CMB and LSS constraints on a single-field model of inflation

A new inflationary scenario whose exponential potential V (Phi) has a quadratic dependence on the field Phi in addition to the standard linear term is confronted with the five-year observations of the Wilkinson-Microwave Anisotropy Probe and the Sloan Digital Sky Survey data. The number of e-folds (N), the ratio of tensor-to-scalar perturbations (r), the spectral scalar index of the primordial power spectrum (n(s)) and its running (dn(s)/d ln k) depend on the dimensionless parameter a multiplying the quadratic term in the potential. In the limit a. 0 all the results of the exponential potential are fully recovered. For values of alpha not equal 0, we find that the model predictions are in good agreement with the current observations of the Cosmic Microwave Background (CMB) anisotropies and Large-Scale Structure (LSS) in the Universe. Copyright (C) EPLA, 2008.

Contributions to the theory of magnetorotational instability and waves in a rotating plasma

The one-fluid magnetohydrodynamic (MHD) theory of magnetorotational instability (MRI) in an ideal plasma is presented. The theory predicts the possibility of MRI for arbitrary 0, where 0 is the ratio of the plasma pressure to the magnetic field pressure. The kinetic theory of MRI in a collisionless plasma is developed. It is demonstrated that as in the ideal MHD, MRI can occur in such a plasma for arbitrary P. The mechanism of MRI is discussed; it is shown that the instability appears because of a perturbed parallel electric field. The electrodynamic description of MRI is formulated under the assumption that the dispersion relation is expressed in terms of the permittivity tensor; general properties of this tensor are analyzed. It is shown to be separated into the nonrotational and rotational parts. With this in mind, the first step for incorporation of MRI into the general theory of plasma instabilities is taken. The rotation effects on Alfven waves are considered.

VACUUM POLARIZATION EFFECTS ON QUASINORMAL MODES IN ELECTRICALLY CHARGED BLACK HOLE SPACE-TIMES

We investigate the influence of vacuum polarization of quantum massive fields on the scalar sector of quasinormal modes in spherically symmetric black holes. We consider the evolution of a massless scalar field on the space-time corresponding to a charged semiclassical black hole, consisting of the quantum-corrected geometry of a Reissner-Nordstrom black hole dressed by a quantum massive scalar field in the large mass limit. Using a sixth order WKB approach we find a shift in the quasinormal mode frequencies due to vacuum polarization.

Quasinormal modes of black holes immersed in a strong magnetic field

We found quasinormal modes, both in time and frequency domains, of the Ernst black holes, that is neutral black holes immersed in an external magnetic field. The Ernst solution reduces to the Schwarzschild solution, when the magnetic field vanishes. It is found that the quasinormal spectrum for massless scalar field in the vicinity of the magnetized black holes acquires an effective ""mass"" mu = 2B vertical bar m vertical bar, where m is the azimuthal number and B is parameter describing the magnetic field. We shall show that in the presence of a magnetic field quasinormal modes are longer lived and have larger oscillation frequencies. The perturbations of higher-dimensional magnetized black holes by Ortaggio and of magnetized dilaton black holes by Radu are considered. (C) 2007 Elsevier B.V. All rights reserved.

On the generalized eigenvalue method for energies and matrix elements in lattice field theory

We discuss the generalized eigenvalue problem for computing energies and matrix elements in lattice gauge theory, including effective theories such as HQET. It is analyzed how the extracted effective energies and matrix elements converge when the time separations are made large. This suggests a particularly efficient application of the method for which we can prove that corrections vanish asymptotically as exp(-(E(N+1) - E(n))t). The gap E(N+1) - E(n) can be made large by increasing the number N of interpolating fields in the correlation matrix. We also show how excited state matrix elements can be extracted such that contaminations from all other states disappear exponentially in time. As a demonstration we present numerical results for the extraction of ground state and excited B-meson masses and decay constants in static approximation and to order 1/m(b) in HQET.

Detailed analysis of the charge transfer complex N,N-dimethylaniline-SO(2) by Raman spectroscopy and density functional theory calculations

Although the amine sulfur dioxide chemistry was well characterized in the past both experimentally and theoretically, no systematic Raman spectroscopic study describes the interaction between N,N-dimethylaniline (DMA) and sulfur dioxide (SO(2)). The formation of a deep red oil by the reaction of SO(2) with DMA is an evidence of the charge transfer (CT) nature of the DMA-SO(2) interaction. The DMA -SO(2) normal Raman spectrum shows the appearance of two intense bands at 1110 and 1151 cm(-1), which are enhanced when resonance is approached. These bands are assigned to nu(s)(SO(2)) and nu(phi-N) vibrational modes, respectively, confirming the interaction between SO(2) and the amine via the nitrogen atom. The dimethyl group steric effect favors the interaction of SO(2) with the ring pi electrons, which gives rise to a pi-pi* low-energy CT electronic transition, as confirmed by time-dependent density functional theory (TDDFT) calculations. In addition, the calculated Raman DMA-SO(2) spectrum at the B3LYP/6-311++g(3df,3pd) level shows good agreement with the experimental results (vibrational wavenumbers and relative intensities), allowing a complete assignment of the vibrational modes. A better understanding of the intermolecular interactions in this model system can be extremely useful in designing new materials to absorb, detect, or even quantify SO(2). Copyright (C) 2009 John Wiley & Sons, Ltd.

Kunskapsöverföring- att leda rätt : Ledarens roll vid kunskapsöverföring i en organisation

I en rapport som Svensk Näringsliv (2010) har utfört beskriver de att företag redan idag och inom en snar framtid står inför den största pensionsavgången någonsin i Svensk historia. 40- talisternas avgång ställer företag inför stora utmaningarna, framförallt att lyckas genomföra en lyckad generationsväxling. De personer som går i pension har under sitt yrkesverksamma liv utvecklat en kunskap som många organisationer vilar på. En stor del av denna kunskap måste överföras för att organisationerna ska kunna fortsätta att vara effektiva på marknaden. Syftet med denna studie var att få en djupare förståelse för ledarskapets betydelse gällande kunskapsöverföring i en organisation, samt bidra med praktiska verktyg till chefer och medarbetare för att undvika att förlora värdefull kunskap vid en generationsväxling. Industriföretaget LEAX har själva identifierat ett problem i att överföra viktig kunskap i och med kommande generationsväxling. Deras önskan var att få hjälp med praktiska verktyg för hur de ska tänka och verka för att mildra kunskapsglappet som kan uppstå. För att undersöka detta och därmed uppfylla denna studies syfte har intervjuer genomförts med fyra produktionsledare, fyra medarbetare som förväntas dela kunskap och tre medarbetare som förväntas ta till sig kunskap. Innan intervjuerna genomfördes läste vi in oss på teori om kunskap, kunskapsöverföring och ledarskap. Eftersom begreppet kunskap har en bred betydelse och kan definieras olika beroende om den är individuell eller organisatorisk, började vi i vårt teoriavsnitt att bena ut detta begrepp. Nonaka och Takeuchi (1995) gör en förenklad bild av kunskap som ett isberg, där den explicita kunskapen benämns som toppen. Väl synlig över ytan på vattnet är den enkel att upptäcka och ta till sig. Under vattnet döljer sig en osynlig kunskap som är svår att upptäcka, så kallas implicit eller tyst kunskap. Denna kunskap utgör en enorm del av isberget och blir därmed viktig att bevara. Dock är denna kunskap svår att överföra då den är osynlig och svår att ta på. För att förstå vad kunskapsöverföring innebär, behöver organisationer identifiera vilken sorts kunskap som behöver överföras för att kunskapsöverföringen ska bli lyckad (Jonsson, 2012). Men även fast organisationer gör detta måste även ledningen förstå att kunskapsöverföring är en strategisk angelägenhet som kan ses som en process som involverar medarbetare. I denna studie har vi undersökt hur ledare kan skapa motivation, engagemang och resurser för medarbetare att vilja medverka och bidra till kunskapsöverföring. För att försöka förstå hur kunskap överförs i en organisation har vi använt oss av Nonaka och Takeuchi, (1995) SECI-modell. Modellen bygger på samspelet mellan den tysta och explicita kunskapen, vilket sker i fyra processer. Dessa processer har vi sedan utvecklat till en egen modell som inkluderar institutionella, organisatoriska och kognitiva faktorer. Utifrån dessa faktorer har vi skapat praktiska förslag på hur ledare tillsammans med medarbetarna kan planera kunskapsöverföring. Dessa praktiska förslag gynnar både individuell- och organisatorisk utveckling, samt bidrar till att mildra kunskapsförlust vid generationsväxlingen. Ett av de praktiska exempel vi utformat är en kompetensprofil, som är ett hjälpmedel för organisationer att identifiera vilken kunskap som medarbetarna besitter, vilket synliggör vilken kunskap det är som kan gå förlorad. Kompetensprofilen tillsammans med vår modell kan appliceras på liknande företag, men även på organisationer som verkar inom andra branscher. Eftersom denna kompetensprofil är utvecklad efter de krav som finns inom aktuell verksamhet, finns det möjlighet att anpassa efter andra verksamheter.

Hamiltonian constraint analysis of vector field theories with spontaneous Lorentz symmetry breaking

Recent investigations of various quantum-gravity theories have revealed a variety of possible mechanisms that lead to Lorentz violation. One of the more elegant of these mechanisms is known as Spontaneous Lorentz Symmetry Breaking (SLSB), where a vector or tensor field acquires a nonzero vacuum expectation value. As a consequence of this symmetry breaking, massless Nambu-Goldstone modes appear with properties similar to the photon in Electromagnetism. This thesis considers the most general class of vector field theories that exhibit spontaneous Lorentz violation-known as bumblebee models-and examines their candidacy as potential alternative explanations of E&M, offering the possibility that Einstein-Maxwell theory could emerge as a result of SLSB rather than of local U(1) gauge invariance. With this aim we employ Dirac's Hamiltonian Constraint Analysis procedure to examine the constraint structures and degrees of freedom inherent in three candidate bumblebee models, each with a different potential function, and compare these results to those of Electromagnetism. We find that none of these models share similar constraint structures to that of E&M, and that the number of degrees of freedom for each model exceeds that of Electromagnetism by at least two, pointing to the potential existence of massive modes or propagating ghost modes in the bumblebee theories.

A note on an application of Arrow's theorem: sufficient conditions for Lucas' inflation and welfare

Bellman's methods for dynamic optimization constitute the present mainstream in economics. However, some results associated with optimal controI can be particularly usefuI in certain problems. The purpose of this note is presenting such an example. The value function derived in Lucas' (2000) shopping-time economy in Infiation and Welfare need not be concave, leading this author to develop numerical analyses to determine if consumer utility is in fact maximized along the balanced path constructed from the first order conditions. We use Arrow's generalization of Mangasarian's results in optimal control theory and develop sufficient conditions for the problem. The analytical conclusions and the previous numerical results are compatible .

Two additions to Lucas's "inflation and welfare"

This work adds to Lucas (2000) by providing analytical solutions to two problems that are solved only numerically by the author. The first part uses a theorem in control theory (Arrow' s sufficiency theorem) to provide sufficiency conditions to characterize the optimum in a shopping-time problem where the value function need not be concave. In the original paper the optimality of the first-order condition is characterized only by means of a numerical analysis. The second part of the paper provides a closed-form solution to the general-equilibrium expression of the welfare costs of inflation when the money demand is double logarithmic. This closed-form solution allows for the precise calculation of the difference between the general-equilibrium and Bailey's partial-equilibrium estimates of the welfare losses due to inflation. Again, in Lucas's original paper, the solution to the general-equilibrium-case underlying nonlinear differential equation is done only numerically, and the posterior assertion that the general-equilibrium welfare figures cannot be distinguished from those derived using Bailey's formula rely only on numerical simulations as well.

Essays on monetary and banking theory

Esta tese de Doutorado é dedicada ao estudo de instabilidade financeira e dinâmica em Teoria Monet ária. E demonstrado que corridas banc árias são eliminadas sem custos no modelo padrão de teoria banc ária quando a popula ção não é pequena. É proposta uma extensão em que incerteza agregada é mais severa e o custo da estabilidade financeira é relevante. Finalmente, estabelece-se otimalidade de transições na distribui ção de moeda em economias em que oportunidades de trocas são escassas e heterogêneas. Em particular, otimalidade da inflação depende dos incentivos dinâmicos proporcionados por tais transi ções. O capí tulo 1 estabelece o resultado de estabilidade sem custos para economias grandes ao estudar os efeitos do tamanho populacional na an álise de corridas banc árias de Peck & Shell. No capí tulo 2, otimalidade de dinâmica é estudada no modelo de monet ário de Kiyotaki & Wright quando a sociedade é capaz de implementar uma polí tica inflacion ária. Apesar de adotar a abordagem de desenho de mecanismos, este capí tulo faz um paralelo com a an álise de Sargent & Wallace (1981) ao destacar efeitos de incentivos dinâmicos sobre a interação entre as polí ticas monet ária e fiscal. O cap ítulo 3 retoma o tema de estabilidade fi nanceira ao quanti car os custos envolvidos no desenho ótimo de um setor bancário à prova de corridas e ao propor uma estrutura informacional alternativa que possibilita bancos insolventes. A primeira an álise mostra que o esquema de estabilidade ótima exibe altas taxas de juros de longo prazo e a segunda que monitoramento imperfeito pode levar a corridas bancárias com insolvência.

Inflation when the planner wants less spending

I study optima in a random-matching model of outside money. The examples in this paper show a conflict between private and collective interests. While the planner worry about the extensive and intensive margin effects of trades in a steady state, people want the exhaust the gains from trades immediately, i.e., once in a meeting, consumers prefer spend more for a better output than take the risk of saving money and wait for good meetings in the future. Thus, the conflict can force the planner to choose allocations with a more disperse money distribution, mainly if people are im- patient. When the patient rate is low enough, the planner uses a expansionary policy to generate a better distribution of money for future trades.

A restatement of the welafare costs of inflation. The wast of scarce resources in the manufacturing , banking and household sectors

Lucas (2000) estimates that the US welfare costs of inflation are around 1% of GDP. This measurement is consistent with a speci…c distorting channel in terms of the Bailey triangle under the demand for monetary base schedule (outside money): the displacement of resources from the production of consumption goods to the household transaction time à la Baumol. Here, we consider also several new types of distortions in the manufacturing and banking industries. Our new evidences show that both banks and firms demand special occupational employments to avoid the inflation tax. We de…ne the concept of ”the foat labor”: The occupational employments that are aflected by the in‡ation rates. More administrative workers are hired relatively to the bluecollar workers for producing consumption goods. This new phenomenon makes the manufacturing industry more roundabout. To take into account this new stylized fact and others, we redo at same time both ”The model 5: A Banking Sector -2” formulated by Lucas (1993) and ”The Competitive Banking System” proposed by Yoshino (1993). This modelling allows us to characterize better the new types of misallocations. We …nd that the maximum value of the resources wasted by the US economy happened in the years 1980-81, after the 2nd oil shock. In these years, we estimate the excess resources that are allocated for every speci…c distorting channel: i) The US commercial banks spent additional resources of around 2% of GDP; ii) For the purpose of the firm foating time were used between 2.4% and 4.1% of GDP); and iii) For the household transaction time were allocated between 3.1% and 4.5 % of GDP. The Bailey triangle under the demand for the monetary base schedule represented around 1% of GDP, which is consistent with Lucas (2000). We estimate that the US total welfare costs of in‡ation were around 10% of GDP in terms of the consumption goods foregone. The big di¤erence between our results and Lucas (2000) are mainly due to the Harberger triangle in the market for loans (inside money) which makes part of the household transaction time, of the …rm ‡oat labor and of the distortion in the banking industry. This triangle arises due to the widening interest rates spread in the presence of a distorting inflation tax and under a fractionally reserve system. The Harberger triangle can represent 80% of the total welfare costs of inflation while the remaining percentage is split almost equally between the Bailey triangle and the resources used for the bank services. Finally, we formulate several theorems in terms of the optimal nonneutral monetary policy so as to compare with the classical monetary theory.