A novel “magnetic” field and its dual non-commutative phase space

In this Letter we have studied a new form of non-commutative (NC) phase space with an operatorial form of noncommutativity. A point particle in this space feels the effect of an interaction with an “internal  ” magnetic field, that is singular at a specific position θ⁻¹${\theta }^{\mathrm{-1}}$. By “internal” we mean that the effective magnetic fields depends essentially on the particle properties and modifies the symplectic structure. Here θ is the NC parameter and induces the coupling between the particle and the “internal” magnetic field. The magnetic moment of the particle is computed. Interaction with an external physical magnetic field reveals interesting features induced by the inherent fuzziness of the NC phase space: introduction of non-trivial structures into the charge and mass of the particle and possibility of the particle dynamics collapsing to a Hall type of motion. The dynamics is studied both from Lagrangian and symplectic (Hamiltonian) points of view. The canonical (Darboux) variables are also identified. We briefly comment, that the model presented here, can play interesting role in the context of (recently observed) real space Berry curvature in material systems.     

Plant elemental composition and portable X‐ray fluorescence (pXRF) spectroscopy: quantification under different analytical parameters

Emergence of portable X‐ray fluorescence (pXRF) systems presents new opportunities for rapid, low‐cost plant analysis, both as a lab system and in situ system. Numerous studies have extolled the virtues of using pXRF for a wide range of plant applications, however, for many such applications, there is need for further assessment with regards to analytical parameters for plant analysis. While pXRF is a potential powerful research tool for elemental composition analysis, its successful use in plant analysis is made more likely by having an understanding of X‐ray physics, calibration process, and ability to test a variety of homogenous and well‐characterized materials for developing a matrix‐specific calibration. Because potential pXRF users may often underestimate the complexity of proper analysis, this study aims at providing a technical background for plant analysis using pXRF. The focus is on elemental quantification under different analytical parameters and different methods of sample presentation: direct surface contact under vacuum, placement in a sample cup with prolene as a seal, and without the aid of a vacuum. Direct analysis on the surface of a pXRF provided highest sensitivity and accuracy (R² > 0.90) for light elements (Mg to P). Sulfur, K, and Ca can be reliably measured without the aid of a vacuum (R² > 0.99, 0.97, and 0.93 respectively), although lower detection limits may be compromised. pXRF instruments provide plant data of sufficient accuracy for many applications and will reduce the overall time and budget compared with the use of conventional techniques. Sensitivity and accuracy are dependent on the instrument's settings, make, and model. © 2015 The Authors. X‐Ray Spectrometry published by John Wiley & Sons, Ltd.     

Response to “The Mössbauer rotor experiment and the general theory of relativity” by C. Corda

We show that a new attempt by Corda (2016), just like his previous attempt (Corda, 2015) that we had answered before (A.L. Kholmetskii et al., 2015), to reinterpret Mössbauer experiments in a rotating system as a “new, strong and independent proof of the correctness of Einstein’s vision of gravity” is erroneous. In addition, we demonstrate that Corda’s criticism of Yarman–Arik–Kholmetskii gravitation theory (in short YARK), is based on the application of ill-posed logic; thus rendering his claims against YARK as unfounded.     

Investigation into the elemental composition of sapropel from Lake Kirek (West Siberia) by SR XFA technique

The synchrotron radiation X-ray fluorescence analysis (SRXFA) technique was applied for scanning two sapropel cores: 6.2 m (coordinates of boring 56°11??93?? N, 84°23??22?? E) and 3.6 m (56°10??93?? N, 84°22??94?? E), obtained at a depth of 5 and 7 m, respectively, in Lake Kirek (southern part of Tomsk oblast, West Siberia). Based on variations in the content of eight chemical elements in stratified core horizons, the geochemical types of the sapropels and their prevalence were established. In the sediment of the 6.2-m core within the overall boundaries of the Holocene, low-ferric calcareous sapropel dominates, the geochemical characteristic of which is presented by the average values of 13 chemical elements in the strata grouped by the main climatic periods of the Holocene. Organic-ferrous sapropel 90 cm in depth was uncovered in the 3.6-m core in the range 215?C305 cm (age of 7-4 ka). For the other core horizons, the deposit is represented by calcareous sapropel, but with higher contents of iron in comparison with the first type. The geochemical differentiation of these two types of sapropels (in 3.6-m core) is characterized by average contents of 31 chemical elements. The consistency of the compositions and concentrations of chemical elements in sapropels in the Holocene section of the deposits is evidence of the identical formation conditions for these types of sapropel.     

Particle production in the double dual pomeron region

By an indirect method we calculate the missing mass discontiniuty of the dual two-loop graph in the double-pomeron region. We confirm the central region scaling and determine the P_⊥ dependence.     

Reply to the comment on “Light propagation in the Fresnel region - New numerical approach”

The paper is an answer to the comment on the approach for light propagation in the Fresnel region [W. Zhang, W. Huang, Z. Ye, T. Zhao, F. Yu, Opt. Commun. 281 (2008) 3977]. The examples presented in the commented paper entitled “Light propagation in the Fresnel region - New numerical approach” [M. Sypek, Opt. Commun. 116 (1995) 43] were sufficiently rigorous. A quantitative comparison of the results obtained for non-zero padding and zero-padding techniques are included. The divided steps approach which was the major contribution introduced by the modified convolution method could help reduce the aliasing error for the large propagation range, but only with the simultaneous use of the zero-padding technique. In this paper examples are presented. Additional explanations are enclosed.     

The dual string spectrum in Polyakov's quantization (I)

We consider the quantization of Liouville's equation in a box, with appropriate boundary conditions, as comes out of Polyakov's analysis of the Nambu action. The answer to this problem gives the spectrum of the dual string in this new approach. In this first paper, we concentrate mostly on the classical theory, including the inverse scattering method, which are needed to separate the modes, a prerequisite to an exact canonical quantization. In particular, we point out the important role of a parameter appearing in the boundary conditions, which depends on the space-time dimension, and we show that the system reduces to an involved set of harmonic oscillators.     

The elemental composition of Stradivari's musical instruments: new results through non‐invasive EDXRF analysis

During recent decades, many researchers have tried to understand the main influences on the extraordinary sound and beauty of the masterpieces made by the ancient violin makers. This is still a challenge for many others today. Mainly because of a lack of written historical documents, the rediscovery of some of the ancient violin‐making processes was made possible thanks to scientific analyses performed on their materials by means of diagnostic techniques. However, understanding which substances were adopted is a very hard task, because the analyses are influenced by many factors: for example, alterations, wear, retouches, and the heterogeneity of materials. This paper presents some new EDXRF results collected on eight‐stringed musical instruments made by Antonio Stradivari between 1669 and 1734 (“Clisbee” 1669, “Hellier” 1679, “Ford‐Rougemont” 1703, “Joachim‐Ma” 1714, “Russian Federation” viola 1715, “Cremonese” 1715, “Vesuvius” 1727, and “Scotland” 1734) and now preserved at the Museo del Violino in Cremona. A brief comparison with a modern violin made by Simone Ferdinando Sacconi (“Hellier copy” 1941), one of the most eminent violin makers of the 20th century and one of the greatest experts on Stradivari's work, is also provided. This represents the first comparative analysis of a wide number of ancient musical instruments made by the same violin maker over an extended period. A non‐destructive and non‐invasive approach was followed to (a) understand the elemental composition differences between the best conserved and most worn‐out surfaces; (b) check if there are elemental similarities among the finishing materials of violins made in different years by the same violin maker; (c) give new suggestions about the materials used. To distinguish the best conserved areas from the worn‐out ones, a preliminary investigation by UV‐induced fluorescence photography was performed. In addition, stereomicroscopic observations and Fourier transform infrared spectroscopy (FTIR) analyses were performed on selected areas to validate the hypotheses. The results, in some cases comparable with previous research on Stradivari instruments, have increased the pool of information about materials and treatments adopted in the Stradivari workshop.     

Geometrical relationship between elemental composition and molecular size in carbonaceous materials

Thermal treatment of carbonaceous materials shows two related phenomena: the graphene molecule (or carbon layer) increases in size and its carbon content also increases. In this work, a simple relationship between both effects was deducted, based on the structure geometry of carbonaceous materials. This relationship provides an approach to the mean size of graphene molecules which is more accurate than that acquired through different experimental techniques.     

The Mu-MASS (muonium laser spectroscopy) experiment

We present a new experiment, Mu-MASS, aiming for a 1000-fold improvement in the determination of the 1S-2S transition frequency of Muonium (M), the positive-muon/electron bound state. This substantial improvement beyond the current state-of-the-art relies on the novel cryogenic M converters and confinement techniques we developed, on the new excitation and detection schemes which we implemented for positronium spectroscopy and the tremendous advances in generation of UV radiation. This experiment is planned to be performed at the Paul Scherrer Institute (PSI). Interesting anomalies in the muon sector have accumulated: notably the famous anomalous muon magnetic moment (g-2) and the muonic hydrogen Lamb shift measurement which prompted the so-called proton charge radius puzzle. These tantalizing results triggered vibrant activity on both experimental and theoretical sides. Different explanations have been put forward including exciting solutions invoking New Physics beyond the Standard Model. Mu-MASS could contribute to clarifying the origin of these anomalies by providing robust and reliable values of fundamental constants such as the muon mass and a value of the Rydberg constant independent of finite size effects.     

高动态范围激光等离子体诊断系统及其在惯性约束聚变实验中的应用

基于高功率激光等离子体X射线辐射谱特性,设计和研制了一种大画幅高动态范围MCP选通型分幅相机. 单画幅宽度13mm,长度36mm,曝光时间0.5—5ns可调.与X射线CCD比较,系统在1.0—10keV的谱响应相对平整,无高能增强效应.利用高功率激光打靶实验进行了性能考核实验,结果表明,系统的信噪比明显好于X射线CCD系统,动态范围大于3×10³. 系统已经在神光Ⅱ装置ICF物理实验中获得成功应用. 关键词： 动态范围 谱响应 激光等离子体诊断 分幅相机