Laser cooling with a single laser beam and a planar diffractor

A planar triplet of diffraction gratings is used to transform a single laser beam into a four-beam tetrahedral magneto-optical trap. This `flat' pyramid diffractor geometry is ideal for future microfabrication. We demonstrate the technique by trapping and subsequently sub-Doppler cooling 87Rb atoms to 30microKelvin.Comment: 3 pages, 4 figure

Spatial interference from well-separated condensates

We use magnetic levitation and a variable-separation dual optical plug to obtain clear spatial interference between two condensates axially separated by up to 0.25 mm -- the largest separation observed with this kind of interferometer. Clear planar fringes are observed using standard (i.e. non-tomographic) resonant absorption imaging. The effect of a weak inverted parabola potential on fringe separation is observed and agrees well with theory.Comment: 4 pages, 5 figures - modified to take into account referees' improvement

Demonstration of an inductively coupled ring trap for cold atoms

We report the first demonstration of an inductively coupled magnetic ring trap for cold atoms. A uniform, ac magnetic field is used to induce current in a copper ring, which creates an opposing magnetic field that is time-averaged to produce a smooth cylindrically symmetric ring trap of radius 5 mm. We use a laser-cooled atomic sample to characterize the loading efficiency and adiabaticity of the magnetic potential, achieving a vacuum-limited lifetime in the trap. This technique is suitable for creating scalable toroidal waveguides for applications in matter-wave interferometry, offering long interaction times and large enclosed areas

NOSTROMO - D5.1 - ATM Performance Metamodels - Preliminary Release

This deliverable presents the results obtained with the meta-modelling process presented in D3.1 and D3.2 applied to the two micromodels (or simulators), Mercury and FLITAN, themselves implementing concepts from four SESAR solutions, PJ01.01, PJ07.02, PJ08-01, and PJ02.08. The objective of the meta-modelling process is explained briefly again in the introduction, in particular with respect to performance assessment. The rationale for the selection of the SESAR solutions implemented in the simulators are briefly explained too. The simulators are presented in two distinct chapters. First, a general presentation of each simulator is given, with past challenges and development, before explaining the development steps carried out to implement the concepts from the chosen solutions. Domain research questions that could be answered by these implementations are highlighted along the way. The meta-modelling process is then briefly explained again, followed by the results obtained with the two simulators, in distinct sections. The results highlight the performance of the meta-model with respect to approximating the output of the micromodels, but not the performance of the models themselves with respect to the research questions, which will be explored in WP7 instead. The deliverable closes with some considerations on the meta-modelling performance and next steps for this line of work

Detecting sterile neutrinos with KATRIN like experiments

A sterile neutrino with mass in the eV range, mixing with the electron antineutrino, is allowed and possibly even preferred by cosmology and oscillation experiments. If such eV-mass neutrinos exist they provide a much better target for direct detection in beta decay experiments than the active neutrinos which are expected to have sub-eV masses. Their relatively high mass would allow for an easy separation from the primary decay signal in experiments such as KATRIN.Comment: 23 pages, 7 figures. References & Figures updated. Text reviewed and revised. Accepted for publication JCA

Explainable Metamodels for ATM Performance Assessment

Fast-time simulation constitutes a well-known and long-established technique within the Air Traffic Management (ATM) community. However, it is often the case that simulation input and output spaces are underutilized, limiting the full understandability, transparency, and interpretability of the obtained results. In this paper, we propose a methodology that combines simulation metamodeling and SHapley Additive exPlanations (SHAP) values, aimed at uncovering the intricate hidden relationships among the input and output variables of a simulated ATM system in a rather practical way. Whereas metamodeling provides explicit functional approximations mimicking the behavior of the simulators, the SHAP-based analysis delivers a systematic framework for improving their explainability. We illustrate our approach using a state-of-the-art ATM simulator across two case studies in which two delay-centered performance metrics are analyzed. The results show that the proposed methodology can effectively make simulation and its results more explainable, facilitating the interpretation of the obtained emergent behavior, and additionally opening new opportunities towards novel performance assessment processes within the ATM research field