bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of MHD modes on EAST using a deep learning framework
Authors: Kong Lingyi , Guo Bihao , Shen Biao , Shi Tonghui , Chen Dalong , Huang Yao , Zhang Qirui , Xiao Bingjia 
Published: December 2023

Abstract
The improvement of plasma parameters is severely limited by magnetohydrodynamic (MHD) instabilities. The identification of MHD modes is crucial for the study and control of MHD instabilities. In this study, an MHD mode identifier is developed based on a temporal convolutional network and long short-term memory (LSTM) network. The identifier is trained and tested on a small dataset containing 33 shots. Firstly, the temporal convolutional network encodes 27 diagnostic signals and then decodes them using LSTM network with different parameters to obtain the MHD modes and their frequency and intensity. The identifier exhibits an accuracy of approximately 98.38% on the test set and can accurately calculate the frequency and intensity of the MHD modes. To further examine the performance of the identifier, seven shots outside the dataset are used for shot-by-shot testing. The identifier can accurately identify the time period of tearing modes, and the identification accuracies of 2/1 and 3/2 tearing modes are 92.7% and 100%, respectively. The identification accuracy of the fishbone mode is slightly worse, only 82.1%. This is because the fishbone mode occurs intermittently. The frequent switching between the fishbone mode and no MHD behavior affects the identification of the fishbone mode. Overall, through the training of the small datasets, the identifier exhibits a good identification performance for the MHD modes. The proposed data-driven identifier can serve as a reference for establishing a large MHD mode database of EAST as well as a real-time MHD identification and control algorithm.
Quantum phase transitions in two-dimensional superconductors: a review on recent experimental progress
Authors: Wang Ziqiao , Liu Yi , Ji Chengcheng , Wang Jian 
Published: December 2023

Abstract
Superconductor–insulator/metal transition (SMT) as a paradigm of quantum phase transition has been a research highlight over the last three decades. Benefit from recent developments in the fabrication and measurements of two-dimensional (2D) superconducting films and nanodevices, unprecedented quantum phenomena have been revealed in the quantum phase transitions of 2D superconductors. In this review, we introduce the recent progress on quantum phase transitions in 2D superconductors, focusing on the quantum Griffiths singularity (QGS) and anomalous metal state. Characterized by a divergent critical exponent when approaching zero temperature, QGS of SMT is discovered in ultrathin crystalline Ga films and subsequently detected in various 2D superconductors. The universality of QGS indicates the profound influence of quenched disorder on quantum phase transitions. Besides, in a 2D superconducting system, whether a metallic ground state can exist is a long-sought mystery. Early experimental studies indicate an intermediate metallic state in the quantum phase transition of 2D superconductors. Recently, in high-temperature superconducting films with patterned nanopores, a robust anomalous metal state (i.e. quantum metal or Bose metal) has been detected, featured as the saturated resistance in the low temperature regime. Moreover, the charge-2e quantum oscillations are observed in nanopatterned films, indicating the bosonic nature of the anomalous metal state and ending the debate on whether bosons can exist as a metal. The evidences of the anomalous metal states have also been reported in crystalline epitaxial thin films and exfoliated nanoflakes, as well as granular composite films. High quality filters are used in these works to exclude the influence of external high frequency noises in ultralow temperature measurements. The observations of QGS and metallic ground states in 2D superconductors not only reveal the prominent role of quantum fluctuations and dissipations but also provide new perspective to explore quantum phase transitions in superconducting systems.
Silicon ultrafast recovery diode with leakage current reduced via the combined lifetime process of gold diffusion and electron-beam irradiation
Authors: Onishi Hideto , Shirai Hajime 
Published: December 2023

Abstract
We investigated the reduction in the reverse-biased leakage current of Si ultrafast recovery diodes via a combined lifetime process involving Au diffusion and bulk electron-beam irradiation (EI). The leakage current of the combined-processed diode was significantly reduced to less than one-third of that of the diode processed solely with Au diffusion, maintaining a similar switching time of 32 ns. This reduction was not achievable with the sole use of EI. Deep-level transient spectroscopy revealed that the reduction in the leakage current was due to the coexistence of the deep trap level of Au (E
c-0.51 eV) and the shallow trap level of the defects (E
c-0.39 eV) generated via EI as lifetime killers. By combining the deep and shallow trap levels, the lifetime of the carriers generated in the depletion layer of the reverse-biased p-n junction becomes long and consequently, the leakage current is reduced. By maintaining the trap density ratio of defects to diffused Au above 0.28, the leakage current was reduced to less than one-third of that in the solely Au-diffused diode, while maintaining a similar switching time.
Epitaxial growth of high-quality Ge layers on Si with Ge2H6 under UHV-CVD conditions
Authors: Xie Changjiang , Li Yue , Xu Chi , Wang Yixin , Cong Hui , Xue Chunlai 
Published: December 2023

Abstract
Epitaxial growth of Ge films on Si(100) substrates has been studied under ultra-high vacuum chemical vapor deposition (CVD) conditions by using digermane (Ge2H6) as the precursor. It was found out that high quality layers with thicknesses beyond 500 nm could be produced at complementary metal–oxide–semiconductor compatible conditions, demonstrating low defect density, sharp and narrow x-ray diffraction peaks, as well as room temperature photoluminescence around 1550 nm. The surface roughness values are comparable to prior reduced pressure CVD results at similar growth temperatures. By employing higher growth temperatures, growth rates are significantly enhanced, resulting in much thicker layers beyond 2000 nm. Smoother sample surface could also be obtained, yielding a state-of-the-art surface root-mean-square roughness value of 0.34 nm for the as-grown sample. At the same time, after being annealed at 750 °C for 20 min, the full width at half maximum (FWHM) of x-ray diffraction 004 rocking curve spectrum of the Ge layer is as low as 88 arcseconds, which stands the best among all Ge/Si samples. The current work has provided important reference for Ge/Si growth with Ge2H6 in low pressure regime and solidified material grounding for Ge-based optoelectronics and Si photonics.
Vascular adaptation model from force balance: Physarum polycephalum as a case study
Authors: Marbach Sophie , Ziethen Noah , Alim Karen 
Published: December 2023

Abstract
Understanding vascular adaptation, namely what drives veins to shrink or grow, is key for the self-organization of flow networks and their optimization. From the top–down principle of minimizing flow dissipation at a fixed metabolic cost within flow networks, flow shear rate resulting from the flows pervading veins is hypothesized to drive vein adaptation. Yet, there is no proposed mechanism of how flow forces impact vein dynamics. From the physical principle of force balance, shear rate acts parallel to vein walls, and hence, naively shear rate could only stretch veins and not dilate or shrink them. We, here, resolve this paradox by theoretically investigating force balance on a vein wall in the context of the vascular network of the model organism Physarum polycephalum. We propose, based on previous mechanical studies of cross-linked gels, that shear induces a nonlinear, orthogonal response of the actomyosin gel making up vein walls, that can indeed drive vein dilatation. Furthermore, our force balance approach allows us to identify that shear feedback occurs with a typical timescale and with a typical target shear rate that are not universal properties of the material but instead depend smoothly on the vein’s location within the network. In particular, the target shear rate is related to the vein’s hydrostatic pressure, which highlights the role of pressure in vascular adaptation in this context. Finally, since our derivation is based on force balance and fluid mechanics, we believe our approach can be extended, giving attention to specific differences, to describe vascular adaptation in other organisms.
Superconducting pump manipulated by non-topologically quasi and topological interface states
Authors: Ding Zixuan , Wang Sake , Li Mengyao , Tao Yongchun , Wang Jun 
Published: December 2023

Abstract
We propose an adiabatic superconducting charge pump based on massive Dirac electrons. A superconductor is sandwiched in between two pumping sources, which are formed by introducing the time-dependent and out-of-phase staggered potentials in graphene as pumping parameters. The pump is shown to be characterized by not only the topological interface state (TIS) but also the non-topologically quasi interface state (QIS). Hereafter, our attention is focused on the pumping currents

I

L

NR

and

I

L

AR

from the normal and Andreev reflections, respectively, which predominate by making the electron energy reside in the effective energy gap. It is found that modulating the energy E, superconductor length L
0, and pumping source length

L

P

results in the considerable variation of competitive behaviors between

I

L

NR

and

I

L

AR

. In particular, the reversal effect of current direction can be realized by tuning

L

P

. More interestingly, the current-phase relationship exhibits the platform behaviors, which can be manipulated by

L

P

and the pumping strength. All the above pumping properties are attributed to the adiabatic evolution of TIS and non-topologically QIS, particularly the conversion between each other is the crucial origin. We also obtain the quantized pumping current by adjusting

L

P

and L
0, and present the corresponding qualitative explanation through the pumping contour circled by the two parameters. In addition, we discuss the features of pumping current based on the armchair graphene as well.
Continuous-time quantum harmonic oscillator state engineering
Authors: García Herrera E , Torres-Leal F , Rodríguez-Lara B M 
Published: December 2023

Abstract
The center of mass motion of trapped ions and neutral atoms is suitable for approximation by a time-dependent driven quantum harmonic oscillator whose frequency and driving strength may be controlled with high precision. We show the time evolution for these systems with continuous differentiable time-dependent parameters in terms of the three basic operations provided by its underlying symmetry, rotation, displacement, and squeezing, using a Lie algebraic approach. Our factorization of the dynamics allows for the intuitive construction of protocols for state engineering, for example, creating and removing displacement and squeezing, as well as their combinations, optimizing squeezing, or more complex protocols that work for slow and fast rates of change in the oscillator parameters.
Color image ROI encryption algorithm based on a novel 4D hyperchaotic system
Authors: Wang Lujie , Chen Zhong , Sun Xiyu , He Chenchen 
Published: December 2023

Abstract
The significance of safeguarding the security of image information has escalated significantly, owing to the exponential proliferation of digital images containing sensitive information being disseminated on the Internet. In this paper, we first propose a novel 4D hyperchaotic system and design a new image encryption algorithm in conjunction with the hyperchaotic system. The algorithm uses a split random swap permutation method to permute the image and combines the S-box to diffuse the image. To improve the diffusivity of this encryption algorithm, a cross-random diffusion method is designed to diffuse the image again. Then, we propose a region of interest (ROI) encryption scheme for images. This scheme can automatically identify irregular privacy targets in images and encrypt them. To ensure the security of the region of interest location information during transmission, the scheme compresses the location information of the privacy target using a run-length encoding technique and then embeds the compressed data into the ciphertext image using reversible steganography based on histogram shift. The experimental results and security analysis unequivocally demonstrate that the image encryption algorithm proposed in this paper exhibits robust resistance against a wide array of attacks, thereby ensuring a high level of security. Additionally, the devised image ROI encryption scheme effectively safeguards diverse privacy targets.
Matter bounce scenario in matter geometry coupled theory
Authors: Suzuki T , Almutairi Bander , Aman H 
Published: December 2023

Abstract
This paper studies the cosmographic and matter bounce scenario in modified theory. The corresponding field equations are evaluated after considering special corrections of a Hubble parameter. The linear corrections to the Gauss-Bonnet gravity are being taken to analyze the behavior of Hubble and deceleration parameters. We derive dynamical parameters in a very general way to analyze different energy conditions that would lead to understanding the behavior of the equation of state parameters in cosmography. Finally, the removal of the initial singularity is observed to understand the late-time cosmic acceleration.
General relativity and background Lorentz transformations solve Supplee's submarine paradox
Authors: Karkout Osama 
Published: December 2023

Abstract
A submarine moving at relativistic horizontal velocity sinks in Earth's rest frame due to length contraction while appearing to float in its own frame. Using spacetime geometry and the Lorentz transformations, we show that the resolution lies in how metric components transform between reference frames in relative motion. This solution frees us from assumptions made in previous studies on how a Newtonian gravitational force should transform. The method of background Lorentz transformations is technically simpler than previous treatments in the framework of general relativity. Moreover, we find a novel and intuitive understanding of the paradox, and correct an erroneous expression for the gravitational force obtained by Supplee and used again in the literature.
Theory of
k⃗⋅p⃗
electronic structure and effective masses of ultra-wide bandgap wurtzite aluminum nitride
Authors: Tripathi Gouri S 
Published: December 2023

Abstract
I develop a

k

⃗

·

p

⃗

theory of electronic structure for wurtzite(W)-Aluminium Nitride, based on the three uppermost valence bands and the lowest conduction band at the Γ-point. As distinguished from the Chuang-Chang approach [9], where the

k

⃗

·

p

⃗

Hamiltonian is diagonalised considering all the bands, through an

8
×
8

matrix, I follow a different procedure. In my approach, initially I follow a two-band approximation for the

k

⃗

·

p

⃗

matrix, where the

k

⃗

·

p

⃗

Hamiltonian is diagonalised by treating the conduction band and each of the valence bands separately. Thus, I diagonalise three different

4
×
4

matrices, for obtaining the dispersions of the valence bands. The conduction band energy is obtained from the first diagonalization, involving band edge states. Effect of other two valence bands on a given valence band is considered through second order perturbation theory. Details of this procedure are outlined in Appendix A. It gives analytic expressions for the dispersion of the bands. I compare the results obtained for W-AlN with recent calculations and note satisfactory agreements. I also calculate the effective masses of holes in the valence bands both at the Γ-point and also as functions of the wavevector. My results agree fairly well with a recent calculation [3]. The hole effective masses for all the bands show large anisotropy. The effective mass of the electron in the conduction band does not show appreciable anisotropy.
Predicting interloper fraction with graph neural networks
Authors: Massara Elena , Villaescusa-Navarro Francisco , Percival Will J. 
Published: December 2023

Abstract
Upcoming emission-line spectroscopic surveys, such as Euclid and the Roman Space Telescope, will be affected by systematic effects due to the presence of interlopers: galaxies whose redshift and distance from us are miscalculated due to line confusion in their emission spectra. Particularly pernicious are interlopers involving the confusion between two lines with close emitted wavelengths, like Hβ emitters confused as [O iii], since those are strongly spatially correlated with the target galaxies. They introduce a particular pattern in the 3D distribution of the observed galaxy catalog that can shift the position of the BAO peak in the galaxy correlation function and bias any cosmological analysis performed with that sample. Here we present a novel method to predict the fraction of interlopers in a galaxy catalog, using Graph Neural Networks (GNNs) to learn the posterior distribution of the interloper fraction while marginalizing over cosmology and galaxy bias. The method is developed using simulations with halos acting as a proxy for galaxies. The GNN can infer the mean and standard deviation of the posterior distribution of interloper fraction using small-scale information that is usually not considered in cosmological analyses. The injection of large-scale information into the graph as a global attribute improves the performance of the GNN when marginalizing over cosmology.
Reheating constraints and consistency relations of the Starobinsky model and some of its generalizations
Authors: Garcia Marcos A.G. , Germán Gabriel , Gonzalez Quaglia R. , Moran Colorado A.M. 
Published: December 2023

Abstract
Building on the success of the Starobinsky model in describing the inflationary period of the universe, we investigate two simple generalizations of this model and their constraints imposed by the reheating epoch. The first generalization takes the form R
2p
, while the second is the α-Starobinsky model. We first focus on the case where p = 1 or equivalently, α = 1, which corresponds to the original Starobinsky model.
We derive exact consistency relations between observables and cosmological quantities, without neglecting any terms, and impose the reheating condition 0 < ω
re
< 0.25, where ω
re
is the equation of state parameter at the end of reheating. This allows us to obtain new bounds for ns
and r that satisfy this condition and apply them to other observables and cosmological quantities. We repeat this process for the cases where p ≠ 1 and α ≠ 1 and find that these generalizations only result in minor modifications of the Starobinsky model, including the potential and the bounds on observables and cosmological quantities.
Gravitational interaction of ultralight dark matter with interferometers
Authors: Kim Hyungjin 
Published: December 2023

AbstractUltralight dark matter exhibits an order-one density fluctuation over the spatial scale of its wavelength. These fluctuations gravitationally interact with gravitational wave interferometers, leading to distinctive signals in detectors. We investigate the ultralight dark matter-induced effects in the gravitational wave interferometers. We perform a systematic computation of the power spectrum of ultralight dark matter in interferometers. We show that the ultralight dark matter-induced effect is most relevant for the interferometers with long baseline and that it is only a sub-leading effect compared to the estimated noise level in the case of Laser Interferometer Space Antenna or future interferometers with an arm-length comparable to a few astronomical units. Gravitational wave interferometers can then place upper limits on the ultralight dark matter density in the solar system. We find that, under certain assumptions, future interferometers with AU-scale arm-length might probe the dark matter density a few hundred times the local dark matter density, which is measured over a much larger spatial scale.
Non-standard cosmic expansion histories: neutrino decoupling and primordial nucleosynthesis signatures
Authors: Aristizabal Sierra D. , Gariazzo S. , Villanueva A. 
Published: December 2023

Abstract
Cosmological scenarios with a non-standard equation of state can
involve ultrastiff fluids, understood as primordial fluids for which p/ρ > 1. Their energy densities can dominate the Universe
energy budget at early times, in the otherwise radiation dominated
epoch. During that period the Universe undergoes a faster expansion,
that has implications for any decoupling process that takes place in
that era. Quintessence models or Ekpyrotic cosmologies are good
examples of such scenarios. Assuming the ultrastiff state to be
thermally decoupled at very early times, if ever coupled, its
observational imprints are left solely in the Universe expansion
rate and in the radiation energy density. We consider a complete set
of ultrastiff fluids and study their signatures in the neutrino
decoupling and BBN eras. Measurements of N
eff alone place
mild constraints on these scenarios, with forthcoming measurements
from the Simons Observatory in the Chilean Atacama desert being able
to test regions where still sizable effects are observable. However,
when BBN data is taken into account, those regions are proven to be
barely reconcilable with primordial helium-4 and deuterium
abundances measurements. Our findings show that measurements of the
primordial helium-4 abundance imply the tightest constraints, with
measurements of primordial deuterium being — to a certain
extent — competitive as well. We point out that a ∼ 60%
improvement on the statistical uncertainty of the primordial
helium-4 abundance measurement, will test these scenarios in the
region where they can produce sizable effects. Beyond that precision
the regions that are accessible degenerate with standard
expectations. In that case, although potentially present, neither
neutrino decoupling nor BBN observables will be sensitive probes.
Modified gravity and massive neutrinos: constraints from the full shape analysis of BOSS galaxies and forecasts for Stage IV surveys
Authors: Moretti Chiara , Tsedrik Maria , Carrilho Pedro , Pourtsidou Alkistis 
Published: December 2023

Abstract
We constrain the growth index γ by performing a
full-shape analysis of the power spectrum multipoles measured from
the BOSS DR12 data. We adopt a theoretical model based on the
Effective Field theory of the Large Scale Structure (EFTofLSS) and
focus on two different cosmologies: γCDM and γνCDM, where we
also vary the total neutrino mass. We explore different choices for
the priors on the primordial amplitude As
and spectral index ns
, finding that informative priors are necessary to alleviate
degeneracies between the parameters and avoid strong projection
effects in the posterior distributions. Our tightest constraints
are obtained with 3σ Planck priors on As
and ns
: we
obtain γ = 0.647 ± 0.085 for γCDM and γ = 0.612+0.075
-0.090, Mν
< 0.30 for γνCDM at 68% c.l.,
in both cases ∼ 1σ consistent with the ΛCDM
prediction γ ≃ 0.55. Additionally, we produce forecasts
for a Stage-IV spectroscopic galaxy survey, focusing on a DESI-like
sample. We fit synthetic data-vectors for three different galaxy
samples generated at three different redshift bins, both
individually and jointly. Focusing on the constraining power of the
Large Scale Structure alone, we find that forthcoming data can give
an improvement of up to ∼ 85% in the measurement of γ with respect to the BOSS dataset when no CMB priors are imposed. On
the other hand, we find the neutrino mass constraints to be only
marginally better than the current ones, with future data able to
put an upper limit of Mν
< 0.27 eV. This result can be
improved with the inclusion of Planck priors on the primordial
parameters, which yield Mν
< 0.18 eV.