cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Automatic Spectral Classification of Stars using Machine Learning: An Approach based on the use of Unbalanced Data
Creators: name: Oyarzo, Marco
Publisher: name: Zenodo
Year: 2024

description: With the increase in astronomical surveys, astronomers are faced with the challenging task of analyzing a large amount of data in order to classify observed objects into hard-to-distinguish classes. This article presents a machine learning-based method for the automatic spectral classification of stars from the latest release of the SDSS database. We propose the combinatorial use of spectral data, derived stellar data, and calculated data to create patterns. Using these patterns as inputs, we develop a Random Forest model that outputs the spectral class of the observed star. Our model is able to classify data into six complex classes: A, F, G, K, M, and Carbon stars. Due to the unbalanced nature of the data, we train our model considering three data use cases: using the original data, using under-sampling, and over-sampling data techniques. We further test our model by using a fixed dataset and a stratified dataset. From this, we analyze the performance of our model through statistical metrics. The experimental results showed that the combinatorial use of data as an input pattern contributes to improve the prediction scores in all data use cases, meanwhile, the model trained with augmented data outperforms the other cases. Our results suggest that machine learning-based spectral classification of stars may be useful for astronomers.
The consequences of dependence between the formal area efficiency and the macroscopic electric field on linearity behavior in Fowler-Nordheim plots
Creators: name: de Assis, Thiago A.
name: DAgnol, Fernando F.
name: Andrade, Roberto F. S.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: This work presents a theoretical explanation for a crossover in the linear behavior in Fowler-Nordheim (FN) plots based on cold field electron emission (CFE) experimental data. It is characterized by a clear change in the decay rate of usually single-slope FN plots, and has been reported when non-uniform nano-emitters are subject to high macroscopic electric field $F_M$. We assume that the number of emitting spots, which defines an apparent formal area efficiency of CFE surfaces, depends on the macroscopic electric field. Non-uniformity is described by local enhancement factors $\left\{γ_j\right\}$, which are randomly assigned to each distinct emitter of a conducting CFE surface, from a discrete probability distribution $ρ{(γ_{j})}$, with $j=1,2$. It is assumed that $ρ{(γ_{1})} < ρ{(γ_{2})}$, and that $γ_{1} > γ_{2}$. The local current density is evaluated by considering a usual Schottky-Nordheim barrier. The results reproduce the two distinct slope regimes in FN plots when $F_M \in $ $[2,20]$ V/$μ$m and are analyzed by taking into account the apparent formal area efficiency, the distribution $ρ$, and the slopes in the corresponding FN plot. Finally, we remark that our results from numerical solution of Laplace's equation, for an array of conducting nano-emitters with uniform apex radii $50$ nm but different local height, supports our theoretical assumptions and could used in orthodox CFE experiments to test our predictions.
Get your own house in order”: Qualitative dialogue groups with non-vaccinating parents on how measles outbreaks in their community should be managed.
Creators: name: Ward, Paul
Publisher: name: Torrens University Australia
Year: 2023
Subjects: Health promotion

description: Communities with high levels of vaccine rejection present unique challenges to vaccine-preventable disease outbreak management. We sought perspectives of nonvaccinating parents to inform public health responses in such communities. Methods: Nineteen purposively sampled nonvaccinating Australian parents participated in one of seven online dialogue groups. We asked what they thought parents, school principals and public health professionals should do in a hypothetical school measles outbreak and used a framework approach to data analysis. Results: Parents' views were grounded in strong beliefs in parental responsibility and the belief that vaccines are not effective, thus unvaccinated children do not therefore pose a threat. They then reasoned that the forced exclusion of unvaccinated children from school in a measles outbreak was disproportionate to the risk they pose, and their child's right to education should not be overridden. Nonvaccinating parents judged that all parents should keep sick children at home regardless of disease or vaccination status; that school principals should communicate directly with parents and avoid using social media; that public health professionals should provide information to parents so they can decide for themselves about excluding their children from school; that public health responses should avoid accidental identification of unvaccinated children and that mainstream media should be avoided as a communication tool. Conclusion: Nonvaccinating parents do not always agree with current Australian approaches to measles outbreak management. Their perspectives can inform approaches to outbreak responses in communities with high levels of vaccine rejection. Patient or Public Contribution: We sought input from individuals who did and did not vaccinate on study design in its early phases. Individual conversations were used deliberately as we felt the group advisory situation may have felt less safe for nonvaccinating parents, given the divisive and often hostile nature of the topic.
Diphoton Resonances in the Renormalizable Coloron Model
Creators: name: Chivukula, R. Sekhar
name: Farzinnia, Arsham
name: Mohan, Kirtimaan
name: Simmons, Elizabeth H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The renormalizable coloron model, which has previously been shown in the literature to be consistent with a wide array of theoretical and precision electroweak constraints, includes a pair of spinless bosons (one scalar, one pseudoscalar). We show that either of them, or both together if they are degenerate, could be responsible for the diphoton resonance signal for which both CMS and ATLAS have seen evidence. Because either of these bosons would be produced and decay through loops of spectator fermions, the absence of signals in dijet, $t\bar{t}$, and electroweak boson pair channels is not a surprise.
description: 18 pages, 5 figures. (Modified to respond to referee comments, discussion of Landau poles in scalar couplings added.)
title: Prozesskettenorientierte Herstellbarkeitsanalyse von Produkten durch die Nutzung eines Constraint-Satisfaction-Problems
title: Process chain-oriented manufacturability assessment of products by using a constraint satisfaction problem
titleType: AlternativeTitle
Creators: name: Herrmann, Kevin
name: Pusch, Felix
name: Plappert, Stefan
name: Bode, Behrend
name: Mozgova, Iryna
name: Gembarski, Paul Christoph
name: Lachmayer, Roland
Publisher: name: Stuttgart : Fraunhofer IAO
Year: 2023
Subjects: subject: design for manufacturing
subject: constraint satisfaction problem
subject: tailored forming
subject: knowledge-based engineering
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau
subject: Dewey Decimal Classification::600 | Technik::670 | Industrielle und handwerkliche Fertigung
subject: Dewey Decimal Classification::600 | Technik::650 | Management

description: Dieser Beitrag stellt eine rechnergestützte Modellierungsstrategie vor, um Prozesskettenwissen, wie die Gestaltung der Fertigungsstufen, prozessübergreifende Fertigungsrestriktionen oder Fertigungshilfsmittel, für die Produktgestaltung zu formalisieren und im Kontext des Design for Manufacturing für Produkt- und Prozessgestaltungsentscheidungen bereitzustellen. Dabei werden am Beispiel einer Tailored-Forming-Prozesskette die Herstellungsschritte einer Multimaterial-Welle mittels eines Constraint-Satisfaction-Problems (CSP) modelliert, indem die geometrischen Transformationen einzelner Fertigungsstufen sowie Fertigungsrestriktionen in Form von Constraints und Fertigungsstufen sowie Fertigungshilfsmittel über Parameter in den CSP-Variablen formuliert werden. Das CSP ist damit in der Lage, ausgehend von einem Geometriemodell eines Bauteils eine prozesskettenorientierte Restriktionsprüfung zur Herstellbarkeitsbewertung durchzuführen und automatisiert Fertigungsstufen sowie Fertigungshilfsmittel zu konfigurieren.
description: This paper presents a computer-aided modeling strategy to formalize process chain knowledge, such as the design of manufacturing stages, cross-process manufacturing constraints or manufacturing tools, for product design and to provide it for product and process design decisions in the context of design for manufacturing. Using the example of a tailored forming process chain, the manufacturing steps of a multi-material shaft are modeled by means of a constraint satisfaction problem (CSP) by formulating the geometric transformations of individual manufacturing steps as well as manufacturing restrictions in the form of constraints, and manufacturing steps as well as manufacturing resources via parameters in the CSP variables. The CSP is thus able to perform a process-chain-oriented restriction check for manufacturability evaluation based on a geometry model of a component and to automatically configure manufacturing stages and manufacturing resources and tools.
Borel summability of perturbative series in 4d N=2 and 5d N=1 theories
Creators: name: Honda, Masazumi
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We study weak coupling perturbative series in 4d N=2 and 5d N=1 supersymmetric gauge theories with Lagrangians. We prove that the perturbative series of these theories in zero instanton sector are Borel summable for various observables. Our result for 4d $\mathcal{N}=2$ case supports an expectation from a recent proposal on a semiclassical realization of infrared renormalons in QCD-like theories, where the semiclassical solution does not exist in N=2 theories and the perturbative series are unambiguous, namely Borel summable. We also prove that the perturbative series in arbitrary number of instanton sector are Borel summable for a wide class of theories. It turns out that exact results can be obtained by summing over the Borel resummations in each number of instanton sector.
description: 7 pages; v3: abstract, introduction and discussions are improved, accepted to PRL
Microstructural Pattern Formation during Far-from-Equilibrium Alloy Solidification
Creators: name: Ji, Kaihua
name: Dorari, Elaheh
name: Clarke, Amy J.
name: Karma, Alain
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Pattern Formation and Solitons (nlin.PS)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We introduce a new phase-field formulation of rapid alloy solidification that quantitatively incorporates nonequilibrium effects at the solid-liquid interface over a very wide range of interface velocities. Simulations identify a new dynamical instability of dendrite tip growth driven by solute trapping at velocities approaching the absolute stability limit. They also reproduce the formation of the widely observed banded microstructures, revealing how this instability triggers transitions between dendritic and microsegregation-free solidification. Predicted band spacings agree quantitatively with observations in rapidly solidified Al-Cu thin films.
The Radius of PSR J0740+6620 from NICER with NICER Background Estimates
Creators: name: Salmi, Tuomo
name: Vinciguerra, Serena
name: Choudhury, Devarshi
name: Riley, Thomas E.
name: Watts, Anna L.
name: Remillard, Ronald A.
name: Ray, Paul S.
name: Bogdanov, Slavko
name: Guillot, Sebastien
name: Arzoumanian, Zaven
name: Chirenti, Cecilia
name: Dittmann, Alexander J.
name: Gendreau, Keith C.
name: Ho, Wynn C. G.
name: Miller, M. Coleman
name: Morsink, Sharon M.
name: Wadiasingh, Zorawar
name: Wolff, Michael T.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We report a revised analysis for the radius, mass, and hot surface regions of the massive millisecond pulsar PSR J0740+6620, studied previously with joint fits to NICER and XMM-Newton data by Riley et al. (2021) and Miller et al. (2021). We perform a similar Bayesian estimation for the pulse-profile model parameters, except that instead of fitting simultaneously the XMM-Newton data, we use the best available NICER background estimates to constrain the number of photons detected from the source. This approach eliminates any potential issues in the cross-calibration between these two instruments, providing thus an independent check of the robustness of the analysis. The obtained neutron star parameter constraints are compatible with the already published results, with a slight dependence on how conservative the imposed background limits are. A tighter lower limit causes the inferred radius to increase, and a tighter upper limit causes it to decrease. We also extend the study of the inferred emission geometry to examine the degree of deviation from antipodality of the hot regions. We show that there is a significant offset to an antipodal spot configuration, mainly due to the non-half-cycle azimuthal separation of the two emitting spots. The offset angle from the antipode is inferred to be above 25 degrees with 84% probability. This seems to exclude a centered-dipolar magnetic field in PSR J0740+6620.
description: 29 pages, 18 figures (10 of which are figure sets), 1 animation, 10 tables. Published in ApJ
On The Non-Gaussian Errors in High-z Supernovae Type Ia Data
Creators: name: Singh, Meghendra
name: Pandey, Ashwini
name: Sharma, Amit
name: Gupta, Shashikant
name: Sharma, Satendra
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The nature of random errors in any data set that is Gaussian is a well established fact according to the Central Limit Theorem. Supernovae type Ia data have played a crucial role in major discoveries in cosmology. Unlike in laboratory experiments, astronomical measurements can not be performed in controlled situations. Thus, errors in astronomical data can be more severe in terms of systematics and non-Gaussianity compared to those of laboratory experiments. In this paper, we use the Kolmogorov-Smirnov statistic to test non-Gaussianity in high-z supernovae data. We apply this statistic to four data sets, i.e., Gold data(2004), Gold data(2007), Union2 catalogue and the Union2.1 data set for our analysis. Our results shows that in all four data sets the errors are consistent with the Gaussian distribution.
description: 7 Pages, 2 Figures , Accepted in Research in Astronomy & Astrophysics
Orbital-Active Dirac Materials from the Symmetry Principle
Creators: name: Xu, Shenglong
name: Wu, Congjun
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Dirac materials, starting with graphene, have drawn tremendous research interest in the past decade. Instead of focusing on the $p_z$ orbital as in graphene, we move a step further and study orbital-active Dirac materials, where the orbital degrees of freedom transform as a two-dimensional irreducible representation of the lattice point group. Examples of orbital-active Dirac materials occur in a broad class of systems, including transition-metal-oxide heterostructures, transition-metal dichalcogenide monolayers, germanene, stanene, and optical lattices. Different systems are unified based on symmetry principles. The band structure of orbital-active Dirac materials features Dirac cones at $K(K')$ and quadratic band touching points at $Γ$, regardless of the origin of the orbital degrees of freedom. In the strong anisotropy limit, i.e., when the $π$-bonding can be neglected, flat bands appear due to the destructive interference. These features make orbital-active Dirac materials an even wider playground for searching for exotic states of matter, such as the Dirac semi-metal, ferromagnetism, Wigner crystallization, quantum spin Hall state, and quantum anomalous Hall state.
description: 14 pages, 5 figures
Cosmological and black hole islands in multi-event horizon spacetimes
Creators: name: Yadav, Gopal
name: Joshi, Nitin
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, we have analyzed the information paradox and its resolution using island proposal in Schwarzschild de-Sitter black hole spacetime. First, we study the information paradox for the black hole patch by treating de-Sitter patch on both sides as a frozen background (by inserting thermal opaque membrane) and then we carry out similar study for de-Sitter patch also. In both cases, when there is no island surface then the entanglement entropy has as usual the linear time dependence whereas in the presence of an island surface entanglement entropy become constant (equal to twice of thermal entropy of black hole/de-Sitter patch). Therefore, we obtain the Page curves for the black hole and de-Sitter patch consistent with the unitary evolution of black holes. In our case, we have found that black hole island is located inside the black hole event horizon in contrast to universal result for eternal black holes and also cosmological island is located inside the cosmological event horizon. Further, we have studied the "effect of temperature" on the Page curves and found that Page curves appear at later times for low temperature black holes/de-Sitter patch and it exhibit opposite behavior for high temperature. This implies that "dominance of islands" and "information recovery" takes more time for low temperature black holes/de-Sitter patch in contrast to high temperature black holes/de-Sitter patch. We also make comments on the challenges to study the information paradox in SdS spacetime without the thermal opaque membrane.
description: v3: 1+27 pages, 6 figures, LaTeX; references and discussion on bulk gravitational effect near thermal opaque membranes added, published in PRD
Non-equilibrium and non-homogeneous phenomena around a first-order quantum phase transition
Creators: name: Del Re, Lorenzo
name: Fabrizio, Michele
name: Tosatti, Erio
Publisher: name: arXiv
Year: 2015
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We consider non-equilibrium phenomena in a very simple model that displays a zero-temperature first-order phase transition. The quantum Ising model with a four-spin exchange is adopted as a general representative of first-order quantum phase transitions that belong to the Ising universality class, such as for instance the order-disorder ferroelectric transitions, and possibly first-order T = 0 Mott transitions. In particular, we address quantum quenches in the exactly solvable limit of infinite connectivity and show that, within the coexistence region around the transition, the system can remain trapped in a metastable phase, as long as it is spatially homogeneous so that nucleation can be ignored. Motivated by the physics of nucleation, we then study in the same model static but inhomogeneous phenomena that take place at surfaces and interfaces. The first order nature implies that both phases remain locally stable across the transition, and with that the possibility of a metastable wetting layer showing up at the surface of the stable phase, even at T=0. We use mean-field theory plus quantum fluctuations in the harmonic approximation to study quantum surface wetting.
Metrizability of CHART groups
Creators: name: Reznichenko, Evgenii
Publisher: name: arXiv
Year: 2022
Subjects: subject: Group Theory (math.GR)
subject: Dynamical Systems (math.DS)
subject: Functional Analysis (math.FA)
subject: General Topology (math.GN)
subject: FOS: Mathematics
subject: 57S10 22C05 37B05 54H15

description: For compact Hausdorff admissible right topological (CHART) group $G$, we prove $w(G)=πχ(G)$. This equality is well known for compact topological groups. This implies the criteria for the metrizability of CHART groups: if $G$ is first-countable (2013, Moors, Namioka) or $G$ is Fréchet (2013, Glasner, Megrelishvili), or $G$ has countable $π$-character (2022, Reznichenko) then $G$ is metrizable. Under the continuum hypothesis (CH) assumption, a sequentially compact CHART group is metrizable. Namioka's theorem that metrizable CHART groups are topological groups extends to CHART groups with small weight.
Small field inflation in ${\cal N}=1$ supergravity with a single chiral superfield
Creators: name: Bernardo, Heliudson
name: Nastase, Horatiu
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We consider "new inflation" inflationary models at small fields, embedded in minimal ${\cal N}=1$ supergravity with a single chiral superfield. Imposing a period of inflation compatible with experiment severely restricts possible models, classified in perturbation theory. If moreover we impose that the field goes to large values and very small potential at the current time, like would be needed for instance for the inflaton being the volume modulus in large extra dimensional scenarios, the possible models are restricted to very contrived superpotentials.
description: 25 pages, no figures; references and explanation added
Does credit supply affect real estate cap rates?
Creators: name: Priest, Alex
Publisher: name: The University of Texas at Austin
Year: 2023
Subjects: Real estate
Credit supply
Asset pricing

description: In this dissertation, I examine the relationship between availability of credit and commercial real estate cap rates. Understanding whether and how the supply of credit affects property cap rates has important implications for investors and asset values. In the first chapter, I introduce background information about the commercial real estate industry, discuss related research and present the primary hypotheses. Finally, I discuss the data that is used and overview some summary statistics about cap rates. In the second chapter, I explore the relationship between credit supply and real estate cap rates. I first document some stylized facts about the commercial real estate lending industry and find significant differences in credit markets across different local real estate markets. I provide cross-sectional analysis and show that proxies for greater availability of credit are associated with reduced cap rates. To causally identify the effect, I utilize two research designs: firm-wide lender credit suspensions and historical concentration of depository locations. I find evidence consistent with credit supply impacting cap rates through non-fundamental valuation effects. In the third chapter, I study lender incentives and underwriting behavior. The findings are consistent with lenders loosening underwriting standards to compete for loan origination in a "race-to-the-bottom". Finally, in the fourth chapter I conclude and discuss opportunities for additional research.
Proofreading of DNA Polymerase: a new kinetic model with higher-order terminal effects
Creators: name: Song, Yong-Shun
name: Shu, Yao-Gen
name: Zhou, Xin
name: Ou-Yang, Zhong-Can
name: Li, Ming
Publisher: name: arXiv
Year: 2016
Subjects: subject: Subcellular Processes (q-bio.SC)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: The fidelity of DNA replication by DNA polymerase (DNAP) has long been an important issue in biology. While numerous experiments have revealed details of the molecular structure and working mechanism of DNAP which consists of both a polymerase site and an exonuclease (proofreading) site, there were quite few theoretical studies on the fidelity issue. The first model which explicitly considered both sites was proposed in 1970s' and the basic idea was widely accepted by later models. However, all these models did not systematically and rigorously investigate the dominant factor on DNAP fidelity, i.e, the higher-order terminal effects through which the polymerization pathway and the proofreading pathway coordinate to achieve high fidelity. In this paper, we propose a new and comprehensive kinetic model of DNAP based on some recent experimental observations, which includes previous models as special cases. We present a rigorous and unified treatment of the corresponding steady-state kinetic equations of any-order terminal effects, and derive analytical expressions for fidelity in terms of kinetic parameters under bio-relevant conditions. These expressions offer new insights on how the the higher-order terminal effects contribute substantially to the fidelity in an order-by-order way, and also show that the polymerization-and-proofreading mechanism is dominated only by very few key parameters. We then apply these results to calculate the fidelity of some real DNAPs, which are in good agreements with previous intuitive estimates given by experimentalists.
description: 11 figures
Predigt und Predigtverständnis in den Freikirchen
Creators: name: Stadelmann, Helge
Publisher: name: Jahrbuch für evangelikale Theologie
Year: 2025

description: 1646720628
description: Jahrbuch für evangelikale Theologie, V. 23 (2009): Jahrbuch für evangelikale Theologie, Band 23
Dark Current and Single Photon Detection by 1550nm Avalanche Photodiodes: Dead Time Corrected Probability Distributions and Entropy Rates
Creators: name: Menkart, Nicole
name: Hart, Joseph D.
name: Murphy, Thomas E.
name: Roy, Rajarshi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Instrumentation and Detectors (physics.ins-det)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Single photon detectors have dark count rates that depend strongly on the bias level for detector operation. In the case of weak light sources such as novel lasers or single-photon emitters, the rate of counts due to the light source can be comparable to that of the detector dark counts. In such cases, a characterization of the statistical properties of the dark counts is necessary. The dark counts are often assumed to follow a Poisson process that is statistically independent of the incident photon counts. This assumption must be validated for specific types of photodetectors. In this work, we focus on single-photon avalanche photodiodes (SPADs) made for 1550nm. For the InGaAs detectors used, we find the measured distributions often differ significantly from Poisson due to the presence of dead time and afterpulsing with the difference increasing with the bias level. When the dead time is increased to remove the effects of afterpulsing, it is necessary to correct the measured distributions for the effects of the dead time. To this end, we apply an iterative algorithm to remove dead time effects from the probability distribution for dark counts as well as for the case where light from an external weak laser source (known to be Poisson) is detected together with the dark counts. We believe this to be the first instance of the comprehensive application of this algorithm to real data and find that the corrected probability distributions are Poisson distributions in both cases. We additionally use the Grassberger-Procaccia algorithm to estimate the entropy production rates of the dark count processes, which provides a single metric that characterizes the temporal correlations between dark counts as well as the shape of the distribution. We have thus developed a systematic procedure for taking data with 1550nm SPADs and obtaining accurate photocount statistics to examine novel light sources.
description: 14 pages, 8 figures
How are mobility and friction related in viscoelastic fluids?
Creators: name: Caspers, Juliana
name: Ditz, Nikolas
name: Kumar, Karthika Krishna
name: Ginot, Félix
name: Bechinger, Clemens
name: Fuchs, Matthias
name: Krüger, Matthias
Publisher: name: arXiv
Year: 2022
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The motion of a colloidal probe in a viscoelastic fluid is described by friction or mobility, depending on whether the probe is moving with a velocity or feeling a force. While the Einstein relation describes an inverse relationship valid for Newtonian solvents, both concepts are generalized to time-dependent memory kernels in viscoelastic fluids. We theoretically and experimentally investigate their relation by considering two observables: the recoil after releasing a probe that was moved through the fluid and the equilibrium mean squared displacement (MSD). Applying concepts of linear response theory, we generalize Einstein's relation and thereby relate recoil and MSD, which both provide access to the mobility kernel. With increasing concentration, however, MSD and recoil show distinct behaviors, rooted in different behaviors of the two kernels. Using two theoretical models, a linear two-bath particle model and hard spheres treated by mode-coupling theory, we find a Volterra relation between the two kernels, explaining differing timescales in friction and mobility kernels under variation of concentration.
description: 12 pages, 7 figures
Two-dimensional electronic spectroscopy of an ultracold gas
Creators: name: Landmesser, Friedemann
name: Sixt, Tobias
name: Dulitz, Katrin
name: Bruder, Lukas
name: Stienkemeier, Frank
Publisher: name: arXiv
Year: 2022
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Femtosecond coherent multidimensional spectroscopy is demonstrated for an ultracold gas. For this, a setup for phase modulation spectroscopy is used to probe the $3^2\mathrm{S}_{1/2} - 2^2\mathrm{P}_{1/2, 3/2}$ transition in an 800 $μ$K-cold sample of $^7$Li atoms confined in a magneto-optical trap. The observation of a double quantum coherence response, a signature of interparticle interactions, paves the way for detailed investigations of few- and many-body effects in ultracold atomic and molecular gases using this technique. The experiment combines a frequency resolution of 3 GHz with a potential time resolution of 200 fs, which allows for high-resolution studies of ultracold atoms and molecules both in the frequency and in the time domain.
description: 5 pages, 4 figures. This manuscript has been accepted for publication in Optics Letters. {\copyright}2022 Optica Publishing Group. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited
Finite-dimensional signature of spinodal instability in an athermal hysteretic transition
Creators: name: Banerjee, Anurag
name: Bar, Tapas
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We study the off-equilibrium critical phenomena across a hysteretic first-order transition in disordered athermal systems. The study focuses on the zero temperature random field Ising model (ZTRFIM) above the critical disorder for spatial dimensions $d=2,3,$ and $4$. We use Monte Carlo simulations to show that disorder suppresses critical slowing down in phase ordering time for finite-dimensional systems. The dynamic hysteresis scaling, the measure of explicit finite-time scaling, is used to subsequently quantify the critical slowing down. The scaling exponents in all dimensions increase with disorder strength and finally reach a stable value where the transformation is no longer critical. The associated critical behavior in the mean-field limit is very different, where the exponent values for various disorders in all dimensions are similar. The non-mean-field exponents asymptotically approach the mean-field value ($Υ\approx 2/3$) with increase in dimensions. The results suggest that the critical features in the hysteretic metastable phase are controlled by inherent mean-field spinodal instability that gets blurred by disorder in low-dimension athermal systems.
description: 10 pages, 7 figures
MACARONS: A Modular and Open-Sourced Automation System for Vertical Farming
Creators: name: Wichitwechkarn, Vijja
name: Fox, Charles
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: The Modular Automated Crop Array Online System (MACARONS) is an extensible, scalable, open hardware system for plant transport in automated horticulture systems such as vertical farms. It is specified to move trays of plants up to 1060mm x 630mm and 12.5kg at a rate of 100mm/s along the guide rails and 41.7mm/s up the lifts, such as between stations for monitoring and actuating plants. The cost for the construction of one grow unit of MACARONS is 144.96USD which equates to 128.85USD/m2 of grow area. The designs are released and meets the requirements of CERN-OSH-W, which includes step-by-step graphical build instructions and can be built by a typical technical person in one day at a cost of 1535.50USD. Integrated tests are included in the build instructions are used to validate against the specifications, and we report on a successful build. Through a simple analysis, we demonstrate that MACARONS can operate at a rate sufficient to automate tray loading/unloading, to reduce labour costs in a vertical farm.
Stackelberg-Nash null controllability for a non linear coupled degenerate parabolic equations
Creators: name: Djomegne, Landry
name: Kenne, Cyrille
name: Dorville, René
name: Zongo, Pascal
Publisher: name: arXiv
Year: 2022
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: The main purpose of this paper is to apply the notion of hierarchical control to a coupled degenerate non linear parabolic equations. We use the Stackelberg-Nash strategy with one leader and two followers. The followers solve a Nash equilibrium corresponding to a bi-objective optimal control problem and the leader a null controllability problem. Since the considered problem is non linear, the associated cost is non-convex. We first prove the existence, uniqueness and the characterization of the Nash quasiequilibrium, which is a weak formulation of the Nash equilibrium because the cost associated to the non linear problem is non-convex. Next, we show that under suitable conditions, the Nash quasi-equilibrium is equivalent to the Nash equilibrium. Finally using some Carleman inequalities that we established, and the Kakutani's fixed point Theorem, we brough the states of our system to the rest at final time T .
description: arXiv admin note: substantial text overlap with arXiv:2209.12450. substantial text overlap with arXiv:2209.12450, arXiv:2209.04441
Onsager's Cross Coupling Effects in Gas Flows Confined to Micro-channels
Creators: name: Wang, Ruijie
name: Xu, Xinpeng
name: Xu, Kun
name: Qian, Tiezheng
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: In rarefied gases, mass and heat transport processes interfere with each other, leading to the mechano-caloric effect and thermo-osmotic effect, which are of interest to both theoretical study and practical applications. We employ the unified gas-kinetic scheme to investigate these cross coupling effects in gas flows in micro-channels. Our numerical simulations cover channels of planar surfaces and also channels of ratchet surfaces, with Onsager's reciprocal relation verified for both cases. For channels of planar surfaces, simulations are performed in a wide range of Knudsen number and our numerical results show good agreement with the literature results. For channels of ratchet surfaces, simulations are performed for both the slip and transition regimes and our numerical results not only confirm the theoretical prediction [Phys. Rev. Lett. 107, 164502 (2011)] for Knudsen number in the slip regime but also show that the off-diagonal kinetic coefficients for cross coupling effects are maximized at a Knudsen number in the transition regime. Finally, a preliminary optimization study is carried out for the geometry of Knudsen pump based on channels of ratchet surfaces.
One-shot calculation of temperature-dependent optical spectra and phonon-induced band-gap renormalization
Creators: name: Zacharias, Marios
name: Giustino, Feliciano
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Recently, Zacharias et al [Phys. Rev. Lett. 115, 177401 (2015)] developed a new ab initio theory of temperature-dependent optical absorption spectra and band gaps in semiconductors and insulators. In that work the zero-point renormalization and the temperature dependence were obtained by sampling the nuclear wavefunctions using a stochastic approach. In the present work, we show that the stochastic sampling can be replaced by fully deterministic supercell calculations based on a single optimal configuration of the atomic positions. We demonstrate that a single calculation is able to capture the temperature-dependent band gap renormalization including quantum nuclear effects in direct and indirect-gap semiconductors, as well as phonon-assisted optical absorption in indirect-gap semiconductors. In order to demonstrate this methodology we calculate from first principles the temperature-dependent optical absorption spectra and the renormalization of direct and indirect band gaps in Si, C, and GaAs, and we obtain good agreement with experiment and with previous calculations. In this work we also establish the formal connection between the Williams-Lax theory of optical transitions and the related theories of indirect absorption by Hall, Bardeen, and Blatt, and of temperature-dependent band structures by Allen and Heine. Furthermore, we identify an additional band gap renormalization that arises in the case of degenerate band extrema, and which has not been considered in previous work. The present methodology enables systematic ab initio calculations of optical absorption spectra at finite temperature, including both direct and indirect transitions. This feature will be useful for high-throughput calculations of optical properties at finite temperature, and for calculating temperature-dependent optical properties using high-level theories such as GW and Bethe-Salpeter approaches.
description: 20 pages, 10 figures
Current-induced birefringent absorption and non-reciprocal plasmons in graphene
Creators: name: Van Duppen, Ben
name: Tomadin, Andrea
name: Grigorenko, Alexander N.
name: Polini, Marco
Publisher: name: arXiv
Year: 2015
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present extensive calculations of the optical and plasmonic properties of a graphene sheet carrying a dc current. By calculating analytically the density-density response function of current-carrying states at finite temperature, we demonstrate that an applied dc current modifies the Pauli blocking mechanism and that absorption acquires a birefringent character with respect to the angle between the in-plane light polarization and current flow. Employing the random phase approximation at finite temperature, we show that graphene plasmons display a degree of non-reciprocity and collimation that can be tuned with the applied current. We discuss the possibility to measure these effects.
description: 12 pages, 9 figures
Power counting for nuclear forces in chiral effective field theory
Creators: name: Long, Bingwei
Publisher: name: arXiv
Year: 2016
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The present note summarizes the discourse on power counting issues of chiral nuclear forces, with an emphasis on renormalization-group invariance. Given its introductory nature, I will lean toward narrating a coherent point of view on the concepts, rather than covering comprehensively the development of chiral nuclear forces in different approaches.
description: To appear in the special issue of the International Journal of Modern Physics E on "Effective Field Theory in Nuclear Physics", published version, added references
Data-driven Enhancement of the Time-domain First-order Regular Perturbation Model
Creators: name: Barreiro, Astrid
name: Liga, Gabriele
name: Alvarado, Alex
Publisher: name: arXiv
Year: 2022
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: A normalized batch gradient descent optimizer is proposed to improve the first-order regular perturbation coefficients of the Manakov equation, often referred to as kernels. The optimization is based on the linear parameterization offered by the first-order regular perturbation and targets enhanced low-complexity models for the fiber channel. We demonstrate that the optimized model outperforms the analytical counterpart where the kernels are numerically evaluated via their integral form. The enhanced model provides the same accuracy with a reduced number of kernels while operating over an extended power range covering both the nonlinear and highly nonlinear regimes. A $6-7$~dB gain, depending on the metric used, is obtained with respect to the conventional first-order regular perturbation.
PSR J1024-0719: A Millisecond Pulsar in an Unusual Long-Period Orbit
Creators: name: Kaplan, D. L.
name: Kupfer, T.
name: Nice, D. J.
name: Irrgang, A.
name: Heber, U.
name: Arzoumanian, Z.
name: Beklen, E.
name: Crowter, K.
name: DeCesar, M. E.
name: Demorest, P. B.
name: Dolch, T.
name: Ellis, J. A.
name: Ferdman, R. D.
name: Ferrara, E. C.
name: Fonseca, E.
name: Gentile, P. A.
name: Jones, G.
name: Jones, M. L.
name: Kreuzer, S.
name: Lam, M. T.
name: Levin, L.
name: Lorimer, D. R.
name: Lynch, R. S.
name: McLaughlin, M. A.
name: Miller, A. A.
name: Ng, C.
name: Pennucci, T. T.
name: Prince, T. A.
name: Ransom, S. M.
name: Ray, P. S.
name: Spiewak, R.
name: Stairs, I. H.
name: Stovall, K.
name: Swiggum, J.
name: Zhu, W.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: PSR J1024$-$0719 is a millisecond pulsar that was long thought to be isolated. However, puzzling results concerning its velocity, distance, and low rotational period derivative have led to reexamination of its properties. We present updated radio timing observations along with new and archival optical data that show PSR J1024$-$0719 is most likely in a long period (2$-$20 kyr) binary system with a low-mass ($\approx 0.4\,M_\odot$) low-metallicity ($Z \approx -0.9\,$ dex) main sequence star. Such a system can explain most of the anomalous properties of this pulsar. We suggest that this system formed through a dynamical exchange in a globular cluster that ejected it into a halo orbit, consistent with the low observed metallicity for the stellar companion. Further astrometric and radio timing observations such as measurement of the third period derivative could strongly constrain the range of orbital parameters.
description: Accepted by ApJ. 14 pages, 8 figures
A hydrodynamical description of gravitational waves
Creators: name: Mei, Jianwei
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: It is easy to reason that gravity might be the effect of a fluid in disguise, as it will naturally arise in emergent gravity models where gravity is due to the effect of some fundamental particles, with the latter expected to behave collectively like a fluid at the macroscopic scale. We call this the fluid/gravity equivalence. The key difficulty with the fluid/gravity equivalence is to find the correct metric-fluid relation (the relation between the emergent metric and the fluid properties) so that the fluid not only has physically acceptable properties but also obeys the usual hydrodynamic equations, while at the same time the emergent metric also obeys the Einstein equations. Faced with the problem, we have previously made a tentative proposal of the metric-fluid relation, focusing only on obtaining physically acceptable predictions on the fluid properties. In this paper, however, we find that for the general gravitational wave spacetime near the null infinity, the underlying fluid not only has physically acceptable properties, but also satisfies the expected relativistic hydrodynamic equations in the Minkowski background, thus providing a concrete example satisfying both of the major requirements expected for the fluid/gravity equivalence.
description: published version
Investigating the nature of opportunities for proving-related activities in Korean, Singaporean, and United States secondary textbooks
Creators: name: Kim, Hangil
Publisher: name: The University of Texas at Austin
Year: 2023
Subjects: Proof
Reasoning
Textbook analysis
Secondary

description: This dissertation examines the nature of proving-related tasks included in textbooks from Korea, the United States, and Singapore. As an international comparative study, the nature of proving-related activities is analyzed in regard to how frequently proving-related tasks appear in textbook, what kinds of proving-related activities are expected from student, what prompts are used to solicit which of proving-related activities from student, and how consistently prompts are used. In this study, proving-related activities include identifying patterns, formulating generalized statements or conjectures, and justifying conjectures. The dissertation is composed of three distinct articles which are in equivalent form of articles seen in peer-reviewed journals. Using Herbel-Eisenmann’s (2007) framework, the first article examines the voice of the text to address the research questions: What prompts are used to solicit which of proving-related activities from student and how consistently prompts are used. The second article reports on lessons learned from the international comparative study on the nature of proving-related tasks discussing issues and challenges of decision making in the process of conducting the study. The last article discusses implications of the dissertation for teachers to implement proving-related tasks with attention to what teachers need to know and what might be helpful to support students when engaging in proving-related tasks. Findings from the dissertation indicate that textbooks tend to contribute a small fraction of the volume to proving-related tasks, that the vast majority of expected proving-related activities is testing the truth of a conjecture with the exception of the Korean textbook, that the select textbook series commonly use prompts, explain, tell, and what with relatively higher frequency than others, and that prompts are used with consistency indicating that prompts are associated with particular kinds of proving-related activities.