Ultraviolet modified photons and anisotropies in the cosmic microwave background radiation

We discuss a minimal canonical modification of electrodynamics in order to account for ultraviolet Lorentz violating effects. This modification creates a birefringence that rotates the polarization planes from different directions. Such effects might be detectable in the anisotropic polarization of the Cosmic Microwave Background radiation.Comment: RevTeX, 4p

Exotic galilean symmetry and the Hall effect

The ``Laughlin'' picture of the Fractional Quantum Hall effect can be derived using the ``exotic'' model based on the two-fold centrally-extended planar Galilei group. When coupled to a planar magnetic field of critical strength determined by the extension parameters, the system becomes singular, and ``Faddeev-Jackiw'' reduction yields the ``Chern-Simons'' mechanics of Dunne, Jackiw, and Trugenberger. The reduced system moves according to the Hall law.Comment: Talk given by P. A. Horvathy at the Joint APCTP- Nankai Symposium. Tianjin (China), Oct.2001. To appear in the Proceedings, to be published by Int. Journ. Mod. Phys. B. 7 pages, LaTex, IJMPB format. no figure

Null Branes in String Theory Backgrounds

We consider null bosonic p-branes moving in curved space-times and develop a method for solving their equations of motion and constraints, which is suitable for string theory backgrounds. As an application, we give an exact solution for such background in ten dimensions.Comment: 11 pages, LaTeX. Final version, to appear in Phys. Rev.

The Mass Spectrum of the 2-dimensional Conformal String

We present the mass spectrum of the tensionless string in 2 dimensions where it has been found that the space time conformal symmetry survives quantization. A BRST treatment of the physical states reveals that the string collapses into a massless particle, a result which agrees with the classical treatment.Comment: 18 pages, latex, no figure

Gauge Field Theory in the Infrared Regime

We propose that the low energy behavior of a pure gauge theory can be studied by simply assuming violation of Lorentz invariance which is implemented through a deformation of the canonical Poisson brackets of the theory depending on an infrared scale. The resulting theory is equivalent to a pure gauge theory with a Chern-Simons like term. It is shown that at low energies this theory can be identified with three dimensional QCD where the mass of the fermion is related to the infrared scale.Comment: 4pp, ReVte

Sede social de Hazen. Madrid – España

For the greatly renowned firm in the field of musical Instruments, Hazen, a building has been constructed in the outskirts of Madrid to house a permanent exhibition of pianos as well as the head offices of the firm. It comprises basement and two storeys and on the ground floor there is a big exhibition hall with adjoining rooms for assembling the pianos. The packed Instruments are stored in the basement which further contains a garage, two small offices and the living quarters of the porter. The management section and the main offices are situated on the second floor. Externally, there is a sharp contrast between the light weight of the enclosure of the ground floor, made of metal frames and glass, and that of the top floor which is a solid volume, which hides the roof and has Windows only on the sides. The construction is surrounded by big gardens.Para la firma Hazen, de gran prestigio en el campo de los instrumentos musicales, se ha construido un edificio en las afueras de Madrid destinado a albergar una exposición permanente de pianos y sus oficinas centrales. Consta de un sótano y dos plantas sobre el terreno, situándose en la planta noble la gran sala de exposición, con un local anexo para el montaje de los pianos. En el sótano se almacenan los instrumentos embalados; completan este nivel un garaje, dos pequeñas oficinas y una vivienda para el conserje. La zona principal de oficinas y los despachos de dirección se distribuyen en la planta superior. Exteriormente, contrasta de manera clara la ligereza del cerramiento de la planta baja, a base de carpintería metálica con acristalamiento total, y la planta superior, constituida por un volumen macizo que oculta la cubierta y que solamente tiene huecos en sus fachadas laterales. Rodeando la construcción hay una amplia zona verde cuidadosamente ajardinada

Aharonov-Casher effect for spin one particles in a noncommutative space

In this work the Aharonov-Casher (AC) phase is calculated for spin one particles in a noncommutative space. The AC phase has previously been calculated from the Dirac equation in a noncommutative space using a gauge-like technique [17]. In the spin-one, we use kemmer equation to calculate the phase in a similar manner. It is shown that the holonomy receives non-trivial kinematical corrections. By comparing the new result with the already known spin 1/2 case, one may conjecture a generalized formula for the corrections to holonomy for higher spins.Comment: 9 page