cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
title: Физические и технологические основы наплавки деталей металлургического оборудования
Creators: name: ELS IPR BOOKS
Publisher: name: Липецкий государственный технический университет, Профобразование
Year: 2023

description: В учебном пособии рассмотрены классификация методов наплавки и основные виды наплавочных материалов. Описаны основные способы наплавки: электродуговая, электрошлаковая, плазменная, индукционная, газовая и др. Изложены вопросы развития технологий наплавки прокатных валков, описаны типичные дефекты, возникающие в наплавленных слоях, специфические особенности механической обработки наплавленных слоёв. Подготовлено в соответствии с требованиями Федерального государственного образовательного стандарта среднего профессионального образования. Учебное пособие может быть использовано студентами, обучающимися по профессии 15.01.05 «Сварщик (ручной и частично механизированной сварки (наплавки)», при изучении дисциплин «Ручная дуговая сварка (наплавка, резка) плавящимся покрытым электродом», «Техника и технология ручной дуговой сварки (наплавки, речки) покрытым электродом», «Ручная дуговая сварка (наплавка) неплавящимся электродом в защитном газе», «Техника и технология ручной дуговой сварки (наплавки) неплавящимся электродом в защитном газе», «Частично механизированная сварка (наплавка) плавлением», «Техника и технология частично механизированной сварки (наплавки) плавлением в защитном газе», «Газовая сварка (наплавка)», «Техника и технология газовой сварки (наплавки)».
A Cryogenic SiGe Low Noise Amplifier Optimized for Phased Array Feeds
Creators: name: Groves, Wavley M.
name: Morgan, Matthew A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The growing number of phased array feeds (PAF) being built for radio astronomy demonstrates an increasing need for low noise amplifiers (LNA) that are designed for repeatability, low noise, and ease of manufacture. Specific design features which help to achieve these goals include the use of unpackaged transistors (for cryogenic operation), single-polarity biasing, straight plug-in RF interfaces to facilitate installation and re-work, and the use of off-the shelf components. The focal L-band array for the Green Bank Telescope (FLAG) is a cooperative effort by Brigham Young University (BYU) and the National Radio Astronomy Observatory (NRAO) using warm dipole antennae and cryogenic Silicon Germanium Heterojunction Bipolar Transistor (SiGe HBT) LNAs. These LNAs have an in band gain average of 38 dB and 4.85 Kelvin average noise temperature. Although the FLAG instrument was the driving instrument behind this development, most of the key features of the design and the advantages they offer apply broadly to other array feeds, including independent-beam and phased, and for many antenna types such as horn, dipole, Vivaldi, connected-bowtie, etc. This paper will focus on the unique requirements array feeds have for low noise amplifiers and how amplifier manufacturing can accommodate these needs.
Ultraviolet Spectropolarimetry:Conservative and Nonconservative Mass Transfer in OB Interacting Binaries
Creators: name: Peters, Geraldine J.
name: Gayley, Ken
name: Ignace, Richard
name: Jones, Carol E.
name: Naze, Yael
name: St-Louis, Nicole
name: Stevance, Heloise
name: Vink, Jorick S.
name: Richardson, Noel D.
name: Hoffman, Jennifer L.
name: Lomax, Jamie R.
name: Shenar, Tomer
name: Fullard, Andrew G.
name: Scowen, Paul A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: One objective of the Polstar spectropolarimetry mission is to characterize the degree of nonconservative mass transfer that occurs at various stages of binary evolution, from the initial mass reversal to the late Algol phase. The proposed instrument combines spectroscopic and polarimetric capabilities, where the spectroscopy can resolve Doppler shifts in UV resonance lines with 10 km/s precision, and polarimetry can resolve linear polarization with 1e-3 precision or better. The spectroscopy will identify absorption by mass streams seen in projection against the stellar disk as a function of orbital phase, hot accretion spots, as well as scattering from extended splash structures, circumbinary disks, and other flows in and above/below the orbital plane (e.g. jets) that fail to be transferred conservatively. The polarimetry affects more the light coming from material not seen against the stellar disk, allowing the geometry of the scattering to be tracked, resolving ambiguities left by the spectroscopy and light-curve information. For example, nonconservative mass streams ejected in the polar direction will produce polarization of the opposite sign from conservative transfer accreting in the orbital plane. Also, time domain coverage over a range of phases of the binary orbit are well supported by the Polstar observing strategy. Combining these elements will significantly improve our understanding of the mass transfer process and the amount of mass that can escape from the system, an important channel for changing the final mass, and ultimate supernova, of the large number of massive stars found in binaries at close enough separation to undergo interaction.
description: Refereed paper in Ap&SS 367:Topical Collection, 23 pages, 10 figures
Molecular Gas, Dust and Star Formation in Galaxies: II. Dust properties and scalings in \sim\ 1600 nearby galaxies
Creators: name: Orellana, G.
name: Elbaz, N. M. Nagar D.
name: Calderón-Castillo, P.
name: Leiton, R.
name: Ibar, E.
name: Magnelli, B.
name: Daddi, E.
name: Messias, H.
name: Cerulo, P.
name: Slater, R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We aim to characterize the relationship between dust properties. We also aim to provide equations to estimate accurate dust properties from limited observational datasets. We assemble a sample of 1,630 nearby (z<0.1) galaxies-over a large range of Mstar, SFR - with multi-wavelength observations available from wise, iras, planck and/or SCUBA. The characterization of dust emission comes from SED fitting using Draine & Li dust models, which we parametrize using two components (warm and cold ). The subsample of these galaxies with global measurements of CO and/or HI are used to explore the molecular and/or atomic gas content of the galaxies. The total Lir, Mdust and dust temperature of the cold component (Tc) form a plane that we refer to as the dust plane. A galaxy's sSFR drives its position on the dust plane: starburst galaxies show higher Lir, Mdust and Tc compared to Main Sequence and passive galaxies. Starburst galaxies also show higher specific Mdust (Mdust/Mstar) and specific Mgas (Mgas/Mstar). The Mdust is more closely correlated with the total Mgas (atomic plus molecular) than with the individual components. Our multi wavelength data allows us to define several equations to estimate Lir, Mdust and Tc from one or two monochromatic luminosities in the infrared and/or sub-millimeter. We estimate the dust mass and infrared luminosity from a single monochromatic luminosity within the R-J tail of the dust emission, with errors of 0.12 and 0.20dex, respectively. These errors are reduced to 0.05 and 0.10 dex, respectively, if the Tc is used. The Mdust is correlated with the total Mism (Mism \propto Mdust^0.7). For galaxies with Mstar 8.5
description: 24 pages, 28 figures, 6 tables, Accepted for publication in A&A
Evaluation of Machine Learning Techniques for Forecast Uncertainty Quantification
Creators: name: Sacco, Maximiliano A.
name: Ruiz, Juan J.
name: Pulido, Manuel
name: Tandeo, Pierre
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Ensemble forecasting is, so far, the most successful approach to produce relevant forecasts with an estimation of their uncertainty. The main limitations of ensemble forecasting are the high computational cost and the difficulty to capture and quantify different sources of uncertainty, particularly those associated with model errors. In this work we perform toy-model and state-of-the-art model experiments to analyze to what extent artificial neural networks (ANNs) are able to model the different sources of uncertainty present in a forecast. In particular those associated with the accuracy of the initial conditions and those introduced by the model error. We also compare different training strategies: one based on a direct training using the mean and spread of an ensemble forecast as target, the other ones rely on an indirect training strategy using an analyzed state as target in which the uncertainty is implicitly learned from the data. Experiments using the Lorenz'96 model show that the ANNs are able to emulate some of the properties of ensemble forecasts like the filtering of the most unpredictable modes and a state-dependent quantification of the forecast uncertainty. Moreover, ANNs provide a reliable estimation of the forecast uncertainty in the presence of model error. Preliminary experiments conducted with a state-of-the-art forecasting system also confirm the ability of ANNs to produce a reliable quantification of the forecast uncertainty.
description: preprint
A hybrid classical-quantum algorithm for solution of nonlinear ordinary differential equations
Creators: name: Shukla, Alok
name: Vedula, Prakash
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: 81P68, 34A34, 42C10

description: A hybrid classical-quantum approach for the solution of nonlinear ordinary differential equations using Walsh-Hadamard basis functions is proposed. Central to this hybrid approach is the computation of the Walsh-Hadamard transform of arbitrary vectors, which is enabled in our framework using quantum Hadamard gates along with state preparation, shifting, scaling, and measurement operations. It is estimated that the proposed hybrid classical-quantum approach for the Walsh-Hadamard transform of an input vector of size N results in a considerably lower computational complexity (O(N) operations) compared to the Fast Walsh-Hadamard transform (O(N log2(N)) operations). This benefit will also be relevant in the context of the proposed hybrid classical-quantum approach for the solution of nonlinear differential equations. Comparisons of results corresponding to the proposed hybrid classical-quantum approach and a purely classical approach for the solution of nonlinear differential equations (for cases involving one and two dependent variables) were found to be satisfactory. Some new perspectives relevant to the natural ordering of Walsh functions (in the context of both classical and hybrid approaches for the solution of nonlinear differential equations) and representation theory of finite groups are also presented here.
description: 29 pages, 10 figures
NNLO solution of nonlinear GLR-MQ evolution equation to determine gluon distribution function using Regge like ansatz
Creators: name: Phukan, P.
name: Lalung, M.
name: Sarma, J. K.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this work we have suggested a solution of the Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) nonlinear evolution equation at next-to-next-to-leading order (NNLO). The range of $Q^2$ in which we have solved the GLR-MQ equation is Regge region of the range $5 GeV^2 \leq Q^2 \leq 25 GeV^2$ and so we have incorporated the Regge like behavior to obtain $Q^2$ evolution of gluon distribution function $G(x, Q^2)$. We have also checked the sensitivity of our results for different values of correlation radius (R) between two interacting gluons, viz. $R=2 GeV^{-1}$ and $R= 5 GeV^{-1}$ as well as for different values of Regge intercept $λ_G$. Our computed results are compared with those obtained by the most recent global DGLAP fits to the parton distribution functions viz. PDF4LHC15, NNPDF3.0, HERAPDF15, CT14 and ABM12.
description: 15 pages, 14 figures, the language is slightly changed
STITCH: A Subgrid-Scale Model for Energy Buildup in the Solar Corona
Creators: name: Dahlin, Joel T.
name: DeVore, C. Richard
name: Antiochos, Spiro K.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: The solar corona routinely exhibits explosive activity, in particular coronal mass ejections and their accompanying eruptive flares, that have global-scale consequences. These events and their smaller counterparts, coronal jets, originate in narrow, sinuous filament channels. The key processes that form and evolve the channels operate on still smaller spatial scales and much longer time scales, culminating in a vast separation of characteristic lengths and times that govern these explosive phenomena. In this article, we describe implementation and tests of an efficient subgrid-scale model for generating eruptive structures in magnetohydrodynamics (MHD) coronal simulations. STITCH -- STatistical InjecTion of Condensed Helicity -- is a physics-based, reduced representation of helicity condensation: a process wherein small-scale vortical surface convection forms ubiquitous current sheets, and pervasive reconnection across the sheets mediates an inverse cascade of magnetic helicity and free energy, thereby forming the filament channels. STITCH abstracts these complex processes into a single new term, in the MHD Ohm's law and induction equation, which directly injects tangential magnetic flux into the low corona. We show that this approach is in very good agreement with a full helicity-condensation calculation that treats all of the dynamics explicitly, while enabling substantial reductions in temporal duration especially, but also in spatial resolution. In addition, we illustrate the flexibility of STITCH at forming localized filament channels and at energizing complex surface flux distributions that have sinuous boundaries. STITCH is simple to implement and computationally efficient, making it a powerful new technique for event-based, data-driven modeling of solar eruptions.
description: 18 pages, 9 figures, submitted to ApJ
Fast Reconstruction of High-qubit Quantum States via Low Rate Measurements
Creators: name: Li, K.
name: Zhang, J.
name: Cong, S.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: Quantum Physics (quant-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Due to the exponential complexity of the resources required by quantum state tomography (QST), people are interested in approaches towards identifying quantum states which require less effort and time. In this paper, we provide a tailored and efficient method for reconstructing mixed quantum states up to $12$ (or even more) qubits from an incomplete set of observables subject to noises. Our method is applicable to any pure or nearly pure state $ρ$, and can be extended to many states of interest in quantum information processing, such as multi-particle entangled $W$ state, GHZ state and cluster states that are matrix product operators of low dimensions. The method applies the quantum density matrix constraints to a quantum compressive sensing optimization problem, and exploits a modified Quantum Alternating Direction Multiplier Method (Quantum-ADMM) to accelerate the convergence. Our algorithm takes $8,35$ and $226$ seconds respectively to reconstruct superposition state density matrices of $10,11,12$ qubits with acceptable fidelity, using less than $1 \%$ of measurements of expectation. To our knowledge it is the fastest realization that people can achieve using a normal desktop. We further discuss applications of this method using experimental data of mixed states obtained in an ion trap experiment of up to $8$ qubits.
Fluctuating hydrodynamics and the Brownian motion of an active colloid near a wall
Creators: name: Singh, Rajesh
name: Adhikari, R.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The traction on the surface of a spherical active colloid in a thermally fluctuating Stokesian fluid contains passive, active, and Brownian contributions. Here we derive these three parts systematically, by "projecting out" the fluid using the boundary-domain integral representation of slow viscous flow. We find an exact relation between the statistics of the Brownian traction and the thermal forces in the fluid and derive, thereby, fluctuation-dissipation relations for every irreducible tensorial harmonic traction mode. The first two modes give the Brownian force and torque, from which we construct the Langevin and Smoluchowski equations for the position and orientation of the colloid. We emphasize the activity-induced breakdown of detailed balance and provide a prescription for computing the configuration-dependent variances of the Brownian force and torque. We apply these general results to an active colloid near a plane wall, the simplest geometry with configuration-dependent variances, and show that the stationary distribution is non-Gibbsian. We derive a regularization of the translational and rotational friction tensors, necessary for Brownian dynamics simulations, that ensures positive variances at all distances from the wall. The many-body generalization of these results is indicated.
description: add journal reference
The strategic taxation of memory: preschooler and adult attention to expectation-violating events and the impact on learning of future content
Creators: name: Macias-Cervantes, Carla-Keyanna Rose
Publisher: name: No Publisher Supplied
Year: 2022

description: Young children learn a lot about the world within their first few years of life. Learning is critically intertwined with working memory—the ability to maintain and manipulate information in mind— yet children have limited working memory resources early on in development. How might we reconcile a developing working memory system with this rapid learning? One possibility is that children have some control over what kinds of information are prioritized in memory—consistent with work showing that other cognitive capacities, like attention and action, can be rationally directed (e.g. Bonawitz et al., 2012; Kidd et al., 2012). Through empirical studies with adults and children, this dissertation investigates whether learners are selective in the kinds of information they prioritize for processing in working memory, whether this comes at the cost of learning other information, and if the processing of information can be manipulated by the promise of an explanation.First, how do learners decide what information to attend to and remember for later use? Previous literature suggests that Expectation-Violating events are more likely to provide opportunities for learning, and be better remembered than Expectation-Consistent events (Stahl & Feigenson, 2015). I suggest that learners selectively attend to Expectation-Violating information as a rational learning strategy, at the cost of learning subsequent (unrelated) information. We explore this question in preschoolers using a modified surprise paradigm (Stahl & Feigenson, 2017) and in older children and adults using age-appropriate trivia tasks (Wade & Kidd, 2019). Adult behavioral data support this prediction; however, behavioral data from preschoolers’ and older children do not. Second, how might memory for information be impacted when there is a promise of a future explanation? Explanations play an important role in learning. I propose that when learners believe that an explanation for an Expectation-Violating event will be available later, they will no longer display a deficit in subsequent learning. Results from adult behavioral data do not support this predication. Together this work informs our understanding of how memory is influenced by different kinds of expectation-related information. These results suggest that the impact expectation-related information has on memory may be age and/or task dependent.
Experimental study of submerged liquid metal jet in transverse magnetic field
Creators: name: Belyaev, Ivan A.
name: Mironov, Ivan S.
name: Luchinkin, Nikita A.
name: Listratov, Yaroslav I.
name: Kolesnikov, Yuri B.
name: Kransnov, Dmitry
name: Zikanov, Oleg
name: Molokov, Sergey
Publisher: name: arXiv
Year: 2021
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: A liquid metal flow in the form of a submerged round jet entering a square duct in the presence of a transverse magnetic field is studied experimentally. A range of high Reynolds and Hartmann numbers is considered. Flow velocity is measured using electric potential difference probes. A detailed study of the flow in the duct's cross-section about seven jet's diameters downstream of the inlet reveals the dynamics, which is unsteady and dominated by high-amplitude fluctuations resulting from instability of the jet. The flow structure and fluctuation properties are largely determined by the value of the Stuart number N. At moderate N, the mean velocity profile retains a central jet with three-dimensional perturbations increasingly suppressed by the magnetic field as N grows. At higher values of N, the flow becomes quasi-two-dimensional and acquires the form of an asymmetric macrovortex, with high-amplitude velocity fluctuations reemerging.
Recovery and Setup Validation from Experimental challenges in determining the rheological properties of bacterial biofilms
Creators: name: Geisel, Steffen
name: Secchi, Eleonora
name: Vermant, Jan
Publisher: name: The Royal Society
Year: 2022
Subjects: subject: Biophysics
subject: 110601 Biomechanics
subject: FOS: Health sciences
subject: 90301 Biomaterials
subject: FOS: Medical engineering

description: Recovery of biofilms over time and validation of the precision of our rheometer measuring setup
Small Languages, Big Models: A Study of Continual Training on Languages of Norway
Creators: name: Samuel, David
name: Mikhailov, Vladislav
name: Velldal, Erik
name: Øvrelid, Lilja
name: Charpentier, Lucas Georges Gabriel
name: Kutuzov, Andrey
name: Oepen, Stephan
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computation and Language (cs.CL)
subject: FOS: Computer and information sciences

description: Training large language models requires vast amounts of data, posing a challenge for less widely spoken languages like Norwegian and even more so for truly low-resource languages like Northern Sámi. To address this issue, we present a novel three-stage continual training approach that substantially improves the downstream performance together with the inference efficiency for the target languages. Based on our findings, we train, evaluate, and openly release a new generative language model for Norwegian Bokmål, Nynorsk, and Northern Sámi with 11.4 billion parameters: NorMistral-11B.
description: Published at NoDaLiDa 2025
title: Dynamic Parameters of Hypothermic Machine Perfusion—An Image of Initial Graft Function in Adult Kidney Transplantation?
Creators: name: Weberskirch, Sebastian
name: Katou, Shadi
name: Reuter, Stefan Johannes
name: Kneifel, Felicia
name: Morgul, M. Haluk
name: Becker, Felix
name: Houben, Philipp
name: Pascher, Andreas
name: Vogel, Thomas
name: Radunz, Sonia
Publisher: name: University of Muenster, Institutional Repository MIAMI
Year: 2023
Subjects: subject: 330 Economics

description: Kidney allografts are subjected to ischemia reperfusion injury during the process of transplantation. Hypothermic machine perfusion (HMP) of deceased donor kidneys from organ procurement until transplantation is associated with a superior outcome when compared to static cold storage (SCS). Nevertheless, cold ischemia time (CIT) remains an independent risk factor for delayed graft function (DGF) in HMP-preserved kidney allografts as well. We performed a retrospective single-center study including all adult recipients who underwent deceased donor kidney-only transplantation at our center between January 2019 and December 2020. Beside the clinicopathological donor and recipient data, flow and resistance data during HMP were assessed. Short- and long-term kidney allograft outcome after end-ischemic HMP and SCS were analyzed and compared. Organ preservation consisted of either SCS (n = 88) or HMP (n = 45). There were no differences in recipient demographics and donor details between groups. CIT was significantly longer in the HMP group (16.5 [8.5–28.5] vs. 11.3 [5.4–24.1], p < 0.0001). The incidence of DGF as well as serum creatinine at discharge and at 1 year post transplant were comparable between groups. Duration of SCS prior to HMP was comparable among grafts with and without DGF. Flow rate and organ resistance at the start of HMP were significantly worse in DGF-kidney grafts (arterial flow 22.50 [18.00–48.00] vs. 51.83 [25.50–92.67] ml/min, p = 0.0256; organ resistance 123.33 [57.67–165.50] vs. 51.33 [28.17–111.50] mmHg/mL/min, p = 0.0050). Recipients with DGF had significantly worse creatinine levels at discharge (2.54 [1.08–7.64] vs. 1.67 [0.90–6.56], p < 0.0001) and at 1 year post transplant (1.80 [1.09–7.95] vs. 1.59 [0.87–7.40], p = 0.0105). In conclusion, baseline HMP parameters could be applied as a predictive tool for initial graft function, which in turn determines long-term outcome.
description: Finanziert durch den Open-Access-Publikationsfonds der Westfälischen Wilhelms-Universität Münster (WWU Münster).
On Kinetic Slow Modes, Fluid Slow Modes, and Pressure-balanced Structures in the Solar Wind
Creators: name: Verscharen, Daniel
name: Chen, Christopher H. K.
name: Wicks, Robert T.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Space Physics (physics.space-ph)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Observations in the solar wind suggest that the compressive component of inertial-range solar-wind turbulence is dominated by slow modes. The low collisionality of the solar wind allows for non-thermal features to survive, which suggests the requirement of a kinetic plasma description. The least-damped kinetic slow mode is associated with the ion-acoustic (IA) wave and a non-propagating (NP) mode. We derive analytical expressions for the IA-wave dispersion relation in an anisotropic plasma in the framework of gyrokinetics and then compare them to fully-kinetic numerical calculations, results from two-fluid theory, and MHD. This comparison shows major discrepancies in the predicted wave phase speeds from MHD and kinetic theory at moderate to high $β$. MHD and kinetic theory also dictate that all plasma normal modes exhibit a unique signature in terms of their polarization. We quantify the relative amplitude of fluctuations in the three lowest particle velocity moments associated with IA and NP modes in the gyrokinetic limit and compare these predictions with MHD results and in-situ observations of the solar-wind turbulence. The agreement between the observations of the wave polarization and our MHD predictions is better than the kinetic predictions, suggesting that the plasma behaves more like a fluid in the solar wind than expected.
description: 8 pages, 5 figures
Imprinting chirality on atoms using synthetic chiral light fields
Creators: name: Mayer, Nicola
name: Patchkovskii, Serguei
name: Morales, Felipe
name: Ivanov, Misha
name: Smirnova, Olga
Publisher: name: arXiv
Year: 2021
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Atoms are usually thought of as achiral objects. However, one can construct superpositions of atomic states that are chiral [1]. Here we show how to excite such superpositions with tailored light fields both in the weak-field and strong-field regimes, using realistic laser parameters. First, we use time-dependent Schrodinger equation (TDSE) simulations to demonstrate the creation of a time-dependent bound chiral wavepacket in sodium atoms. Second, we show how the time-dependent handedness of this wavepacket can be probed by photoelectron circular dichroism, in spite of the central symmetry of the core potential. Third, we use TDSE simulations to show how chirality can be directly imprinted on a photoelectron wavepacket created by strong-field ionization and introduce an unambigous chiral measure that allows us to characterize its handedness.
title: Электрический привод. Скорректированные системы частотного асинхронного электропривода
Creators: name: ELS IPR BOOKS
Publisher: name: Липецкий государственный технический университет, Профобразование
Year: 2023

description: В учебном пособии приведено математическое описание частотного асинхронного электропривода, проанализирован режим оптимального управления с обеспечением минимума тока статора. Даны схемные решения с реализацией оптимальных режимов с помощью корректирующих средств. Подготовлено в соответствии с требованиями Федерального государственного образовательного стандарта среднего профессионального образования. Учебное пособие может быть использовано при изучении дисциплины «Электрический привод» по укрупненной группе специальностей 13.00.00 «Электро- и теплоэнергетика».
On the geometry of the orthogonal momentum amplituhedron
Creators: name: Lukowski, Tomasz
name: Moerman, Robert
name: Stalknecht, Jonah
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Combinatorics (math.CO)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: In this paper we study the orthogonal momentum amplituhedron $\mathcal{O}_k$, a recently introduced positive geometry that encodes the tree-level scattering amplitudes in ABJM theory. We generate the full boundary stratification of $\mathcal{O}_k$ and show that its boundaries can be labelled by so-called orthogonal Grassmannian forests (OG forests). We also determine the generating function for enumerating boundaries according to their dimension and show that the Euler characteristic of $\mathcal{O}_k$ equals one. This provides a strong indication that the orthogonal momentum amplituhedron is homeomorphic to a ball. This paper is supplemented with the Mathematica package "orthitroids" which contains useful functions for studying the positive orthogonal Grassmannian and the orthogonal momentum amplituhedron.
description: 19 pages, 7 figures
Topology and Geometry of the Third-Party Domains Ecosystem: Measurement and Applications
Creators: name: Iordanou, Costas
name: Papadopoulos, Fragkiskos
Publisher: name: arXiv
Year: 2021
Subjects: subject: Social and Information Networks (cs.SI)
subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: Over the years, web content has evolved from simple text and static images hosted on a single server to a complex, interactive and multimedia-rich content hosted on different servers. As a result, a modern website during its loading time fetches content not only from its owner's domain but also from a range of third-party domains providing additional functionalities and services. Here, we infer the network of the third-party domains by observing the domains' interactions within users' browsers from all over the globe. We find that this network possesses structural properties commonly found in complex networks, such as power-law degree distribution, strong clustering, and small-world property. These properties imply that a hyperbolic geometry underlies the ecosystem's topology. We use statistical inference methods to find the domains' coordinates in this geometry, which abstract how popular and similar the domains are. The hyperbolic map we obtain is meaningful, revealing the large-scale organization of the ecosystem. Furthermore, we show that it possesses predictive power, providing us the likelihood that third-party domains are co-hosted; belong to the same legal entity; or merge under the same entity in the future in terms of company acquisition. We also find that complementarity instead of similarity is the dominant force driving future domains' merging. These results provide a new perspective on understanding the ecosystem's organization and performing related inferences and predictions.
Who is using Knowledge Graphs in NFDI? An overview by the Working Group "Knowledge Graphs"
Creators: name: Limani, Fidan
name: Shigapov, Renat
name: Degbelo, Auriol
name: Schimmler, Sonja
name: Zapilko, Benjamin
name: Rossenova, Lozana
name: Dietze, Stefan
name: Förstner, Konrad U.
name: Karmakar, Saurav
name: Czerniak, Andreas
Publisher: name: Zenodo
Year: 2023
Subjects: Knowledge Graphs
FAIR
semantic interoperability
NFDI

description: The NFDI Working Group “Knowledge Graphs” (WG KGs) promotes the use and creation of knowledge graphs in NFDI as a key technology for ensuring interoperability for both humans and machines. The members of the WG meet regularly to share knowledge about KG creation and use, as well as to develop KG-based basic service proposals for Base4NFDI. In this poster we describe the activities of this WG and share our ongoing overview of the KGs in NFDI. This poster summarizes survey data from the WG KGs, which you can access at https://zenodo.org/record/8124286.
Distribution of zeros of the S-matrix of chaotic cavities with localized losses and Coherent Perfect Absorption: non-perturbative results
Creators: name: Fyodorov, Yan V.
name: Suwunarat, Suwun
name: Kottos, Tsampikos
Publisher: name: arXiv
Year: 2017
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Mathematical Physics (math-ph)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: We employ the Random Matrix Theory framework to calculate the density of zeroes of an $M$-channel scattering matrix describing a chaotic cavity with a single localized absorber embedded in it. Our approach extends beyond the weak-coupling limit of the cavity with the channels and applies for any absorption strength. Importantly it provides an insight for the optimal amount of loss needed to realize a chaotic coherent perfect absorbing (CPA) trap. Our predictions are tested against simulations for two types of traps: a complex network of resonators and quantum graphs.
description: published version
The hydrodynamics of slender swimmers near deformable interfaces
Creators: name: Nambiar, Sankalp
name: Wettlaufer, John S
Publisher: name: arXiv
Year: 2021
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Biological Physics (physics.bio-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We study the coupled hydrodynamics between a motile slender microswimmer and a deformable interface that separates two Newtonian fluid regions. From the disturbance field generated by the swimming motion, we quantitatively characterize the interface deformation and the manner in which the coupling modifies the microswimmer translation itself. We treat the role of the swimmer type (pushers and pullers), size and model an interface that can deform due to both surface tension and bending elasticity. Our analysis reveals a strong dependence of the hydrodynamics on the swimmer orientation and position. Given the viscosities of the two fluid media, the interface properties and the swimmer type, a swimmer can either migrate towards or away from the interface depending on its configurations. When the swimmer is oriented parallel to the interface, a pusher-type swimmer is repelled from the interface at short times if it is swimming in the more viscous fluid. At long times however, pushers are always attracted to the interface, and pullers are always repelled from it. On the other hand, swimmers oriented orthogonal to the interface exhibit a migration pattern opposite to the parallel swimmers. In consequence, a host of complex migration trajectories emerge for swimmers arbitrarily oriented to the interface. We find that confining a swimmer between a rigid boundary and a deformable interface results in regimes of attraction towards both surfaces depending on the swimmer location in the channel, irrespective viscosity ratio. The differing migration patterns are most prominent in a region of order the swimmer size from the interface, where the slender swimmer model yields a better approximation to the coupled hydrodynamics.
Conditions for Super-Eddington Accretion onto the First Black Holes
Creators: name: Gordon, Simone T.
name: Smith, Britton D.
name: Khochfar, Sadegh
name: Beckmann, Ricarda S.
Publisher: name: arXiv
Year: 2024
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Observations of supermassive black holes at high redshift challenge our understanding of the evolution of the first generation of black holes (BHs) in proto-galactic environments. One possibility is that they grow much more rapidly than current estimates of feedback and accretion efficiency permit. Following our previous analysis of super-Eddington accretion onto stellar-mass black holes in mini-haloes under no-feedback conditions, we now investigate whether this can be sustained when thermal feedback is included. We use four sets of cosmological simulations at sub-pc resolution with initial black hole masses varying from $1 \times 10^3 - 6 \times 10^4 M_\odot$, exploring a range of feedback efficiencies. We also vary the feedback injection radius to probe the threshold of numerical overcooling. We find that super-Eddington growth sustained on the order of $\sim$$100 \, \rm kyr$ is possible with very weak thermal feedback efficiency in all environments and moderate efficiency for two of the BHs. Trans-Eddington growth is possible for a $3 \times 10^3 - 6 \times 10^3 M_\odot$ BH at moderate feedback efficiencies. We discuss the effectiveness of thermal feedback in heating the gas, suppressing accretion, and driving outflows at these parameter configurations. Our results suggest that super-Eddington growth may be possible in the presence of thermal feedback for black holes formed from the first stars.
description: Accepted by MNRAS. 17 pages, 9 figures
Holographic bulk reconstruction beyond (super)gravity
Creators: name: Roy, Shubho R.
name: Sarkar, Debajyoti
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We outline a holographic recipe to reconstruct $α'$ corrections to AdS (quantum) gravity from an underlying CFT in the strictly planar limit ($N\rightarrow\infty$). Assuming that the boundary CFT can be solved in principle to all orders of the 't Hooft coupling $λ$, for scalar primary operators, the $λ^{-1}$ expansion of the conformal dimensions can be mapped to higher curvature corrections of the dual bulk scalar field action. Furthermore, for the metric pertubations in the bulk, the AdS/CFT operator-field isomorphism forces these corrections to be of the Lovelock type. We demonstrate this by reconstructing the coefficient of the leading Lovelock correction, aka the Gauss-Bonnet term in a bulk AdS gravity action using the expression of stress-tensor two-point function up to sub-leading order in $λ^{-1}$.
description: 19 pages, typos corrected, published version (journal version title is different)
Exotic Non-Abelian Topological Defects in Lattice Fractional Quantum Hall States
Creators: name: Liu, Zhao
name: Möller, Gunnar
name: Bergholtz, Emil J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We investigate extrinsic wormholelike twist defects that effectively increase the genus of space in lattice versions of multicomponent fractional quantum Hall systems. Although the original band structure is distorted by these defects, leading to localized midgap states, we find that a new lowest flat band representing a higher genus system can be engineered by tuning local single-particle potentials. Remarkably, once local many-body interactions in this new band are switched on, we identify various Abelian and non-Abelian fractional quantum Hall states, whose ground-state degeneracy increases with the number of defects, i.e, with the genus of space. This sensitivity of topological degeneracy to defects provides a "proof of concept" demonstration that genons, predicted by topological field theory as exotic non-Abelian defects tied to a varying topology of space, do exist in realistic microscopic models. Specifically, our results indicate that genons could be created in the laboratory by combining the physics of artificial gauge fields in cold atom systems with already existing holographic beam shaping methods for creating twist defects.
description: 10 pages, 11 figures, including a Supplementary Material. Published version
Does the Streaming Instability exist within the Terminal Velocity Approximation?
Creators: name: Zhuravlev, V. V.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Terminal velocity approximation is appropriate to study the dynamics of gas-dust mixture with solids tightly coupled to the gas. This work reconsiders its compatibility with physical processes giving rise to the resonant Streaming Instability in the low dust density limit. It is shown that the linearised equations have been commonly used to study the Streaming Instability within the terminal velocity approximation actually exceed the accuracy of this approximation. For that reason, the corresponding dispersion equation recovers the long wavelength branch of the resonant Streaming Instability caused by the stationary azimuthal drift of the dust. However, the latter must remain beyond the terminal velocity approximation by its physical definition. The refined equations for gas-dust dynamics in the terminal velocity approximation does not lead to the resonant Streaming Instability. The work additionally elucidates the physical processes responsible for the instability.
description: 11 pages, no figures, no tables, accepted to ApJ
Viscosity bound for anisotropic superfluids with dark matter sector
Creators: name: Rogatko, Marek
name: Wysokinski, Karol I.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Superconductivity (cond-mat.supr-con)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The shear viscosity to the entropy density ratio $η/s$ of the anisotropic superfluid has been calculated by means of the gauge/gravity duality in the presence of the {\it dark matter} sector. The {\it dark matter} has been described by the Yang-Mills field analogous to the one describing visible matter sector and it is assumed to interact with the visible field with coupling constant $α$. Close to the superfluid transition temperature ($T_c$) the analytical solution has been given up to the leading order in a symmetry breaking parameter and the ratio of the gravitational constant and Yang-Mils coupling. The tensor element of ratio $η/s$ remains unaffected by the {\it dark matter} for the viscosity tensor in the plane perpendicular to the symmetry breaking direction (here $yz$). The temperature dependence and the linear correction in $(1-α)$ in the plane containing this direction (here $xy$) was also revealed. The correction linearly vanishes for temperature tending to the critical one $T\rightarrow T_c$.
description: 14 pages, some comments and references added
Entanglement between superconducting qubits and a tardigrade
Creators: name: Lee, K. S.
name: Tan, Y. P.
name: Nguyen, L. H.
name: Budoyo, R. P.
name: Park, K. H.
name: Hufnagel, C.
name: Yap, Y. S.
name: Møbjerg, N.
name: Vedral, V.
name: Paterek, T.
name: Dumke, R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: Quantum and biological systems are seldom discussed together as they seemingly demand opposing conditions. Life is complex, "hot and wet" whereas quantum objects are small, cold and well controlled. Here, we overcome this barrier with a tardigrade -- a microscopic multicellular organism known to tolerate extreme physiochemical conditions via a latent state of life known as cryptobiosis. We observe coupling between the animal in cryptobiosis and a superconducting quantum bit and prepare a highly entangled state between this combined system and another qubit. The tardigrade itself is shown to be entangled with the remaining subsystems. The animal is then observed to return to its active form after 420 hours at sub 10 mK temperatures and pressure of $6\times 10^{-6}$ mbar, setting a new record for the conditions that a complex form of life can survive.
Neutrinoless double-beta decay: combining quantum Monte Carlo and the nuclear shell model with the generalized contact formalism
Creators: name: Weiss, Ronen
name: Soriano, Pablo
name: Lovato, Alessandro
name: Menendez, Jaview
name: Wiringa, R. B.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We devise a framework based on the generalized contact formalism that combines the nuclear shell model and quantum Monte Carlo methods and compute the neutrinoless double-beta decay of experimentally relevant nuclei, including $^{76}$Ge, $^{130}$Te, and $^{136}$Xe. In light nuclei, we validate our nuclear matrix element calculations by comparing against accurate variational Monte Carlo results. Due to additional correlations captured by quantum Monte Carlo and introduced within the generalized contact formalism, in heavier systems, we obtain long-range nuclear matrix elements that are about 30% smaller than previous shell-model results. We also evaluate the recently recognized short-range nuclear matrix element estimating its coupling by the charge-independence-breaking term of the Argonne $v_{18}$ potential used in the Monte Carlo calculations. Our results indicate an enhancement of the total nuclear matrix element by around 30%.
description: 14 pages, 8 figures