cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Investigation of the Quantum Correlations for a S=1/2 Ising- Heisenberg Model on a Symmetrical Diamond Chain
Creators: name: Faizi, E.
name: Eftekhari, H.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: 81Vxx

description: We consider the quantum correlations for a S=1/2 Ising- Heisenberg model of a symmetrical diamond chain. Firstly, we compare concurrence, quantum discord and 1- norm geometric quantum discord of an ideal diamond chain in the absence of magnetic field. The results show no simple ordering relations between these quantum correlations, so that quantum discord may be smaller or larger than the 1-norm geometric quantum discord, which this observation contradict the previous result that provided by F. M. Paula [1]. Symmetrical behavior of quantum correlation versus ferromagnetic and anti- ferromagnetic coupling constant J is considerable. The effect of external magnetic field H and temperature- dependence is also considered. Furthermore, we study quantum discord and geometric measure of quantum discord with the effect of next nearest neighbor interaction between nodal Ising sites for a generalized diamond chain, and we observe coexistence of phases with different values of magnetic field for quantum correlations. Moreover, entanglement sudden death occurs while quantum discord, 1- norm geometric quantum discord and geometric quantum discord are immune from sudden death.
description: 12 pages, 7 figures
Martian M2 peak behavior in the dayside near-terminator ionosphere during interplanetary coronal mass ejections
Creators: name: Ram, L.
name: Rout, D.
name: Rathi, R.
name: Withers, P.
name: Sarkhel, S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: The interplanetary coronal mass ejections (ICMEs) can pose significant impacts on the Martian ionosphere, resulting in plasma depletion, variability, and escape to space. However, the connections between the ICMEs and the associated responses of the dayside near-terminator Martian ionospheric primary peak (M2) are not well understood. The present study primarily investigates the behavior of the ionospheric peak density (Nm) and height (hm) during the passage of ICMEs using observations from the Radio Occultation Science Experiment (ROSE) aboard MAVEN spacecraft. We have selected 8 such ICMEs (during 2017-2022) at Mars from the existing catalogs and studied the ROSE electron density profiles during quiet and disturbed time (ICMEs) for identical solar zenith angle range. We observed the elevation of the M2 peak (hm ~4-16 km) during disturbed time (ICMEs) with a decrease in Nm (0.41-2.8*10^10 m-3) in comparison to the quiet time. The present study, for the first time, addressed the influence of ICMEs on the M2 peak parameters (Nm and hm). We have proposed that the development of large vertical pressure gradient and electron temperature enhancement are plausible causes for ionospheric variability. Therefore, the present study provides new insights to understand peak plasma behavior in the dayside near-terminator ionosphere during ICMEs.
description: Icarus (2023)
Precontractual Damages as a Result of an Irrevocable Offer – A Resolution Within the CISG
Creators: name: Zeller, Bruno
name: Walters, Robert
Publisher: name: Nordic Journal of Commercial Law
Year: 2020

description: This paper is written in response to the arguments that have been put forward by Anne Rossen, Maria Pedersen, and Thomas Neumann, titled “How far does the dynamic doctrine go? Looking for the basis of precontractual liability in the CISG”. On the backdrop of this paper, it is worth noting that the United Nations Convention on Contracts for the International Sale of Goods (CISG) is one of the most successful international commercial law treaties ever devised. It has been ratified by most of the world's important trading countries and has become a template for the drafting of commercial law treaties. The CISG is considered a self-executing treaty, as it creates a private right of action in federal court under federal law. It provides the default set of rules that govern contracts for the sale of goods between parties located in different Contracting States. In some cases, the CISG also addresses situations in which only one of the parties is located in a Contracting State. This article argues that the CISG can accommodate breaches of precontractual conditions through the same procedure applied to breaches of contract. It is a controversial issue but, nevertheless, it is arguable that the CISG can cover the internal gap via general principles embedded within its four corners. For this reason, this article will look at Article 16(2). In particular, the following issues will be relevant: the revoking of an irrevocable offer; the effects of Article 4; and the effects of Articles 71- 77.
description: Nordic Journal of Commercial Law, No. 1 (2020)
Orbital-selective charge-density wave in TaTe$_4$
Creators: name: Xu, R. Z.
name: Du, X.
name: Zhou, J. S.
name: Gu, X.
name: Zhang, Q. Q.
name: Li, Y. D.
name: Zhao, W. X.
name: Zheng, F. W.
name: Arita, M.
name: Shimada, K.
name: Kim, T. K.
name: Cacho, C.
name: Guo, Y. F.
name: Liu, Z. K.
name: Chen, Y. L.
name: Yang, L. X.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: TaTe$_4$, a metallic charge-density wave (CDW) material discovered decades ago, has attracted renewed attention due to its rich interesting properties such as pressure-induced superconductivity and candidate non-trivial topological phase. Here, using high-resolution angle-resolved photoemission spectroscopy and ab-initio calculation, we systematically investigate the electronic structure of TaTe$_4$. At 26 K, we observe a CDW gap as large as 290 meV, which persists up to 500 K. The CDW-modulated band structure shows a complex reconstruction that closely correlates with the lattice distortion. Inside the CDW gap, there exist highly dispersive energy bands contributing to the remnant Fermi surface and metallic behavior in the CDW state. Interestingly, our ab-initio calculation reveals that the large CDW gap mainly opens in the electronic states with out-of-plane orbital components, while the in-gap metallic states originate from in-plane orbitals, suggesting an orbital texture that couples with the CDW order. Our results shed light on the interplay between electron, lattice, and orbital in quasi-one-dimensional CDW materials.
description: to appear in npj Quantum Materials
Efficient numerical methods for Anisotropic Diffusion of Galactic Cosmic Rays
Creators: name: Deka, Pranab J.
name: Kissmann, Ralf
name: Einkemmer, Lukas
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Numerical Analysis (math.NA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: Anisotropic diffusion is imperative in understanding cosmic ray diffusion across the Galaxy, the heliosphere, and the interplay of cosmic rays with the Galactic magnetic field. This diffusion term contributes to the highly stiff nature of the cosmic ray transport equation. To conduct numerical simulations of time-dependent cosmic ray transport, implicit integrators (namely, Crank-Nicolson (CN)) have been traditionally favoured over the CFL-bound explicit integrators in order to be able to take large step sizes. We propose exponential methods to treat the linear anisotropc diffusion equation in the presence of advection and time-independent and time-dependent sources. These methods allow us to take even larger step sizes that can substantially speed-up the simulations whilst generating highly accurate solutions. In or subsequent work, we will use these exponential solvers in the Picard code to study anisotropic cosmic ray diffusion and we will consider additional physical processes such as continuous momentum losses and reacceleration.
description: The 38th International Cosmic Ray Conference (ICRC2023)
VERITAS Observations of the Microquasar Cygnus X-3
Creators: name: Archambault, S.
name: Beilicke, M.
name: Benbow, W.
name: Berger, K.
name: Bird, R.
name: Bouvier, A.
name: Buckley, J. H.
name: Bugaev, V.
name: Byrum, K.
name: Cerruti, M.
name: Chen, X.
name: Ciupik, L.
name: Connolly, M. P.
name: Cui, W.
name: Duke, C.
name: Dumm, J.
name: Errando, M.
name: Falcone, A.
name: Federici, S.
name: Feng, Q.
name: Finley, J. P.
name: Fortson, L.
name: Furniss, A.
name: Galante, N.
name: Gillanders, G. H.
name: Griffin, S.
name: Griffiths, S. T.
name: Grube, J.
name: Gyuk, G.
name: Hanna, D.
name: Holder, J.
name: Hughes, G.
name: Humensky, T. B.
name: Kaaret, P.
name: Kertzman, M.
name: Khassen, Y.
name: Kieda, D.
name: Krawczynski, H.
name: Lang, M. J.
name: Madhavan, A. S
name: Maier, G.
name: Majumdar, P.
name: McArthur, S.
name: McCann, A.
name: Moriarty, P.
name: Mukherjee, R.
name: Nieto, D.
name: de Bhróithe, A. O'Faoláin
name: Ong, R. A.
name: Otte, A. N.
name: Pandel, D.
name: Park, N.
name: Perkins, J. S.
name: Pohl, M.
name: Popkow, A.
name: Prokoph, H.
name: Quinn, J.
name: Ragan, K.
name: Rajotte, J.
name: Reyes, L. C.
name: Reynolds, P. T.
name: Richards, G. T.
name: Roache, E.
name: Sembroski, G. H.
name: Sheidaei, F.
name: Smith, A. W.
name: Staszak, D.
name: Telezhinsky, I.
name: Theiling, M.
name: Tucci, J. V.
name: Tyler, J.
name: Varlotta, A.
name: Vincent, S.
name: Wakely, S. P.
name: Weekes, T. C.
name: Weinstein, A.
name: Williams, D. A.
name: Zitzer, B.
name: McCollough, M. L.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We report results from TeV gamma-ray observations of the microquasar Cygnus X-3. The observations were made with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) over a time period from 2007 June 11 to 2011 November 28. VERITAS is most sensitive to gamma rays at energies between 85 GeV to 30 TeV. The effective exposure time amounts to a total of about 44 hours, with the observations covering six distinct radio/X-ray states of the object. No significant TeV gamma-ray emission was detected in any of the states, nor with all observations combined. The lack of a positive signal, especially in the states where GeV gamma rays were detected, places constraints on TeV gamma-ray production in Cygnus X-3. We discuss the implications of the results.
description: 23 pages, 4 figures, 3 tables, accepted for publication in ApJ
Uniformly Distributed Category Prototype-Guided Vision-Language Framework for Long-Tail Recognition
Creators: name: Fu, Siming
name: He, Xiaoxuan
name: Ding, Xinpeng
name: Cao, Yuchen
name: Wang, Hualiang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences
subject: I.4.10
subject: 14J60 (Primary) 14F05, 14J26 (Secondary)

description: Recently, large-scale pre-trained vision-language models have presented benefits for alleviating class imbalance in long-tailed recognition. However, the long-tailed data distribution can corrupt the representation space, where the distance between head and tail categories is much larger than the distance between two tail categories. This uneven feature space distribution causes the model to exhibit unclear and inseparable decision boundaries on the uniformly distributed test set, which lowers its performance. To address these challenges, we propose the uniformly category prototype-guided vision-language framework to effectively mitigate feature space bias caused by data imbalance. Especially, we generate a set of category prototypes uniformly distributed on a hypersphere. Category prototype-guided mechanism for image-text matching makes the features of different classes converge to these distinct and uniformly distributed category prototypes, which maintain a uniform distribution in the feature space, and improve class boundaries. Additionally, our proposed irrelevant text filtering and attribute enhancement module allows the model to ignore irrelevant noisy text and focus more on key attribute information, thereby enhancing the robustness of our framework. In the image recognition fine-tuning stage, to address the positive bias problem of the learnable classifier, we design the class feature prototype-guided classifier, which compensates for the performance of tail classes while maintaining the performance of head classes. Our method outperforms previous vision-language methods for long-tailed learning work by a large margin and achieves state-of-the-art performance.
description: 11pages, 5figures
XTribe: a web-based social computation platform
Creators: name: Caminiti, Saverio
name: Cicali, Claudio
name: Gravino, Pietro
name: Loreto, Vittorio
name: Servedio, Vito D. P.
name: Sîrbu, Alina
name: Tria, Francesca
Publisher: name: arXiv
Year: 2014
Subjects: subject: Computers and Society (cs.CY)
subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: In the last few years the Web has progressively acquired the status of an infrastructure for social computation that allows researchers to coordinate the cognitive abilities of human agents in on-line communities so to steer the collective user activity towards predefined goals. This general trend is also triggering the adoption of web-games as a very interesting laboratory to run experiments in the social sciences and whenever the contribution of human beings is crucially required for research purposes. Nowadays, while the number of on-line users has been steadily growing, there is still a need of systematization in the approach to the web as a laboratory. In this paper we present Experimental Tribe (XTribe in short), a novel general purpose web-based platform for web-gaming and social computation. Ready to use and already operational, XTribe aims at drastically reducing the effort required to develop and run web experiments. XTribe has been designed to speed up the implementation of those general aspects of web experiments that are independent of the specific experiment content. For example, XTribe takes care of user management by handling their registration and profiles and in case of multi-player games, it provides the necessary user grouping functionalities. XTribe also provides communication facilities to easily achieve both bidirectional and asynchronous communication. From a practical point of view, researchers are left with the only task of designing and implementing the game interface and logic of their experiment, on which they maintain full control. Moreover, XTribe acts as a repository of different scientific experiments, thus realizing a sort of showcase that stimulates users' curiosity, enhances their participation, and helps researchers in recruiting volunteers.
description: 11 pages, 2 figures, 1 table, 2013 Third International Conference on Cloud and Green Computing (CGC), Sept. 30 2013-Oct. 2 2013, Karlsruhe, Germany
Automated Test Generation for Medical Rules Web Services: A Case Study at the Cancer Registry of Norway
Creators: name: Laaber, Christoph
name: Yue, Tao
name: Ali, Shaukat
name: Schwitalla, Thomas
name: Nygård, Jan F.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: The Cancer Registry of Norway (CRN) collects, curates, and manages data related to cancer patients in Norway, supported by an interactive, human-in-the-loop, socio-technical decision support software system. Automated software testing of this software system is inevitable; however, currently, it is limited in CRN's practice. To this end, we present an industrial case study to evaluate an AI-based system-level testing tool, i.e., EvoMaster, in terms of its effectiveness in testing CRN's software system. In particular, we focus on GURI, CRN's medical rule engine, which is a key component at the CRN. We test GURI with EvoMaster's black-box and white-box tools and study their test effectiveness regarding code coverage, errors found, and domain-specific rule coverage. The results show that all EvoMaster tools achieve a similar code coverage; i.e., around 19% line, 13% branch, and 20% method; and find a similar number of errors; i.e., 1 in GURI's code. Concerning domain-specific coverage, EvoMaster's black-box tool is the most effective in generating tests that lead to applied rules; i.e., 100% of the aggregation rules and between 12.86% and 25.81% of the validation rules; and to diverse rule execution results; i.e., 86.84% to 89.95% of the aggregation rules and 0.93% to 1.72% of the validation rules pass, and 1.70% to 3.12% of the aggregation rules and 1.58% to 3.74% of the validation rules fail. We further observe that the results are consistent across 10 versions of the rules. Based on these results, we recommend using EvoMaster's black-box tool to test GURI since it provides good results and advances the current state of practice at the CRN. Nonetheless, EvoMaster needs to be extended to employ domain-specific optimization objectives to improve test effectiveness further. Finally, we conclude with lessons learned and potential research directions, which we believe are generally applicable.
description: 12 pages, 2 figures, 5 tables; accepted to the industry track of the 31st ACM Joint European Software Engineering Conference and Symposium on the Foundations of Software Engineering (ESEC/FSE '23)
Three-dimensional energy-dependent $C$-metric: black hole solutions
Creators: name: Panah, B. Eslam
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Considering a three-dimensional $C$-metric and adding energy-dependent to this spacetime, we first create a three-dimensional energy-dependent $C$-metric. Then, we extract accelerating BTZ black hole solutions in gravity's rainbow. Besides, we show that (A)dS black holes cover by an event horizon that depends on all the parameters of this theory. Using the definition of Hawking temperature, we obtain the temperature of these black holes and study the effects of various parameters on this quantity. We find a critical radius in which the temperature is always positive (negative) before (after) it. Then, we obtain the entropy of such black holes. Our analysis indicates that there is the same behavior for entropy, similar to the temperature. Indeed, before (after) the critical radius, the entropy is positive (negative). In order to study the local stability of such black holes, we calculate the heat capacity. We find two different behaviors for the heat capacity, which depend on the cosmological energy-dependent constant. As a final result, accelerating AdS BTZ black holes can satisfy the physical condition and local stability at the same time.
description: 8 pages, 2 figures, accepted in Physics Letters B
Limit to the radio emission from a putative central compact source in SN1993J
Creators: name: Marti-Vidal, I.
name: Marcaide, J. M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: SN1993J in M81 is the best studied young radio-luminous supernova in the Northern Hemisphere. We recently reported results from the analysis of a complete set of VLBI observations of this supernova at 1.7, 2.3, 5.0, and 8.4 GHz, covering a time baseline of more than one decade. Those reported results were focused on the kinematics of the expanding shock, the particulars of its evolving non-thermal emission, the density profile of the circumstellar medium, and the evolving free-free opacity by the supernova ejecta. In the present paper, we complete our analysis by performing a search for any possible signal from a compact source (i.e., a stellar-mass black hole or a young pulsar nebula) at the center of the expanding shell. We have performed a stacking of all our VLBI images at each frequency, after subtraction of our best-fit shell model at each epoch, and measured the peak intensity in the stacked residual image. Given the large amount of available global VLBI observations, the stacking of all the residual images allows us to put upper limits to the eventual emission of a putative compact central source at the level of $\sim102$ $μ$Jy at 5 GHz (or, more conservatively, $\sim192$ $μ$Jy, if we make a further correction for the ejecta opacity) and somewhat larger at other wavelengths.
description: 4 pages, 3 figures. Accepted for publication in A&A
Quantum Electrodynamic Corrections to Cyclotron States in a Penning Trap
Creators: name: Jentschura, Ulrich D.
name: Moore, Christopher
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We analyze the leading and higher-order quantum electrodynamic corrections to the energy levels for a single electron bound in a Penning trap, including the Bethe logarithm correction due to virtual excitations of the reference quantum cyclotron state. The effective coupling parameter alpha_c in the Penning trap is identified as the square root of the ratio of the cyclotron frequency, converted to an energy via multiplication by the Planck constant, to the electron rest mass energy. We find a large, state-independent, logarithmic one-loop self-energy correction of order alpha alpha_c^4 m c^2 ln(alpha_c^(-2)), where m is the electron rest mass and c is the speed of light. Furthermore, we find a state-independent "trapped" Bethe logarithm. We also obtain a state-dependent higher-order logarithmic self-energy correction of order alpha alpha_c^6 m c^2 ln(alpha_c^(-2)). In the high-energy part of the bound-state self energy, we need to consider terms with up to six magnetic interaction vertices inside the virtual photon loop.
description: 11 pages; RevTeX
Iterative Graph Filtering Network for 3D Human Pose Estimation
Creators: name: Islam, Zaedul
name: Hamza, A. Ben
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Graph convolutional networks (GCNs) have proven to be an effective approach for 3D human pose estimation. By naturally modeling the skeleton structure of the human body as a graph, GCNs are able to capture the spatial relationships between joints and learn an efficient representation of the underlying pose. However, most GCN-based methods use a shared weight matrix, making it challenging to accurately capture the different and complex relationships between joints. In this paper, we introduce an iterative graph filtering framework for 3D human pose estimation, which aims to predict the 3D joint positions given a set of 2D joint locations in images. Our approach builds upon the idea of iteratively solving graph filtering with Laplacian regularization via the Gauss-Seidel iterative method. Motivated by this iterative solution, we design a Gauss-Seidel network (GS-Net) architecture, which makes use of weight and adjacency modulation, skip connection, and a pure convolutional block with layer normalization. Adjacency modulation facilitates the learning of edges that go beyond the inherent connections of body joints, resulting in an adjusted graph structure that reflects the human skeleton, while skip connections help maintain crucial information from the input layer's initial features as the network depth increases. We evaluate our proposed model on two standard benchmark datasets, and compare it with a comprehensive set of strong baseline methods for 3D human pose estimation. Our experimental results demonstrate that our approach outperforms the baseline methods on both datasets, achieving state-of-the-art performance. Furthermore, we conduct ablation studies to analyze the contributions of different components of our model architecture and show that the skip connection and adjacency modulation help improve the model performance.
Spurious-Free Lithium Niobate Bulk Acoustic Resonator for Piezoelectric Power Conversion
Creators: name: Nguyen, Kristi
name: Stolt, Eric
name: Braun, Weston
name: Chulukhadze, Vakhtang
name: Segovia-Fernandez, Jeronimo
name: Chakraborty, Sombuddha
name: Rivas-Davila, Juan
name: Lu, Ruochen
Publisher: name: arXiv
Year: 2023
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Recently, piezoelectric power conversion has shown great benefits from replacing the bulky and lossy magnetic inductor in a traditional power converter with a piezoelectric resonator due to its compact size and low loss. However, the converter performance is ultimately limited by existing resonator designs, specifically by moderate quality factor (Q), moderate electromechanical coupling (kt2), and spurious modes near resonance. This work reports a spurious-free lithium niobate (LiNbO3) thickness-extensional mode bulk acoustic resonator design, demonstrating Q of 4000 and kt2 of 30% with a fractional suppressed region of 62%. We first propose a novel grounded ring structure for spurious-free resonator design, then validate its performance experimentally. Upon further work, this design could be extended to applications requiring spurious suppression, such as filters, tunable oscillators, transformers, etc.
description: 4 pages, 6 figures, presented at IEEE IFCS 2023
Improved Nucleon Properties in the Extended Quark Sigma Model
Creators: name: Abu-Shady, M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The quark sigma model describes the quarks interacting via exchange the pions and sigma meson fields. A new version of mesonic potential is suggested in the frame of some aspects of the quantum chromodynamics (QCD). The field equations have been solved in the mean-field approximation for the hedgehog baryon state. The obtained results are compared with previous works and other models. We conclude that the suggested mesonic potential successfully calculates nucleon properties.
description: 13 pages. arXiv admin note: text overlap with arXiv:0912.3576
A Porous, Layered Heliopause
Creators: name: Swisdak, M.
name: Drake, J. F.
name: Opher, M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: The picture of the heliopause (HP) -- the boundary between the domains of the sun and the local interstellar medium (LISM) -- as a pristine interface with a large rotation in the magnetic field fails to describe recent Voyager 1 (V1) spacecraft data. Magnetohydrodynamic (MHD) simulations of the global heliosphere reveal that the rotation angle of the magnetic field across the HP at V1 is small. Particle-in-cell simulations, based on cuts through the MHD model at the location of V1, suggest that the sectored region of the heliosheath (HS) produces large-scale magnetic islands that reconnect with the interstellar magnetic field and mix LISM and HS plasma. Cuts across the simulation data reveal multiple, anti-correlated jumps in the number densities of LISM and HS particles at the magnetic separatrices of the islands, similar to those observed by V1. A model is presented, based on both the observations and simulation data, of the HP as a porous, multi-layered structure threaded by magnetic fields. This model further suggests that, contrary to the conclusions of recent papers, V1 has already crossed the HP.
description: 7 pages, 4 figures
Multidisciplinary Engineering Models: Methodology and Case Study in Spreadsheet Analytics
Creators: name: Birch, David
name: Liang, Helen
name: Kelly, Paul H J
name: Mullineux, Glen
name: Field, Tony
name: Ko, Joan
name: Simondetti, Alvise
Publisher: name: arXiv
Year: 2014
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: This paper demonstrates a methodology to help practitioners maximise the utility of complex multidisciplinary engineering models implemented as spreadsheets, an area presenting unique challenges. As motivation we investigate the expanding use of Integrated Resource Management(IRM) models which assess the sustainability of urban masterplan designs. IRM models reflect the inherent complexity of multidisciplinary sustainability analysis by integrating models from many disciplines. This complexity makes their use time-consuming and reduces their adoption. We present a methodology and toolkit for analysing multidisciplinary engineering models implemented as spreadsheets to alleviate such problems and increase their adoption. For a given output a relevant slice of the model is extracted, visualised and analysed by computing model and interdisciplinary metrics. A sensitivity analysis of the extracted model supports engineers in their optimisation efforts. These methods expose, manage and reduce model complexity and risk whilst giving practitioners insight into multidisciplinary model composition. We report application of the methodology to several generations of an industrial IRM model and detail the insight generated, particularly considering model evolution.
description: 12 Pages, 8 Colour figures
A formation mechanism for "Wrong Way" Radio Relics
Creators: name: Böss, Ludwig M.
name: Steinwandel, Ulrich P.
name: Dolag, Klaus
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Radio Relics are typically found to be arc-like regions of synchrotron emission in the outskirts of merging galaxy clusters, bowing out from the cluster center. In most cases they show synchrotron spectra that steepen towards the cluster center, indicating that they are caused by relativistic electrons being accelerated at outwards traveling merger shocks. A number of radio relics break with this ideal picture and show morphologies that are bent the opposite way and show spectral index distributions which do not follow expectations from the ideal picture. We propose that these `Wrong Way' Relics can form when an outwards travelling shock wave is bent inwards by an in-falling galaxy cluster or group. We test this in an ultra-high resolution zoom-in simulation of a massive galaxy cluster with an on-the-fly spectral Cosmic Ray model. This allows us to study not only the synchrotron emission at colliding shocks, but also their synchrotron spectra to adress the open question of relics with strongly varying spectral indices over the relic surface.
description: 13 pages, 7 figures, accepted for publication in ApJL. arXiv admin note: text overlap with arXiv:2308.00448
Nonunitary projective transcorrelation theory inspired by the F12 ansatz
Creators: name: Ten-no, Seiichiro L.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: An alternative nonunitary transcorrelation, inspired by the F12 ansatz, is investigated. In contrast to the Jastrow transcorrelation of Boys-Handy, the effective Hamiltonian of this projective transcorrelation features: 1. a series terminating formally at four-body interactions. 2. no spin-contamination within the non-relativistic framework. 3. simultaneous satisfaction of the singlet and triplet first-order cusp conditions. 4. arbitrary choices of pairs for correlation including frozen core approximations. We discuss the connection between the projective transcorrelation and F12 theory with applications to small molecules, to show that the cusp conditions play an important role to reduce the uncertainty arising from the nonunitary transformation.
Conductivity of epitaxial and CVD graphene with correlated line defects
Creators: name: Radchenko, T. M.
name: Shylau, A. A.
name: Zozoulenko, I. V.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Transport properties of single-layer graphene with correlated one-dimensional defects are studied using the time-dependent real-space Kubo-Greenwood formalism. Such defects are present in epitaxial graphene, comprising atomic terraces and steps due to the substrate morphology, and in polycrystalline chemically-vapor-deposited (CVD) graphene due to the grain boundaries, composed of a periodic array of dislocations, or quasi-periodic nanoripples originated from the metal substrate. The extended line defects are described by the long-range Lorentzian-type scattering potential. The dc conductivity is calculated numerically for different cases of distribution of line defects. This includes a random (uncorrelated) and a correlated distribution with a prevailing direction in the orientation of lines. The anisotropy of the conductivity along and across the line defects is revealed, which agrees with experimental measurements for epitaxial graphene grown on SiC. We performed a detailed study of the conductivity for different defect correlations, introducing the correlation angle alpha_max (i.e. the maximum possible angle between any two lines). We find that for a given electron density, the relative enhancement of the conductivity for the case of fully correlated line defects in comparison to the case of uncorrelated ones is larger for a higher defect density. Finally, we study the conductivity of realistic samples where both extended line defects as well as point-like scatterers such as adatoms and charged impurities are presented.
description: 8 pages, 7 figures
Analysis Methods for Gamma-ray Astronomy
Creators: name: Malyshev, Denys
name: Mohrmann, Lars
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The launch of the Fermi satellite in 2008, with its Large Area Telescope (LAT) on board, has opened a new era for the study of gamma-ray sources at GeV ($10^9$ eV) energies. Similarly, the commissioning of the third generation of imaging atmospheric Cherenkov telescopes (IACTs) - H.E.S.S., MAGIC, and VERITAS - in the mid-2000's has firmly established the field of TeV ($10^{12}$ eV) gamma-ray astronomy. Together, these instruments have revolutionised our understanding of the high-energy gamma-ray sky, and they continue to provide access to it over more than six decades in energy. In recent years, the ground-level particle detector arrays HAWC, Tibet, and LHAASO have opened a new window to gamma rays of the highest energies, beyond 100 TeV. Soon, next-generation facilities such as CTA and SWGO will provide even better sensitivity, thus promising a bright future for the field. In this chapter, we provide a brief overview of methods commonly employed for the analysis of gamma-ray data, focusing on those used for Fermi-LAT and IACT observations. We describe the standard data formats, explain event reconstruction and selection algorithms, and cover in detail high-level analysis approaches for imaging and extraction of spectra, including aperture photometry as well as advanced likelihood techniques.
description: 56 pages, 12 figures. Invited chapter for "Handbook of X-ray and Gamma-ray Astrophysics" (Eds. C. Bambi and A. Santangelo, Springer Singapore, expected in 2023)
Feasibility of Neutron Coincidence Counting for Spent Fuel
Creators: name: Fang, Ming
name: Di Fulvio, Angela
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: High-temperature gas reactors rely on TRIstructural-ISOtropic (TRISO) fuel for enhanced fission product retention. Accurate fuel characterization would improve monitoring of efficient fuel usage and accountability. We developed a new neutron multiplicity counter (NMC) based on boron coated straw (BCS) detectors and used it in coincidence mode for 235U assay in TRISO fuel. In this work, we demonstrate that a high-efficiency version of the NMC encompassing 396 straws is able to estimate the 235U in used TRISO-fueled pebbles or compacts with a relative uncertainty below 2.5% in 100 s. We performed neutronics and fuel depletion calculation of the HTR-10 pebble bed reactor to estimate the neutron and gamma-ray source strengths of used TRISO-fueled pebbles with burnup between 9 and 90 GWd/t. Then, we measured a gamma-ray intrinsic efficiency of 10^-12 at an exposure rate of 340.87 R/h. The low gamma-ray sensitivity and high neutron detection efficiency enable the inspection of used fuel.
description: 25 pages, 19 figures
Millimeter Wave Thin-Film Bulk Acoustic Resonator in Sputtered Scandium Aluminum Nitride
Creators: name: Cho, Sinwoo
name: Barrera, Omar
name: Simeoni, Pietro
name: Marshall, Emily N.
name: Kramer, Jack
name: Motoki, Keisuke
name: Hsu, Tzu-Hsuan
name: Chulukhadze, Vakhtang
name: Rinaldi, Matteo
name: Doolittle, W. Alan
name: Lu, Ruochen
Publisher: name: arXiv
Year: 2023
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This work reports a millimeter wave (mmWave) thin-film bulk acoustic resonator (FBAR) in sputtered scandium aluminum nitride (ScAlN). This paper identifies challenges of frequency scaling sputtered ScAlN into mmWave and proposes a stack and new fabrication procedure with a sputtered Sc0.3Al0.7N on Al on Si carrier wafer. The resonator achieves electromechanical coupling (k2) of 7.0% and quality factor (Q) of 62 for the first-order symmetric (S1) mode at 21.4 GHz, along with k2 of 4.0% and Q of 19 for the third-order symmetric (S3) mode at 55.4 GHz, showing higher figures of merit (FoM, k2xQ) than reported AlN/ScAlN-based mmWave acoustic resonators. The ScAlN quality is identified by transmission electron microscopy (TEM) and X-ray diffraction (XRD), identifying the bottlenecks in the existing piezoelectric-metal stack. Further improvement of ScAlN/AlN-based mmWave acoustic resonators calls for better crystalline quality from improved thin-film deposition methods.
description: 3 pages, 7 figures, submitted to JMEMS
Nonlinear Parametric Inversion using Interpolatory Model Reduction
Creators: name: de Sturler, Eric
name: Gugercin, Serkan
name: Kilmer, Misha E.
name: Chaturantabut, Saifon
name: Beattie, Christopher
name: O'Connell, Meghan
Publisher: name: arXiv
Year: 2013
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65F10, 65N22, 93A15, 93C05

description: Nonlinear parametric inverse problems appear in several prominent applications; one such application is Diffuse Optical Tomography (DOT) in medical image reconstruction. Such inverse problems present huge computational challenges, mostly due to the need for solving a sequence of large-scale discretized, parametrized, partial differential equations (PDEs) in the forward model. In this paper, we show how interpolatory parametric model reduction can significantly reduce the cost of the inversion process in DOT by drastically reducing the computational cost of solving the forward problems. The key observation is that function evaluations for the underlying optimization problem may be viewed as transfer function evaluations along the imaginary axis; a similar observation holds for Jacobian evaluations as well. This motivates the use of system-theoretic model order reduction methods. We discuss the construction and use of interpolatory parametric reduced models as surrogates for the full forward model. Within the DOT setting, these surrogate models can approximate both the cost functional and the associated Jacobian with very little loss of accuracy while significantly reducing the cost of the overall inversion process. Four numerical examples illustrate the efficiency of the proposed approach. Although we focus on DOT in this paper, we believe that our approach is applicable much more generally.
ClusterFusion: Leveraging Radar Spatial Features for Radar-Camera 3D Object Detection in Autonomous Vehicles
Creators: name: Kurniawan, Irfan Tito
name: Trilaksono, Bambang Riyanto
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences
subject: I.4.8; I.4.10

description: Thanks to the complementary nature of millimeter wave radar and camera, deep learning-based radar-camera 3D object detection methods may reliably produce accurate detections even in low-visibility conditions. This makes them preferable to use in autonomous vehicles' perception systems, especially as the combined cost of both sensors is cheaper than the cost of a lidar. Recent radar-camera methods commonly perform feature-level fusion which often involves projecting the radar points onto the same plane as the image features and fusing the extracted features from both modalities. While performing fusion on the image plane is generally simpler and faster, projecting radar points onto the image plane flattens the depth dimension of the point cloud which might lead to information loss and makes extracting the spatial features of the point cloud harder. We proposed ClusterFusion, an architecture that leverages the local spatial features of the radar point cloud by clustering the point cloud and performing feature extraction directly on the point cloud clusters before projecting the features onto the image plane. ClusterFusion achieved the state-of-the-art performance among all radar-monocular camera methods on the test slice of the nuScenes dataset with 48.7% nuScenes detection score (NDS). We also investigated the performance of different radar feature extraction strategies on point cloud clusters: a handcrafted strategy, a learning-based strategy, and a combination of both, and found that the handcrafted strategy yielded the best performance. The main goal of this work is to explore the use of radar's local spatial and point-wise features by extracting them directly from radar point cloud clusters for a radar-monocular camera 3D object detection method that performs cross-modal feature fusion on the image plane.
description: Accepted for publication in IEEE Access
Residency Octree: A Hybrid Approach for Scalable Web-Based Multi-Volume Rendering
Creators: name: Herzberger, Lukas
name: Hadwiger, Markus
name: Krüger, Robert
name: Sorger, Peter
name: Pfister, Hanspeter
name: Gröller, Eduard
name: Beyer, Johanna
Publisher: name: arXiv
Year: 2023
Subjects: subject: Graphics (cs.GR)
subject: FOS: Computer and information sciences

description: We present a hybrid multi-volume rendering approach based on a novel Residency Octree that combines the advantages of out-of-core volume rendering using page tables with those of standard octrees. Octree approaches work by performing hierarchical tree traversal. However, in octree volume rendering, tree traversal and the selection of data resolution are intrinsically coupled. This makes fine-grained empty-space skipping costly. Page tables, on the other hand, allow access to any cached brick from any resolution. However, they do not offer a clear and efficient strategy for substituting missing high-resolution data with lower-resolution data. We enable flexible mixed-resolution out-of-core multi-volume rendering by decoupling the cache residency of multi-resolution data from a resolution-independent spatial subdivision determined by the tree. Instead of one-to-one node-to-brick correspondences, each residency octree node is mapped to a set of bricks from different resolution levels. This makes it possible to efficiently and adaptively choose and mix resolutions, adapt sampling rates, and compensate for cache misses. At the same time, residency octrees support fine-grained empty-space skipping, independent of the data subdivision used for caching. Finally, to facilitate collaboration and outreach, and to eliminate local data storage, our implementation is a web-based, pure client-side renderer using WebGPU and WebAssembly. Our method is faster than prior approaches and efficient for many data channels with a flexible and adaptive choice of data resolution.
description: VIS 2023 - full paper
Energy spectrum of valence band in HgTe quantum wells on the way from a two to the three dimensional topological insulator
Creators: name: Minkov, G. M.
name: Rut, O. E.
name: Sherstobitov, A. A.
name: Dvoretski, S. A.
name: Mikhailov, N. N.
name: Aleshkin, V. Ya.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The magnetic field, temperature dependence and the Hall effect have been measured in order to determine the energy spectrum of the valence band in HgTe quantum wells with the width (20-200)nm. The comparison of hole densities determined from the period Shubnikov-de Haas oscillations and the Hall effect shows that states at the top of valence band are double degenerate in teh entry quantum wells width the width range. The cyclotron mass determined from temperature dependence of SdH oscillations increases monotonically from (0.2-0.3) mass of the free electron, with increasing hole density from 2e11 to 6e11 cm^-2. The determined dependence has been compared to theoretical one calculate within the four band kp model. The experimental dependence was found to be strongly inconsistent with this predictions. It has been shown that the inclusion of additional factors (electric field, strain) does not remove the contradiction between experiment and theory. Consequently it is doubtful that the mentioned kp calculations adequately describe the valence band for any width of quantum well.
description: 7 pages 8 figures
Giant modification of atomic transitions probabilities induced by magnetic field: forbidden transitions become predominant
Creators: name: Sargsyan, A.
name: Tonoyan, A.
name: Hakhumyan, G.
name: Papoyan, A.
name: Mariotti, E.
name: Sarkisyan, D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Magnetic field-induced giant modification of probabilities for seven components of 6S1/2 (Fg=3) - 6P3/2 (Fe=5) transition of Cs D2 line forbidden by selection rules is observed experimentally for the first time. For the case of excitation with circularly-polarized laser radiation, the probability of Fg=3,mF=-3 - Fe=5,mF=-2 transition becomes the largest among 25 transitions of Fg=3 - Fe=2,3,4,5 group in a wide range of magnetic field 200 - 3200 G. Moreover, the modification is the largest among D2 lines of alkali metals. A half-wave-thick cell (length along the beam propagation axis L=426 nm) filled with Cs has been used in order to achieve sub-Doppler resolution which allows for separating the large number of atomic transitions that appear in the absorption spectrum when an external magnetic field is applied. For B > 3 kG the group of seven transitions Fg=3 - Fe=5 is completely resolved and is located at the high frequency wing of Fg=3 - Fe=2,3,4 transitions. The applied theoretical model very well describes the experimental curves.
description: 7 pages, 8 figures