Dark Neutrinos

Solar, atmospheric and reactor neutrino experiments established that neutrinos are massive. It is quite natural then to consider neutrinos as candidate particles for explaining the dark matter in halos around galaxies. We study the gravitational clustering of these neutrinos within a model of a massive core and a surrounding spherical neutrino halo. The neutrinos form a degenerate Fermi gas and a loaded polytropic equation is established. We solve the equation and we obtain the neutrino density in a galaxy, the size of the galaxy and the galactic rotational curves. The available data favor a neutrino with a mass around 10eV. The consequent cosmological implications are examined.Comment: 5 pages, 2 figure

Towards a Holistic CAD Platform for Nanotechnologies

Silicon-based CMOS technologies are predicted to reach their ultimate limits by the middle of the next decade. Research on nanotechnologies is actively conducted, in a world-wide effort to develop new technologies able to maintain the Moore's law. They promise revolutionizing the computing systems by integrating tremendous numbers of devices at low cost. These trends will have a profound impact on the architectures of computing systems and will require a new paradigm of CAD. The paper presents a work in progress on this direction. It is aimed at fitting requirements and constraints of nanotechnologies, in an effort to achieve efficient use of the huge computing power promised by them. To achieve this goal we are developing CAD tools able to exploit efficiently these huge computing capabilities promised by nanotechnologies in the domain of simulation of complex systems composed by huge numbers of relatively simple elements.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Neutrino Shortcuts in Spacetime

Theories with large extra dimensions may be tested using sterile neutrinos living in the bulk. A bulk neutrino can mix with a flavor neutrino localized in the brane leading to unconventional patterns of neutrino oscillations. A resonance phenomenon, strong mixing between the flavor and the sterile neutrino, allows to determine the radius of the large extra dimension. If our brane is curved, then the sterile neutrino can take a shortcut through the bulk, leading to an apparent superluminal neutrino speed. The amount of "superluminality" is directly connected to parameters determining the shape of the brane. On the experimental side, we suggest that a long baseline neutrino beam from CERN to NESTOR neutrino telescope will help to clarify these important issues.Comment: To appear in Mod. Phys. Lett. A 201

TeV Neutrinos in a dense medium

The dispersion relation of energetic (few TeV) neutrinos traversing a medium is studied. We use the real time formalism of thermal field theory and we include the effects from the propagator of the W gauge boson. We consider then the MSW oscillations for cosmic neutrinos traversing the Earth, adopting for the neutrino parameters values suggested by the LSND results. It is found that the $\nu_\mu$ flux, for neutrinos passing through the center of the Earth, will appear reduced by 15% for energies around 10 TeV.Comment: 12 pages, latex, 2 figure

Roadrunners and Eagles

Our previous research on perception of gated casual English by university students suggests that ceteris paribus, Polish students are much more accurate than Greeks. A recent pilot study of casually-spoken Polish leads us to the conclusion that many shortcuts found in English are also common in Polish, so that similar perceptual strategies can be used in both languages, though differing in detail. Based on these preliminary results, it seems likely that perceptual strategies across languages tend towards the “eagle” approach - where a birds-eye view of the acoustic terrain without too much emphasis on detail is found - or the “roadrunner” approach, where phonetic detail is followed closely. In the former case, perceivers adjust easily to alternation caused by casual speech phonology while in the latter, perceivers expect little variation and possibly even find it confusing. Native speakers of Greek are “roadrunners”, since there is little phonological reduction in their language there is little difference, for example, between stressed and unstressed syllables. We suggest that native speakers of Polish join English speakers as “eagles”, which gives them a natural perceptual advantage in English. There is a conceptual similarity between this idea and that of the stress- or syllable-timed language, and we hypothesise that as in this case, there is a cline rather than a sharp division between eagles and roadrunners. As usual, more research is called for

String Quantization in Curved Spacetimes: Null String Approach

We study quantum strings in strong gravitational fields. The relevant small parameter is $g=R_c{\sqrt T_0}$, where $R_c$ is the curvature of the spacetime and $T_0$ is the string tension. Within our systematic expansion we obtain to zeroth order the null string (string with zero tension), while the first order correction incorporates the string dynamics. We apply our formalism to quantum null strings in de Sitter spacetime. After a reparametrization of the world-sheet coordinates, the equations of motion are simplified. The quantum algebra generated by the constraints is considered, ordering the momentum operators to the right of the coordinate operators. No critical dimension appears. It is anticipated however that the conformal anomaly will appear when the first order corrections proportional to $T_0$, are introduced.Comment: 6 pages, plain Tex, no figure