¿Uno 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

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

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