191 research outputs found

    La adveración sacramental del testamento en la Cataluña altomedieval

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    La adveración sacramental, incorrectamente denominada testamento sacramental, es una tipología documental de una forma testamentaria relacionada con testamentos orales y escritos, muy interesantes para conocer diferentes aspectos sobre la muerte. Testimoniada en el Liber Iudiciorum, fue incorporada al privilegio de Barcelona de 1283 y a las "Constitucions i altres drets de Catalunya". Pero sufrió una evolución, con diversos cambios sobre todo en el siglo XII, y a medida que el derecho visigodo fue desapareciendo sustituido por el derecho común se hizo cada vez más raraAdveración sacramental, incorrectly named testamento sacramental, is a documentary typology of a testamentary norm related to oral and written wills, and very interesting to know some different aspects about death. Attested it in the Liber Iudiciorum, it was incorporated into Barcelona's privilegy of 1283 and "Constitucions i altres drets de Catalunya". But this underwent an evolution with significant changes overcoat in the 12th century, and in proportion as Visigothic law was vanishing and Common law was prevailing, this one became rar

    Third harmonic generation from collective modes in disordered superconductors

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    Recent experiments with strong THz fields in both conventional and unconventional superconductors have clearly evidenced a marked third-harmonic generation below the superconducting temperature TcT_c. Its interpretation challenged substantial theoretical work aimed at establishing the relative efficiency of quasiparticle excitations and collective modes in triggering such a resonant response. Here we compute the non-linear current by implementing a time-dependent Bogoljubov de-Gennes approach, with the twofold aim to account non-perturbatively for the effect of local disorder, and to include the contribution of all collective modes, i.e. superconducting amplitude (Higgs) and phase fluctuations, and charge fluctuations. We show that, in agreement with previous work, already at small disorder the quasiparticle response is dominated by paramagnetic effects. We further demonstrate that paramagnetic processes mediate also the response of all collective modes, with a substantial contribution of charge/phase fluctuations. These processes, which have been overlooked so far, turn out to dominate the third-order current at strong disorder. In addition, we show that disorder strongly influences the polarization dependence of the non-linear response, with a marked difference between the clean and the disordered case. Our results are particularly relevant for recent experiments in cuprates, whose band structure is in a first approximation reproduced by our lattice model

    Observational and Numerical Simulation Study of a Sequence of Eight Atmospheric Density Currents in Northern Spain

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    A sequence of eight atmospheric density current fronts occurred in consecutive days are identified and analyzed using micrometeorological time series and numerical simulations. Observations were collected in the context of the INTERCLE project, which took place from September 2002 to November 2003 at the CIBA (Research Centre for the Lower Atmosphere) site located over the northern Spanish plateau. Numerical simulations used the Weather Research and Forecast (WRF) model with fine horizontal resolution (1 km). Both observations and simulations agree that the arrival of the density currents are characterized by a sharp change in temperature, wind velocity, wind direction and specific humidity and a source of intermittent turbulence. However, comparison between model and observations shows that the model predicts the intrusion of the density currents earlier than is observed. In addition, wavelet techniques applied to the data help distinguish the different scales present in the events, and therefore can reveal traces of gravity waves induced by the arrival of the density currents

    Terahertz electric-field driven dynamical multiferroicity in SrTiO3_3

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    The emergence of collective order in matter is among the most fundamental and intriguing phenomena in physics. In recent years, the ultrafast dynamical control and creation of novel ordered states of matter not accessible in thermodynamic equilibrium is receiving much attention. Among those, the theoretical concept of dynamical multiferroicity has been introduced to describe the emergence of magnetization by means of a time-dependent electric polarization in non-ferromagnetic materials. In simple terms, a large amplitude coherent rotating motion of the ions in a crystal induces a magnetic moment along the axis of rotation. However, the experimental verification of this effect is still lacking. Here, we provide evidence of room temperature magnetization in the archetypal paraelectric perovskite SrTiO3_3 due to this mechanism. To achieve it, we resonantly drive the infrared-active soft phonon mode with intense circularly polarized terahertz electric field, and detect a large magneto-optical Kerr effect. A simple model, which includes two coupled nonlinear oscillators whose forces and couplings are derived with ab-initio calculations using self-consistent phonon theory at a finite temperature, reproduces qualitatively our experimental observations on the temporal and frequency domains. A quantitatively correct magnitude of the effect is obtained when one also considers the phonon analogue of the reciprocal of the Einsten - de Haas effect, also called the Barnett effect, where the total angular momentum from the phonon order is transferred to the electronic one. Our findings show a new path for designing ultrafast magnetic switches by means of coherent control of lattice vibrations with light.Comment: Main text: 10 pages, 4 figures, methods and 8 supplemental figure
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