cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Non-parametric bayesian methods for structured topic models
Creators: name: Du, Lan
Publisher: name: The Australian National University
Year: 2011
Subjects: subject: Mathematical statistics Data processing.
subject: Natural language processing (Computer science)
subject: Information storage and retrieval systems Data processing.
subject: Markov processes Mathematical models

description: The proliferation of large electronic document archives requires new techniques for automatically analysing large collections, which has posed several new and interesting research challenges. Topic modelling, as a promising statistical technique, has gained significant momentum in recent years in information retrieval, sentiment analysis, images processing, etc. Besides existing topic models, the field of topic modelling still needs to be further explored using more powerful tools. One potentially useful area is to directly consider the document structure ranging from semantically high-level segments (e.g., chapters, sections, or paragraphs) to low-level segments (e.g., sentences or words) in topic modeling. This thesis introduces a family of structured topic models for statistically modeling text documents together with their intrinsic document structures. These models take advantage of non-parametric Bayesian techniques (e.g., the two-parameter Poisson-Dirichlet process (PDP)) and Markov chain Monte Carlo methods. Two preliminary contributions of this thesis are 1. The Compound Poisson-Dirichlet process (CPDP): it is an extension of the PDP that can be applied to multiple input distributions. 2. Two Gibbs sampling algorithms for the PDP in a finite state space: these two samplers are based on the Chinese restaurant process that provides an elegant analogy of incremental sampling for the PDP. The first, a two-stage Gibbs sampler, arises from a table multiplicity representation for the PDP. The second is built on top of a table indicator representation. In a simply controlled environment of multinomial sampling, the two new samplers have fast convergence speed. These support the major contribution of this thesis, which is a set of structured topic models: Segmented Topic Model (STM) which models a simple document structure with a four-level hierarchy by mapping the document layout to a hierarchical subject structure. It performs significantly better than the latent Dirichlet allocation model and other segmented models at predicting unseen words. Sequential Latent Dirichlet Allocation (SeqLDA) which is motivated by topical correlations among adjacent segments (i.e., the sequential document structure). This new model uses the PDP and a simple first-order Markov chain to link a set of LDAs together. It provides a novel approach for exploring the topic evolution within each individual document. Adaptive Topic Model (AdaTM) which embeds the CPDP in a simple directed acyclic graph to jointly model both hierarchical and sequential document structures. This new model demonstrates in terms of per-word predictive accuracy and topic distribution profile analysis that it is beneficial to consider both forms of structures in topic modelling. - provided by Candidate.
Self-Similar Shocks and Winds in Galaxy Clusters
Creators: name: Lou, Yu-Qing
name: Jiang, Yan-Fei
name: Jin, Chi-Chuan
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A theoretical model framework of spherical symmetry is presented for a composite astrophysical system of two polytropic fluids coupled together by gravity to explore large-scale shocks and flow dynamics in clusters of galaxies or in globular clusters. The existence of such large-scale shocks in clusters of galaxies as inferred by high-resolution X-ray and radio imaging observations implies large-scale systematic flows that are beyond usual static models for clusters of galaxies. Here, we explore self-similar two-fluid flow solutions with shocks for a hot polytropic gas flow in a cluster of galaxies in the presence of a massive dark matter (DM) flow after the initiation of a gravitational core collapse or a central AGN activity or a large-scale merging process. In particular, the possibility of DM shocks or sharp jumps of mass density and of velocity dispersion in dark matter halo is discussed and such DM shocks might be detectable through gravitational lensing effects. To examine various plausible scenarios for clusters of galaxies, we describe three possible classes of shock flows within our model framework for different types of temperature, density and flow speed profiles. Depending upon sensible model parameters and shock locations, the hot ICM and DM halo may have various combinations of asymptotic behaviours of outflow, breeze, inflow, contraction or static envelopes at large radii at a given time. We refer to asymptotic outflows of hot ICM at large radii as the galaxy cluster wind. As a result of such galaxy cluster winds and simultaneous contractions of DM halo during the course of galaxy cluster evolution, there would be less hot ICM within clusters of galaxies as compared to the average baryon fraction in the Universe.
description: 26 pages, 20 figures
Dielectronic recombination of rubidium-like tungsten ions
Creators: name: Wu, Z. W.
name: Zhang, Y. Z.
name: Fu, Y. B.
name: Surzhykov, A.
name: Fritzsche, S.
name: Dong, C. Z.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
The contact network of patients in a regional healthcare system
Creators: name: Liljeros, Fredrik
name: Holme, Petter
name: Giesecke, Johan
Publisher: name: arXiv
Year: 2005
Subjects: subject: Other Quantitative Biology (q-bio.OT)
subject: Physics and Society (physics.soc-ph)
subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: Yet in spite of advances in hospital treatment, hospitals continue to be a breeding ground for several airborne diseases and for diseases that are transmitted through close contacts like SARS, methicillin-resistant Staphylococcus aureus (MRSA), norovirus infections and tuberculosis (TB). Here we extract contact networks for up to 295,108 inpatients for durations up to two years from a database used for administrating a local public healthcare system serving a population of 1.9 million individuals. Structural and dynamical properties of the network of importance for the transmission of contagious diseases are then analyzed by methods from network epidemiology. The contact networks are found to be very much determined by an extreme (age independent) variation in duration of hospital stays and the hospital structure. We find that that the structure of contacts between in-patients exhibit structural properties, such as a high level of transitivity, assortativity and variation in number of contacts, that are likely to be of importance for the transmission of less contagious diseases. If these properties are considered when designing prevention programs the risk for and the effect of epidemic outbreaks may be decreased.
Explaining Excess Dipole in NVSS Data Using Superhorizon Perturbation
Creators: name: Das, Kaustav K.
name: Sankharva, Kishan
name: Jain, Pankaj
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Many observations in recent times have shown evidence against the standard assumption of isotropy in the Big Bang model. Introducing a superhorizon scalar metric perturbation has been able to explain some of these anomalies. In this work, we probe the net velocity arising due to the perturbation. We find that this extra component does not contribute to the CMB dipole amplitude while it does contribute to the dipole in large scale structures. Thus, within this model's framework, our velocity with respect to the large scale structure is not the same as that extracted from the CMB dipole, assuming it to be of purely kinematic origin. Taking this extra velocity component into account, we study the superhorizon mode's implications for the excess dipole observed in the NRAO VLA Sky Survey (NVSS). We find that the mode can consistently explain both the CMB and NVSS observations. We also find that the model leads to small contributions to the local bulk flow and the dipole in Hubble parameter, which are consistent with observations. The model leads to several predictions which can be tested in future surveys. In particular, it implies that the observed dipole in large scale structure should be redshift dependent and should show an increase in amplitude with redshift. We also find that the Hubble parameter should show a dipole anisotropy whose amplitude must increase with redshift in the CMB frame. Similar anisotropic behaviour is expected for the observed redshift as a function of the luminosity distance.
description: 21 pages, 6 figures, Accepted for publication in JCAP
In search of play : a performance kit
Creators: name: Taylor, William Douglas
Publisher: name: University of British Columbia
Year: 2009

description: My thesis is about educating through play. I have been playing, experimenting, thinking, and living my thesis for eight teaching years. At times insight has come with certainty and passion; more often, insight has not come, or it has been diluted or made problematic. I have read educational philosophy, and history, and psychology; I have experimented with evaluative models; I have tried product and process approaches. No matter how fancy the language that I use, no matter how simple and direct the models I create, no matter how intricate and accountable my evaluative strategies are, teaching and learning work best when the heart is at the centre of the enterprise. Becoming educated is learning how to love: to wonder, to question, to quest. Educating is about loving, about finding ways to bring people confidence, and hope, and openness. Play bridges the opposition between order/chaos. It helps me locate the generative, constructive forces in our schools. As a reader of this thesis, I invite you to become a play director. The stories told here do not live on the pages. They do not even really live in the spaces between text and active reader. The only way for these stories to live is if they're played to life through performance. I invite you to read these stories about writing, and community, and culture in the classroom as a producer would read a playscript. To that end, this thesis is presented in the form of a performance kit which contains theory on acting and directing, specific production strategies, the scripts themselves, and background information on the generation of these scripts. I believe that this extended metaphor—teacher as director, students as players, community as audience—can serve as a useful aid to bring play back to the multi-vocal theoretical literature of our discipline and to the stories enacted daily in our classrooms.
Analysis of the $P_{cs}(4459)$ as the hidden-charm pentaquark state with QCD sum rules
Creators: name: Wang, Zhi-Gang
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this article, we study the scalar-diquark-scalar-diquark-antiquark type $udsc\bar{c}$ pentaquark state with the QCD sum rules, the predicted mass $M_P=4.47\pm0.11\,\rm{GeV}$ is in excellent agreement with the experimental data $ 4458.8 \pm 2.9 {}^{+4.7}_{-1.1} \mbox{ MeV}$ from the LHCb collaboration, and supports assigning the $P_{cs}(4459)$ to be the hidden-charm pentaquark state with the spin-parity $J^P={\frac{1}{2}}^-$. We take into account the flavor $SU(3)$ mass-breaking effect, and estimate the mass spectrum of the diquark-diquark-antiquark type $udsc\bar{c}$ pentaquark states with the strangeness $S=-1$.
description: 12 pages, 5 figures
Assessment of a quantum phase gate operation based on nonlinear optics
Creators: name: Rebic, S.
name: Ottaviani, C.
name: Di Giuseppe, G.
name: Vitali, D.
name: Tombesi, P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We analyze in detail the proposal for a two-qubit gate for travelling single-photon qubits recently presented by C. Ottaviani \emph{et al}. [Phys. Rev. A \textbf{73}, 010301(R) (2006)]. The scheme is based on an ensemble of five-level atoms coupled to two quantum and two classical light fields. The two quantum fields undergo cross-phase modulation induced by electromagnetically induced transparency. The performance of this two-qubit quantum phase gate for travelling single-photon qubits is thoroughly examined in the steady-state and transient regimes, by means of a full quantum treatment of the system dynamics. In the steady-state regime, we find a general trade-off between the size of the conditional phase shift and the fidelity of the gate operation. However, this trade-off can be bypassed in the transient regime, where a satisfactory gate operation is found to be possible, significantly reducing the gate operation time.
description: 12 pages, 15 figures
Composite Fermion Nonlinear Sigma Models
Creators: name: Lee, Chao-Jung
name: Kumar, Prashant
name: Mulligan, Michael
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the integer quantum Hall plateau transition using composite fermion mean-field theory. We show that the topological $θ= π$ term in the associated nonlinear sigma model [P. Kumar et al., Phys. Rev. B 100, 235124 (2019)] is stable against a certain particle-hole symmetry violating perturbation, parameterized by the composite fermion effective mass. This result, which applies to both the Halperin, Lee, and Read and Dirac composite fermion theories, represents an emergent particle-hole symmetry. For a disorder ensemble without particle-hole symmetry, we find that $θ$ can vary continuously within the diffusive regime. Our results call for further study of the universality of the plateau transition.
description: 12 pages + two appendices; v2 various corrections, clarifications, and additional references
Measuring the 13-mixing angle and the CP phase with neutrino telescopes
Creators: name: Serpico, P. D.
name: Kachelriess, M.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The observed excess of high-energy cosmic rays from the Galactic plane in the energy range \sim 10^18 eV may be naturally explained by neutron primaries generated in the photo-dissociation of heavy nuclei. In this scenario, neutrons with lower energy decay before reaching the Earth and produce a detectable flux in a 1 km^3 neutrino telescope. The initial flavor composition of these neutrinos, ϕ(\barν_e):ϕ(\barν_μ):ϕ(\barν_τ)=1:0:0, offers the opportunity to perform a combined \barν_μ/\barν_τappearance and \barν_e disappearance experiment. The observable ratio ϕ(\barν_μ)/ϕ(\barν_e+\barν_τ) of fluxes arriving on Earth depends appreciably on the 13-mixing angle θ_13 and the leptonic CP phase δ_CP, opening thus a new experimental avenue to measure these two quantities.
description: 4 pages, 2 eps figures. Enlarged discussion, references added. Matches version to appear in PRL
Dynamical evolution of Population III stellar systems and the resulting binary statistics
Creators: name: Liu, Boyuan
name: Meynet, Georges
name: Bromm, Volker
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We use N-body simulations to study the dynamical evolution of Population III (Pop III) stellar systems and the resulting binary statistics. We design a physically-motivated framework for the initial conditions of Pop III star clusters, based on small-scale hydrodynamic simulations and the scale-free nature of disk evolution during Pop III star formation. Our novel approach enables us to explore the dependence of binary statistics on initial conditions and arrive at more robust predictions for the signals of Pop III X-ray binaries (XRBs) and binary black hole (BBH) mergers, compared to simple extrapolations of Pop III protostar systems. We find that binary properties are highly sensitive to the initial cluster size and distribution of binary separation, while the effect of initial mass function is relatively minor. Our simulations predict less close binaries, and thus, significantly lower efficiencies (by a factor of $\sim 10-10^{4}$) for the formation and accretion of Pop III XRBs, than found in previous studies, implying that the contribution of Pop III XRBs to the cosmic X-ray background is negligible and their feedback effects are unimportant. We estimate the efficiency of Pop III BBH mergers as $\sim 10^{-5}-10^{-4}\ \rm M_{\odot}^{-1}$, for which 3-body hardening by surrounding stars in dense star clusters or close binary interactions is required to facilitate in-spirals of BBHs. All simulation data, including catalogs of Pop III binaries and multiple systems, are publicly available.
description: 19 + 4 pages, 15 + 3 figures, accepted for publication in MNRAS, data available at https://drive.google.com/drive/folders/1JHBjhSBDPT3jdipdQtmr2IJ5TV6Xe6Id?usp=sharing
Rheology of cholesteric blue phases
Creators: name: Dupuis, A.
name: Marenduzzo, D.
name: Orlandini, E.
name: Yeomans, J. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Blue phases of cholesteric liquid crystals offer a spectacular example of naturally occurring disclination line networks. Here we numerically solve the hydrodynamic equations of motion to investigate the response of three types of blue phases to an imposed Poiseuille flow. We show that shear forces bend and twist and can unzip the disclination lines. Under gentle forcing the network opposes the flow and the apparent viscosity is significantly higher than that of an isotropic liquid. With increased forcing we find strong shear thinning corresponding to the disruption of the defect network. As the viscosity starts to drop, the imposed flow sets the network into motion. Disclinations break-up and re-form with their neighbours in the flow direction. This gives rise to oscillations in the time-dependent measurement of the average stress.
description: 4 pages, 4 figures
Multi-Layer Wind Velocity Field Visualization in Infrared Images of Clouds for Solar Irradiance Forecasting
Creators: name: Terrén-Serrano, Guillermo
name: Martínez-Ramón, Manel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Image and Video Processing (eess.IV)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The energy available in a solar energy powered grid is uncertain due to the weather conditions at the time of generation. Forecasting global solar irradiance could address this problem by providing the power grid with the capability of scheduling the storage and dispatch of energy. The occlusion of the Sun by clouds is the main cause of instabilities in the generation of solar energy. This investigation proposes a method to visualize the wind velocity field in sequences of longwave infrared images of clouds when there are multiple wind velocity fields in an image. This method can be used to forecast the occlusion of the Sun by clouds, providing stability in the generation of solar energy. Unsupervised learning is implemented to infer the distribution of the clouds' velocity vectors and heights in multiple wind velocity fields in an infrared image. A multi-output weighted support vector machine with flow constraints is used to extrapolate the wind velocity fields to the entire frame, visualizing the path of the clouds. The proposed method is capable of approximating the wind velocity field in a small air parcel using the velocity vectors and physical features of clouds extracted from infrared images. Assuming that the streamlines are pathlines, the visualization of the wind velocity field can be used for forecasting cloud occlusions of the Sun. This is of importance when considering ways of increasing the stability of solar energy generation.
Towards a fast calculator for the radiation characteristics of radiative recombination and radiative electron capture
Creators: name: Weber, G.
name: Ding, H.
name: Herdrich, M. O.
name: Surzhykov, A.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Tightening weak lensing constraints on the ellipticity of galaxy-scale dark matter haloes
Creators: name: Schrabback, Tim
name: Hoekstra, Henk
name: Van Waerbeke, Ludovic
name: van Uitert, Edo
name: Georgiou, Christos
name: Asgari, Marika
name: Côté, Patrick
name: Cuillandre, Jean-Charles
name: Erben, Thomas
name: Ferrarese, Laura
name: Gwyn, Stephen D. J.
name: Heymans, Catherine
name: Hildebrandt, Hendrik
name: Kannawadi, Arun
name: Kuijken, Konrad
name: Leauthaud, Alexie
name: Makler, Martin
name: Mei, Simona
name: Miller, Lance
name: Raichoor, Anand
name: Schneider, Peter
name: Wright, Angus
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Cosmological simulations predict that galaxies are embedded into triaxial dark matter haloes, which appear approximately elliptical in projection. Weak gravitational lensing allows us to constrain these halo shapes and thereby test the nature of dark matter. Weak lensing has already provided robust detections of the signature of halo flattening at the mass scales of groups and clusters, whereas results for galaxies have been somewhat inconclusive. Here we combine data from five surveys (NGVSLenS, KiDS/KV450, CFHTLenS, CS82, and RCSLenS) in order to tighten observational constraints on galaxy-scale halo ellipticity for photometrically selected lens samples. We constrain $f_\rm{h}$, the average ratio between the aligned component of the halo ellipticity and the ellipticity of the light distribution, finding $f_\rm{h}=0.303^{+0.080}_{-0.079}$ for red lenses and $f_\rm{h}=0.217^{+0.160}_{-0.159}$ for blue lenses when assuming elliptical NFW density profiles and a linear scaling between halo ellipticity and galaxy ellipticity. Our constraints for red galaxies constitute the currently most significant ($3.8σ$) systematics-corrected detection of the signature of halo flattening at the mass scale of galaxies. Our results are in good agreement with expectations from the Millennium Simulation that apply the same analysis scheme and incorporate models for galaxy-halo misalignment. Assuming these misalignment models and the analysis assumptions stated above are correct, our measurements imply an average dark matter halo ellipticity for the studied red galaxy samples of $\langle|ε_\rm{h}|\rangle=0.174\pm 0.046$, where $|ε_{h}|=(1-q)/(1+q)$ relates to the ratio $q=b/a$ of the minor and major axes of the projected mass distribution. Similar measurements based on larger upcoming weak lensing data sets can help to calibrate models for intrinsic galaxy alignments. [abridged]
description: 23 pages, 11 figures, 2 tables. Accepted for publication in A&A. In this version corrections from the A&A language editor have been applied. Comments welcome
In the wind clothes dance on a line : performative inquiry--a (re)search methodology : possibilities and absences within a space-moment of imagining a universe
Creators: name: Fels, Lynn
Publisher: name: University of British Columbia
Year: 2009

description: in the wind clothes dance on a line is the conceptualization and articulation of performative inquiry as a research methodology within the field of education. Performative inquiry invites innovative and non-linear investigations, playing upon the multiple realities and interpretations of co-evolving worlds realized and recognized through creative action and interaction between researcher/teacher and participants/students within individual and shared, existing and imagined environments through motivating (im)pulse(s) of inquiry. Performative inquiry is elusively and momentarily balanced on the "edge of chaos" within the interstices of enactivism, complexity, interpretation, and performance. In articulating an ecological-cognitive reading of performance, I am in company with curricular theorists who envision curriculum as a journey and expression of students' and teachers' shared investigations within co-evolving landscapes of action and interaction., in the wind clothes dance on a line is a playfull response to current conversations among researchers seeking recognition and articulation of arts-based processes as legitimate site(s) and praxis of research. Performative inquiry offers researchers —- in drama education, in particular, and in education, in general, — a theoretical and practical venue to investigate their fields of inquiry through an integrated vehicle of body, mind and imagination. This dissertation is informed by a three year science education research project (1995- 1997) conducted with science educator, Karen Meyer. Our research investigated the teaching and learning of science education through drama and storytelling, culminating in a performance piece, Light Sound Movin' Around: What Are Monsters Made Of? Follow-up interviews with pre-service teachers speak eloquently to the possibility and power of performative inquiry as a research tool and learning vehicle in science education, in the wind clothes dance on a line has been imagined "in the air" through moments realized and recognized during the science education research project and through my work as a performing arts educator. And it is these moments that set the clothes dancing in the wind. in the wind clothes dance on a line is a conceptual piece, a performative work through which the reader will hopefully realize and recognize his or her own imaginings and interstandings of possible universes within education.
Lepton spectroscopy at storage rings: from electrons at ESR to positrons at HESR
Creators: name: Hillenbrand, P.
name: Hagmann, S.
name: King, F.
name: Litvinov, Y.
name: Schippers, S.
name: Stiebing, K. E.
name: Stöhlker, T.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Optical and spin manipulation of non-Kramers rare-earth ions under weak magnetic field for quantum memory applications
Creators: name: Etesse, Jean
name: Holzäpfel, Adrian
name: Ortu, Antonio
name: Afzelius, Mikael
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Rare-earth ion doped crystals have proven to be solid platforms for implementing quantum memories. Their potential use for integrated photonics with large multiplexing capability and unprecedented coherence times is at the core of their attractiveness. The best performances of these ions are however usually obtained when subject to a dc magnetic field, but consequences of such fields on the quantum memory protocols have only received little attention. In this article, we focus on the effect of a dc bias magnetic field on the population manipulation of non-Kramers ions with nuclear quadrupole states, both in the spin and optical domains, by developing a simple theoretical model. We apply this model to explain experimental observations in a ${}^{151}$Eu:Y$_2$SiO$_5$ crystal, and highlight specific consequences on the AFC spin-wave protocol. The developed analysis should allow to predict optimal magnetic field configurations for various protocols.
Precise polarization studies of radiative electron capture
Creators: name: Weber, G.
name: Ding, H.
name: Bräuning, H.
name: Heß, R.
name: Heß, S.
name: Märtin, R.
name: Spillmann, U.
name: Trotsenko, S.
name: Winters, D.
name: Stöhlker, T.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Two-Loop Photonic Corrections to Massive Bhabha Scattering
Creators: name: Penin, A. A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We describe the details of the evaluation of the two-loop radiative photonic corrections to Bhabha scattering. The role of the corrections in the high-precision luminosity determination at present and future electron-positron colliders is discussed.
description: 20 pages, Latex; discussion, references added; to appear in Nucl.Phys.B
Angular Momentum Accretion onto a Gas Giant Planet
Creators: name: Machida, Masahiro N.
name: Kokubo, Eiichiro
name: Inutsuka, Shu-ichiro
name: Matsumoto, Tomoaki
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate the accretion of angular momentum onto a protoplanet system using three-dimensional hydrodynamical simulations. We consider a local region around a protoplanet in a protoplanetary disk with sufficient spatial resolution. We describe the structure of the gas flow onto and around the protoplanet in detail. We find that the gas flows onto the protoplanet system in the vertical direction crossing the shock front near the Hill radius of the protoplanet, which is qualitatively different from the picture established by two-dimensional simulations. The specific angular momentum of the gas accreted by the protoplanet system increases with the protoplanet mass. At Jovian orbit, when the protoplanet mass M_p is M_p < 1 M_J, where M_J is Jovian mass, the specific angular momentum increases as j \propto M_p. On the other hand, it increases as j \propto M_p^2/3 when the protoplanet mass is M_p > 1 M_J. The stronger dependence of the specific angular momentum on the protoplanet mass for M_p < 1 M_J is due to thermal pressure of the gas. The estimated total angular momentum of a system of a gas giant planet and a circumplanetary disk is two-orders of magnitude larger than those of the present gas giant planets in the solar system. A large fraction of the total angular momentum contributes to the formation of the circumplanetary disk. We also discuss the satellite formation from the circumplanetary disk.
description: 39 pages,13 figures, Submitted to ApJ, For high resolution figures see http://www2.scphys.kyoto-u.ac.jp/~machidam/jupiter2/ms08jan22.pdf
Search for pair production of third-generation scalar leptoquarks decaying into a top quark and a $τ$-lepton in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
Creators: name: ATLAS Collaboration
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A search for pair production of third-generation scalar leptoquarks decaying into a top quark and a $τ$-lepton is presented. The search is based on a dataset of $pp$ collisions at $\sqrt{s}=13$ TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. Events are selected if they have one light lepton (electron or muon) and at least one hadronically decaying $τ$-lepton, or at least two light leptons. In addition, two or more jets, at least one of which must be identified as containing $b$-hadrons, are required. Six final states, defined by the multiplicity and flavour of lepton candidates, are considered in the analysis. Each of them is split into multiple event categories to simultaneously search for the signal and constrain several leading backgrounds. The signal-rich event categories require at least one hadronically decaying $τ$-lepton candidate and exploit the presence of energetic final-state objects, which is characteristic of signal events. No significant excess above the Standard Model expectation is observed in any of the considered event categories, and 95% CL upper limits are set on the production cross section as a function of the leptoquark mass, for different assumptions about the branching fractions into $tτ$ and $bν$. Scalar leptoquarks decaying exclusively into $tτ$ are excluded up to masses of 1.43 TeV while, for a branching fraction of 50% into $tτ$, the lower mass limit is 1.22 TeV.
description: 59 pages in total, author list starting page 43, 15 figures, 10 tables, submitted to JHEP. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2019-15/
Improved accuracy of in-ring laser spectroscopy by in-situ electron cooler voltage measurement
Creators: name: Ullmann, J.
name: Andelkovic, Z.
name: Maass, B.
name: Litvinov, Y.
name: Lochmann, M.
name: Meisner, J.
name: Murböck, T.
name: Sanchez Alarcon, R. M.
name: Schmidt, S.
name: Steck, M.
name: Schmidt, M.
name: Stöhlker, T.
name: Dax, A.
name: Thompson, R. C.
name: Vollbrecht, J.
name: Weinheimer, C.
name: Nörtershäuser, Wilfried
name: Winters, D.
name: Brandau, C.
name: Trageser, C.
name: Nolden, F.
name: Geithner, W.
name: Geppert, C.
name: Gorges, C.
name: Hammen, M.
name: Hannen, V.
name: Kaufmann, S.
name: König, K.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Transport in metallic multi-island Coulomb blockade systems: A systematic perturbative expansion in the junction transparency
Creators: name: Kubala, Björn
name: Johansson, Göran
name: König, Jürgen
Publisher: name: arXiv
Year: 2005
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study electronic transport through metallic multi-island Coulomb-blockade systems. Based on a diagrammatic real-time approach, we develop a computer algorithm that generates and calculates all transport contributions up to second order in the tunnel-coupling strengths for arbitrary multi-island systems. This comprises sequential and cotunneling, as well as terms corresponding to a renormalization of charging energies and tunneling conductances. Multi-island cotunneling processes with energy transfer between different island are taken into account. To illustrate our approach we analyze the current through an island in Coulomb blockade, that is electrostatically coupled to a second island through which a large current is flowing. In this regime both cotunneling processes involving one island only as well as multi-island processes are important. The latter can be understood as photon-assisted sequential tunneling in the blockaded island, where the photons are provided by potential fluctuations due to sequential tunneling in the second island. We compare results of our approach to a P(E)-theory for photon-assisted tunneling in the weak coupling limit.
description: 14 pages, 7 figures, published version; minor changes in Sec. IV E
MgO surface lattice phonons observation during Interstellar ice transition
Creators: name: Chavarría-Sibaja, A.
name: Marín-Sosa, S.
name: Bolaños-Jiménez, E.
name: Hernández-Calderon, M.
name: Herrera-Sancho, O. A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Relevant information on the origins of the solar system and the early evolution of life itself can be derive from systematic and controlled exploration of amorphous water ice here on Earth. Therefore, over the last decades, a huge effort on experimental methodologies has been made to study the multiple crystal ice phases, which are observed outside our home-gravitational-potential. By employing (100)-oriented MgO lattice surface as a microcantilever sensor, we conducted the first ever study on the dynamics of the Structural Phase Transition at 185 K in amorphous water ice by means of coherent elastic scattering of electron diffraction. We estimate the amount of phonons caused by this transition applying precise quantum computing key tools, resulting in a maximum value of 1.23 $\pm$ 0.02. Further applications of our microcantilever sensor were assessed using unambiguous mapping of the surface stress induced by the c(4$\times$2) $\longleftrightarrow$ p(3$\times$2) Structural Phase Transition of the interstellar ice formulated on the Williamsom-Hall model. This development paves the way and thus establishes an efficient characterization tool of the surface mechanical strains of materials with potential applications arising from interstellar ice inclusive glaciers to the wide spectrum of solid-state physics.
Capturing highly charged ions in the SpecTrap penning trap
Creators: name: Murböck, T.
name: Birkl, G.
name: Martin, A.
name: König, K.
name: Nörtershäuser, W.
name: Schmidt, S.
name: Andelkovic, Z.
name: Vogel, M.
name: Hannen, V.
name: Jonas, V.
name: Weinheimer, C.
name: Segal, D.
name: Thompson, R.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Auto-heterodyne characterization of narrow-band photon pairs
Creators: name: Prakash, Vindhiya
name: Sierant, Aleksandra
name: Mitchell, Morgan W.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We describe a technique to measure photon pair joint spectra by detecting the time-correlation beat note when non-degenerate photon pairs interfere at a beamsplitter. The technique implements a temporal analog of the Ghosh-Mandel effect with one photon counter and a time-resolved Hong-Ou-Mandel interference with two. It is well suited to characterize pairs of photons, each of which can interact with a single atomic species, as required to study recently predicted photon-photon interaction in sub-wavelength atomic arrays. With this technique, we characterize photon pairs from cavity-enhanced parametric downconversion with a bandwidth $\approx$ 5 MHz and frequency separation of $\sim$ 200 MHz near the D$_1$ line of atomic Rb.
description: 5 pages, 4 figures
Development of ion detectors for the 1–10 MeV/u energy range
Creators: name: Hahn, C.
name: Bräuning-Demian, A.
name: Gumberidze, A.
name: Lamour, E.
name: Rangama, J.
name: Stöhlker, T.
name: Vernhet, D.
name: Weber, G.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Monte-Carlo rejection as a tool for measuring the energy landscape scaling of simple fluids
Creators: name: Naumis, Gerardo G.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: A simple modification of the Monte-Carlo algortihm is proposed to explore the topography and the scaling of the energy landscape. We apply this idea to a simple hard-core fluid. The results for different packing fractions show a power law scaling of the landscape boundary, with a characteristic scale that separates the values of the scaling exponents. Finally, it is shown how the topology determines the freezing point of the system due to the increasing importance and complexity of the boundary.
The Effect of Communicative Practice on Oral Speaking Exam Performance in High School Spanish Students
Creators: name: Powell, Kelley
Publisher: name: Maryland Shared Open Access Repository
Year: 2010
Subjects: subject: Education -- Research papers (Graduate)

description: The purpose of this study was to determine whether or not the implementation of additional
communicative activities in the Spanish IV classroom increased speaking fluency in high school
students. The Powell Rubric was the instrument used to determine success on the speaking
exams. Students came from a convenience sample and were non-randomly assigned to the
control group which was only exposed to the standard curriculum (N=26) or the experimental
group that was allotted extra instructional time to engage in communicative activities in addition
to the standard curriculum (N=22). The control group (Mean = 42.88, SD = 6.09) was not found
to differ significantly from the experimental group (Mean=43.32, SD=4.04) on speaking fluency
prior to the intervention based on an independent sample t-test comparing performances on a pretest
[t(46) =- .29, p > .05]. The treatment took place during a period of 12 weeks. The groups
were compared on a score based on performances on two assessments—one that took place
during the intervention and one that took place after the intervention. The control group
(Mean=92.96, SD=10.37) did not differ significantly from the experimental group (Mean=96.09,
SD=10.11) on the fluency scores [t(46)= -1.05, p>.05]. Therefore the null hypothesis failed to be
rejected. Practical and theoretical implications as well as threats to validity are discussed.
Recommendations for future research are discussed, including the ideas that research be
conducted over a longer period of time and there be an increase in the intensity of the treatment
applied to the experimental group.
Electron-exciton interactions in the exciton-polaron problem
Creators: name: Efimkin, Dmitry K.
name: Laird, Emma K.
name: Levinsen, Jesper
name: Parish, Meera M.
name: MacDonald, Allan H.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Recently, it has been demonstrated that the absorption of moderately doped two-dimensional semiconductors can be described in terms of exciton-polarons. In this scenario, attractive and repulsive polaron branches are formed due to interactions between a photo-excited exciton and a Fermi sea of excess charge carriers. These interactions have previously been treated in a phenomenological manner. Here, we present a microscopic derivation of the electron-exciton interactions which utilizes a mixture of variational and perturbative approaches. We find that the interactions feature classical charge-dipole behaviour in the long-range limit and that they are only weakly modified for moderate doping. We apply our theory to the absorption properties and show that the dependence on doping is well captured by a model with a phenomenological contact potential.
description: 16 pages, and 10 figures. Published version
Collet, Giancarlo: Das Missionsverständnis der Kirche in der gegenwärtigen Diskussion
Creators: name: Gensichen, Hans-Werner
Publisher: name: Ökumenische Rundschau
Year: 2025

description: Ökumenische Rundschau, Bd. 34 Nr. 4 (1985): Ökumenische Rundschau, Band 34, Heft 4
The Effect of Administration in the School on Holding Teachers Accountable
Creators: name: Keith, Brittney M
Publisher: name: Maryland Shared Open Access Repository
Year: 2010
Subjects: subject: Education -- Research papers (Graduate)

description: The purpose of this study was to determine whether teachers would do their assigned hall duty if
they were held accountable. Teachers were pre-assigned to an intervention group, in which
attendance was actively monitored by administrators or to a control group. A comparison of
attendance rates pre and post intervention showed significant improvement for all teachers.
There was no difference between treatment and control participants.
Emulating quantum teleportation of a Majorana zero mode qubit
Creators: name: Huang, He-Liang
name: Narozniak, Marek
name: Liang, Futian
name: Zhao, Youwei
name: Castellano, Anthony D.
name: Gong, Ming
name: Wu, Yulin
name: Wang, Shiyu
name: Lin, Jin
name: Xu, Yu
name: Deng, Hui
name: Rong, Hao
name: Dowling, Jonathan P.
name: Peng, Cheng-Zhi
name: Byrnes, Tim
name: Zhu, Xiaobo
name: Pan, Jian-Wei
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Topological quantum computation based on anyons is a promising approach to achieve fault-tolerant quantum computing. The Majorana zero modes in the Kitaev chain are an example of non-Abelian anyons where braiding operations can be used to perform quantum gates. Here we perform a quantum simulation of topological quantum computing, by teleporting a qubit encoded in the Majorana zero modes of a Kitaev chain. The quantum simulation is performed by mapping the Kitaev chain to its equivalent spin version, and realizing the ground states in a superconducting quantum processor. The teleportation transfers the quantum state encoded in the spin-mapped version of the Majorana zero mode states between two Kitaev chains. The teleportation circuit is realized using only braiding operations, and can be achieved despite being restricted to Clifford gates for the Ising anyons. The Majorana encoding is a quantum error detecting code for phase flip errors, which is used to improve the average fidelity of the teleportation for six distinct states from $70.76 \pm 0.35 \% $ to $84.60 \pm 0.11 \%$, well beyond the classical bound in either case.
description: comments are welcome
Modelling techniques for compositional data using distributions defined on the hypersphere
Creators: name: Scealy, Janice Lea
Publisher: name: The Australian National University
Year: 2010
Subjects: subject: QA273.6 S34 2010
subject: Distribution (Probability theory)
subject: Correlation (Statistics)
subject: Multivariate analysis

description: Compositional data can be transformed to directional data by the square root transformation and then modelled using distributions defined on the hypersphere. The purpose of this thesis is to investigate new modelling techniques for a general p-dimensional compositional data vector using this square root transformation approach. One advantage is that zero components are catered for naturally in the models. The Kent distribution for directional data is a good candidate model because it has a sufficiently general covariance structure. We investigate the properties of the Kent distribution in p-dimensions and develop asymptotic normal theory results and an acceptance sampling algorithm. We propose a new regression model which models the mean direction of the Kent distribution as a function of a vector of covariates. Our estimators for the regression model parameters are motivated by asymptotic approximations and moment estimators and can be regarded as asymptotic maximum likelihood estimators. We show that these estimators perform well and are suitable for typical compositional datasets, including those with zero components. One advantage of our approach to estimation is that it is not computationally intensive and the parametric bootstrap is used for inference. Using two real example datasets we demonstrate a modelling strategy in practice, including how to check the model assumptions. A simulation study is also undertaken, confirming the value of our proposed estimators in typical cases. We also demonstrate in certain cases that our new approach for modelling compositional data should work much better than more traditional methods such as those based on logratio transformations.
On the Generator of Lorentz Boost
Creators: name: Wang, Zhi-Yong
name: Xiong, Cai-Dong
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Traditionally, the theory related to the spatial angular momentum has been studied completely, while the investigation in the generator of Lorentz boost is inadequate. In this paper we show that the generator of Lorentz boost has a nontrivial physical significance, it endows a charged system with an electric moment, and has an important significance for the electrical manipulations of electron spin in spintronics. An alternative treatment and interpretation for the traditional Darwin term and spin-orbit coupling are given.
description: 9 pages