Ultracold bosons in disordered superlattices: Mott-insulators induced by tunneling

We analyse the phase diagram of ultra-cold bosons in a one-dimensional superlattice potential with disorder using the time evolving block decimation algorithm for infinite sized systems (iTEBD). For degenerate potential energies within the unit cell of the superlattice loophole-shaped insulating phases with non-integer filling emerge with a particle-hole gap proportional to the boson hopping. Adding a small amount of disorder destroys this gap. For not too large disorder the loophole Mott regions detach from the axis of vanishing hopping giving rise to insulating islands. Thus the system shows a transition from a compressible Bose-glass to a Mott-insulating phase with increasing hopping amplitude. We present a straight forward effective model for the dynamics within a unit cell which provides a simple explanation for the emergence of Mott-insulating islands. In particular it gives rather accurate predictions for the inner critical point of the Bose-glass to Mott-insulator transition

Discretized vs. continuous models of p-wave interacting fermions in 1D

We present a general mapping between continuous and lattice models of Bose- and Fermi-gases in one dimension, interacting via local two-body interactions. For s-wave interacting bosons we arrive at the Bose-Hubbard model in the weakly interacting, low density regime. The dual problem of p-wave interacting fermions is mapped to the spin-1/2 XXZ model close to the critical point in the highly polarized regime. The mappings are shown to be optimal in the sense that they produce the least error possible for a given discretization length. As an application we examine the ground state of a interacting Fermi gas in a harmonic trap, calculating numerically real-space and momentum-space distributions as well as two-particle correlations. In the analytically known limits the convergence of the results of the lattice model to the continuous one is shown.Comment: 7 pages, 5 figure

"Wenn ich alle Pillen genommen habe, bin ich satt" : Multimorbidität und Multimedikation: Herausforderungen in einer alternden Gesellschaft

Mit den Krankheiten häuft sich im Alter auch die Zahl der einzunehmenden Medikamente. Das bringt viele Probleme mit sich. Das Institut für Allgemeinmedizin der Goethe-Universität untersucht in enger Kooperation mit der Universität Maastricht die Folgen der Multimedikation und entwickelt gemeinsam mit Hausärzten Strategien, um unerwünschte Wirkungen zu vermeiden

A Conceptual Evaluation of Sustainable Variable-Rate Agricultural Residue Removal

Agricultural residues have near-term potential as a feedstock for bioenergy production, but their removal must be managed carefully to maintain soil health and productivity. Recent studies have shown that subfield scale variability in soil properties (e.g., slope, texture, and organic matter content) that affect grain yield significantly affect the amount of residue that can be sustainably removed from different areas within a single field. This modeling study examines the concept of variable-rate residue removal equipment that would be capable of on-the-fly residue removal rate adjustments ranging from 0 to 80%. Thirteen residue removal rates (0% and 25–80% in 5% increments) were simulated using a subfield scale integrated modeling framework that evaluates residue removal sustainability considering wind erosion, water erosion, and soil carbon constraints. Three Iowa fields with diverse soil, slope, and grain yield characteristics were examined and showed sustainable, variable-rate agricultural residue removal that averaged 2.35, 7.69, and 5.62 Mg ha−1, respectively. In contrast, the projected sustainable removal rates using rake and bale removal for the entire field averaged 0.0, 6.40, and 5.06 Mg ha−1, respectively. The modeling procedure also projected that variable-rate residue harvest would result in 100% of the land area in all three fields being managed in a sustainable manner, whereas Field 1 could not be sustainably managed using rake and bale removal, and only 83 and 62% of the land area in Fields 2 and 3 would be managed sustainably using a rake and bale operation for the entire field. In addition, it was found that residue removal adjustments of 40 to 65% are sufficient to collect 90% of the sustainably available agricultural residue

Datasets from a vapor diffusion mineral precipitation protocol for Dictyostelium stalks

Datasets from a slow carbonate vapor diffusion and mineral precipitation protocol for Dictyostelium ECM and cellulose stalks show examples for composite materials obtained by an in vitro approach, which differs substantially from the in vivo approach reported in The Journal of Structural Biology, doi: 10.1016/j.jsb.2016.03.015 [1]. Methods for obtaining the datasets include bright field transmitted light microscopy, fluorescence microscopy, LC-PolScope birefringence microscopy, variable pressure scanning electron microscopy (VP-SEM/ESEM), and Raman imaging spectroscopy

An Integrated Modeling and Data Management Strategy for Cellulosic Biomass Production Decisions

Emerging cellulosic bioenergy markets can provide land managers with additional options for crop production decisions. For example, integrating dedicated bioenergy crops such as perennial grasses and short rotation woody species within the agricultural landscape can have positive impacts on several environmental processes including increased soil organic matter in degraded soils, reduced sediment and nutrient loading in watersheds, and lower green house gas fluxes. Implementing this type of diverse bioenergy production system to maximize the potential environmental benefits requires a detailed understanding of the many interwoven aspects of environmental landscapes. This paper presents a dynamic framework-based integrated modeling and data management strategy that can design sustainable bioenergy cropping systems within the existing row crop production landscape of the Midwestern U.S. Critical environmental processes— including soil erosion from wind and water, and soil organic matter changes—are quantified by this integrated model to determine sustainable removal rates of agricultural residues for bioenergy production at the sub-field scale. Seven land management options for a 59 ha Iowa field are examined using the integrated model. These include a baseline case of sustainable residue removal and various incorporations of rye cover cropping and switchgrass use in marginal land. Relative to the baseline metrics, the adoption of rye cover crops with sustainable residue removal increases the total biomass sustainably available for biofuel production by 289% and reduces soil loss by 42%. Combining rye cover crops while displacing less productive and at-risk areas of the field with switchgrass increases the sustainable biomass available by 436% and decreases soil loss by 64%