Creating better superconductors by periodic nanopatterning

The quest to create superconductors with higher transition temperatures is as old as superconductivity itself. One strategy, popular after the realization that (conventional) superconductivity is mediated by phonons, is to chemically combine different elements within the crystalline unit cell to maximize the electron-phonon coupling. This led to the discovery of NbTi and Nb3Sn, to name just the most technologically relevant examples. Here, we propose a radically different approach to transform a `pristine' material into a better (meta-) superconductor by making use of modern fabrication techniques: designing and engineering the electronic properties of thin films via periodic patterning on the nanoscale. We present a model calculation to explore the key effects of different supercells that could be fabricated using nanofabrication or deliberate lattice mismatch, and demonstrate that specific pattern will enhance the coupling and the transition temperature. We also discuss how numerical methods could predict the correct design parameters to improve superconductivity in materials including Al, NbTi, and MgB

On propagators and three-point functions in Landau gauge QCD and QCD-like theories

Recent progress in our studies of propagators and three-point functions in Landau gauge for QCD and QCD-like theories is presented. Special emphasis is put on the properties of the three-gluon vertex and the quark-gluon vertex. The effect of unquenching is investigated. Furthermore, an exploratory study for a large number of light flavours is described, from where clear evidence for the qualitative behaviour of propagators in the so-called conformal window can be extracted.Comment: 13 pages, 9 figures; Proceedings of the workshop QCD-TNT-III, ECT* Trento, Sept. 2-6, 2013; references update

Trends in Air Temperature and Precipitation in Southeastern Czech Republic, 1961-2020

This study presents a summary of sixty years of air temperature and precipitation measurements at the Žabčice weather station, located in the southeastern Czech Republic and operated by Mendel University in Brno. An instrumental dataset spanning two climatological normal periods (1961-1990 and newly established 1991-2020) is analyzed for long term linear trends with monthly data presented in full span in Appendices. In the new climate normal period, the mean annual temperature increased from 9.3 oC to 10.3 oC with growing trend of 0.34 oC/10 years (p < 0.001). Every calendar month of year is warmer, with the highest and fastest increase in August (+2.0 oC, 0.64 oC/10 years, p < 0.001) and the lowest in October (+0.2 oC). Annual precipitation sum increased negligibly (+11.1 mm), however, the quarterly distribution significantly changes towards drier second quarter (-22.9 mm, p < 0.05) and wetter third quarter (+37.1 mm, p < 0.05). Number of tropical days (maximum daily air temperature > 30 oC) significantly increased (+4.44/10 years, p < 0.001), whereas number of frost days is negligibly decreasing (-0.88/10 years). Temperature derived Huglin index for vineyards increased by 369 oC to a seasonal sum 2062 oC (+84 oC/10 years, p < 0.001). This study provides evidence of the rate of changing climate at this southern Moravia lowland site.O

Five myths about an EU ETS carbon price floor. CEPS Policy Insights No 2018/17, December 2018

This policy insight builds on the workshop EU ETS Reform: Taking Stock and Examining Carbon Price Floor Options, held at the Centre for European Policy Studies (CEPS) in Brussels on July 3, 2018. The workshop was cosponsored by CEPS and the AHEAD and Mistra Carbon Exit projects. While the paper draws on insights from workshop discussions, its views are solely those of the authors. It outlines different perspectives on the past performance of the EU Emissions Trading System (ETS) in terms of its allowance price (Section 1), analyses how the recent reform responded to related challenges (Section 2), and considers the case for introducing a carbon price floor in the EU ETS (Section 3). The main part of the paper (Section 4) identifies five myths in the debate about an EU ETS price floor and critically challenges them. Section 5 concludes by discussing potential entry points for introducing a carbon price floor in the context of the upcoming EU climate policy process

Broadband Distributed-Feedback Quantum Cascade Laser Array Operating From 8.0 to 9.8 um

An ultra-broadband distributed-feedback quantum cascade laser array was fabricated, using a heterogeneous cascade based on two bound-to-continuum designs centered at 8.4 and 9.6 mum. This array emitted in a range over 220 cm-1 near a 9-mu m wavelength, operated in pulsed mode at room temperature. The output power of the array varied between 100- and 1100-mW peak intensity.Engineering and Applied Science