Spin-orbit induced chirality of Andreev states in Josephson junctions

We study Josephson junctions (JJs) in which the region between the two superconductors is a multichannel system with Rashba spin-orbit coupling (SOC) where a barrier or a quantum point contact (QPC) is present. These systems might present unconventional Josephson effects such as Josephson currents for zero phase difference or critical currents that \textit{depend on} the current direction. Here, we discuss how the spin polarizing properties of the system in the normal state affect the spin characteristic of the Andreev bound states inside the junction. This results in a strong correlation between the spin of the Andreev states and the direction in which they transport Cooper pairs. While the current-phase relation for the JJ at zero magnetic field is qualitatively unchanged by SOC, in the presence of a weak magnetic field a strongly anisotropic behavior and the mentioned anomalous Josephson effects follow. We show that the situation is not restricted to barriers based on constrictions such as QPCs and should generically arise if in the normal system the direction of the carrier's spin is linked to its direction of motion.Comment: 19 pages, 9 figures. To appear in PR

Magnetic Moment Formation in Quantum Point Contacts

We study the formation of local magnetic moments in quantum point contacts. Using a Hubbard-like model to describe point contacts formed in a two dimensional system, we calculate the magnetic moment using the unrestricted Hartree approximation. We analyze different type of potentials to define the point contact, for a simple square potential we calculate a phase diagram in the parameter space (Coulomb repulsion - gate voltage). We also present an analytical calculation of the susceptibility to give explicit conditions for the occurrence of a local moment, we present a simple scaling argument to analyze how the stability of the magnetic moment depends on the point contact dimensions.Comment: 7 pages, 2 figure

Les couples clandestins devant la justice d'Eglise : réflexions sur la normalisation matrimoniale judiciaire dans la France du Nord-Ouest à la fin du Moyen Age

The purpose of this paper is to study how, why and to what ends men and women in Western France are summoned to appear by ecclesiastical judges in the Later Middle Ages for secret, irregular or so-called “clandestine” marriage. Some couples were brought before the court for a clandestine marriage, because of a lack of witnesses, banns, or certificates, or a lack of ceremony in facie ecclesie. They were sentenced to pay a pecuniary fine and, if consents had been proved, to solemnize their marriage afterwards. Some other people instituted proceedings in order to be recognized as the legal husband or wife of someone who wanted to marry someone else, or because they feared his or her partner might desert or their children might be considered as illegitimate. The lack of ceremony in many clandestine marriages could weaken matrimonial bounds. When the man and the woman did not question the reality of a marriage which was irregularly celebrated from the legal viewpoint, standing trial and being penalized could be a possible way to perfect afterwards matrimonial bounds which could have to be quickly contracted. The study of clandestine marriage involves considering many attitudes to the matrimonial norms (canonical, social) and their uses by the laity. Because of the variety of forms of this matrimonial infraction, one has to consider the variety of uses of justice by the laity: ecclesiastical judges condemned or putted in order; couples submitted or tried in a way to take advantages of legal proceedings

Anomalous Josephson Current in Junctions with Spin-Polarizing Quantum Point Contacts

We consider a ballistic Josephson junction with a quantum point contact in a two-dimensional electron gas with Rashba spin-orbit coupling. The point contact acts as a spin filter when embedded in a circuit with normal electrodes. We show that with an in-plane external magnetic field an anomalous supercurrent appears even for zero phase difference between the superconducting electrodes. In addition, the external field induces large critical current asymmetries between the two flow directions, leading to supercurrent rectifying effects.Comment: 4 pages, 4 figures, to appear in PR

Spin order in the one-dimensional Kondo and Hund lattices

We study numerically the one-dimensional Kondo and Hund lattices consisting of localized spins interacting antiferro or ferromagnetically with the itinerant electrons, respectively. Using the Density Matrix Renormalization Group we find, for both models and in the small coupling regime, the existence of new magnetic phases where the local spins order forming ferromagnetic islands coupled antiferromagnetically. Furthermore, by increasing the interaction parameter $|J|$ we find that this order evolves toward the ferromagnetic regime through a spiral-like phase with longer characteristic wave lengths. These results shed new light on the zero temperature magnetic phase diagram for these models.Comment: PRL, to appea

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

Medication errors at hospital admission and discharge in Type 1 and 2 diabetes

International audienceAIMS: To assess the prevalence and characteristics of medication errors at hospital admission and discharge in people with Type 1 and Type 2 diabetes, and identify potential risk factors for these errors. METHODS: This prospective observational study included all people with Type 1 (n~=~163) and Type 2 diabetes (n~=~508) admitted to the Diabetology-Department of the University Hospital of Montpellier, France, between 2013 and 2015. Pharmacists conducted medication reconciliation within 24~h of admission and at hospital discharge. Medication history collected from different sources (patient/family interviews, prescriptions/medical records, contact with community pharmacies/general practitioners/nurses) was compared with admission and discharge prescriptions to detect unintentional discrepancies in medication indicating involuntary medication changes. Medication errors were defined as unintentional medication discrepancies corrected by physicians. Risk factors for medication errors and serious errors (i.e. errors that may cause harm) were assessed using logistic regression. RESULTS: A total of 322 medication errors were identified and were mainly omissions. Prevalence of medication errors in Type 1 and Type 2 diabetes was 21.5% and 22.2% respectively at admission, and 9.0% and 12.2% at discharge. After adjusting for age and number of treatments, people with Type 1 diabetes had nearly a twofold higher odds of having medication errors (odds ratio (OR) 1.72, 95% confidence interval (CI) 1.02-2.94) and serious errors (OR 2.17, 95% CI 1.02-4.76) at admission compared with those with Type 2 diabetes. CONCLUSIONS: Medication reconciliation identified medication errors in one third of individuals. Clinical pharmacists should focus on poly-medicated individuals, but also on other high-risk people, for example, those with Type 1 diabetes

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

Phase diagram and optical conductivity of the one-dimensional spinless Holstein model

The effects of quantum lattice fluctuations on the Peierls transition and the optical conductivity in the one-dimensional Holstein model of spinless fermions have been studied by developing an analytical approach, based on the unitary transformation method. We show that when the electron-phonon coupling constant decreases to a finite critical value the Peierls dimerization is destroyed by the quantum lattice fluctuations. The dimerization gap is much more reduced by the quantum lattice fluctuations than the phonon order parameter. The calculated optical conductivity does not have the inverse-square-root singularity but have a peak above the gap edge and there exists a significant tail below the peak. The peak of optical-conductivity spectrum is not directly corresponding to the dimerized gap. Our results of the phase diagram and the spectral-weight function agree with those of the density matrix renormalization group and the exact diagonalization methods.Comment: 9 pages, 4 figures include