Primordial Entropy Production and Lambda-driven Inflation from Quantum Einstein Gravity

We review recent work on renormalization group (RG) improved cosmologies based upon a RG trajectory of Quantum Einstein Gravity (QEG) with realistic parameter values. In particular we argue that QEG effects can account for the entire entropy of the present Universe in the massless sector and give rise to a phase of inflationary expansion. This phase is a pure quantum effect and requires no classical inflaton field.Comment: 12 pages, 4 figures, IGCG-07 Pun

The stability of the O(N) invariant fixed point in three dimensions

We study the stability of the O(N) fixed point in three dimensions under perturbations of the cubic type. We address this problem in the three cases $N=2,3,4$ by using finite size scaling techniques and high precision Monte Carlo simulations. It is well know that there is a critical value $2<N_c<4$ below which the O(N) fixed point is stable and above which the cubic fixed point becomes the stable one. While we cannot exclude that $N_c<3$, as recently claimed by Kleinert and collaborators, our analysis strongly suggests that $N_c$ coincides with 3.Comment: latex file of 18 pages plus three ps figure

Tracing CP-violation in Lepton Flavor Violating Muon Decays

Although the Lepton Flavor Violating (LFV) decay $\mu^+\to e^+ \gamma$ is forbidden in the Standard Model (SM), it can take place within various theories beyond the SM. If the branching ratio of this decay saturates its present bound [{\it i.e.,} Br$(\mu^+ \to e^+\gamma)\sim 10^{-11}$], the forthcoming experiments can measure the branching ratio with high precision and consequently yield information on the sources of LFV. In this letter, we show that for polarized $\mu^+$, by studying the angular distribution of the transversely polarized positron and linearly polarized photon we can derive information on the CP-violating sources beyond those in the SM. We also study the angular distribution of the final particles in the decay $\mu^+\to e^+_1 e^- e^+_2$ where $e^+_1$ is defined to be the more energetic positron. We show that transversely polarized $e_1^+$ can provide information on a certain combination of the CP-violating phases of the underlying theory which would be lost by averaging over the spin of $e^+_1$.Comment: 6 pages, 2 figure

On the gravitational field of static and stationary axial symmetric bodies with multi-polar structure

We give a physical interpretation to the multi-polar Erez-Rozen-Quevedo solution of the Einstein Equations in terms of bars. We find that each multi-pole correspond to the Newtonian potential of a bar with linear density proportional to a Legendre Polynomial. We use this fact to find an integral representation of the $\gamma$ function. These integral representations are used in the context of the inverse scattering method to find solutions associated to one or more rotating bodies each one with their own multi-polar structure.Comment: To be published in Classical and Quantum Gravit

A general formula of the effective potential in 5D SU(N) gauge theory on orbifold

We show a general formula of the one loop effective potential of the 5D SU(N) gauge theory compactified on an orbifold, $S^1/Z_2$. The formula shows the case when there are fundamental, (anti-)symmetric tensor and adjoint representational bulk fields. Our calculation method is also applicable when there are bulk fields belonging to higher dimensional representations. The supersymmetric version of the effective potential with Scherk-Schwarz breaking can be obtained straightforwardly. We also show some examples of effective potentials in SU(3), SU(5) and SU(6) models with various boundary conditions, which are reproduced by our general formula.Comment: 22 pages;minor corrections;references added;typos correcte

Scale-dependent metric and causal structures in Quantum Einstein Gravity

Within the asymptotic safety scenario for gravity various conceptual issues related to the scale dependence of the metric are analyzed. The running effective field equations implied by the effective average action of Quantum Einstein Gravity (QEG) and the resulting families of resolution dependent metrics are discussed. The status of scale dependent vs. scale independent diffeomorphisms is clarified, and the difference between isometries implemented by scale dependent and independent Killing vectors is explained. A concept of scale dependent causality is proposed and illustrated by various simple examples. The possibility of assigning an "intrinsic length" to objects in a QEG spacetime is also discussed.Comment: 52 page

Kaon mixing and the charm mass

We study contributions to the Delta S=2 weak Chiral Lagrangian producing K0-K0bar mixing which are not enhanced by the charm mass. For the real part, these contributions turn out to be related to the box diagram with up quarks but, unlike in perturbation theory, they do not vanish in the limit m_u->0. They increase the leading contribution to the K_L-K_S mass difference by ~10%. This means that short distances amount to (90+-15)% of this mass difference. For the imaginary part, we find a correction to the lambda_c^2 m_c^2 term of -5% from the integration of charm, which is a small contribution to epsilon_K. The calculation is done in the large-Nc limit and we show explicitly how to match short and long distances.Comment: 20 pages, 5 figures. Typos fixe

Supersymmetry, quark confinement and the harmonic oscillator

We study some quantum systems described by noncanonical commutation relations formally expressed as [q,p]=ihbar(I + chi H), where H is the associated (harmonic oscillator-like) Hamiltonian of the system, and chi is a Hermitian (constant) operator, i.e. [H,chi]=0 . In passing, we also consider a simple (chi=0 canonical) model, in the framework of a relativistic Klein-Gordon-like wave equation.Comment: To be published in Journal of Physics A: Mathematical and Theoretical (2007

Language of Lullabies: The Russification and De-Russification of the Baltic States

This article argues that the laws for promotion of the national languages are a legitimate means for the Baltic states to establish their cultural independence from Russia and the former Soviet Union

Protection and Identification of Stateless Persons Through EU Law

A number of recent studies confirm that statelessness is a widespread phenomenon in the EU, which is not receiving adequate attention. The lack of well-functioning statelessness determination procedures is at the root of many problems associated with statelessness in the EU. These are, in particular, the inadequate protection of stateless persons and deficiencies in the prevention and reduction of statelessness. This paper argues in favour of common EU action on the identification and protection of stateless persons by analyzing the EU competence to pass relevant legislation, and explaining the desirability for such legislation