Hexagon-singlet solid ansatz for the spin-1 kagome antiferromagnet

We perform a systematic investigation on the hexagon-singlet solid (HSS) states, which are a class of spin liquid candidates for the spin-1 kagome antiferromagnet. With the Schwinger boson representation, we show that all HSS states have exponentially decaying correlations and can be interpreted as a (special) subset of the resonating Affleck-Kennedy-Lieb-Tasaki (AKLT) loop states. We provide a compact tensor network representation of the HSS states, with which we are able to calculate physical observables efficiently. We find that the HSS states have vanishing topological entanglement entropy, suggesting the absence of intrinsic topological order. We also employ the HSS states to perform a variational study of the spin-1 kagome Heisenberg antiferromagnetic model. When we use a restricted HSS ansatz preserving lattice symmetry, the best variational energy per site is found to be $e_0 = -1.3600$. In contrast, when allowing lattice symmetry breaking, we find a trimerized simplex valence bond crystal with a lower energy, $e_0=-1.3871$.Comment: 14 pages, 12 figures, published versio

Pitching for PIDs: European support for a sustainable PID infrastructure - Avoiding a PIDfall

The TechLib libraries (DTU Copenhagen, ETH Zurich, TIB Hannover and TU Delft) would like to start a community discussion around European support for sustainable PID infrastructures. Please take the time to read our pitch. We would very much appreciate your thoughts and ideas

An open-source, stochastic, six-degrees-of-freedom rocket flight simulator, with a probabilistic trajectory analysis approach

Predicting the flight-path of an unguided rocket can help overcome unnecessary risks. Avoiding residential areas or a car-park can improve the safety of launching a rocket significantly. Furthermore, an accurate landing site prediction facilitates recovery. This paper introduces a six-degrees-of-freedom flight simulator for large unguided model rockets that can fly to altitudes of up to 13 km and then return to earth by parachute. The open-source software package assists the user with the design of rockets, and its simulation core models both the rocket flight and the parachute descent in stochastic wind conditions. Furthermore, the uncertainty in the input variables propagates through the model via a Monte Carlo wrapper, simulating a range of possible flight conditions. The resulting trajectories are captured as a Gaussian process, which assists in the statistical assessment of the flight conditions in the face of uncertainties, such as changes in wind conditions, failure to deploy the parachute, and variations in thrust. This approach also facilitates concise presentation of such uncertainties via visualisation of trajectory ensembles

Data supporting the paper: 1D stability

These video files show the evolution of the components of the one-dimensional morphoelastic model for contraction in burn injuries. In the corresponding paper, we analyse the stability of the model and we validate these stability constraints numerically. This supplementary material is a collection of videos that correspond to Figure 1, Figure 2 and Figure 4 in the paper. In the captions of these figures, we referred to these videos.</div

Video’s supporting the paper: 1D morpho stability

These video files show the evolution of the components of the one-dimensional morphoelastic model for contraction in burn injuries. In the corresponding paper, we analyse the stability of the model and we validate these stability constraints numerically. This supplementary material is a collection of videos that correspond to Figure 1, Figure 2 and Figure 4 in the paper. In the captions of these figures, we referred to these videos.</div

AHN analyse celtic field Doorwerth

A detailed elevation model of the Netherlands has been acquired with the use of Airborne Laser Altimetry and is managed by AHN (Actueel Hoogtebestand Nederland). This elevation model can be used for a large amount of applications. Using a suited illumination technique it turned out to be possible to find and visualize so-called Celtic fields, agricultural fields systems of about 2500 years old in the AHN data. Here we will show that the visualization of Celtic fields out of AHN data can be enhanced by applying a geostatistical filter technique that removes the raw topography from the data set such that only the micro-topography, including the Celtic fields, remains. Visualization of this micro-topography not only enhances the images of the already known Celtic fields but also shows that the spatial extend of the field system is larger than expected