École normale supérieure de Cachan

About: École normale supérieure de Cachan is a education organization based out in Cachan, Île-de-France, France. It is known for research contribution in the topics: Decidability & Nonlinear system. The organization has 2717 authors who have published 5585 publications receiving 175925 citations.

Near-field optical microscopy with a nanodiamond-based single-photon tip

Abstract: We introduce a point-like scanning single-photon source that operates at room temperature and offers an exceptional photostability (no blinking, no bleaching). This is obtained by grafting in a controlled way a diamond nanocrystal (size around 20 nm) with single nitrogen-vacancy color-center occupancy at the apex of an optical probe. As an application, we image metallic nanostructures in the near-field, thereby achieving a near-field scanning single-photon microscopy working at room temperature on the long term. Our work may be of importance to various emerging fields of nanoscience where an accurate positioning of a quantum emitter is required such as for example quantum plasmonics.

Splitting methods with complex times for parabolic equations

Abstract: Using composition procedures, we build up high order splitting methods to solve evolution equations posed in finite or infinite dimensional spaces. Since high-order splitting methods with real time are known to involve large and/or negative time steps, which destabilizes the overall procedure, the key point of our analysis is, we develop splitting methods that use complex time steps having positive real part: going to the complex plane allows to considerably increase the accuracy, while keeping small time steps; on the other hand, restricting our attention to time steps with positive real part makes our methods more stable, and in particular well adapted in the case when the considered evolution equation involves unbounded operators in infinite dimensional spaces, like parabolic (diffusion) equations.

Multimode Storage and Retrieval of Microwave Fields in a Spin Ensemble

Abstract: Quantum computing promises to tackle computational problems that are intractable with classical computers. Researchers demonstrate that spin ensembles can store quantum information over longer times than previously achieved, a significant step toward a quantum memory.

Delayed-Damage Modelling for Fracture Prediction of Laminated Composites under Dynamic Loading

Abstract: The basic aspects of a damage meso-model with delay effects for laminated composites are presented. The applications concern fracture prediction under severe and multiaxial dynamic loading. In order to illustrate the possibilities and the mechanical significance of the proposed model for the prediction of rupture, especially the role of the delay effect, various simulations of one-dimensional wave propagation are performed. Then, a more complex finite element calculation is presented in order to show the ability of the model to predict the response of a composite structure until complete fracture.