bluuebunny/crossref_metadata_2025 huggingface dataset:
Magneto-optical detection of terahertz cavity magnon-polaritons in antiferromagnetic HoFeO3
Authors: Blank T. G. H. , Grishunin K. A. , Kimel A. V.
Published: February 2023

An intense THz pulse excites a high-Q magnetic resonance mode in the antiferromagnetic insulator HoFeO3 by the THz Zeeman torque. By using magneto-optical detection and sweeping the temperature, we observed an anomalous beating in the magnon dynamics for certain temperatures. The beating originates from the formation of cavity magnon-polaritons upon the intersection of the antiferromagnetic resonance frequency with the frequencies of the Fabry–Pérot modes inside the etalon formed by the sample cavity in the weak coupling limit. The validity of this idea is demonstrated by simulations using Maxwell's equations. Furthermore, the observed beating pattern depends on the polarization of the probe pulse. This dependence can be reproduced in the simulations by considering an imaginary Verdet constant, which could be a result of an interplay between the magneto-optical Faraday effect and static linear birefringence.
Control of electron beam current, charge, and energy spread using density downramp injection in laser wakefield accelerators
Authors: Hue Céline S. , Wan Yang , Levine Eitan Y. , Malka Victor
Published: February 2023

Density downramp injection has been demonstrated to be an elegant and efficient approach for generating high-quality electron beams in laser wakefield accelerators. Recent studies have demonstrated the possibilities of generating electron beams with charges ranging from tens to hundreds of picocoulombs while maintaining good beam quality. However, the plasma and laser parameters in these studies have been limited to specific ranges or attention has been focused on separate physical processes such as beam loading, which affects the uniformity of the accelerating field and thus the energy spread of the trapped electrons, the repulsive force from the rear spike of the bubble, which reduces the transverse momentum p⊥ of the trapped electrons and results in small beam emittance, and the laser evolution when traveling in the plasma. In this work, we present a comprehensive numerical study of downramp injection in the laser wakefield, and we demonstrate that the current profile of the injected electron beam is directly correlated with the density transition parameters, which further affects the beam charge and energy evolution. By fine-tuning the plasma density parameters, electron beams with high charge (up to several hundreds of picocoulombs) and low energy spread (around 1% FWHM) can be obtained. All these results are supported by large-scale quasi-three-dimensional particle-in-cell simulations. We anticipate that the electron beams with tunable beam properties generated using this approach will be suitable for a wide range of applications.
The electron diffusion region dominated by electromagnetic turbulence in the reconnection current layer
Authors: Fujimoto Keizo , Sydora Richard D.
Published: February 2023

Most of the plasma fluid equations have employed the electrical resistivity to generate the magnetic dissipation required for magnetic reconnection to occur in collisionless plasma. However, there has been no clear evidence that such a model is indeed appropriate in the reconnection diffusion region in terms of the kinetic physics. The present study demonstrates that, using a large-scale 3D kinetic simulation and analytical analysis, the spatial distribution of the non-ideal electric field is consistent with the dissipation due to the viscosity rather than the resistivity, when electromagnetic (EM) turbulence is dominant in the electron diffusion region (EDR). The effective viscosity is caused by the EM turbulence that is driven by the flow shear instabilities leading to the electron momentum transport across the EDR. The result suggests a fundamental modification of the fluid equations using the resistivity in the Ohm's law. In contrast, for the 2D current sheet without significant turbulence activity, the non-ideal field profile does not obey the simple form based on the viscosity, so that further investigation is needed for a better description.
Wigner 6j symbols for SU(N): Symbols with at least two quark-lines
Authors: Alcock-Zeilinger Judith , Keppeler Stefan , Plätzer Simon , Sjodahl Malin
Published: February 2023

We study a class of SU(N) Wigner 6j symbols involving two fundamental representations and derive explicit formulas for all 6j symbols in this class. Our formulas express the 6j symbols in terms of the dimensions of the involved representations, and they are thereby functions of N. We view these explicit formulas as a first step toward efficiently decomposing SU(N) color structures in terms of group invariants.
Dynamic correlations of renewable-energy companies: Evidence from a multilayer network model
Authors: Gao Cuixia , Mao Yu , Li Juan , Sun Mei , Ji Zhangyi
Published: February 2023

Against the background of seeking to achieve carbon neutrality, relationships among renewable-energy companies around the world have become multiple and complex. In this work, the Pearson, Kendall, tail, and partial correlation coefficients were applied to 51 global companies—including solar and wind firms, independent power plants, and utilities—to explore the linear, nonlinear, extreme-risk, and direct relations between them. Sample data from 7 August 2015 to 6 August 2021 were considered, and three sub-periods were extracted from these sample data by analysis of the evolution of multiple correlations combined with event analysis. A four-layer correlation network model was then constructed. The main results are as follows. (1) The multiple relations among the selected firms underwent dramatic changes during two external shocks (the China–US trade war and the COVID-19 pandemic). (2) The extreme-risk network layer verified that the trade war mainly affected the relationships among companies in the solar industries of China and the US. (3) During the COVID-19 pandemic period, the linear and direct relationships among wind firms from Canada, Spain, and Germany were significantly increased. In this sub-period, edge-weight distributions of the four different layers were heterogeneous and varied from power-law features to Gaussian distributions. (4) During all the sub-periods, most companies had similar numbers of neighbors, while the numbers of neighbors of a few companies varied greatly in the four different layers. These findings provide a useful reference for stakeholders and may help them understand the connectedness and evolution of global renewable-energy markets.
Universal cover-time distributions of random motion in bounded granular gases
Authors: Han Wen-Hui , Cheng Ke , Liu Xiao-Nan , Dong Jia-Qi , Chen Xiao-Song , Huang Liang
Published: February 2023

The exhaustive random exploration of a complex domain is a fundamental issue in many natural, social, and engineering systems. The key characterizing quantity is the cover time, which is the time to visit every site in the system. One prototypical experimental platform is the confined granular gas, where the random motion of granular particles mimics the wandering of random walkers in a confined region. Here, we investigate the cover-time distribution of the random motion of tracer particles in granular gases confined in four containers to account for different boundary and angle effects and examine whether the cover time of the heterogeneous random motion of the granular gases can be rescaled into the universal Gumbel distribution according to a recent theory [Dong et al., arXiv:2210.05122 (2022)]. It is found that for long cover times, the experimental results are in full accord, while for short cover times, the agreement is reasonable, with noticeable deviations that can be attributed to spatial correlations of the sites in the covering process. Our results, thus, call for further theoretical investigations in order to take into full account these nonideal issues.
Global well-posedness to the compressible nematic liquid crystal flows with large oscillations and vacuum in 3D exterior domains
Authors: Wang Fuguo , Zhong Xin
Published: February 2023

This paper aims at extending our previous work (Y. Liu and X. Zhong, arXiv:2204.06227) to the exterior problem. We show the global well-posedness of strong solutions to a simplified Ericksen–Leslie model of compressible nematic liquid crystal flows in a three-dimensional exterior domain when the initial total energy is sufficiently small. In order to obtain necessary a priori estimates on the boundary, some new analytic techniques are used.
Elastic, electronic, optical, and thermodynamic properties of M2SeC (M = Hf, Zr) under high pressure
Authors: Akhter Mehnaj , Ahasan Md Shamim , Ali M. A. , Parvin F.
Published: February 2023

The physical properties of the synthesized MAX phases M2SeC (M = Hf, Zr) have been investigated for the first time using the DFT method in the pressure range 0–25 GPa. The computed lattice parameters are consistent with the earlier findings at ambient pressure. The electronic band structure and energy dependent density of states reveal the metallic nature of the titled compounds. The metallic behavior of M2SeC (M = Hf, Zr) remains unchanged within the studied pressure range. Possible changes in the mechanical properties between Hf2SeC and Zr2SeC are revealed by analyzing the peaks in the density of states (DOS) for both compounds. Partial DOS is also considered under different pressures. The studied compounds remain mechanically stable up to 25 GPa. Both Hf2SeC and Zr2SeC are elastically anisotropic and brittle, but as the pressure increases up to 25 GPa, the brittleness of the materials decreases. At 5 and 10 GPa, however, both compounds exhibit a ductile behavior. The optical properties of Hf2SeC have been computed for the first time and compared with those of Zr2SeC. The investigated compounds are promising as solar heat reflectors due to their higher reflectivity in the low energy state. Different thermal properties, such as Debye temperature, melting temperature, and minimum thermal conductivity, have been explored within the studied pressure range to recognize their suitability for high-temperature applications. Both Hf2SeC and Zr2SeC have the potential to be used as coating materials for thermal barriers, although Hf2SeC is a better option.
The SET oncoprotein promotes estrogen-induced transcription by facilitating establishment of active chromatin
Authors: Guo Changying , Meza-Sosa Karla F. , Valle-Garcia David , Zhao Guomeng , Gao Kun , Yu Liting , Zhang Hongying , Chen Yeqing , Sun Liang , Rockowitz Shira , Wang Shouyu , Jiang Sheng , Lieberman Judy
Published: February 2023

SET is a multifunctional histone-binding oncoprotein that regulates transcription by an unclear mechanism. Here we show that SET enhances estrogen-dependent transcription. SET knockdown abrogates transcription of estrogen-responsive genes and their enhancer RNAs. In response to 17β-estradiol (E2), SET binds to the estrogen receptor α (ERα) and is recruited to ERα-bound enhancers and promoters at estrogen response elements (EREs). SET functions as a histone H2 chaperone that dynamically associates with H2A.Z via its acidic C-terminal domain and promotes H2A.Z incorporation, ERα, MLL1, and KDM3A loading and modulates histone methylation at EREs. SET depletion diminishes recruitment of condensin complexes to EREs and impairs E2-dependent enhancer-promoter looping. Thus, SET boosts E2-induced gene expression by establishing an active chromatin structure at ERα-bound enhancers and promoters, which is essential for transcriptional activation.
Soft, strong, tough, and durable protein-based fiber hydrogels
Authors: Wang Mingkun , Sun Shuofei , Dong Gening , Long Feifei , Butcher Jonathan T.
Published: February 2023

Load-bearing soft tissues normally show J-shaped stress–strain behaviors with high compliance at low strains yet high strength at high strains. They have high water content but are still tough and durable. By contrast, naturally derived hydrogels are weak and brittle. Although hydrogels prepared from synthetic polymers can be strong and tough, they do not have the desired bioactivity for emerging biomedical applications. Here, we present a thermomechanical approach to replicate the combinational properties of soft tissues in protein-based photocrosslinkable hydrogels. As a demonstration, we create a gelatin methacryloyl fiber hydrogel with soft tissue-like mechanical properties, such as low Young’s modulus (0.1 to 0.3 MPa), high strength (1.1 ± 0.2 MPa), high toughness (9,100 ± 2,200 J/m
3
), and high fatigue resistance (2,300 ± 500 J/m
2
). This hydrogel also resembles the biochemical and architectural properties of native extracellular matrix, which enables a fast formation of 3D interconnected cell meshwork inside hydrogels. The fiber architecture also regulates cellular mechanoresponse and supports cell remodeling inside hydrogels. The integration of tissue-like mechanical properties and bioactivity is highly desirable for the next-generation biomaterials and could advance emerging fields such as tissue engineering and regenerative medicine.
Characterization of a unique polysaccharide monooxygenase from the plant pathogen
Magnaporthe oryzae
Authors: Martinez-D’Alto Alejandra , Yan Xia , Detomasi Tyler C. , Sayler Richard I. , Thomas William C. , Talbot Nicholas J. , Marletta Michael A.
Published: February 2023

Blast disease in cereal plants is caused by the fungus
Magnaporthe oryzae
and accounts for a significant loss in food crops. At the outset of infection, expression of a putative polysaccharide monooxygenase (
Mo
PMO9A) is increased.
Mo
PMO9A contains a catalytic domain predicted to act on cellulose and a carbohydrate-binding domain that binds chitin. A sequence similarity network of the
Mo
PMO9A family AA9 showed that 220 of the 223 sequences in the
Mo
PMO9A-containing cluster of sequences have a conserved unannotated region with no assigned function. Expression and purification of the full length and two
Mo
PMO9A truncations, one containing the catalytic domain and the domain of unknown function (DUF) and one with only the catalytic domain, were carried out. In contrast to other AA9 polysaccharide monooxygenases (PMOs),
Mo
PMO9A is not active on cellulose but showed activity on cereal-derived
m
ixed (1→3, 1→4)-
β
-D-
g
lucans (MBG). Moreover, the DUF is required for activity.
Mo
PMO9A exhibits activity consistent with C4 oxidation of the polysaccharide and can utilize either oxygen or hydrogen peroxide as a cosubstrate. It contains a predicted 3-dimensional fold characteristic of other PMOs. The DUF is predicted to form a coiled-coil with six absolutely conserved cysteines acting as a zipper between the two α-helices.
Mo
PMO9A substrate specificity and domain architecture are different from previously characterized AA9 PMOs. The results, including a gene ontology analysis, support a role for
Mo
PMO9A in MBG degradation during plant infection. Consistent with this analysis, deletion of
Mo
PMO9A results in reduced pathogenicity.
Seasonal dynamics of
Anopheles stephensi
and its implications for mosquito detection and emergent malaria control in the Horn of Africa
Authors: Whittaker Charles , Hamlet Arran , Sherrard-Smith Ellie , Winskill Peter , Cuomo-Dannenburg Gina , Walker Patrick G. T. , Sinka Marianne , Pironon Samuel , Kumar Ashwani , Ghani Azra , Bhatt Samir , Churcher Thomas S.
Published: February 2023

Invasion of the malaria vector
Anopheles stephensi
across the Horn of Africa threatens control efforts across the continent, particularly in urban settings where the vector is able to proliferate. Malaria transmission is primarily determined by the abundance of dominant vectors, which often varies seasonally with rainfall. However, it remains unclear how
An. stephensi
abundance changes throughout the year, despite this being a crucial input to surveillance and control activities. We collate longitudinal catch data from across its endemic range to better understand the vector’s seasonal dynamics and explore the implications of this seasonality for malaria surveillance and control across the Horn of Africa. Our analyses reveal pronounced variation in seasonal dynamics, the timing and nature of which are poorly predicted by rainfall patterns. Instead, they are associated with temperature and patterns of land use; frequently differing between rural and urban settings. Our results show that timing entomological surveys to coincide with rainy periods is unlikely to improve the likelihood of detecting
An. stephensi.
Integrating these results into a malaria transmission model, we show that timing indoor residual spraying campaigns to coincide with peak rainfall offers little improvement in reducing disease burden compared to starting in a random month. Our results suggest that unlike other malaria vectors in Africa, rainfall may be a poor guide to predicting the timing of peaks in
An. stephensi
-driven malaria transmission. This highlights the urgent need for longitudinal entomological monitoring of the vector in its new environments given recent invasion and potential spread across the continent.
Effect of Sn on the microstructural evolution of quasicrystal-reinforced Mg–Zn–Y alloy
Authors: Wang Jiang , Chen Yu'an , Pan Fusheng
Published: February 2023

The effect of Sn content on the microstructure evolution of the as-cast, as-extruded and as-aged Mg-8Zn-2Y- xSn alloys were systematically investigated. The results show that addition of Sn not only refines the grains but also promotes the precipitation of quasicrystal I-phase and the formation of Sn3Y5. The phase transformations during solidification were also studied in detail. After extrusion, the broken second phase particles (I-phase) are more uniformly and densely distributed in the matrix with Sn addition. Moreover, ultra-fine dynamically recrystallized grains are obtained in extruded Mg-8Zn-2Y-0.5Sn alloy. In addition, high density nano-scale precipitates are uniformly dispersed by aging, and these precipitates are identified to be Mg-Zn particles, I phase and mixture of the [Formula: see text] Mg-Zn precipitates and I-phase.
Violence Risk Assessment Tools and Indigenous Peoples: Colonialism as an Underlying Cause of Risk Ratings on the SAVRY
Authors: Muir Nicole M. , Viljoen Jodi L. , Shepherd Stephane M.
Published: February 2023

Violence risk assessment tools are used around the world with people who have committed crimes to determine the risk factors that may have contributed to their offending. These tools can carry great consequences for people’s liberty. Violence risk assessment tools are also used with Indigenous people who are overrepresented in the Canadian justice system. A major issue with these risk assessment tools is that they do not use a colonial lens to understand the underlying mechanisms of violence. Using the Structured Assessment of Violence Risk in Youth (SAVRY) as an example, we examined how colonialism underlies risk and protective ratings. Colonialism increases the probability that Indigenous youth will be rated higher on some risk factors on the SAVRY. Novel interventions to reduce Indigenous overrepresentation include addressing the colonial factors behind violence risk and protective factors. Given that colonialism underlies scores on risk assessment tools, service providers need to link risk ratings to colonialism in their service formulations, carefully attend to culturally relevant factors, and provide interventions and support that specifically address colonialism. Suggestions for future research that include Indigenous community involvement are also provided. A short case analysis, cultural formulation and treatment suggestions are provided as an illustration.
Dynamic control of Fano-like interference in the graphene periodic structure
Authors: Li Boxun , Liu Mingliang , Wen Ruquan , Wei Yi , Zeng Lili , Deng Chaosheng
Published: February 2023

We propose and investigate a graphene periodic subsurface structure consisting of a coplanar pair of graphene ring resonators and a graphene ribbon. The Fano-like interference can be actively regulated by the applied magnetic field, incident angle and Fermi energy. Since the excited charges of graphene monolayer have cyclotron properties in the external magnetic field, the transmittance and line-shape can be effectively controlled. At a certain frequency, different magnetic fields have different effects on the conductivity tensor of graphene, which affects the metallic properties of graphene, leading to changes in the transmittance. The Fano-like line-shape can be regulated by adjusting the incident angle to delay the phase between adjacent graphene sheets. In addition, the resonance frequency can be electrically regulated through Fermi energy. Finite element method is introduced to analyze the graphene periodic structure and the results are demonstrated by multimode interference coupled mode theory. The Faraday rotation angle exceeding 85° are observed in a small magnetic flux density B of about 0.5 T. Moreover, a plasma-optic switching with high ON/OFF ratio and large modulation depth (MD) is designed, whose ON/OFF ratio (η) and MD are 19.921 dB and 98.982%, respectively. Notably, combining the influence of magnetic flux density on transmittance and the modulation of resonance frequency by Fermi energy, optical switching can be implemented at any frequency within the frequency range studied. These results provide methods for active regulation of electromagnetic waves in the terahertz field and have potential applications in optical switching and integrated photonic circuit.
Characterization of susceptibility artifacts in magnetic resonance thermometry images during laser interstitial thermal therapy: dimension analysis and temperature error estimation
Authors: De Landro Martina , Giraudeau Céline , Verde Juan , Ambarki Khalid , Korganbayev Sanzhar , Wolf Alexey , Odéen Henrik , Saccomandi Paola
Published: February 2023

Objective. Laser interstitial thermal therapy (LITT) is a minimally invasive procedure used to treat a lesion through light irradiation and consequent temperature increase. Magnetic resonance thermometry imaging (MRTI) provides a multidimensional measurement of the temperature inside the target, thus enabling accurate monitoring of the damaged zone during the procedure. In proton resonance frequency shift-based thermometry, artifacts in the images may strongly interfere with the estimated temperature maps. In our work, after noticing the formation of the dipolar-behavior artifact linkable to magnetic susceptibility changes during in vivo LITT, an investigation of susceptibility artifacts in tissue-mimicking phantoms was implemented. Approach. The artifact was characterized: (i) by measuring the area and total volume of error regions and their evolution during the treatment; and (ii) by comparison with temperature reference provided by three temperature sensing needles. Lastly, a strategy to avoid artifacts formation was devised by using the temperature-sensing needles to implement a temperature-controlled LITT. Main results. The artifact appearance was associated with gas bubble formation and with unwanted treatment effects producing magnetic susceptibility changes when 2 W laser power was set. The analysis of the artifact’s dimension demonstrated that in the sagittal plane the dipolar-shape artifact may consistently spread following the temperature trend until reaching a volume 8 times bigger than the ablated one. Also, the artifact shape is quite symmetric with respect to the laser tip. An absolute temperature error showing a negative Gaussian profile in the area of susceptibility artifact with values up to 64.4 °C was estimated. Conversely, a maximum error of 2.8 °C is measured in the area not-affected by artifacts and far from the applicator tip. Finally, by regulating laser power, susceptibility artifacts formation was avoided, and appreciable thermal damage was induced. Significance. These findings may help in improving the MRTI-based guidance of thermal therapies.
The roles of Kerr nonlinearity in a bosonic quantum neural network
Authors: Xu Huawen , Krisnanda Tanjung , Bao Ruiqi , Liew Timothy C H
Published: February 2023

The emerging technology of quantum neural networks (QNNs) offers a quantum advantage over classical artificial neural networks (ANNs) in terms of speed or efficiency of information processing tasks. It is well established that nonlinear mapping between input and output is an indispensable feature of classical ANNs, while in a QNN the roles of nonlinearity are not yet fully understood. As one tends to think of QNNs as physical systems, it is natural to think of nonlinear mapping originating from a physical nonlinearity of the system, such as Kerr nonlinearity. Here we investigate the effect of Kerr nonlinearity on a bosonic QNN in the context of both classical (simulating an XOR gate) and quantum (generating Schrödinger cat states) tasks. Aside offering a mechanism of nonlinear input-output mapping, Kerr nonlinearity reduces the effect of noise or losses, which are particularly important to consider in the quantum setting. We note that nonlinear mapping may also be introduced through a nonlinear input-output encoding rather than a physical nonlinearity: for example, an output intensity is already a nonlinear function of input amplitude. While in such cases Kerr nonlinearity is not strictly necessary, it still increases the performance in the face of noise or losses.
Feasibility of a Pulsed Ponderomotive Phase Plate for Electron Beams
Authors: van Leeuwen K A H (Ton) , Schaap Walter Jouke , Buijsse Bart , Borrelli Simona , Kempers Stefan , Verhoeven Wouter , Luiten O Jom
Published: February 2023

We propose a scheme for constructing a phase plate for use in an ultrafast Zernike-type phase contrast electron microscope, based on the interaction of the electron beam with a strongly focused, high-power femtosecond laser pulse and a pulsed electron beam. Analytical expressions for the phase shift using the time-averaged ponderomotive potential and a paraxial approximation for the focused laser beam are presented, as well as more rigorous quasiclassical simulations based on the quantum phase integral along classical, relativistic electron trajectories in an accurate, non-paraxial description of the laser beam. The results are shown to agree well unless the laser beam is focused to a waist size below a wavelength. For realistic (off-the-shelf) laser parameters the optimum phase shift of -π/2 is shown to be achievable. When combined with RF-cavity based electron chopping and compression techniques to produce electron pulses, a femtosecond regime pulsed phase contrast microscope can be constructed. The feasibility and robustness of the scheme are further investigated using the simulations, leading to motivated choices for design parameters such as wavelength, focus size and polarization.
A novel chaotic DICOM image encryption algorithm based on pseudo-random polyline and rapid diffusion-scrambling
Authors: Zhang Ziying , Teng Lin
Published: February 2023

This paper proposes a novel chaotic DICOM image encryption algorithm based on pseudo-random polyline and rapid diffusion-scrambling. This paper proposes to preprocess the image twice in the encryption process to ensure that any type of image can be encrypted, including images with negative pixel values, which increases the practicability of the algorithm. Two pseudo-random polylines are generated to segment the image during the encryption process. The pseudo-random polylines are generated from the information of the plaintext image, which ensures that each image produces different pseudo-random polylines and increases the security of the algorithm. In the encryption process, rapid diffusion-scrambling is used to avoid the waste of extra space. And piecewise diffusion and non-adjacent matrix reading are adopted to make the encryption more unpredictable. The scheme is analyzed from the performance indicators such as pixel correlation and key space, and the results demonstrated strong security and performance of the algorithm.
Spherical collapse of non-top-hat profiles in the presence of dark
energy with arbitrary sound speed
Authors: Batista R.C. , de Oliveira H.P. , Abramo L.R.W.
Published: February 2023

We study the spherical collapse of non-top-hat matter fluctuations in the presence of
dark energy with arbitrary sound speed. The model is described by a system of partial differential
equations solved using a pseudo-spectral method with collocation points. This method can reproduce
the known analytical solutions in the linear regime with an accuracy better than 10-6% and
better than 10-2% for the virialization threshold given by the usual spherical collapse
model. We show the impact of nonlinear dark energy fluctuations on matter profiles, matter
peculiar velocity and gravitational potential. We also show that phantom dark energy models with
low sound speed can develop a pathological behaviour around matter halos, namely negative energy
density. The dependence of the virialization threshold density for collapse on the dark energy
sound speed is also computed, confirming and extending previous results in the limit for
homogeneous and clustering dark energy.
Threshold of primordial black hole formation against
velocity dispersion in matter-dominated era
Authors: Harada Tomohiro , Kohri Kazunori , Sasaki Misao , Terada Takahiro , Yoo Chul-Moon
Published: February 2023

We study the effects of velocity dispersion on the formation of primordial black
holes (PBHs) in a matter-dominated era. The velocity dispersion is generated through the
nonlinear growth of perturbations and has the potential to impede the gravitational collapse and
thereby the formation of PBHs. To make discussions clear, we consider two distinct length
scales. The larger one is where gravitational collapse occurs which could lead to PBH formation,
and the smaller one is where the velocity dispersion develops due to nonlinear interactions. We
estimate the effect of the velocity dispersion on the PBH formation by comparing the free-fall
timescale and the timescale for a particle to cross the collapsing region. As a demonstration, we
consider a log-normal power spectrum for the initial density perturbation with the peak value 
σ
0
2 at a scale that corresponds to the larger scale. We find that the threshold value of
the density perturbation δ̃
th at the horizon entry for the PBH formation
scales as δ̃
th ∝ σ
0
2/5 for σ
0 ≪ 1.
Family of CV states of definite parity and their metrological power
Authors: Podoshvedov Mikhail S , Podoshvedov Sergey A
Published: February 2023

We introduce a new family of continuous variable (CV) states of definite parity originating from the single mode squeezed vacuum (SMSV) state by subtracting an arbitrary number of photons from it. A beam splitter with arbitrary transmittance and reflectance parameters redirects input photons in an indistinguishable manner to the output and measuring modes followed by probabilistic measurement, thereby converting the initial SMSV photon distribution into a new one after we know the number of registered photons. The family of the measurement-induced CV states is solely determined by the SMSV parameter which inevitably decreases when generating the CV states. We show that the quantum state engineering of CV states of definite parity by subtraction of multiphoton state from input SMSV state can significantly enhance their nonclassical properties (more squeezing, larger value of quantum Fisher information) compared to the initial state from which they originate, which, combined with a significant gain in brightness, makes them attractive for ultra-precise measurements. The potential of the new family of CV states of a certain parity, to which original SMSV, no doubt, belongs, can become decisive for a new push to implementation of optical quantum metrology protocols.
Investigation of Z-boson decay into

and

baryons within the NRQCD factorization approach*
Authors: Luo Xuan , Fu Hai-Bing , Tian Hai-Jiang
Published: February 2023

Z-boson decay provides a good opportunity to search for the

baryon because a large number of its events can be collected at high energy colliders. In this paper, we perform a complete investigation of the indirect production of the

and

baryons via the Z-boson decay process

with a

quark under the NRQCD factorization approach. After considering the contribution from the diquark states

,

,

, and

, the calculated branching fractions are

and

. Furthermore, the

and

production events are predicted to be of the order of

and

at the LHC collider, and the order of

and

for the CEPC collider. We then estimate the production ratio for

with

in Z-boson decay, that is,

and

, respectively. Finally, we present the differential decay widths of

and

with respect to

and z distributions and analyze the uncertainties.
Open quantum system approach for heavy quark thermalization*
Authors: Xie Zhuoxuan , Chen Baoyi
Published: February 2023

We treat heavy quark as an open quantum system in a hot medium and rederive the stochastic Schrödinger equation (SSE) from the full Schrödinger equation for both heavy quarks and the medium. We apply the SSE to the dynamical evolutions of a heavy quark (as a system) in the static hot medium (as an environment). Heavy quarks interact with the medium via random scatterings, which exchange the momentum and phase factor randomly between two wave functions of the system and the environment. The exchange of momentum and phase factor results in the transition between different eigenstates of the system. These are included via an external stochastic potential in the Hamiltonian of SSE. Stochastic wave functions of a heavy quark are evolved with the stochastic external potential. The mean wave functions and corresponding momentum distributions of heavy quarks are obtained after the ensemble average over a large set of stochastic wave functions. We present the thermalization of heavy quarks in the static medium with different coupling strengths.
Modern multiloop calculations
Authors: Lee Roman N.
Published: February 2023

Loop integrals and methods of their evaluations are vital for perturbative calculations in any quantum field theory. As the order of perturbation theory increases the complexity of the relevant multiloop integrals explodes rapidly. In the present contribution I review methods of modern multiloop calculations with the emphasis on the method based on the IBP reduction and differential equations.
Normalizing Flows for LHC Theory
Authors: Butter Anja
Published: February 2023

Over the next years, measurements at the LHC and the HL-LHC will provide us with a wealth of new data. The best hope to answer fundamental questions, like the nature of dark matter, is to adopt big data techniques in simulations and analyses to extract all relevant information. On the theory side, LHC physics crucially relies on our ability to simulate events efficiently from first principles. These simulations will face unprecedented precision requirements to match the experimental accuracy. Innovative ML techniques like generative networks can help us overcome limitations from the high dimensionality of the phase space. Such networks can be employed within established simulation tools or as part of a new framework. Since neural networks can be inverted, they open new avenues in LHC analyses.
The STEM paradox: Factors affecting diversity in STEM fields
Authors: Cherney I D
Published: February 2023

Women obtain more than half of U.S. undergraduate degrees in biology, chemistry, and mathematics, yet they earn less than 20% of computer science, engineering, and physics undergraduate degrees (NSF). Why are women represented in some STEM fields more than others? The STEM Paradox or Gender Equality Paradox show that countries with greater gender equality have a lower percentage of female STEM graduates. This phenomenon as well as other factors explaining gender disparities in STEM participation and some possible solutions are discussed.
Outlook on software framework in low and intermediate energy nuclear physics
Authors: Matta Adrien
Published: February 2023

Over the past decades nuclear physics experiments have seen a drastic increase in complexity. With the arrival of second generation radioactive ion beam facilities all over the world, the run for exploring more and more exotic nuclei is raging. The low intensity of RI-beams requires more complex setup, larger solid angle coverage and detection of a wider variety of charged and neutral particles. Design, construction and operation of a variety of complex instruments used in such experiments require many software developments. The short lifetime of experimental setups and multiple combinations of instruments demand a strong methodology. As the community is shifting to this new paradigm, the quest for the optimum framework is becoming central in the field. In this outlook we will introduce the specificity of the nuclear physics community, technical needs of such frameworks, and give an overview of the existing ones, with an emphasize on the difficult balance between computing performances, versatility and integration with other frameworks.
Quantum computing for data science
Authors: Sanders Barry C.
Published: February 2023

I provide a perspective on the development of quantum computing for data science, including a dive into state-of-the-art for both hardware and algorithms and the potential for quantum machine learning.
Anomaly detection of I/O behaviours in HEP computing cluster based on unsupervised machine learning
Authors: Wang Lu , Hu Qingbao , Chen Juan
Published: February 2023

Problematic I/O pattern is the major cause of low efficient HEP jobs. In a cluster with tens of thousands of job slots, locating the source of an anomalous workload is a nontrivial task. Automatic anomaly detection can largely shorten the recovery time of these situations and reduce manpower for problem diagnoses. This paper provides a data-driven approach to solve this problem. We design and implement an anomaly detection system based on Isolation Forest, a very efficient and scalable machine learning algorithm for spatial anomaly detection in high dimension space. Historical monitoring I/O patterns collected from the Lustre file system provides a sufficient statistical basis for model training and updating. Routine model updates and job tagging ensures adaptability and promptness. Web-based visualization and sorting tools facilitate the validation of model prediction. With the detection system, time spent on tracing the source of a problematic workload can be reduced from hours to minutes.
An array-oriented Python interface for FastJet
Authors: Roy Aryan , Pivarski Jim , Freer Chad Wells
Published: February 2023

Analysis on HEP data is an iterative process in which the results of one step often inform the next. In an exploratory analysis, it is common to perform one computation on a collection of events, then view the results (often with histograms) to decide what to try next. Awkward Array is a Scikit-HEP Python package that enables data analysis with array-at-a-time operations to implement cuts as slices, combinatorics as composable functions, etc. However, most C++ HEP libraries, such as FastJet, have an imperative, one-particle-at-a-time interface, which would be inefficient in Python and goes against the grain of the array-at-a-time logic of scientific Python. Therefore, we developed fastjet, a pip-installable Python package that provides FastJet C++ binaries, the classic (particle-at-a-time) Python interface, and the new array-oriented interface for use with Awkward Array. The new interface streamlines interoperability with scientific Python software beyond HEP, such as machine learning. In one case, adopting this library along with other array-oriented tools accelerated HEP analysis code by a factor of 20. It was designed to be easily integrated with libraries in the Scikit-HEP ecosystem, including Uproot (file I/O), hist (histogramming), Vector (Lorentz vectors), and Coffea (high-level glue). We discuss the design of the fastjet Python library, integrating the classic interface with the array oriented interface and with the Vector library for Lorentz vector operations. The new interface was developed as open source.
Clustering in the Heterogeneous Reconstruction Chain of the CMS HGCAL Detector
Authors: Alves Bruno , Pantaleo Felice , Rovere Marco
Published: February 2023

We present an important milestone for the CMS High Granularity Calorimeter (HGCAL) event reconstruction: the deployment of the GPU clustering algorithm (CLUE) to the CMS software. The connection between GPU CLUE and the preceding GPU calibration step is thus made possible, further extending the heterogeneous chain of HGCAL’s reconstruction framework. In addition to improvements brought by CLUE’s deployment, new recursive device kernels are added to efficiently calculate the position and energy of CLUE clusters. Data conversions between GPU and CPU are included to facilitate the validation of the algorithms and increase the flexibility of the reconstruction. For the first time in HGCAL, conditions data are deployed to the GPU and made available on demand at any stage of the heterogeneous reconstruction. This is achieved via a new geometry ordering scheme in which physical and memory locations are connected. This scheme is successfully tested with the GPU CLUE version reported here, and is expected to have a broad range of applicability for future heterogeneous developments in CMS. Finally, the performance of the combined calibration and clustering algorithms on GPU is assessed and compared to its CPU counterpart.
Commissioning LHCb’s GPU high level trigger
Authors: Agapopoulou Christina
Published: February 2023

From 2022 onward, the upgraded LHCb experiment will use a triggerless readout system collecting data at an event rate of 30 MHz. A software-only High Level Trigger will enable unprecedented flexibility for trigger selections. During the first stage (HLT1), a sub-set of the full offline track reconstruction for charged particles is run to select particles of interest based on single or two-track selections. This includes decoding the raw data, clustering of hits, pattern recognition, as well as track fitting, ghost track rejection with machine learning techniques and finally event selections. HLT1 will be processed entirely on O(100) GPUs. We will present the integration of the GPU HLT1 into LHCb’s data acquisition system in preparation for data taking in 2022.
Configuration Information System for online processing and data monitoring in the NICA experiments
Authors: Alexandrov E. , Alexandrov I. , Chebotov A. , Gertsenberger K. , Filozova I. , Priakhina D. , Shestakova G.
Published: February 2023

The collection, storage and processing of experimental data are an integral part of modern high-energy physics experiments. The Configuration Information System (CIS) based on the Configuration Database (ConfigDb) is an essential element of a complex of information systems developed for the NICA experiments. The CIS is used to store and provide data on the configuration of the experiment hardware and software systems when collecting data from the detectors in online mode. The ConfigDb stores both a set of various configuration parameters and descriptions of a sequence of online software tasks to be started and run during experiment sessions. The system allows loading configuration information, activating hardware setups and launching all necessary software applications with the required parameters on the specified distributed nodes. The CIS architecture mainly contains the ConfigDb and Configuration Manager, which uses the Dynamic Deployment System API for managing tasks and providing intercommunication. The manager loads configuration data from the database, starts software tasks in a described sequence and supports task process management. The client-server architecture of the CIS is presented. The client has been implemented as a Web service to manage configuration parameters by users.
Data Handling Optimization in Russian Data Lake Prototype
Authors: Alekseev A , Kiryanov A , Klimentov A , Korchuganova T , Mitsyn V , Oleynik D , Petrosyan A , Smirnov S , Zarochentsev A
Published: February 2023

CERN experiments are preparing for the HL-LHC era, which will bring an unprecedented volume of scientific data. These data will need to be stored and processed by thousands of physicists, but expected resource growth is nowhere near the extrapolated requirements of existing models, in terms of both storage volume and compute power. Opportunistic CPU resources such as HPCs and university clusters can provide extra CPU cycles, but there is no opportunistic storage. In this article, we will present the main architectural ideas, deployment details, and test results, with emphasis on our research to build a prototype of a distributed data processing and storage system with a focus on optimizing the efficiency of resources by reducing overhead costs for accessing the data. The described prototype was built using the geographically distributed WLCG sites and university clusters in Russia.
Detray: a compile time polymorphic tracking geometry description
Authors: Salzburger A , Niermann J , Yeo B , Krasznahorkay A
Published: February 2023

A detailed geometry description is essential to any high quality track reconstruction application. In current C++ based track reconstruction software libraries this is often achieved by an object oriented, polymorphic geometry description that implements different shapes and objects by extending a common base class. Such a design, however, has been shown to be problematic when attempting to adapt these applications to run on heterogeneous computing hardware, particularly on hardware accelerators. We present detray, a compile time polymorphic and yet accurate track reconstruction geometry description which is part of the ACTS parallelization R&D effort. detray is built as an index based geometry description with a shallow memory layout, that uses variadic template programming to allow custom shapes and intersection algorithms rather than inheritance from abstract base classes. It is designed to serve as a potential geometry and navigation backend for ACTS and as such implements the ACTS navigation model of boundary portals and purely surface based geometric entities. detray is designed to work with a dedicated memory management library and thus can be instantiated as a geometry model in host and device code.
Development of the automatic procedures for spinor matrix element calculation with massive particles
Authors: Dydyshka Y
Published: February 2023

We present a new version the procedure for calculation helicity amplitudes with massive particles. First, we introduce a massive 4-momentum into higher dimensional space, where it can be treated as massless. Secondly, we apply the symmetry properties of gauge theories and get quite simple matrix elements in terms of the field strength.
Distributed file systems performance tests on Kubernetes/Docker clusters
Authors: Fornari Federico , Cavalli Alessandro , Cesini Daniele , Falabella Antonio , Fattibene Enrico , Morganti Lucia , Prosperini Andrea , Sapunenko Vladimir
Published: February 2023

Modern data centers need distributed file systems to provide user applications with access to data stored on a large number of nodes. The ability to mount a distributed file system and leverage its native application programming interfaces in a Docker container, combined with the advanced orchestration features provided by Kubernetes, can improve flexibility in installing, monitoring and recovering data management and transfer services. At INFN-CNAF some distributed file systems (i.e. IBM Spectrum Scale, CephFS and Lustre-ZFS) deployment tests with Kubernetes and Docker have been conducted recently with positive results. The purpose of this paper is to show the throughput scores of the previously mentioned file systems when their servers are containerized and run on bare metal machines using a container orchestration framework. This is a preliminary study: for the time being, only sequential read/write tests have been considered.