bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidences for local non-centrosymmetricity and strong phonon anomaly in EuCu2As2: a Raman spectroscopy and lattice dynamics study
Authors: Swain Debasmita , Dey Sarkar Mainak , Ptok Andrzej , Vaitheeswaran G , Roy Anushree , D Das Sitikantha 
Published: April 2024

Abstract
Phonon modes and their association with the electronic states have been investigated for the metallic EuCu2As2 system. In this work, we present the Raman spectra of this pnictide system which clearly shows the presence of seven well defined peaks above 100 cm−1 that is consistent with the locally non-centrosymmetric P4/nmm crystal structure, contrary to that what is expected from the accepted symmorphic I4/mmm structure. Lattice dynamics calculations using the P4/nmm symmetry attest that there is a commendable agreement between the calculated phonon spectra at the Γ point and the observed Raman mode frequencies, with the most intense peak at

∼

232

cm−1 being ascribed to the A

1
g

mode. Temperature dependent Raman measurements show that there is a significant deviation from the expected anharmonic behaviour around 165 K for the A

1
g

mode, with anomalies being observed for several other modes as well, although to a lesser extent. Attempts are made to rationalize the observed anomalous behavior related to the hardening of the phonon modes, with parallels being drawn from metal dichalcogenide and allied systems. Similarities in the evolution of the Raman peak frequencies with temperature seem to suggest a strong signature of a subtle electronic density wave instability below 165 K in this compound.
Calibration of absorption coefficients of liquid solutions for measuring liquid film thickness by absorptiometry
Authors: Zhao Yu , Xu Haitao 
Published: April 2024

Abstract
Infrared absorptiometry is a widely used non-intrusive method for measuring the thickness of liquid films. The accuracy of that measurement depends crucially on having high-accuracy data of the absorption coefficient of the laser light used, which is, however, not easily available, especially for the wavelength range where the absorption is strong. Here we propose a method to calibrate the absorption coefficients in such cases. By measuring the light intensity reduction while scanning through a liquid film formed in a wedge, whose angle can be adjusted and determined a priori from interferometry, the absorption coefficient of the liquid can be accurately obtained without the need to create a flat liquid film with exact known thickness. The method is verified by calibrating the absorption coefficient of pure water at an infrared wavelength and the result agrees very well with the values found in the literature. As a demonstration of the application of the method, the absorption coefficients of soap solutions with different compositions were calibrated and used to measure the thicknesses of draining soap films. The results from the absorptiometry are in good agreement with the film thickness measured simultaneously from interferometry.
A new teaching-learning sequence to promote secondary school students’ learning of quantum physics using Dirac notation
Authors: Hennig Fabian , Tóth Kristóf , Förster Moritz , Bitzenbauer Philipp 
Published: April 2024

Abstract
This paper describes the design of a new teaching-learning sequence on quantum physics aimed at upper secondary school students. In this teaching-learning sequence, GeoGebra simulations and interactive screen experiments are used to investigate the behaviour of a single photon at beam splitter and single photon interference in a Michelson interferometer. We propose a minimal formalism using Dirac notation, which avoids complex numbers and elaborate vector calculus, to make a quantitative description of the quantum optics experiments accessible to secondary school students. With this new educational pathway, we take into account findings from physics education research, which suggest that the introduction of a mathematical formalism tailored to students’ abilities might help them to overcome naive-realist views of quanta or space-time descriptions of quantum phenomena, while at the same time facilitating a transition to a functional understanding of quantum models.
The driven unicycle
Authors: Mungan Carl E , Kabutz Heiko 
Published: April 2024

Abstract
The free-body diagram of a unicycle pedalled across level ground is analysed, showing that riders must tilt their bodies into the direction of the acceleration. A comparison is made with an unpowered round object rolling without slipping up or down an inclined plane. A Newtonian analysis predicts an acceleration of the unicycle as a function of the tilt angle that is in good agreement with measurements of an actual unicycle using a smartphone.
Illuminating dark matter: I. A guide for physics teachers
Authors: Pinochet Jorge 
Published: April 2024

Abstract
One of the great mysteries of contemporary science is dark matter, an exotic substance of unknown nature that, in theory, makes up about 27% of the total mass-energy density of the Universe, and which does not appear to emit, absorb, or reflect any kind of light, meaning that it is invisible and can only be detected through its gravitational effects on objects around it. Dark matter is a frontier topic, involving highly complex subjects that usually exceed the training of a physics teacher. Given this difficulty, the aim of this paper is to shed some light on dark matter, and to offer a broad, up-to-date introduction that is mainly directed at physics teachers in training and in practice. Due to the breadth of the subject, the article has been divided into two parts. In Part I, we deal with general concepts, which serve as an introduction to the more specific topics analysed in Part II.
ChatGPT as a tool for honing teachers’ Socratic dialogue skills
Authors: Gregorcic Bor , Polverini Giulia , Sarlah Andreja 
Published: April 2024

Abstract
In this proof-of-concept paper, we propose a specific kind of pedagogical use of ChatGPT—to help teachers practice their Socratic dialogue skills. We follow up on the previously published paper ‘ChatGPT and the frustrated Socrates’ by re-examining ChatGPT’s ability to engage in Socratic dialogue in the role of a physics student. While in late 2022 its ability to engage in such dialogue was poor, we see significant advancements in the chatbot’s ability to respond to leading questions asked by a human teacher. We suggest that ChatGPT now has the potential to be used in teacher training to help pre- or in-service physics teachers hone their Socratic dialogue skills. In the paper and its supplemental material, we provide illustrative examples of Socratic dialogues with ChatGPT and present a report on a pilot activity involving pre-service physics and mathematics teachers conversing with it in a Socratic fashion.
The internal resistance of a non-ideal inductor in an RLC series circuit at resonance
Authors: Torriente-García Ives , Muñoz-Pérez Francisco M , Castro-Palacio Juan C , Monsoriu Juan A 
Published: April 2024

Abstract
The measured voltage at the inductor in an RLC series circuit connected to a sinusoidal electromotive force depends on the current and the impedance. The latter does not only include the inductive reactance only but also the ohmic resistance of the inductor. This fact has a clear consequence on the result of the measurement as the measured voltage at the inductor is not in counterphase with the measured voltage at the capacitance as shown in theory where ideal inductors are usually considered. In this work, the resistance of a coil in an RLC circuit is obtained from the direct measurements of the phase of the voltage at the coil at resonance and the resonant frequency for different values of capacitance. This value is compared with the resistance of the coil determined directly with an ohmmeter. The agreement between both values is very good. The conventional signal generator has been replaced by a smartphone which is a very familiar device for the students. The smartphone can provide the necessary voltage supply for the experiment to be carried out successfully.
Penalty weight tuning in high dose rate brachytherapy using multi-objective Bayesian optimization
Authors: Jafarzadeh Hossein , Antaki Majd , Mao Ximeng , Duclos Marie , Maleki Farhard , Enger Shirin A 
Published: April 2024

Abstract

Objective. Treatment plan optimization in high dose rate brachytherapy often requires manual fine-tuning of penalty weights for each objective, which can be time-consuming and dependent on the planner's experience. To automate this process, this study used a multi-criteria approach called multi-objective Bayesian optimization with q-noisy expected hypervolume improvement as its acquisition function (MOBO-qNEHVI). Approach. The treatment plans of 13 prostate cancer patients were retrospectively imported to a research treatment planning system, RapidBrachyMTPS, where fast mixed integer optimization (FMIO) performs dwell time optimization given a set of penalty weights to deliver 15 Gy to the target volume. MOBO-qNEHVI was used to find patient-specific Pareto optimal penalty weight vectors that yield clinically acceptable dose volume histogram metrics. The relationship between the number of MOBO-qNEHVI iterations and the number of clinically acceptable plans per patient (acceptance rate) was investigated. The performance time was obtained for various parameter configurations. Main results. MOBO-qNEHVI found clinically acceptable treatment plans for all patients. With increasing the number of MOBO-qNEHVI iterations, the acceptance rate grew logarithmically while the performance time grew exponentially. Fixing the penalty weight of the tumour volume to maximum value, adding the target dose as a parameter, initiating MOBO-qNEHVI with 25 parallel sampling of FMIO, and running 6 MOBO-qNEHVI iterations found solutions that delivered 15 Gy to the hottest 95% of the clinical target volume while respecting the dose constraints to the organs at risk. The average acceptance rate for each patient was 89.74% ± 8.11%, and performance time was 66.6 ± 12.6 s. The initiation took 22.47 ± 7.57 s, and each iteration took 7.35 ± 2.45 s to find one Pareto solution.Significance. MOBO-qNEHVI combined with FMIO can automatically explore the trade-offs between treatment plan objectives in a patient specific manner within a minute. This approach can reduce the dependency of plan quality on planner’s experience and reduce dose to the organs at risk.
Optimizing control for strike point sweeping using lower divertor coil in EAST
Authors: Qiu Qinglai , Zhang Yang , Zhang Xiaodong , Yuan Qiping , Luo Zhengping , Wang Zhaoliang , Wu Yibing , Qian Jing , Guo Bin , Liang Ruirong , Wang Yuehang , Chen Jianjun , Huang Yao , Xiao Bingjia , Meng Lingyi ,   the East Team
Published: April 2024

Abstract
In 2021, EAST was equipped with a full-ring divertor coil to facilitate research on the fish tail divertor concept. Initially, it was observed that the coil current had a negligible ability to sweep the strike point. Conversely, when the amplitude and frequency of the alternating current were marginally increased, there was a significant interruption to plasma control. This perturbation was attributed to the poloidal control field’s limited response rate to the coil’s fluctuations. To address this issue, novel control methodologies were devised to ensure stable and effective sweeping of the strike point using the divertor coil. The devised methods are twofold: For high-frequency strike point control, a low-pass filter decoupling technique based on ISOFLUX control strategy enabled achieving a sweeping frequency of 100 Hz. This strategy allowed for consistent plasma management without compromising average stored energy or density regulation. Resulting from this proficient manipulation of the strike point, a reduction in the peak temperature of the divertor plate was observed. For low-frequency sweeping, a static multi-input multi-output decoupling approach was developed, facilitating concurrent sweeping of both the outer and inner strike points.
Suprathermal-ion-driven fusion chain reactions in the pure deuterium system
Authors: Robinson A P L 
Published: April 2024

Abstract
It is argued that fusion chain reactions in the D-D system is feasible with supra-thermal deuterons in the MeV regime, with new generations of deuterons being generated either via neutron–deuteron or proton–deuteron collisions. The propagation of supra-thermal deuterons in an infinite, hot, dense deuterium target was studied using a Monte Carlo method that includes multiple nuclear reactions, electron and ion stopping, along with neutron and proton knock-ons. Over a wide range of densities we observed significant, albeit sub-critical chain reactions in the multi-keV temperature regime. At very high densities (over 1000 gcm−3) and temperatures (over 40 keV) we observed chain reactions that reached criticality. These results suggest that there is a case to re-assess the potential of inertial confinement fusion based on deuterium-heavy targets.
Auxetic fixation devices can achieve superior pullout performances compared to standard fixation concepts
Authors: Barnett Elinor , Fletcher James , Gill Harinderjit S , Pegg Elise C , Loukaides Evripides G 
Published: April 2024

Abstract
Despite bone screws being the most commonly inserted implant in orthopaedic surgery, 10% of fracture fixation failure is a result of screw migration or pullout. In this study, the effect of four auxetic structures on the pullout performance of a novel unthreaded bone fastener was investigated through experiments and numerical simulations. The auxetic fasteners included the re-entrant, rotating squares, missing rib, and tetrachiral structures. Parametric CAD models were developed for each, and polymer samples manufactured using a stereolithography process. Pullout testing using bone analogue material found the rotating squares fastener to achieve superior pullout resistance 2.5 times that of the non-auxetic control sample. With a pullout to push-in force ratio of 33.7, this fastener achieved high pullout resistance with a low insertion force improving ease of installation. The Poisson’s ratio of the structure was determined using image analysis to be −1.31, similar to the missing rib and re-entrant types. The low axial stiffness of 12.1 N mm−1 for the rotating squares fastener was the reason for superior performance, allowing axial and resulting transverse strain to be initiated at relatively low load. The effect of increased diametral interference was investigated, and the re-entrant structure found to be superior with pullout resistance improved by 342%. This work provides a foundation for further development of unthreaded auxetic bone fasteners, which have the potential to replace screws for some orthopaedic applications and significantly reduce the prevalence of pullout as a failure mode.
Synchrotron x-ray spectra characterisation for radiation therapy applications at the ESRF - ID17 biomedical beamline
Authors: Di Manici Ilaria , Reyes-Herrera Juan , Day Liam , Sánchez Del Río Manuel , Krisch Michael , Pellicioli Paolo 
Published: April 2024

Abstract

Objective. Radiation therapy requires reliable dosimetry protocols to deliver successful treatments with high accuracy and precision. In this context, accurate knowledge of the beam’s energy spectra is mandatory. The goal of this study was to validate the synchrotron x-ray spectrum of the ID17 beamline at the European Synchrotron Radiation Facility (ESRF). The modification of the synchrotron storage ring and beamline in recent years necessitates a new characterisation of the radiation spectra of the ID17 beamline. The validated spectra will be a starting point for possible future clinical applications. Approach. The half value layer method was used to measure the attenuation of the x-ray spectrum in Al and Cu. Experimental data was validated against theoretical data produced using OASYS; an in-house developed software for calculating beamline spectra. Two different spectral configurations, ‘conventional’ and ‘clinical’, were investigated. The characterised spectra were used to perform dosimetric validation of depth dose profiles measured in a water-equivalent phantom. The dose profile was measured using two different detectors and compared with calculations generated using two different Monte Carlo algorithms. Main results. The results showed good agreement between measured and predicted half value layers, with differences of less than 1% in most cases. Excellent dosimetric agreement to within 3% was obtained, an agreement that satisfies the requirements in conventional radiotherapy for approvable treatment planning. Significance. Accurate spectra have been defined and validated for the ESRF—ID17 Biomedical beamline. The validated spectra can be used as input for future dosimetric studies and treatment planning systems in the context of preclinical studies and possible future clinical trials.
Effect of instrumental polarization with a half-wave plate on the B-mode signal: prediction and correction
Authors: Patanchon Guillaume , Imada Hiroaki , Ishino Hirokazu , Matsumura Tomotake 
Published: April 2024

Abstract
We study the effect of incident unpolarized signal converted to polarized light produced by a realistic half-wave plate (HWP) and evaluate the impact of the effect in the measurement of Cosmic Microwave Background (CMB) B-mode polarization signal targeting to probe the tensor-to-scalar ratio r.
The HWP is modeled with the Mueller formalism, and coefficients are decomposed for any incident angle into harmonics of the HWP rotation frequency due to azimuthal angle dependence. Although we use a general formalism, band-averaged matrix coefficients are calculated as an example for a 9-layer sapphire HWP using EM propagation simulations. We perform simulations of multi-detector observations in a band centered at 140 GHz using LiteBIRD instrumental configuration. We show both theoretically and with the simulations that most of the artefacts on Stokes parameter maps are produced by the dipole leakage on B-modes induced by the fourth harmonics MQI

(4f) and MUI

(4f). The resulting effect is strongly linked to the spin-2 focal plane scanning cross linking parameters. We develop a maximum likelihood-based method to correct the IP leakage by joint fitting of the Mueller matrix coefficients as well as the Stokes parameter maps.
We show that the residual leakage after correction leads to an additional noise limited uncertainty on r of the order of 10-7, independently of the value of the Mueller matrix coefficients. We discuss the impact of the monopole signal and the potential coupling with other systematic effects such as gain variations and detector nonlinearities.
A novel approach to cosmological particle production
Authors: Fiol Bartomeu , Komendyak Mickael , Ruiz-Ponsell Jordi 
Published: April 2024

Abstract
In this work we present a novel approach to the study of cosmological particle production in asymptotically Minkowski spacetimes. We emphasize that it is possible to determine the amount of particle production by focusing on the mathematical properties of the mode function equations, i.e. their singularities and monodromies, sidestepping the need to solve those equations. We consider in detail creation of scalar and spin 1/2 particles in four dimensional asymptotically Minkowski flat FLRW spacetimes. We explain that when the mode function equation for scalar fields has only regular singular points, the corresponding scale factors are asymptotically Minkowski. For Dirac spin 1/2 fields, the requirement of mode function equations with only regular points is more restrictive, and picks up a subset of the aforementioned scale factors. For the scalar case, we argue that there are two different regimes of particle production; while most of the literature has focused on only one of these regimes, the other regime presents enhanced particle production. On the other hand, for Dirac fermions we find a single regime of particle production. Finally, we very briefly comment on the possibility of studying particle production in spacetimes that don't asymptote to Minkowski, by considering mode function equations with irregular singular points.
Modeling neutrino-induced scale-dependent galaxy clustering for photometric galaxy surveys
Authors: Rogozenski P. , Krause E. , Miranda V. 
Published: April 2024

Abstract
The increasing statistical precision of photometric redshift surveys requires improved accuracy of theoretical predictions for large-scale structure observables to obtain unbiased cosmological constraints. In ΛCDM cosmologies, massive neutrinos stream freely at small cosmological scales, suppressing the small-scale power spectrum. In massive neutrino cosmologies, galaxy bias modeling needs to accurately relate the scale-dependent growth of the underlying matter field to observed galaxy clustering statistics. In this work, we implement a computationally efficient approximation of the neutrino-induced scale-dependent bias (NISDB). Through simulated likelihood analyses of Dark Energy Survey Year 3 (DESY3) and Legacy Survey of Space and Time Year 1 (LSSTY1) synthetic data that contain an appreciable NISDB, we examine the impact of linear galaxy bias and neutrino mass modeling choices on cosmological parameter inference. We find model misspecification of the NISDB approximation and neutrino mass models to decrease the constraining power of photometric galaxy surveys and cause parameter biases in the cosmological interpretation of future surveys. We quantify these biases and devise mitigation strategies.
Two-dimensional and absolutely entanglement-breaking subspaces
Authors: Yan Jian , Chen Lin 
Published: April 2024

Abstract
Entanglement-breaking (EB) subspaces determine the additivity of entanglement of formation (EOF), which is a long-standing issue in quantum information. We explicitly construct the two-dimensional EB subspaces of any bipartite system, when system dimensions are equal, and we apply the subspaces to construct EB spaces of arbitrary dimensions. We also present partial construction when system dimensions are different. Then, we present the notion and properties of EB subspaces for some systems, and in particular the absolute EB subspaces. We construct some examples of absolute EB subspaces, as well as EB subspaces for some systems by using multiqubit Dicke states.
Imaging plate scanners calibration and the attenuation behavior of imaging plate signals
Authors: Bo 薄 Nan 楠 , Wang 王 Nai-Yan 乃彦 
Published: April 2024

Abstract
Based on previously reported work, we propose a new method for calibrating image plate (IP) scanners, offering greater flexibility and convenience, which can be extended to the calibration tasks of various scanner models. This method was applied to calibrate the sensitivity of a GE Typhoon FLA 7000 scanner. Additionally, we performed a calibration of the spontaneous signal attenuation behavior for BAS-MS, BAS-SR, and BAS-TR type IPs under the 20±1 °C environmental conditions, and observed significant signal carrier diffusion behavior in BAS-MS IP. The calibration results lay a foundation for further research on the interaction between ultra-short, ultra-intense lasers and matter.
Effects of plasma nonuniformity on toroidal Alfvén eigenmode nonlinear decay
Authors: Cheng Zhiwen , Shen Kexun , Qiu Zhiyong 
Published: April 2024

Abstract
The parametric decay of toroidal Alfvén eigenmode (TAE) in nonuniform plasmas is investigated using nonlinear gyrokinetic equation. It is found that, the plasma nonuniformity not only significantly enhances the nonlinear coupling cross-section, but also qualitatively modifies the decay process. Specifically, the condition for spontaneous decay becomes the toroidal mode number of the sideband TAE being higher than that of the pump TAE, instead of the frequency of the sideband TAE being lower than the pump TAE in uniform plasmas. The consequences on TAE saturation and energetic particle transport are also discussed.