990 research outputs found
Self-dual Ginzburg-Landau vortices in a disk
We study the properties of the Ginzburg-Laundau model in the self-dual point
for a two-dimensional finite system . By a numerical calculation we analyze the
solutions of the Euler-Lagrange equations for a cylindrically symmetric ansatz.
We also study the self-dual equations for this case. We find that the minimal
energy configurations are not given by the Bogomol'nyi equations but by
solutions to the Euler Lagrange ones. With a simple approximation scheme we
reproduce the result of the numerical calculation.Comment: 8 pages, 4 figures, RevTex macro
Non BPS noncommutative vortices
We construct exact vortex solutions to the equations of motion of the Abelian
Higgs model defined in non commutative space, analyzing in detail the
properties of these solutions beyond the BPS point. We show that our solutions
behave as smooth deformations of vortices in ordinary space time except for
parity symmetry breaking effects induced by the non commutative parameter
.Comment: 17 pages, 5 figure
Evolución de la innovación educativa en la Universidad Complutense: proyecto UNICOMEX
La evolución de la educación universitaria en España ha experimentado una enorme evolución en los últimos veinte años. Desde la enseñanza centrada en la clase magistral, con el consiguiente protagonismo del profesor, a lo que sucede actualmente, con el estudiante como eje principal, media todo un cambio en el planteamiento de nuestro sistema educativo universitario. La implantación del Espacio Europeo de Educación Superior (EEES) ha sido uno de los objetivos perseguidos por la Universidad Complutense de Madrid (UCM) en la última década. Con este fin existieron, hasta hace poco, las conocidas como Asignaturas Piloto (AP) e igualmente se convocan periódicamente, desde hace años, los Proyectos de Innovación Educativa (P.I.E.). Ambas herramientas han procurado facilitar dicha adaptación, así como promover un concepto transversal en la transmisión del conocimiento. Nuestro grupo de trabajo puede ser un ejemplo de lo que la UCM ha querido conseguir con ambas cosas. La asignatura ha participado en todas las convocatorias de AP, pasando por una evolución clara desde la clase magistral a los pequeños grupos de trabajo. Ha sido, además, el instrumento útil para ir desarrollando distintos P.I.E., hasta un total de nueve, tras formar un equipo interdisciplinar constituido por profesores universitarios y profesionales de diversos ámbitos. El último de estos PIE, concedido en el curso académico 2011-2012, consiste en la creación de un espacio virtual de referencia para el estudio de los animales exóticos, partiendo de los resultados obtenidos en proyectos anteriores. UNICOMEX (Universidad-Complutense-Exóticos) nace con el objetivo de poner al alcance de cualquiera una serie de recursos virtuales ordenados que faciliten el conocimiento biológico, anatómico y clínico de los animales exóticos, entendiendo como tales aquellos que, siendo de interés veterinario, no se consideran domésticos. La totalidad de su contenido está en español e inglés, con el fin de hacer de ella una herramienta virtual útil y abierta a la comunidad científica y didáctica internacional
The QUIJOTE experiment: project overview and first results
QUIJOTE (Q-U-I JOint TEnerife) is a new polarimeter aimed to characterize the
polarization of the Cosmic Microwave Background and other Galactic and
extragalactic signals at medium and large angular scales in the frequency range
10-40 GHz. The multi-frequency (10-20~GHz) instrument, mounted on the first
QUIJOTE telescope, saw first light on November 2012 from the Teide Observatory
(2400~m a.s.l). During 2014 the second telescope has been installed at this
observatory. A second instrument at 30~GHz will be ready for commissioning at
this telescope during summer 2015, and a third additional instrument at 40~GHz
is now being developed. These instruments will have nominal sensitivities to
detect the B-mode polarization due to the primordial gravitational-wave
component if the tensor-to-scalar ratio is larger than r=0.05.Comment: To appear in "Highlights of Spanish Astrophysics VIII", Proceedings
of the XI Scientific Meeting of the Spanish Astronomical Society, Teruel,
Spain (2014
QUIJOTE Experiment: status of telescopes and instrumentation
The QUIJOTE Experiment (Q-U-I JOint TEnerife) is a combined operation of two telescopes and three instruments working in the microwave band to measure the polarization of the Cosmic Microwave Background (CMB) from the northern hemisphere, at medium and large angular scales. The experiment is located at the Teide Observatory in Tenerife, one of the seven Canary Islands (Spain). The project is a consortium maintained by several institutions: the Instituto de Astrofísica de Canarias (IAC), the Instituto de Física de Cantabria (IFCA), the Communications Engineering Department (DICOM) at Universidad de Cantabria, and the Universities of Manchester and Cambridge. The consortium is led by the IAC
QUIJOTE-CMB experiment: a technical overview
The QUIJOTE-CMB experiment (Q-U-I JOint TEnerife CMB experiment) is an ambitious project to obtain polarization measurements of the sky microwave emission in the 10 to 47 GHz range. With this aim, a pair of 2,5m telescopes and three instruments are being sited at the Teide Observatory, in Tenerife (Canary Islands, Spain). The first telescope and the first instrument (the MFI: Multi Frequency Instrument) are both already operating in the band from 10 to 20 GHz, since November 2012. The second telescope and the second instrument (TGI: Thirty GHz instrument) is planned to be in commissioning by the end of summer 2014, covering the range of 26 to 36 GHz. After that, a third instrument named FGI (Forty GHz instrument) will be designed and manufactured to complete the sky survey in the frequency range from 37 to 47 GHz. In this paper we present an overview of the whole project current status, from the technical point of view
The QUIJOTE TGI
The QUIJOTE TGI instrument is currently being assembled and tested at the IAC in Spain. The TGI is a 31 pixel 26-36 GHz polarimeter array designed to be mounted at the focus of the second QUIJOTE telescope. This follows a first telescope and multi-frequency instrument that have now been observing almost 2 years. The polarimeter design is based on the QUIET polarimeter scheme but with the addition of an extra 90º phase switch which allows for quasiinstantaneous complete QUI measurements through each detector. The advantage of this is a reduction in the systematics associated with differencing two independent radiometer channels. The polarimeters are split into a cold front end and a warm back end. The back end is a highly integrated design by engineers at DICOM. It is also sufficiently modular for testing purposes. In this presentation the high quality wide band components used in the optical design (also designed in DICOM) are presented as well as the novel cryogenic modular design. Each polarimeter chain is accessible individually and can be removed from the cryostat and replaced without having to move the remaining pixels. The optical components work over the complete Ka band showing excellent performance. Results from the sub unit measurements are presented and also a description of the novel calibration technique that allows for bandpass measurement and polar alignment. Terrestrial Calibration for this instrument is very important and will be carried out at three points in the commissioning phase: in the laboratory, at the telescope site and finally a reduce set of calibrations will be carried out on the telescope before measurements of extraterrestrial sources begin. The telescope pointing model is known to be more precise than the expected calibration precision so no further significant error will be added through the telescope optics. The integrated back-end components are presented showing the overall arrangement for mounting on the cryostat. Many of the microwave circuits are in-house designs with performances that go beyond commercially available products. Individual component performance is be presented showing for each of the sub modules
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