Towards a spin foam model description of black hole entropy

We propose a way to describe the origin of black hole entropy in the spin foam models of quantum gravity. This stimulates a new way to study the relation of spin foam models and loop quantum gravity.Comment: 5 pages, 1 figur

Search for Neutrinoless Double Beta Decay with NEMO 3 and SuperNEMO

Since 2003 the NEMO~3 experiment has been searching for neutrinoless double beta decay using about 10 kg of enriched isotopes. A limit of T_(1/2)(0nu) > 5.8 10**23 years at 90 % CL has been obtained for 100-Mo from the first two years of data. Several measurements of two-neutrino double beta decays have also been performed. A first NEMO 3 measurement of the half-life of 130-Te is presented, giving a value of T_(1/2)(2nu) = (7.6 +- 1.5 (stat) +- 0.8 (syst)) 10**20 years. In parallel, there is an active R&D programme for the SuperNEMO experiment which is expected to commence data taking in 2012-2013 with 100-200 kg of enriched isotopes.Comment: 6 pages, 3 figures, Proceedings of the 2007 Europhysics Conference on High Energy Physics, in Manchester, England, 19-25 July 200

Charged polytropic compact stars

In this work, we analyze the effect of charge in compact stars considering the limit of the maximum amount of charge they can hold. We find that the global balance of the forces allows a huge charge (~ 10^{20} Coulomb) to be present in a neutron star producing a very high electric field (~ 10^{21} V/m). We have studied the particular case of a polytropic equation of state and assumed that the charge distribution is proportional to the mass density. The charged stars have large mass and radius as we should expect due to the effect of the repulsive Coulomb force with the M/R ratio increasing with charge. In the limit of the maximum charge the mass goes up to ~ 10 M_sun which is much higher than the maximum mass allowed for a neutral compact star. However, the local effect of the forces experienced by a single charged particle, makes it to discharge quickly. This creates a global force imbalance and the system collapses to a charged black hole

Electrically charged compact stars

We review here the classical argument used to justify the electrical neutrality of stars and show that if the pressure and density of the matter and gravitational field inside the star are large, then a charge and a strong electric field can be present. For a neutron star with high pressure (~ 10^{33} to 10^{35} dynes /cm^2) and strong gravitational field (~ 10^{14} cm/s^2), these conditions are satisfied. The hydrostatic equation which arises from general relativity, is modified considerably to meet the requirements of the inclusion of the charge. In order to see any appreciable effect on the phenomenology of the neutron stars, the charge and the electrical fields have to be huge (~ 10^{21} Volts/cm). These stars are not however stable from the viewpoint that each charged particle is unbound to the uncharged particles, and thus the system collapses one step further to a charged black holeComment: Proceedings of 10th Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relativistic Field Theories (MG X MMIII), Rio de Janeiro, Brazil, 20-26 Jul 200

Development of Bursaphelenchus xylophilus-specific microsatellite markers to assess the genetic diversity of populations from European forests.

The pinewood nematode (PWN), Bursaphelenchus xylophilus (Steiner & Buhrer, 1934), Nickle (Nematoda: Aphelenchoididae) is the causal agent of the pine wilt disease and is currently considered as one of the most important pests and pathogens in the world. Its introduction and spread in new forest ecosystems have considerable consequences both economically and environmentally. Therefore, it is of crucial importance to identify its invasion routes, to determine the origin of new outbreaks and to understand the invasion process of this species to prevent further dissemination of the disease in Europe. In order to address these questions using population genetic approaches, we have been developing a set of PWN-specific microsatellite markers, usable in routine conditions at the individual level, thanks to multiplex PCR coupled with a fast DNA extraction method. Microsatellites were isolated from a genomic library using a procedure combining DNA enrichment and high throughput pyrosequencing as recently described by Malausa et al. (2011). Primers were designed for 71 and 23 perfect and compound microsatellites, respectively, 26 of which were experimentally validated so far. Among them, 18 markers exhibited polymorphism after several rounds of amplification tests. Preliminary results on a set of 190 nematodes from 13 populations indicate a very low level of polymorphism in PWN populations from Portugal and Madeira Island, compared to populations from the native area in North America. The genotyping of a wide collection of samples from Europe, Asia and North America is currently underway in the laboratory. Assessing the genetic diversity of populations indeed constitutes the cornerstone to determine whether the European invasive PWN populations are the result of a single or several independent events of introduction

Multicomponent Strongly Interacting Few-Fermion Systems in One Dimension

The paper examines a trapped one-dimensional system of multicomponent spinless fermions that interact with a zero-range two-body potential. We show that when the repulsion between particles is very large the system can be approached analytically. To illustrate this analytical approach we consider a simple system of three distinguishable particles, which can be addressed experimentally. For this system we show that for infinite repulsion the energy spectrum is sixfold degenerate. We also show that this degeneracy is partially lifted for finitely large repulsion for which we find and describe corresponding wave functions.Comment: Paper in connection with the 22nd European Conference on Few-Body Problems in Physics, Krakow, Poland, 9-13 September 201

Electro-optical properties of an orthoconic liquid crystal mixture (W-182) and its molecular dynamics

We observed that the perfect dark state problem could be solved by using orthoconic antiferroelectric liquid crystal (OAFLC) instead of normal AFLC by comparing the properties of isocontrast and dispersion chromaticity of W-182 OAFLC and normal AFLC CS-4001. We electro-optically observed that several subphases such as SmCγ*, SmC*β, SmC*α and antiferroelectric SmI*A phases exist in W-182 OAFLC. We dielectrically observed in 4 μm thin cell that during heating, several new phases appeared. In the high temperature antiferroelectric region, a higher order than SmC* phase could be detected dielectrically, in the temperature range of 91–98 °C, behaving similar to SmCγ* and also, another phase below SmC* region could be dielectrically detected in the temperature range of 103–1100 °C, behaving similar to SmCα*, and an antiferroelectric, similar to SmIA* phase, was observed in the lower temperature region of the antiferroelectric phase; those are definitely arising due to surface force and interfacial charges interactions. We observed both PH and PL relaxation modes in both cells, although they differed in their strength and relaxation frequency. We studied extensively our observations of PH and PL modes in the antiferroelectric region, a Goldstone mode in the ferroelectric region and a soft mode in the ferroelectric region and SmA* phases

Multipower variation for Brownian semistationary processes

In this paper we study the asymptotic behaviour of power and multipower variations of processes $Y$:$$Y_t=\int_{-\in fty}^tg(t-s)\sigma_sW(\mathrm{d}s)+Z_t,$$ where $g:(0,\infty)\rightarrow\mathbb{R}$ is deterministic, $\sigma >0$ is a random process, $W$ is the stochastic Wiener measure and $Z$ is a stochastic process in the nature of a drift term. Processes of this type serve, in particular, to model data of velocity increments of a fluid in a turbulence regime with spot intermittency $\sigma$. The purpose of this paper is to determine the probabilistic limit behaviour of the (multi)power variations of $Y$ as a basis for studying properties of the intermittency process $\sigma$. Notably the processes $Y$ are in general not of the semimartingale kind and the established theory of multipower variation for semimartingales does not suffice for deriving the limit properties. As a key tool for the results, a general central limit theorem for triangular Gaussian schemes is formulated and proved. Examples and an application to the realised variance ratio are given.Comment: Published in at http://dx.doi.org/10.3150/10-BEJ316 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

Universal properties of Fermi gases in arbitrary dimensions

We consider spin-1/2 Fermi gases in arbitrary, integer or non-integer spatial dimensions, interacting via a Dirac delta potential. We first generalize the method of Tan's distributions and implement short-range boundary conditions to arbitrary dimension and we obtain a set of universal relations for the Fermi gas. Three-dimensional scattering under very general conditions of transversal confinement is described by an effectively reduced-dimensional scattering length, which we show depends on the three-dimensional scattering length in a universal way. Our formula for non-integer dimensions interpolates between the known results in integer dimensions 1, 2 and 3. Without any need to solve the associated multichannel scattering problem, we find that confinement-induced resonances occur in all dimensions different from D=2, while reduced-dimensional contacts, related to the tails of the momentum distributions, are connected to the three-dimensional contact by a correction factor of purely geometric origin.Comment: 6 pages, 0 figure

Neutrino processes in the K0K^0 condensed phase of color flavor locked quark matter

We study weak interactions involving Goldstone bosons in the neutral kaon condensed phase of color flavor locked quark matter. We calculate the rates for the dominant processes that contribute to the neutrino mean free p ath and to neutrino production. A light $K^+$ state, with a mass $\tilde{m}_{K^+} \propto (\Delta/\mu) (\Delta/m_s)(m_d-m_u)$, where $\mu$ and $\Delta$ are the quark chemical potential and superconducting gap respectively, is shown to play an important role. We identify unique characteristics of weak interaction rates in this novel phase and discuss how they might influence neutrino emission in core collapse supernova and neutron stars.Comment: 21 pages, 4 figure