232 research outputs found
ÂżUno o dos Frunimianos en Vita Emiliani y cartas de Braulio de Zaragoza?
[EN] We try to prove, with arguments taken from the texts, that the person named "Fruinianus", to whom Braulio de Saragossa addresses his letters XIII and XIV in his epistolary, is the same Frunimianus as the one from the introductory letter to 'Vita Emiliani', that is, Braulio's brother
RAMON PALERM, V. Plutarco y Nepote. Fuentes e interpretación del modelo biográfico plutarqueo
Ressenyes
Index de les obres ressenyades: V. RAMON PALERM, Plutarco y Nepote. Fuentes e interpretación del modelo biográfico plutarque
Spontaneous symmetry breaking as a resource for noncritically squeezed light
In the last years we have proposed the use of the mechanism of spontaneous
symmetry breaking with the purpose of generating perfect quadrature squeezing.
Here we review previous work dealing with spatial (translational and
rotational) symmetries, both on optical parametric oscillators and four-wave
mixing cavities, as well as present new results. We then extend the phenomenon
to the polarization state of the signal field, hence introducing spontaneous
polarization symmetry breaking. Finally we propose a Jaynes-Cummings model in
which the phenomenon can be investigated at the single-photon-pair level in a
non-dissipative case, with the purpose of understanding it from a most
fundamental point of view.Comment: Review for the proceedings of SPIE Photonics Europe. 11 pages, 5
figures
Whiskers of Al2O3 as reinforcement of a powder metallurgical 6061 aluminium matrix composite
An Al–Mg–Si alloy matrixcomposite reinforced with 10 vol.% of alumina whiskers (Al2O3w) has been processed by powder metallurgy and investigated. The Al2O3w were produced as single crystal c-axis alpha-alumina fibres at pre-pilot scale via vapour–liquid–solid (VLS) deposition in a cold-wall air-tight furnace with alumina linings. As far as we know, this is the first report of the utilization of whiskers of Al2O3 as reinforcing elements for Al alloys. Tensile tests have been performed on the composite at room and high temperatures. Results show that the AA6061 alloy reinforced with the as-produced Al2O3whiskers has remarkably high mechanical properties at room temperature. This is attributed to the high quality of the Al2O3 single crystals and to the strong bonding attained between them and the 6061 alloy matrixFinancial support of Spanish MEC, project MAT2006-01251, and regional government, Xunta de Galicia, PGIDT05TMT23902CTPeer reviewe
Squeezing spectra from s-ordered quasiprobability distributions. Application to dispersive optical bistability
It is well known that the squeezing spectrum of the field exiting a nonlinear
cavity can be directly obtained from the fluctuation spectrum of normally
ordered products of creation and annihilation operators of the cavity mode. In
this article we show that the output field squeezing spectrum can be derived
also by combining the fluctuation spectra of any pair of s-ordered products of
creation and annihilation operators. The interesting result is that the
spectrum obtained in this way from the linearized Langevin equations is exact,
and this occurs in spite of the fact that no s-ordered quasiprobability
distribution verifies a true Fokker-Planck equation, i.e., the Langevin
equations used for deriving the squeezing spectrum are not exact. The
(linearized) intracavity squeezing obtained from any s-ordered distribution is
also exact. These results are exemplified in the problem of dispersive optical
bistability.Comment: 15 pages, no figures, to be published in Journal of Modern Optic
MĂ©todo visual de lectura de imagen aplicada a la reflexiĂłn sobre la identidad docente en la formaciĂłn inicial del profesorado
Videojuegos y aprendizaje colaborativo como herramienta de cambio social y educativo: formando a futuros maestros para su uso y creaciĂłn
Noncritical quadrature squeezing through spontaneous polarization symmetry breaking
We discuss the possibility of generating noncritical quadrature squeezing by
spontaneous polarization symmetry breaking. We consider first type-II
frequency-degenerate optical parametric oscillators, but discard them for a
number of reasons. Then we propose a four-wave mixing cavity in which the
polarization of the output mode is always linear but has an arbitrary
orientation. We show that in such a cavity complete noise suppression in a
quadrature of the output field occurs, irrespective of the parameter values
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