bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation of solitary waves solutions and dynamic visualization of the nonlinear schrödinger equation with efficient techniques
Authors: Majid Sheikh Zain , Asjad Muhammad Imran , Faridi Waqas Ali 
Published: May 2024

Abstract
This article investigates the non-linear generalized geophysical KdV equation, which describes shallow water waves in an ocean. The proposed generalized projective Riccati equation method and modified auxiliary equation method extract a more efficient and broad range of soliton solutions. These include U-shaped, W-shaped, singular, periodic, bright, dark, kink-type, breather soliton, multi-singular soliton, singular soliton with high amplitude, multiple periodic, multiple lump wave soliton, and flat kink-type soliton solutions. The travelling wave patterns of the model are graphically presented with suitable parameter values using the modern software Maple and Wolfram Mathematica. The visual representation of the solutions in 3D, 2D, and contour surfaces enhances understanding of parameter impact. Sensitivity and modulation instability analyses were performed to offer insights into the dynamics of the examined model. The observed dynamics of the proposed model were presented, revealing quasi-periodic chaotic, periodic systems, and quasi-periodic behaviour. This analysis confirms the effectiveness and reliability of the method employed, demonstrating its applicability in discovering travelling wave solitons for a wide range of nonlinear evolution equations.
Two-photon absorption in quantum dots with Hellmann potential
Authors: Hieu Nguyen N , Dinh Le , Poklonski N A , Phan Thi Hai Ha , Phuc Huynh V 
Published: May 2024

Abstract
We study the nonlinear optical absorption properties of a spherical quantum dot (SQD) with Hellmann potential, focusing on the two-photon absorption (TPA) process, using GaAs/AlGaAs material as an example. The radial Schrödinger equation is solved using the Nikiforov-Uvarov method, while the two-photon absorption coefficient is determined through second-order perturbation theory concerning the electron-photon interaction. Our study shows that the intraband transition has a smaller energy transition than the interband transition, leading to TPA spectra for the intraband transition that is restricted within a smaller energy range and exhibits a higher peak value than those for the interband transition. The peak corresponding to the orbital quantum number of electrons in SQD ℓ = 2 consistently appears to the left of the peak corresponding to ℓ = 1 in both intraband and interband transition cases. Additionally, the dependence of the absorption peak position on the order of transition, n, differs between intra- and inter-band transitions. We also observe blue shift behavior in the TPA spectra as all three parameters, r
0, V
0e
, and η, increase. Our investigation has the potential to enable the design of novel photonic devices, ultra-fast optical switches, and highly efficient solar cells through the optimization of quantum dot material properties.
Simulation investigation of effects of substrate and thermal boundary resistance on performances of AlGaN/GaN HEMTs
Authors: Wang Kang , Hu Wenbo , Wu Shengli , Wang Hongxing , Padhiar Muhammad Amin , Ji Yongqiang 
Published: May 2024

Abstract
The temperature distributions and thermal resistances of the GaN HEMTs fabricated on different substrates (sapphire, Si, SiC and diamond) with Mo/Au interlayers were calculated and analyzed by numerical simulation. The results show that the GaN HEMT on the diamond substrate exhibits the lowest channel temperature and thermal resistance, and the thermal resistance rises with the increase of the thermal boundary resistance (TBR) for all the GaN HEMTs with the different substrate materials. Meanwhile, the high TBR (2 × 10−7 m2·K/W) severely hinders the heat exchange between the GaN layer and the substrate, which makes it difficult for the heat flux to pass through the barrier. Even diamond with high thermal conductivity can hardly reduce the channel temperature of the device. Therefore, TBR must be reduced so that the heat flux can be dissipated through a high thermal conductivity substrate. In addition, the Mo/Au interlayer generates a lower thermal boundary resistance, which has little effect on the channel temperature, thermal resistance and interfacial temperature discontinuity of GaN HEMTs.
A new co-infection model for HBV and HIV with vaccination and asymptomatic transmission using actual data from Taiwan
Authors: Ullah Muhammad Asad , Raza Nauman , Omame Andrew , Alqarni M S 
Published: May 2024

Abstract
The co-infection of Human Immunodeficiency Virus (HIV) and Hepatitis B virus (HBV) poses a major threat to public health due to their combined negative impacts on health and increased risk of complications. A novel fractional mathematical model of the dynamics of co-infection between HBV and HIV for Taiwan is presented in this paper. Detailed analyses are conducted on the possible impact of HBV vaccination on the dynamics of HBV and HIV co-infection. The next-generation matrix technique is used to calculate the fundamental reproduction number R
0 = max{R
1, R
2}, where R
1 and R
2 are the reproduction numbers for HBV and HIV, respectively. The disease-free and endemic equilibria of the co-infection model are calculated. An extensive investigation is carried out to determine the local and global stability of the disease-free equilibrium point through Rough Hurtwiz criteria and the construction of Lyapunov function, respectively. We demonstrate that when R
1 < 1 < R
2, HBV infection is eradicated, but HIV remains prevalent. If R
2 < 1 < R
1, the opposite outcome occurs. The real data from 2000-2023 for Taiwan is used to fit the model. The fitting results show how effectively our model handles the data. In addition, numerical simulations are run for different scenarios to observe how the vaccine and fractional parameters changed the model state variables, as well as how the solutions behaved and how quickly they reached the model’s equilibrium points. According to the model’s numerical analysis, greater vaccination efforts against HBV have a positive effect on the propagation of co-infection.
Facile fabrication of MgAl2O4/MWCNT nanocomposite for efficient and stable solar-driven degradation of organic dye
Authors: Ahmad Sajjad , Hussain Tousif , Shuaib Urooj , Mubarik Farrukh Ehtesham , Yasin Amna , Shakir Imran 
Published: May 2024

Abstract
This work reports the synthesis and characterization of Magnesium Aluminate (MgAl2O4) and Magnesium Aluminate/Multi Walled Carbon Nanotube (MgAl2O4/MWCNT) nanocomposite by facile chemical co-precipitation method for the dye degradation application. MgAl2O4 and MgAl2O4/MWCNT nanocomposite are characterized by Scanning Electron Microscopy (SEM), x-ray Diffractometry (XRD), Raman Spectrometry, UV–vis Spectrophotometry (UV–vis), Fourier Transform Infrared Spectroscopy(FTIR), and x-ray Photoelectron Spectroscopy (XPS). Surface morphology of MgAl2O4/MWCNT nanocomposite exhibits entangled needle-like structures while MgAl2O4 spinel comprises agglomerated nanoparticles of different sizes. XRD confirms the formation of MgAl2O4. XPS identifies the chemical states and binding energies of constituent elements present in the sample. Optical properties reveal that addition of MWCNTs in MgAl2O4 decreases the optical bandgap energy from 3.02 eV to 2.78 eV. MgAl2O4/MWCNT nanocomposite shows reduced bandgap compared to pristine MgAl2O4 due to increased chemical defects or vacancies in intergranular regions and chemical interaction between MgAl2O4 and MWCNT, leading to the formation of new energy levels in MgAl2O4/MWCNT nanocomposite. Addition of MWCNTs provides a large surface area, more active sites, and enhances electron mobility between energy levels. MgAl2O4/MWCNT nanocomposite proves itself a better photocatalyst due to the fast degradation of Methyl Blue (MB) in 65 min as compared to MgAl2O4 which degrades the dye in 90 min. MgAl2O4/MWCNT nanocomposite also shows good stability and reusability even after performing the six cycles of dye degradation.
Broadband spin-decoupled metasurface for independent wavefront manipulations of orthogonal circularly-polarized waves
Authors: Chen Wenqiong , Zhang Jingwei , Feng Junlang , Niu Tiaoming , Mei Zhonglei 
Published: May 2024

Abstract
Metasurfaces endowed with spin-decoupled functionalities offer the capability to meticulously customize the electromagnetic wavefronts of incident dual orthogonal circularly-polarized (CP) waves in a desirable manner, that holds immense potential for broadening their application fields. Nevertheless, a major lack that persists in most spin-decoupled metasurfaces is the limited bandwidth or the intricate design requirements. Herein, we propose a broadband spin-decoupled metasurface, consisted of weak-resonant mirror-symmetry unit structures, that enables independent and distinct wavefront manipulations under the incidence of orthogonal CP waves. As a demonstration, we present a dual-channel metasurface that integrates geometric and propagation phases to generate vortex waves with two distinct modes in a wide frequency range from 10 GHz to 16 GHz. Both simulated and experimental results are consistent and collectively confirm the validity of our proposed metasurface. The research provides a practical and efficient avenue for constructing spin-decoupled metasurface within a broad frequency band.
Spectral distortion signatures of step-like inflationary potential
Authors: Mastache Jorge , Barrera Wilson , Henríquez-Ortiz Raúl 
Published: May 2024

Abstract
In this work, we analyze a power-law inflationary potential enhanced with a step that can introduce features in the primordial power spectrum. We focus on the computation of the Spectral Distortions (SD) induced by these features obtained from the inflationary dynamics. In this scenario, we explore the potential of upcoming experimental missions like PIXIE to detect the SD of the model within a power of n = 2/3, a power that agrees with recent tensor-to-scalar ratio constraints. The model offers insights into models with cosmological phases and different scalar field dynamics. Introducing a step in the inflaton potential leads to distinct features in the primordial power spectrum, such as oscillations and localized enhancements/suppressions at specific scales. We analyze the impact of three primary parameters — β, δ, and ϕ
step — on the amplitude and characteristics of the SD. The ϕ
step places the onset of the oscillations in the primordial power spectrum. The β parameter significantly influences the magnitude of the μ-SD, with its increase leading to larger SD and vice versa. Similarly, the δ parameter affects the smoothness of the step in the potential, with larger values resulting in smaller SD. Our findings indicate a distinct parameter space defined by 0.02 < δ/Mpl ≲ 0.026, 0.10 ≲ β < 0.23, and 7.53 ≲ ϕ
step/ Mpl ≲ 7.55, which produces SD potentially detectable by PIXIE. This region also corresponds to the maximum observed values of μ and y SD, which in special cases are an order of magnitude larger than the expected for ΛCDM. However, we also identify parameter ranges where μ and y SD may not be detectable due to the limitations of current observational technology. This comprehensive analysis of SD provides constraints of step-like inflationary models and their implications on its dynamics.
Quantum gravity effects on fermionic dark matter and gravitational waves
Authors: King Stephen F. , Roshan Rishav , Wang Xin , White Graham , Yamazaki Masahito 
Published: May 2024

Abstract
We explore the phenomenological consequences of breaking discrete global symmetries in
quantum gravity (QG). We extend a previous scenario where discrete global symmetries are
responsible for scalar dark matter (DM) and domain walls (DWs), to the case of fermionic DM,
considered as a feebly interacting massive particle, which achieves the correct DM relic density
via the freeze-in mechanism. Due to the mixing between DM and the standard model neutrinos,
various indirect DM detection methods can be employed to constrain the QG scale, the scale of
freeze-in, and the reheating temperature simultaneously. Since such QG symmetry breaking leads to
DW annihilation, this may generate the characteristic gravitational wave background, and hence
explain the recent observations of the gravitational wave spectrum by pulsar timing arrays. This
work therefore highlights a tantalizing possibility of probing the effective scale of QG
from observations.
How robust are gravitational wave predictions from cosmological phase transitions?
Authors: Athron Peter , Morris Lachlan , Xu Zhongxiu 
Published: May 2024

Abstract
Gravitational wave (GW) predictions of cosmological phase transitions are almost invariably evaluated at either the nucleation or percolation temperature. We investigate the effect of the transition temperature choice on GW predictions, for phase transitions with weak, intermediate and strong supercooling. We find that the peak amplitude of the GW signal varies by a factor of a few for weakly supercooled phase transitions, and by an order of magnitude for strongly supercooled phase transitions. The variation in amplitude for even weakly supercooled phase transitions can be several orders of magnitude if one uses the mean bubble separation, while the variation is milder if one uses the mean bubble radius instead. We also investigate the impact of various approximations used in GW predictions. Many of these approximations introduce at least a 10% error in the GW signal, with others introducing an error of over an order of magnitude.
Wide binaries and modified gravity (MOG)
Authors: Moffat J.W. 
Published: May 2024

Abstract
Wide binary stars are used to test the modified gravity called Scalar-Tensor-Vector Gravity or MOG. This theory is based on the additional gravitational degrees of freedom, the scalar field G = GN
(1+α), where GN
is Newton's constant, and the massive (spin-1 graviton) vector field ϕμ
. The wide binaries have separations of 2–30 kAU. The MOG acceleration law, derived from the MOG field equations and equations of motion of a massive test particle for weak gravitational fields, depends on the enhanced gravitational constant G = GN
(1+α) and the effective running mass μ. The magnitude of α depends on the physical length scale or averaging scale ℓ of the system. The modified MOG acceleration law for weak gravitational fields predicts that for the solar system and for the wide binary star systems gravitational dynamics follows Newton's law.
Féeton (B-L gauge boson) dark matter for the 511-keV gamma-ray excess and the prediction of low-energy neutrino flux*
Authors: Sheng 盛 Jie 杰 , Cheng 程 Yu 昱 , Lin 林 Weikang 伟康 , Yanagida Tsutomu T. 
Published: May 2024

Abstract
The féeton is the gauge boson of the

gauge theory. If the gauge coupling constant is extremely small, the féeton becomes a candidate for dark matter. We show that its decay to a pair of an electron and a positron explains the observed Galactic 511-keV gamma-ray excess in a consistent manner. This féeton dark matter decays mainly into pairs neutrino and anti-neutrino. Future low-energy experiments with improved directional capability will enable capturing these neutrino signals. The seesaw-motivated parameter space predicts a relatively short féeton lifetime that is comparable to the current cosmological constraint.
Analysis of fusion alphas interaction with RF waves in D-T plasma at JET
Authors: Kirov K.K. , Auriemma F. , Bonofiglo P.J. , Challis C.D. , De la Luna E. , Eriksson J. , Gallart D. , Garcia J. , Gorelenkova M. , Hobirk J. , Jacquet P. , Kappatou A. , Kazakov Y. , Keeling D. , King D. , Kiptily V. , Lerche E. , Maggi C. , Mailloux J. , Mantica P. , Mantsinen M. , Maslov M. , Menmuir S. , Sharma R. , Siren P. , Stancar Z. , Van Eester D. ,   JET Contributors
Published: May 2024

Abstract
This work studies the influence of radio frequency (RF) waves in the ion cyclotron resonance heating (ICRH) range of frequencies on fusion alphas during the recent JET D-T campaign. Fusion alphas from D-T reactions are created with energies of about 3.5 MeV and therefore have significant Doppler shifts enabling synergistic interactions between them and RF waves at a broad range of frequencies, including the ones foreseen for future fusion machines in ITER (Schneider et al 2021 Nucl. Fusion
61 126058) and SPARC (Creely et al 2020 J. Plasma Phys.
86 865860502). Resonant interactions between RF waves and alphas, also called synergistic effects, will modify the alpha distribution and ultimately will have an impact on alpha orbit losses and heating. Data from JET 3.43 T/2.3 MA pulses based on the hybrid scenario (Hobirk et al 2023 Nucl. Fusion; Hobirk et al 29th IAEA FEC23 Conf. (16–21 October 2023); Challis et al 48th EPS Conf. on Plasma Physics (27 June–1 July 2022) during the DTE2 campaign (Maggi et al 2023 Nucl. Fusion)) were used for the analysis in this study. The impact of synergistic effects on alpha orbit losses and alpha heating are assessed. The conclusions are based on the analysis of experimental data for fast alpha losses, i.e. measurements from neutral particle analyser (NPA), fast ion losses scintillator detector, Faraday cups (FCs), and TRANSP (Hawryluk et al 1980 Physics of Plasmas Close to Thermonuclear Conditions vol 1 (CEC) pp 19–46) simulations. Experimental data and TRANSP analysis indicates that there are indeed changes in the alpha distribution function (DF) due to interaction with RF waves. Data from the NPA show increased 4He flux in the range from a few hundred keV up to 800 keV for pulses with RF power, while TRANSP clearly shows modifications in the fast alpha DF for these energies. Data from the scintillator detector and the FCs were compared for pulses with and without ICRH power and versus cases with enhanced alpha losses due to MHD activity. The trends from these diagnostics consistently show no additional alpha losses due to interaction with RF waves. TRANSP predictions for the impact of ynergistic effects on alpha heating show up to a 42% increase in alpha electron heating and up to a 25% increase in alpha ion heating. These effects, however, become negligibly small, less than 1%, when alpha heating is compared to the total auxiliary heating power in the investigated JET pulses.
Beam dynamics design and error study of the coupled structure with ladder RFQ and IH-DTL
Authors: Li H.P. , Su H.Q. , Kong G.Q. , Pan W.L. , Lin J.R.L. , Lu Y.R. , Wang S. 
Published: May 2024

Abstract
The coupled structure with ladder radio-frequency quadrupole
(RFQ) and interdigital H-type drift tube linac (IH DTL) has been
proposed to accelerate the proton beam to several MeV with high
acceleration gradient and one RF feed-in system. A ladder RFQ-IH DTL
coupled structure was designed to accelerate a proton beam 2.5 MeV
with a peak current of 15 mA. Detailed dynamics optimization and
error study were performed to achieve high transmission efficiency
and small emittance growth, including ladder RFQ, coupling section
and IH DTL section. The Kombinierte Null Grad Struktur (KONUS)
dynamics scheme with two quadrupole doublets (QDs) was adopted in
the IH-DTL section. Start-to-end beam tracking results showed that
the proton beam can be accelerated to the final energy with a length
of 2.11 m and a transmission efficiency above 98.5%. In addition,
we performed error sensitivity analysis and the combined error study
to evaluate the error tolerance limits of the ladder RFQ-IH DTL
coupled structure.
Performance of the mass testing setup for arrays of silicon photomultipliers in the TAO experiment.
Authors: Rybnikov A. , Anfimov N. , Qu M. , Chetverikov A. , Cao G. , Fedoseev D. , Wang H. , Kozhukalov V. , Sharov V. , Sokolov S. , Sotnikov A. 
Published: May 2024

Abstract
Modern neutrino physics detectors often employ thousands,
and sometimes even hundreds of thousands, of Silicon
Photomultipliers (SiPMs). The TAO experiment [1] is a
notable example that utilizes a spherical scintillator barrel with a
diameter of 1.8 meters, housing approximately 130,000 SiPMs
organized into 4,100 tiles. Each tile with size of
5×5 cm2 consists of a 32-SiPM array functioning as a
single detector unit. To achieve an unparalleled energy resolution
of 2% at 1 MeV within this volume, the SiPMs must possess
cutting-edge parameters, including a photon detection efficiency
(PDE) exceeding 50%, cross-talk of approximately 10%, and an
extremely low dark count rate (DCR) below
50 Hz/mm2. Maintaining the setup at a negative temperature of
-50°C is necessary to achieve the desired DCR. This article
presents the setup and methods employed to individually characterize
the mass of SiPMs across all 4,100 tiles at the specified negative
temperature.
Rapid high-latitude cooling in the southeastern Pacific sector driven by North Atlantic warming during 1979–2013 in CESM1
Authors: Yao Shuai-Lei , Wu Renguang , Wang Pengfei , Chen Shangfeng 
Published: May 2024

Abstract
During the 1979–2013 satellite observation period, the sea surface temperature (SST) has cooled substantially in the high-latitude Southern Ocean, with the most pronounced cooling tendency centered in the southeastern Pacific domain. Previous hypotheses have commonly ascribed the recent Southern Ocean cooling to either the tropical eastern Pacific cooling or North Atlantic and tropical Indian Ocean SST warming. However, the mechanisms underpinning significant cooling in the southeastern Pacific sector remain debatable. By diagnosing three pacemaker experiments with a state-of-the-art global climate model in which SSTs in the North Atlantic, tropical central-eastern Pacific, and tropical Indian Ocean-western Pacific are individually nudged to mimic the observed trajectory, we show that the North Atlantic dominates in the cold SST response of the southeastern Pacific sector during 1979–2013. Anomalous North Atlantic warming initiates a quasi-stationary Rossby wave response to a south-to-north cross-equatorial Hadley circulation strengthening, leading to an enhanced Amundsen Sea Low. As a result, due primarily to the increased low-level marine cloud cover, the net surface shortwave radiation reduction triggers rapid SST cooling in the southeastern Pacific domain. The southeastern Pacific cold SST anomalies are further maintained via the shortwave radiation-low-cloud-SST positive feedback on decadal timescales. Our results suggest that the shortwave radiation-low-cloud SST feedback is fundamental to the observed long-term cooling of the high-latitude Southern Ocean, with profound climate consequences worldwide.
Pillar electrodes embedded in the skeletal muscle tissue for selective stimulation of biohybrid actuators with increased contractile distance
Authors: Li Tingyu , Nie Minghao , Morimoto Yuya , Takeuchi Shoji 
Published: May 2024

Abstract
Electrodes are crucial for controlling the movements of biohybrid robots, but their external placement outside muscle tissue often leads to inefficient and non-selective stimulation of nearby biohybrid actuators. To address this, we propose embedding pillar electrodes within the skeletal muscle tissue, resulting in enhanced contraction of the target muscle without affecting the neighbor tissue with a 4 mm distance. We use finite element method simulations to establish a selectivity model, correlating the VIE (volume integration of electric field intensity within muscle tissue) with actual contractile distances under different amplitudes of electrical pulses. The simulated selective index closely aligns with experimental results, showing the potential of pillar electrodes for effective and selective biohybrid actuator stimulation. In experiments, we validated that the contractile distance and selectivity achieved with these pillar electrodes exceed conventional Au rod electrodes. This innovation has promising implications for building biohybrid robots with densely arranged muscle tissue, ultimately achieving more human-like movements. Additionally, our selectivity model offers valuable predictive tools for assessing electrical stimulation effects with different electrode designs.