Inflation with Fayet-Iliopoulos Terms

Two of the most attractive realizations of inflation in supergravity are based upon the presence of a constant Fayet-Iliopoulos (FI) term. In D-term hybrid inflation it is the FI term itself which sets the energy scale of inflation. Alternatively, the breaking of a U(1) symmetry induced by the FI term can dynamically generate the quadratic potential of chaotic inflation. The purpose of this note is to study the possible UV embedding of these schemes in terms of the `field-dependent FI term' related to a string modulus field which is stabilized by a non-perturbative superpotential. We find that in settings where the FI term drives inflation, gauge invariance prevents a decoupling of the modulus from the inflationary dynamics. The resulting inflation models generically contain additional dynamical degrees of freedom compared to D-term hybrid inflation. However, the dynamical realization of chaotic inflation can be obtained in complete analogy to the case of a constant FI term. We present a simple string-inspired toy model of this type.Comment: 20 pages, accepted for publication in PR

Supersymmetric Moduli Stabilization and High-Scale Inflation

We study the back-reaction of moduli fields on the inflaton potential in generic models of F-term inflation. We derive the moduli corrections as a power series in the ratio of Hubble scale and modulus mass. The general result is illustrated with two examples, hybrid inflation and chaotic inflation. We find that in both cases the decoupling of moduli dynamics and inflation requires moduli masses close to the scale of grand unification. For smaller moduli masses the CMB observables are strongly affected.Comment: 5 page

UV Corrections in Sgoldstino-less Inflation

We study the embedding of inflation with nilpotent multiplets in supergravity, in particular the decoupling of the sgoldstino scalar field. Instead of being imposed by hand, the nilpotency constraint on the goldstino multiplet arises in the low energy-effective theory by integrating out heavy degrees of freedom. We present explicit supergravity models in which a large but finite sgoldstino mass arises from Yukawa or gauge interactions. In both cases the inflaton potential receives two types of corrections. One is from the backreaction of the sgoldstino, the other from the heavy fields generating its mass. We show that these scale oppositely with the Volkov-Akulov cut-off scale, which makes a consistent decoupling of the sgoldstino nontrivial. Still, we identify a parameter window in which sgoldstino-less inflation can take place, up to corrections which flatten the inflaton potential.Comment: 7 pages, 1 figure. Comments added, published versio

WAY-KEY – smarter Mobilitätsassistent für Menschen mit Demenzerkrankung

In Österreich sind etwa 1,2 Prozent der Bevölkerung an Demenz erkrankt, was einer Gesamtzahl von rund 100.000 Personen entspricht. Mit zunehmendem Alter nimmt auch die Prävalenz stark zu, was im Zuge der demographischen Alterung daher einen starken Anstieg der Zahl der Betroffenen in der Zukunft erwarten lässt. Der Erhalt von und die Motivation zur Mobilität wirkt aus mehreren Gründen zumindest verzögernd auf den Verlauf dementieller Erkrankungen. Mangelnde Bewegung ist laut Norton et al. jener Risikofaktor, der den meisten vermeidbaren Alzheimer-Demenz-Fällen in den Vereinigten Staaten von Amerika (USA) und Europa zugrunde liegt. Der österreichische Demenzbericht nennt als Risikofaktor bei der Entwicklung demenzieller Erkrankungen: „... weniger als 20 Minuten flotte Bewegung an drei oder mehr Tagen pro Woche oder weniger als 30 Minuten moderate Bewegung an fünf oder mehr Tagen pro Woche...“. Da Mobilität bei Demenz aber auch Risken wie Verlorengehen und Stürze mit sich bringt, zielen bisherige technische Lösungen in erster Linie darauf ab, die Mobilität demenziell erkrankter Menschen von außen her zu überwachen und einzuschränken oder zu verhindern. Sie unterstützen damit in erster Linie Pflegepersonal oder Angehörige und machen Personen mit Demenz zum passiven Teil der Wirkungskette. Dort, wo versucht wurde, ältere Menschen selbst durch technologische Lösungen mobil zu erhalten, wurde bisher auf Smartphones bzw. Smartwatches gesetzt, deren Handhabung demente Personen jedoch überfordert. Das WAY-KEY-Konsortium möchte existierende technische (Teil-)Lösungen der Firmenpartner in einem stark partizipatorisch ausgelegten Designprozess mit Hilfe der Wissenschaftspartner für demenziell Erkrankte zur Förderung ihrer Mobilität nutzbar machen

Challenges for Large-Field Inflation and Moduli Stabilization

We analyze the interplay between K\"ahler moduli stabilization and chaotic inflation in supergravity. While heavy moduli decouple from inflation in the supersymmetric limit, supersymmetry breaking generically introduces non-decoupling effects. These lead to inflation driven by a soft mass term, $m_\varphi^2 \sim m m_{3/2}$, where $m$ is a supersymmetric mass parameter. This scenario needs no stabilizer field, but the stability of moduli during inflation imposes a large supersymmetry breaking scale, $m_{3/2} \gg H$, and a careful choice of initial conditions. This is illustrated in three prominent examples of moduli stabilization: KKLT stabilization, K\"ahler Uplifting, and the Large Volume Scenario. Remarkably, all models have a universal effective inflaton potential which is flattened compared to quadratic inflation. Hence, they share universal predictions for the CMB observables, in particular a lower bound on the tensor-to-scalar ratio, $r \gtrsim 0.05$.Comment: 44+1 pages, 6 figures, minor modifications, references adde

The myeloid expressed EF-hand proteins display a diverse pattern of lipid raft association

AbstractEF-hand proteins are known to translocate to membranes, suggesting that they are involved in signaling events located in the cell membrane. Many proteins involved in signaling events associate cholesterol rich membrane domains, so called lipid rafts, which serve as platforms for controlled protein–protein interaction. Here, we demonstrate that the myeloid expressed EF-hand proteins can be distinguished into three classes with respect to their membrane association. Grancalcin, a myeloid expressed penta EF-hand protein, is constitutively located in lipid rafts. S100A9 (MRP14) and S100A8 (MRP8) are translocated into detergent resistant lipid structures only after calcium activation of the neutrophils. However, the S100A9/A8 membrane association is cholesterol and sphingolipid independent. On the other hand, the association of S100A12 (EN-RAGE) and S100A6 (calcyclin) with membranes is detergent sensitive. These diverse affinities to lipid structures of the myeloid expressed EF-hand proteins most likely reflect their different functions in neutrophils

Modeling of electrochemical double layers in thermodynamic non-equilibrium

We consider the contact between an electrolyte and a solid electrode. At first we formulate a thermodynamic consistent model that resolves boundary layers at interfaces. The model includes charge transport, diffusion, chemical reactions, viscosity, elasticity and polarization under isothermal conditions. There is a coupling between these phenomena that particularly involves the local pressure in the electrolyte. Therefore the momentum balance is of major importance for the correct description of the layers. The width of the boundary layers is typically very small compared to the macroscopic dimensions of the system. In a second step we thus apply the method of asymptotic analysis to derive a simpler reduced model that does not resolve the boundary layers but instead incorporates the electrochemical properties of the layers into a set of new boundary conditions. For a metal-electrolyte interface, we derive a qualitative description of the double layer capacitance without the need to resolve space charge layers

A new perspective on the electron transfer: Recovering the Butler--Volmer equation in non-equilibrium thermodynamics

Understanding and correct mathematical description of electron transfer reaction is a central question in electrochemistry. Typically the electron transfer reactions are described by the Butler-Volmer equation which has its origin in kinetic theories. The Butler-Volmer equation relates interfacial reaction rates to bulk quantities like the electrostatic potential and electrolyte concentrations. Since in the classical form, the validity of the Butler-Volmer equation is limited to some simple electrochemical systems, many attempts have been made to generalize the Butler-Volmer equation. Based on non-equilibrium thermodynamics we have recently derived a reduced model for the electrode-electrolyte interface. This reduced model includes surface reactions but does not resolve the charge layer at the interface. Instead it is locally electroneutral and consistently incorporates all features of the double layer into a set of interface conditions. In the context of this reduced model we are able to derive a general Butler-Volmer equation. We discuss the application of the new Butler-Volmer equations to different scenarios like electron transfer reactions at metal electrodes, the intercalation process in lithium-iron-phosphate electrodes and adsorption processes. We illustrate the theory by an example of electroplating