Hall effect noise: Fluctuations in number or mobility?

The purpose of this paper is to show that the 1/f noise in the Hall voltage as reported by Brophy and Rostoker can be interpreted in terms of fluctuations in the mobility of free-charge carriers. Brophy and Rostoker have claimed that 1/f noise in the Hall voltage is a direct proof of 1/f fluctuations in the free-carrier density. Their conclusion is shown to be wrong.     

Intermittency or noise – an experimental study on the ion-beam driven ion-acoustic instability

Ion-acoustic waves are destabilised in a double-plasma device by ion-beam-plasma interaction. The plasma system destabilises via a supercritical Hopf-bifurcation with the control parameter being subject to noise. This leads to erratic fluctuations between stable and oscillatory states. The experimental results, in particular the statistical properties, show that this has to be distinguished from type-I intermittency transition to chaos as reported previously for similar experimental setups.     

“Could charm (& τ ) transitions be the ‘poor princess’ providing a deeper understanding of fundamental dynamics ?” or: “Finding novel forces”

We know that our Universe is composed of only ～4.5% “known” matter; therefore, our understanding is incomplete. This can be seen directly in the case of neutrino oscillations (without even considering potential other universes). Charm quarks have had considerable impact on our understanding of known matter, and quantum chromodynamics (QCD) is the only local quantum field theory to describe strong forces. It is possible to learn novel lessons concerning strong dynamics by measuring rates around the thresholds of [QˉQ] states with Q = b, c. Furthermore, these states provide us with gateways towards new dynamics (ND), where we must transition from “accuracy” to “precision” eras. Finally, we can make connections with τ transitions and, perhaps, with dark matter. Charm dynamics acts as a bridge between the worlds of light- and heavy-flavor hadrons (namely, beauty hadrons), and finding regional asymmetries in many-body final states may prove to be a “game changer”. There are several different approaches to achieving these goals: for example, experiments such as the Super Tau-Charm Factory, Super Beauty Factory, and the Super Z⁰ Factory act as gatekeepers – and deeper thinking regarding symmetries.     

Density Isomers or Δ-Matter1?

We demonstrate that the appearance of the density isomers depends on the meson-nucleon coupling strengths in addition to the meson-delta coupling strengths within the mean field theory. Furthermore, thein-medium NN → NΔ cross section is studied with different values of the coupling strengths for deltas. We have found that the in-medium NN → NΔ cross section substantially increases with the increasing of scalar meson-delta coupling strength even for the case when the density isomers do not appear within the mean field theory, which shows the possibility of creating Δ-matter in energetic heavy-ion collisions.     

Can colored noise improve stochastic resonance?

The phenomenon of stochastic resonance is studied in the presence of colored noise. Several sources of colored noise are introduced and the consequences for the asymptotic time-periodic probability and the (phase-averaged) power spectrum are discussed. Based on space-time symmetry considerations, selection rules for the occurrence of-spikes in the power spectrum are derived. The effect of colored noise on the amplification of small periodic signals is studied in terms of effective, time-periodic Fokker-Planck equations: In overdamped systems driven by colored noise, we find that SR is suppressed with increasing noise color. In contrast, for colored noise induced by inertia (as well as for asymmetric dichotomic noise), one obtains an enhancement of SR. This latter result is obtained by studying the Kramers equation perturbed by a small periodic force.     

Empty f-states, Kondo insulators—or what?

Empty f-states several eV above the Fermi level may be of no interest, but they can be populated by optical means. However, when they are within thermal energy of the Fermi level, they can be populated at elevated temperatures and thus permit valence changes. We are investigating with various types of measurements, such as optical reflectivity, magneto-optics, photoemission, inverse photoemission, magnetic susceptibility, electrical resistivity and more such materials as LaS, LaSe, LaTe, CeO₂, CeF₄, YbN, TmS, Ce₃Bi₄Pt₃, Ce₃Sb₄Pt₃, and U₃Sb₄Pt₃. Some of these materials are superconductors, insulators, semimetals, metals, Kondo insulators or semiconductors.     

When does noise increase the quantum capacity?

Superactivation is the property that two channels with zero quantum capacity can be used together to yield a positive capacity. Here we demonstrate that this effect exists for a wide class of inequivalent channels, none of which can simulate each other. We also consider the case where one of two zero-capacity channels is applied, but the sender is ignorant of which one is applied. We find examples where the greater the entropy of mixing of the channels, the greater the lower bound for the capacity. Finally, we show that the effect of superactivation is rather generic by providing an example of superactivation using the depolarizing channel.     

The structure of solid salt eutectics — – Why lamellar or conglomerate?

Using KCl/ZnSO₄ eutectic it has been shown that cooling the melt into a room temperature enclosure forms a lamellar structure, whereas cooling into a heated enclosure (225 °C) forms a conglomerate structure, while an enclosure temperature of 125 °C gave a partially conglomerate structure with some lamellae in process of forming conglomerates.Consideration of the thermal gradients imposed on solidification and consequently the relative time available during which the ions are sufficiently mobile to rearrange their positions, can explain the observation that lamellar structures are formed by higher melting point eutectics, whereas eutectics of lower melting point form conglomerate structures.     

Preferable solar cell absorber – Near stoichiometric or stoichiometric CBD CIAS thin films?

Near stoichiometric and stoichiometric [CuIn_(1 − x)Al_(x)Se₂] (CIAS) thin films are prepared by chemical bath deposition (CBD) technique. X-ray diffraction (XRD) analysis have been employed to estimate the structural properties of CBD CIAS thin films and also to identify the near stoichiometric in particular defect free Cu-poor CBD CIAS thin films as preferable solar cell absorber material.     

Environmental dosimetry with the BeOSL personal dosimeter – State of the Art

In the course of this work, the possibility of the measurement of ambient dose equivalent H*(10) with the BeOSL dosimetry system was evaluated. Calculations for the energy response of the 2-element BeOSL dosimeter for irradiation with H*(10) were performed. The response doesn't fulfil the requirements of IEC 62387-1. Especially the response for photon energies of 60–100 keV is to low. It is possible to correct this under response using a modified BeOSL 2-element dosimeter and a linear algorithm. So the national requirements for a H*(10) dosimeter in Germany can be fulfilled. An incidence angle independent measurement is not possible because for several angles of incidences (>60°) the filters of the 2-element dosimeter doesn't shield the correct element. Another material which is more suitable for the H*(10) measurement was tested. So the doping of BeO with Lanthanum leads to an enhanced energy response for measurement of H*(10). Furthermore a higher OSL sensitivity was found for this material. Further tests on the influence of Lanthanum concentration on the dosimetric properties are necessary.     

Mixed-Up-Ness or Entropy?

Simple SummaryThe second law of thermodynamics has a mystical appeal in disciplines with tenuous connections to its origins. We hypothesize that many of these appeals instead should be to another principle heretofore unrecognized: the law of mixed-up-ness (LOM). Instead of using a number such as entropy to characterize randomness, non-thermodynamic systems can be arranged in simple diagrams according to their degree of mixed-up-ness. Curiously, the evolution of such systems from degrees of low to high mixed-up-ness is both consistent with and richer than the principle of increasing entropy.AbstractMixed-up-ness can be traced to unpublished notes by Josiah Gibbs. Subsequently, the concept was developed independently, and under somewhat different names, by other investigators. The central idea of mixed-up-ness is that systems states can be organized in a hierarchy by their degree of mixed-up-ness. In its purest form, the organizing principle is independent of thermodynamic and statistical mechanics principles, nor does it imply irreversibility. Yet, Gibbs and subsequent investigators kept entropy as the essential concept in determining system evolution, thus retaining the notion that systems evolve from states of perfect “order” to states of total “disorder”. Nevertheless, increasing mixed-up-ness is consistent with increasing entropy; however, there is no unique one-to-one connection between the two. We illustrate the notion of mixed-up-ness with an application to the permutation function of integer partitions and then formalize the notion of mixed-up-ness as a fundamental hierarchal principle, the law of mixed-up-ness (LOM), for non-thermodynamic systems.     

Quintessence or Phoenix?

We show that it is impossible to determine the state equation of quintessence models on the basis of pure observational SNIa data. An independent estimate of _M0 is necessary. Also in this most favourable case the situation can be problematic.     

Aniline-planar or nonplanar?

The question whether the NH₂ group of aniline is coplanar with the aromatic ring has been raised many times (1) but the configuration has not yet been established beyond doubt. Evidence from the electronic band system near 2940 Å appears to settle this point, not only for the ground state of aniline but for its first electronically-excited state (¹B₂) also.     

Adaptive iterated function systems filter for images highly corrupted with fixed – Value impulse noise

The Adaptive Iterated Functions Systems (AIFS) Filter presented in this paper has an outstanding potential to attenuate the fixed-value impulse noise in images. This filter has two distinct phases namely noise detection and noise correction which uses Measure of Statistics and Iterated Function Systems (IFS) respectively. The performance of AIFS filter is assessed by three metrics namely, Peak Signal-to-Noise Ratio (PSNR), Mean Structural Similarity Index Matrix (MSSIM) and Human Visual Perception (HVP). The quantitative measures PSNR and MSSIM endorse the merit of this filter in terms of degree of noise suppression and details/edge preservation respectively, in comparison with the high performing filters reported in the recent literature. The qualitative measure HVP confirms the noise suppression ability of the devised filter. This computationally simple noise filter broadly finds application wherein the images are highly degraded by fixed-value impulse noise.     

Can a ‘magnesium sulfate admixtured l-threonine’ crystal be grown by slow evaporation solution growth method?

Slow evaporation of an aqueous solution containing l-threonine and magnesium sulphate heptahydrate, results in the fractional crystallization of the less soluble l-threonine crystal and not any novel optoelectronic ‘magnesium sulfate admixtured l-threonine’ crystal as reported by Puhal Raj et al. in Optik, 124 (2013) 6887–6891.     

SQUIDs – quo vadis?

For many decades R&D on superconducting quantum infererence devices (SQUIDs) has resulted in numerous and very diverse applications. However the commercial success of these applications is still marginal. This contribution analyses the reasons and discusses possible measures to improve this situation particularly for the application of multichannel SQUID systems for magnetoencephalography (MEG) and magnetocardiograpphy (MCG). The possible impact of combining low field magnetresonance imaging (lfMRI) with MEG and/or MCG is considered as well.     

Editorial – Introductory remarks on “Discussion &; Debate: Rogue Waves – Towards a Unifying Concept?”

This short editorial contains the introductory remarks for the special issue “discussions and debates” on the subject of “rogue waves”. This issue is the first of its kind, in the sense that the authors have the chance to discuss the basic concepts of an emerging topic in science. Based on these discussions, an attempt to give a “definition” of a rogue wave is made.     

Sustainable energy storage – with hot air,or cold air or liquid air

In memory of Sir David John Cameron MacKay FRS FInstP FICE (22 April 1967 – 14 April 2016). David was passionate about sustainable energy. One key element for sustainable energy is energy storage. As a small tribute, this article presents a review from a physics perspective of the thermodynamics of compressed air energy storage. Firstly, I treat adiabatic compressed air energy storage, where the heat of compression of the air is kept in the compressed air. Then I discuss improvements that can be made by combining compressed air energy storage with external heat stores. Next, I address isothermal compressed air energy storage, where the temperature is allowed to equilibrate with the environment. In each case, I consider two scenarios: underground caverns and underwater airbags. Finally, I address the case where the air is compressed and cooled so much that it liquifies. Throughout, I explain that the real point is to store available work, called exergy in the engineering community, rather than energy. Although my treatment is mostly from the ideal point of view of quasistatic processes, I give some pointers to technological implementations of the various methods and to some references on their thermodynamic efficiencies.