Les mariages clandestins: impasse disciplinaire, scandale ou moteur de la réflexion doctrinale?

The history of the formalization of marriage law in the Latin medieval West is very much like a series of normative tensions. Although the conflicts of norms cannot be restricted to theological and legal controversies, their interest lies in the fact that they sometimes gave rise to the expression of contradictory norms, depending on the forum at stake. It was more particularly the case when it came to the question of settling the moral and judiciary issues in connexion with the hierarchical status of clandestine marriages and that of public ones, or the one of a “sexual intercourse followed by words of future” and that of a marriage contracted by “words of present”. Which of these processes guaranteed a « true » marriage ?  And according to which normative references ? The different solutions provided by canonical doctrine, theology, the manuals for parish priests and confessors or even synodal statutes enable us to assess the different goals of the clerics concerned by matrimonial issues. Much is at stake, because what is concerned is the salvation of the laity and the balance of the whole society. These normative tensions sometimes led to conceptual and lexical evolutions, but they also entailed certain forms of competition that could undermine the usual means of social regulation, which the actors of matrimonial could sometimes take advantage of

Large amplitude dynamics of micro/nanomechanical resonators actuated with electrostatic pulses

International audienceIn the field of resonant NEMS design, it is a common misconception that large-amplitude motion, and thus large signal-to-noise ratio, can only be achieved at the risk of oscillator instability. In the present paper, we show that very simple closed-loop control schemes can be used to achieve stable largeamplitude motion of a resonant structure, even when jump resonance (caused by electrostatic softening or Duffing hardening) is present in its frequency response. We focus on the case of a resonant accelerometer sensing cell, consisting in a nonlinear clamped-clamped beam with electrostatic actuation and detection, maintained in an oscillation state with pulses of electrostatic force that are delivered whenever the detected signal (the position of the beam) crosses zero. We show that the proposed feedback scheme ensures the stability of the motion of the beam much beyond the critical Duffing amplitude and that, if the parameters of the beam are correctly chosen, one can achieve almost full-gap travel range without incurring electrostatic pull-in. These results are illustrated and validated with transient simulations of the nonlinear closed-loop system

Electron-Doped Manganese Perovskites: The Polaronic State

Using the Lanczos method in linear chains we study the ground state of the double exchange model including an antiferromagnetic super-exchange in the low concentration limit. We find that this ground state is always inhomogeneous, containig ferromagnetic polarons. The extention of the polaron spin distortion, the dispersion relation and their trapping by impurities, are studied for diferent values of the super exchange interaction and magnetic field. We also find repulsive polaron polaron interaction.Comment: 4 pages, 6 embedded figure

Effect of Electron Correlation on the Bragg Reflection

We study the effect of correlation on the Bragg reflection in the 3D electron gas, the 1D Luttinger liquid, and the 1D Hubbard model in an alternating periodic potential at half-filling. In the last system, we suggest a Luttinger-liquid-type quasi-metallic state in the crossover region from the band insulator to the Mott insulator. We explain the appearance of this state in terms of the incompatibility of the Bragg reflection with the concept of Luttinger liquids.Comment: 4 pages, 3 figure

Island phases and charge order in two-dimensional manganites

The ferromagnetic Kondo lattice model with an antiferromagnetic interaction between localized spins is a minimal description of the competing kinetic t and magnetic K energy terms which generate the rich physics of manganite systems. Motivated by the discovery in one dimension of homogeneous ``island phases'', we consider the possibility of analogous phases in higher dimensions. We characterize the phases present at commensurate fillings, and consider in detail the effects of phase separation in all filling and parameter regimes. We deduce that island and flux phases are stable for intermediate values of K/t at the commensurate fillings n = 1/4, 1/3, 3/8, and 1/2. We discuss the connection of these results to the charge and magnetic ordering observed in a wide variety of manganite compounds.Comment: 13 pages, 17 figure

Influence of Hybridization on the Properties of the Spinless Falicov-Kimball Model

Without a hybridization between the localized f- and the conduction (c-) electron states the spinless Falicov-Kimball model (FKM) is exactly solvable in the limit of high spatial dimension, as first shown by Brandt and Mielsch. Here I show that at least for sufficiently small c-f-interaction this exact inhomogeneous ground state is also obtained in Hartree-Fock approximation. With hybridization the model is no longer exactly solvable, but the approximation yields that the inhomogeneous charge-density wave (CDW) ground state remains stable also for finite hybridization V smaller than a critical hybridization V_c, above which no inhomogeneous CDW solution but only a homogeneous solution is obtained. The spinless FKM does not allow for a ''ferroelectric'' ground state with a spontaneous polarization, i.e. there is no nonvanishing $$-expectation value in the limit of vanishing hybridization.Comment: 7 pages, 6 figure