Line-Graph Lattices: Euclidean and Non-Euclidean Flat Bands, and Implementations in Circuit Quantum Electrodynamics

Materials science and the study of the electronic properties of solids are a major field of interest in both physics and engineering. The starting point for all such calculations is single-electron, or non-interacting, band structure calculations, and in the limit of strong on-site confinement this can be reduced to graph-like tight-binding models. In this context, both mathematicians and physicists have developed largely independent methods for solving these models. In this paper we will combine and present results from both fields. In particular, we will discuss a class of lattices which can be realized as line graphs of other lattices, both in Euclidean and hyperbolic space. These lattices display highly unusual features including flat bands and localized eigenstates of compact support. We will use the methods of both fields to show how these properties arise and systems for classifying the phenomenology of these lattices, as well as criteria for maximizing the gaps. Furthermore, we will present a particular hardware implementation using superconducting coplanar waveguide resonators that can realize a wide variety of these lattices in both non-interacting and interacting form

From Eager PFL to Lazy Haskell

The state of a system is expressed using PFL, a process functional language, in an easily understandable manner. The paper presents PFL environment variable -- our basic concept for the state manipulation in the process functional language. Then we introduce the style in which stateful systems are described using monads and state transformers in pure lazy functional language Haskell. Finally, we describe our approach to lazy state manipulation in PFL and correspondence between state manipulation in PFL and the one in a pure lazy functional language Haskell. The proposed translation from eager PFL to a lazy Haskell provides an opportunity to exploit laziness for process functional programs and furthermore for imperative programs. The approach described in this paper was used in implemented PFL to Haskell code generator

Separating Concerns in Programming: Data, Control and Actions

A multi-paradigm language provides an opportunity to a user for exploiting more programming methodologies. It simplifies the language syntax, and extends the application areas by the extended semantics. That is why multi-paradigm languages can align a problem in wider application areas and more flexibly than that based on a single paradigm. In this paper, we present the idea of separating three essential concerns of programming currently being implemented in PFL -- a process functional language. We separate data, control, and actions by the definition of a purely control structure. Then, by the structured application of a structure of actions to a purely control structure, we will express the computation of activated actions in a structured way, considering explicitly defined synchronization in computation

Vertikálna migrácia taxónov vyšších rastlín v alpínskom pásme ako nový, akcelerujúci fenomén

Observed climate change, especially warming, is having significant impacts on the distribution of European flora and these impacts include uphill range shifts, as well as predict potential local and regional extinctions of species. This process can be also called as a vertical migration of species. The related research in subalpine and alpine belt of the European mountains brought several interesting results during the last 15 years, above all by the GLORIA initiative network and a project sUMMITDiv with repeated plant survey from 302 mountain summits across Europe and spanning 145 years of observation. A continent-wide acceleration in the rate of increase in plant species richness, with five times as much species enrichment between 2007 and 2016 as fifty years ago, between 1957 and 1966 has been confirmed (Steinbauer et al., 2018)

Broadband magnetic losses of nanocrystalline ribbons and powder cores

partially_open7sìFinemet type alloys have been investigated from DC to 1 GHz at different induction levels upon different treatments: as amorphous precursors, as ribbons nanocrystallized with and without an applied saturating field, as consolidated powders. The lowest energy losses at all frequencies and maximum Snoek's product are exhibited by the transversally field-annealed ribbons. This is understood in terms of rotation-dominated magnetization process in the low-anisotropy material. Intergrain eddy currents are responsible for the fast increase of the losses with frequency and for early permeability relaxation of the powder cores. Evidence for resonant phenomena at high frequencies and for the ensuing inadequate role of the static magnetic constitutive equation of the material in solving the magnetization dynamics via the Maxwell's diffusion equation of the electromagnetic field is provided. It is demonstrated that, by taking the Landau–Lifshitz–Gilbert equation as a constitutive relation, the excellent frequency response of the transverse anisotropy ribbons can be described by analytical method.partially_openBeatrice, Cinzia; Dobák, Samuel; Ferrara, Enzo; Fiorillo, Fausto; Ragusa, Carlo; Füzer, Ján; Kollár, PeterBeatrice, Cinzia; Dobák, Samuel; Ferrara, Enzo; Fiorillo, Fausto; Ragusa, Carlo; Füzer, Ján; Kollár, Pete

Impact of secondary succession in abandoned fields on some properties of acidic sandy soils

Abandonment of agricultural lands in recent decades is occurring mainly in Europe, North America and Oceania, and changing the fate of landscapes as the ecosystem recovers during fallow stage. The objective of this study was to find the impact of secondary succession in abandoned fields on some parameters of acidic sandy soils in the Borská nížina lowland (southwestern Slovakia). We investigated soil chemical (pH and soil organic carbon content), hydrophysical (water sorptivity, and hydraulic conductivity), and water repellency (water drop penetration time, water repellency cessation time, repellency index, and modified repellency index) parameters, as well as the ethanol sorptivity of the studied soils. Both the hydrophysical and chemical parameters decreased significantly during abandonment of the three investigated agricultural fields. On the other hand, the water repellency parameters increased significantly, but the ethanol sorptivity did not change during abandonment. As the ethanol sorptivity depends mainly on soil pore size, the last finding could mean that the pore size of acidic sandy soils did not change during succession

Influence of domain walls thickness, density and alignment on Barkhausen noise emission in low alloyed steels

This study deals with the characterization of low alloyed steels of diferent yield strengths (varying in the range of 235–1100 MPa) via Barkhausen noise emission. The study investigates the potential of this technique to distinguish among the low alloyed steels and all signifcant aspects contributing to Barkhausen noise, such as the residual stress state, microstructure expressed in terms of dislocation density, grain size, prevailing phase, as well as associated aspects of the domain wall substructure (domain wall thickness, energy, their spacing and density in the matrix). Barkhausen noise in the rolling as well as transversal direction grows along with the yield strength (up to 500 MPa) and the corresponding grain refnement of ferrite. As soon as the martensite transformation occurs in a high strength matrix, this evolution saturates, and remarkable magnetic anisotropy is developed when Barkhausen noise in the transversal direction grows at the expense of the rolling direction. The contribution of residual stresses as well as the domain wall thickness is only minor, and the evolution of Barkhausen noise is driven by the density of the domain walls and their realignment.Web of Science131art. no. 568

Impact of climate, soil properties and grassland cover on soil water repellency

Numerous soil water repellency (SWR) studies have investigated the possible causes of this temporal phenomenon, yet there remains a lack of knowledge on the order of importance of the main driving forces of SWR in the context of changing environmental conditions under grassland ecosystems. To study the separate and combined effects of soil texture, climate, and grassland cover type on inducing or altering SWR, four sites from different climatic and soil regions were selected: Ciavolo (CI, IT), Cs´olyosp´alos (CSP, HU), Pwllpeiran (PW, UK), Sekule (SE, SK). The investigated parameters were the extent (determined by repellency indices RI, RIc and RIm) and persistence (determined by water drop penetration time (WDPT) and water repellency cessation time, WRCT) of SWR, as well as field water (Sw) and ethanol (Se) sorptivity, water sorptivity of hydrophobic soil state (Swh) water sorptivity of nearly wettable soil state (Sww) and field hydraulic conductivity (K). Our findings showed an area of land has a greater likelihood of being water repellent if it has a sandy soil texture and/or a high frequency of prolonged drought events. Water infiltration was positively correlated with all the sorptivities (r = 0.32–0.88), but was mostly negatively correlated with RI (r = – 0.54 at CI), WDPT (r = – 0.47 at CI) and WRCT (r = – 0.58 at CI). The importance of natural and synanthropized vegetation covers with regards to SWR was not coherent; moving to regions having coarser texture or moving to drier climatic zones led to higher risk of SWR conditions. Climate change has been predicted to lead to more frequent extreme weather events and prolonged dry periods across Europe, which will most likely increase the extent of SWR-affected areas and increase the role of SWR in water management of grassland ecosystems. Therefore, there is a need to determine SWR risk zones to prevent decreases in soil moisture content, soil fertility, carbon and nitrogen sink potentials, as well as biomass production of the related agro-ecosystems