cote d‟ Ivore, Egypt, Equatorial Guinea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea Bissau, Kenya, Lesotho, Liberia, Libya, Madagascar, Malawi, Mali, Mauritania, Mauritius, Morocco, Mozambique, Namibia, Niger, Nigeria, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, South Africa, Sudan, Swaziland, Tanzania, Togo, Tunisia, Uganda, Zambia and Zimbabwe. As previously mentioned, of all these countries only 2 countries (i.e. South Africa and Ghana) are inflation targeters while the remaining 44 countries represent non-inflation targeters.
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Non positive scaling factor in probability quantification methods: deriving consumer inflation perceptions and expectations in the whole euro area and Ireland

Non positive scaling factor in probability quantification methods: deriving consumer inflation perceptions and expectations in the whole euro area and Ireland

There  are  problems  with  using  probability  quantification  methods  when  the  scaling  factor  applied in  those  methods becomes non­positive. The way of  adjusting  them proposed in  this  note  and  verified  empirically  allows  using  them  in  such  circumstances.  The  results  for  the  euro area  and Ireland suggest that  the recent financial  crisis  made  consumer inflation  per­ ception and expectations go down, however it did not create deflationary expectations in this  groups of economic agents.  
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Informing the prevention, diagnosis and management of acute rheumatic fever and rheumatic heart disease in Aboriginal Australian and Torres Strait Islander populations

Informing the prevention, diagnosis and management of acute rheumatic fever and rheumatic heart disease in Aboriginal Australian and Torres Strait Islander populations

Primordial and primary prevention aim to prevent disease occurring. In the publication “Primordial and Primary Prevention of ARF/RHD” 2 the candidate undertook a systematic review of the published evidence pertaining to programmes and strategies used to limit the transmission and burden of GAS or the development of ARF once GAS infection has occurred. The effectiveness of primordial prevention is perhaps best illustrated by the decreasing prevalence of ARF and RHD in “affluent” countries with higher socio-economic indices, access to uncrowded shelter, and easily accessible health care systems. Whilst the concept of ‘affluence’ or ‘advantage’ may be easily understood, it is nonetheless unclear exactly what components of such improved living standards are associated with the primordial prevention of ARF and RHD. However, this should not dissuade advocates, whether health care providers, politicians, community leaders or anyone advocating for social and health justice, from exploring mechanisms to alleviate poverty and social and environmental disadvantage, improve housing and education, and increase access to appropriate and effective health care. All these factors are likely to be crucial in addressing ARF/RHD, as well as many other health issues, in remote Australian communities. Given the lack of a defined target there should not be a limited focus on the primordial prevention of ARF/RHD within the health care system. Indeed, it is surely beyond the scope of any health care system to effect such change. Rather, primordial prevention should be
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The relationship of serum vitamin D and Zinc in a nationally  representative sample of Iranian children and adolescents:  The CASPIAN-III study

The relationship of serum vitamin D and Zinc in a nationally representative sample of Iranian children and adolescents: The CASPIAN-III study

MSc, Pediatrics Department, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Non- communicable Disease, Isfahan University of [r]

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Aggregational Gaussianity In The South African Equity Market

Aggregational Gaussianity In The South African Equity Market

inancial time series are well-known to be characterized by certain stylized facts. A stylized fact in finance refers to an empirical finding that is sufficiently ubiquitous across all instruments, markets and time periods as to be accepted as truth. Those stylized facts common to a wide set of financial assets include: a) an absence of autocorrelations, b) heavy tails, c) gain/loss asymmetry, d) intermittency, e) volatility clustering, f) conditional heavy tails, g) a slow decay of autocorrelation in absolute return values, h) a leverage effect, i) volume/volatility correlation, and j) asymmetry in time scales (see Cont, 2001; Sewell, 2011; Li et al., 2010 for an African study). Another well-known stylized fact of financial time series is the property of Aggregational Gaussianity. Aggregational Gaussianity (hereafter AG) is the phenomenon in which the empirical distribution of log-returns tends to normality (or Gaussianity) as the frequency of observations decreases (or the time scale Δt over which the returns are calculated increases); see Eberlein and Keller (1995) and Rydberg (2000). In a financial time-series context, log-returns calculated over shorter time periods are known to be leptokurtotic (heavy- tailed) and often skewed. As the time-interval over which the returns are calculated is increased, the distribution of returns better approximate normality. Hence, the shape of the distribution is different at different time scales, or terms.
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Growth inflation nexus: threshold model of inflation in India

Growth inflation nexus: threshold model of inflation in India

growth rate but not vice versa i.e. causality is uni-directional. Growth and WPI is cointegrated in the order of one. VEC Model is stable but change in WPI has slow error correction whereas change in growth rate is not a good fit but its error correction process is faster than change in WPI. Its residuals are not normal having autocorrelation problem and impulse response functions are diverging. During 2015, WPI has four structural breaks at 1974, 1988, 1995 and 2008 respectively. Above the eshold level of WPI=4.12 with 2010=100, the inflation-growth nexus tends to negative. The paper also found that one per cent increase in consumer price index per year leads to 0.55 per cent increase in GDP growth rate per year in India during 1960-2015. The CPI granger cause growth rate but not vice versa i.e. causality is uni-directional. Growth and CPI is cointegrated in the order of one. VEC Model is stable and is highly good fit but only error correction process of change in growth rate is significant for speedy correction. Its residuals are not normal having autocorrelation problem and impulse response functions are diverging. During 1960-2015, CPI has four structural breaks at 1974,
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Comparison of ICA Non-gaussianity Methods Using Performance Metrics as Correlation Coefficient, Average Execution Time and Computational Speed

Comparison of ICA Non-gaussianity Methods Using Performance Metrics as Correlation Coefficient, Average Execution Time and Computational Speed

algorithm based on Kurtosis. In future some modifications have to be done in design considerations of the proposed algorithm. The assumptions used for ICA are too restrictive for real data. This is because nature of real data cannot be predicted. There is a need of a generalized algorithm which works on both Gaussian distribution and non-Gaussian distributions. Also, in real data noise should be taken into consideration.

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Non Gaussianity and cross scale coupling in interplanetary magnetic field turbulence during a rope–rope magnetic  reconnection event

Non Gaussianity and cross scale coupling in interplanetary magnetic field turbulence during a rope–rope magnetic reconnection event

by Mole and Clarke (1995). Sura and Sardeshmukh (2007) also found a similar skewness–kurtosis parabolic relation using global data of sea-surface temperature fluctuations. Labit et al. (2007) reported a similar skewness–kurtosis de- pendence in electron density fluctuations in plasma con- finement experiments. Medina and Díaz (2016) obtained a skewness–kurtosis parabolic relation for datasets of hu- man reaction times for visual stimuli. Since then, the pres- ence of a skewness–kurtosis relation in different physical scenarios has attracted much attention (Krommes, 2008; Sat- tin et al., 2009; Sandberg et al., 2009; Guszejnov et al., 2013; Bergsaker et al., 2015) and has been associated with the presence of non-Gaussian fluctuations due to coherent struc- tures (Labit et al., 2007; Sandberg et al., 2009; Guszejnov et al., 2013; Bergsaker et al., 2015). The skewness–kurtosis parabolic relation was also found in time series of two-point differences of the modulus of the magnetic field by Vörös et al. (2006). They demonstrated that the parabolic relation is due to nonlocal interaction between large-scale structures and small-scale intermittency.
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Kostka, Philipp
  

(2010):


	Particle Physics Models of Inflation in Supergravity and Grand Unification.


Dissertation, LMU München: Fakultät für Physik

Kostka, Philipp (2010): Particle Physics Models of Inflation in Supergravity and Grand Unification. Dissertation, LMU München: Fakultät für Physik

In this dissertation, we have followed the guiding principle of exploring possible connections between early universe cosmology and particle physics beyond the SM. To accomplish this, we have focused on two aspects of inflation models. One aspect concerns their realization in SUGRA, the other aspect concerns their embedding into the matter sector of a SUSY GUT. On top of that, we have combined both frameworks within the scenario of tribrid inflation to give rise to a working model of inflation in the matter sector of SUGRA SO(10). In the first part of this thesis, we have studied hybrid, tribrid and chaotic inflation models with a special emphasis on different solutions to the η-problem in SUGRA. One such possible solution is to use a general expansion of the K¨ahler potential, wherein appropriate tuning of the expansion parameters ensures a flat inflaton potential. This method always works for inflation models with field values below the Planck scale (such as hybrid or tribrid inflation), however, fails when super-Planckian field values are involved (as in chaotic inflation). A more elegant way to forbid operators which are subject to the η-problem is to impose fundamental symmetries on the K¨ahler potential. Symmetry solutions are appealing since they can even protect a direction with large field values where an expansion in terms of effective operators breaks down. Implementations with either a shift symmetry or a Heisenberg symmetry have been discussed as specific examples.
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