Nanoimprinting and Tapering of Chalcogenide Photonic Crystal Fibers for Cascaded Supercontinuum Generation. (arXiv:1911.08481v1 [physics.optics])

Improved long-wavelength transmission and supercontinuum (SC) generation is demonstrated by anti-reflective (AR) nanoimprinting and tapering of chalcogenide photonic crystal fibers (PCF). Using a SC source input spanning from 1-4.2 {\mu}m, the total transmission of a 15 {\mu}m core diameter PCF was improved from ~53 % to ~74 % by nanoimprinting of AR structures on both…

Modern Antennas and Microwave Circuits — A complete master-level course. (arXiv:1911.08484v1 [eess.SP])

Modern antenna systems include passive antenna structures, passive microwave circuits and interconnections to electronics. Therefore, the antenna engineer should have a deep understanding of antenna theory and should be able to apply microwave engineering concepts. This textbook provides all relevant material for Master-level courses in the domain of antenna systems. The book includes comprehensive material…

Analysis of wall-pressure fluctuation sources from DNS of turbulent channel flow. (arXiv:1911.08534v1 [physics.flu-dyn])

The sources of wall-pressure fluctuation in turbulent channel flow are studied using a novel framework. The wall-pressure power spectral density (PSD) $(\phi_{pp}(\omega))$ is expressed as an integrated contribution from all wall-parallel plane pairs, $\phi_{pp}(\omega)=\int_{-1}^{+1}\int_{-1}^{+1}\Gamma(r,s,\omega)\,\mathrm{dr}\,\mathrm{ds}$, using the Green’s function. $\Gamma(r,s,\omega)$ is termed the net source cross spectral density (CSD) between two wall-parallel planes, $y=r$ and $y=s$.…

Magnetic and electronic phase transitions probed by nanomechanical resonance. (arXiv:1911.08537v1 [cond-mat.mes-hall])

Two-dimensional (2D) materials enable new types of magnetic and electronic phases mediated by their reduced dimensionality like magic-angle induced phase transitions, 2D Ising antiferromagnets and ferromagnetism in 2D atomic layers and heterostructures. However, only a few methods are available to study these phase transitions, which for example is particularly challenging for antiferromagnetic materials. Here, we…

Modulational instability of dust-ion-acoustic mode and associated rogue waves in a non-extensive plasma medium. (arXiv:1911.08557v1 [physics.plasm-ph])

The modulational instability of dust-ion-acoustic (DIA) mode and associated rogue waves in a three component dusty plasma system (containing inertial warm ion and negatively charged dust fluids along with inertialess $q$-distributed electrons) has been theoretically investigated. A nonlinear Schr\”{o}dinger equation (NLSE) has been derived by employing the reductive perturbation method. It is observed that the…

Machine Learning Classification Informed by a Functional Biophysical System. (arXiv:1911.08589v1 [physics.bio-ph])

We present a novel machine learning architecture for classification suggested by experiments on the insect olfactory system. The network separates odors via a winnerless competition network, then classifies objects by projection into a high dimensional space where a support vector machine provides more precision in classification. We build this network using biophysical models of neurons…

Folding Rate Optimization Promotes Frustrated Interactions in Entangled Protein Structures. (arXiv:1911.08590v1 [cond-mat.soft])

Many native structures of proteins accomodate complex topological motifs such as knots, lassos, and other geometrical entanglements. How proteins can fold quickly even in the presence of such topological obstacles is a debated question in structural biology. Recently, the hypothesis that energetic frustration might be a mechanism to avoid topological frustration has been put forward…

Multi-criteria community detection in International Trade Network. (arXiv:1911.08593v1 [physics.soc-ph])

Understanding the community structure has great importance for economic analysis. Communities are characterized by properties different from those of both the individual node and the whole network and they affect various processes on the network. We combine community detection with specific topological indicators. As a result, a new weighted network is constructed by the original…

Causality violation without time-travel: closed lightlike paths in G\”{o}del’s universe. (arXiv:1911.08602v1 [gr-qc])

We revisit the issue of causality violations in G\”{o}del’s universe, restricting to geodesic motions. It is well-known that while there are closed timelike curves in this spacetime, there are no closed causal geodesics. We show further that no observer can communicate directly (i.e.\ using a single causal geodesic) with their own past. However, we show…

Gridspec: A standard for the description of grids used in Earth System models. (arXiv:1911.08638v1 [physics.ao-ph])

The comparative analysis of output from multiple models, and against observational data analysis archives, has become a key methodology in reducing uncertainty in climate projections, and in improving forecast skill of medium- and long-term forecasts. There is considerable momentum toward simplifying such analyses by applying comprehensive community-standard metadata to observational and model output data archives.…