cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Monopole condensation in two-flavour Adjoint QCD
Creators: name: Cossu, G.
name: D'Elia, M.
name: Di Giacomo, A.
name: Lacagnina, G.
name: Pica, C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: In QCD with adjoint fermions (aQCD) the deconfining transition takes place at a lower temperature than the chiral transition. We study the two transitions by use of the Polyakov Loop, the monopole order parameter and the chiral condensate. The deconfining transition is first order, the chiral is a crossover. The order parameters for confinement are not affected by the chiral transition. We conclude that the degrees of freedom relevant to confinement are different from those describing chiral symmetry.
description: 5 pages, 6 figures. Minor corrections, acknowledgments, new references and bigger figures
Supersymmetric Intersecting Branes in Time-dependent Backgrounds
Creators: name: Ohta, Nobuyoshi
name: Panigrahi, Kamal L.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We construct a family of supersymmetric solutions in time-dependent backgrounds in supergravity theories. One class of the solutions are intersecting brane solutions and another class are brane solutions in pp-wave backgrounds, and their intersection rules are also given. The relation to existing literature is also discussed. An example of D1-D5 with linear null dilaton together with its possible dual theory is briefly discussed.
description: 12 pages, corrected typo, added reference, to appear in Phys. Rev. D
Improving the detection of collection-based citizen science projects
Creators: name: Runnel Veljo
name: Wijers Agnes
Publisher: name: Zenodo
Year: 2019

description: Citizen science (CS) is generally understood as public, volunteer participation in scientific research1,2. Kullenberg and Kasperowski demonstrated that citizen science is composed of three main strands of research – in one strand biology, conservation and ecology, and the other two strands being geoinformatics and social science combined with epidemiology3. Natural history collection based research, however, does not emerge in their analysis. They also performed an analysis of term co-occurrences from which some very relevant terms, such as „collections“ or „transcription“ are missing. The more general term “crowdsourcing”, though, is one of the most frequent terms pairing with other CS-related terms. Out of 1935 articles only two were about collection transcription (indicated directly in the title). To facilitate the current analysis, we will in the following sections describe the main types of collection-based citizen science that have direct impact on generating and mobilising of biodiversity data and the relative role of citizen scientists and professionals in this. Later, the aspect of data collection and data classification (or data interpretation) is taken into account separately, following Kosmala et al4 who used this approach for ecological studies.
Probing negative-parity states of $^{24}$Mg probed via proton and alpha inelastic scattering
Creators: name: Kanada-En'yo, Yoshiko
name: Ogata, Kazuyuki
Publisher: name: arXiv
Year: 2020
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: [Background:] The band structure of the negative-parity states of $^{24}$Mg has not yet been clarified. The $K^π=0^-$, $K^π=1^-$, and $K^π=3^-$ bands have been suggested, but the assignments have been inconsistent between experiments and theories. [Purpose:] Negative-parity states of $^{24}$Mg are investigated by microscopic structure and reaction calculations via proton and alpha inelastic scattering to clarify the band assignment for the observed negative-parity spectra. [Method:] The structure of $^{24}$Mg was calculated using the antisymmetrized molecular dynamics~(AMD). Proton and alpha inelastic reactions were calculated using microscopic coupled-channel (MCC) calculations by folding the Melbourne $g$-matrix $NN$ interaction with the AMD densities of $^{24}$Mg. [Results:] The member states of the $K^π=0^+$, $K^π=2^+$, $K^π=0^-$, $K^π=1^-$, and $K^π=3^-$ bands of $^{24}$Mg were obtained through the AMD result. In the MCC+AMD results for proton and alpha elastic and inelastic cross sections, reasonable agreements were obtained with existing data, except in the case of the $4^+_1$ state. [Conclusions:] The $3^-$ state of the $K^π=3^-$ band and the $1^-$ and $3^-$ states of the $K^π=0^-$ bands were assigned to the $3^-_1$(7.62 MeV), $1^-_1$(7.56 MeV), and $3^-_2$(8.36 MeV) states, respectively. The present AMD calculation is the first microscopic structure calculation to reproduce the energy ordering of the $K^π=0^-$, $K^π=1^-$, and $K^π=3^-$ bands of $^{24}$Mg.
description: 14 pages, 9 figures
Second Order Statistics Targets-Specified Virtual Dimensionality
Creators: name: Paylor, Andrew
Publisher: name: Maryland Shared Open Access Repository
Year: 2014
Subjects: Seond Order Statistics
Virtual Dimensionality

description: Hyperspectral imaging has emerged as a productive and useful technique in remote sensing.  With its high spectral resolution the materials in a scene can be detected, discriminated, and identified.  This has come at the cost of challenges in the storage, transmission, and processing of the data to retrieve the information of interest.  Since the number of spectral bands in a datacube is typically much larger than the true dimensionality of the data approaches have been sought to reduce the dimensionality of the data to allieviate the processing requirements. To enable this effectively it is necessary to know the dimensionality of this subspace. The primary focus of this dissertation is the development of unsupervised approaches to determine this subspace.  In this work the focus is on using least-squares techniques to identify the dimensionality and subspace basis.  We are specifically interested in a target-specified approach, that is in identifying a subspace of minimum dimension whose basis vectors are actual signatures present in the image.  To distinguish this from a subspace basis of pure signatures we call these basis vectors virtual endmembers. This work develops a theory of second-order statistics target-specified virtual dimensionality. Virtual dimensionality is defined as the number of spectrally distinct signatures in hyperspectral data.  Unfortunately there is no universal definition of spectrally distinct.  In developing the theory of second-order statistics targets-specified virtual dimensionality spectrally distinct is defined in the second-order statistics sense, thus the number of virtual endmember basis vector is the appropriate virtual dimensionality.
Learning Efficient, Explainable and Discriminative Representations for Pulmonary Nodules Classification
Creators: name: Jiang, Hanliang
name: Shen, Fuhao
name: Gao, Fei
name: Han, Weidong
Publisher: name: arXiv
Year: 2021
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Automatic pulmonary nodules classification is significant for early diagnosis of lung cancers. Recently, deep learning techniques have enabled remarkable progress in this field. However, these deep models are typically of high computational complexity and work in a black-box manner. To combat these challenges, in this work, we aim to build an efficient and (partially) explainable classification model. Specially, we use \emph{neural architecture search} (NAS) to automatically search 3D network architectures with excellent accuracy/speed trade-off. Besides, we use the convolutional block attention module (CBAM) in the networks, which helps us understand the reasoning process. During training, we use A-Softmax loss to learn angularly discriminative representations. In the inference stage, we employ an ensemble of diverse neural networks to improve the prediction accuracy and robustness. We conduct extensive experiments on the LIDC-IDRI database. Compared with previous state-of-the-art, our model shows highly comparable performance by using less than 1/40 parameters. Besides, empirical study shows that the reasoning process of learned networks is in conformity with physicians' diagnosis. Related code and results have been released at: https://github.com/fei-hdu/NAS-Lung.
Retrieving Quantifiable Social Media Data From Human Sensor Networks For Disaster Modeling And Crisis Mapping
Creators: name: Aulov, Oleg
Publisher: name: Maryland Shared Open Access Repository
Year: 2014
Subjects: Disaster Management
Geophysical Modeling
Human Sensor Networks
Natural Disasters
Situational Awareness
Social Media

description: This dissertation presents a novel approach that utilizes quantifiable social media data as a human aware, near real-time observing system, coupled with geophysical predictive models for improved response to disasters and extreme events. It shows that social media data has the potential to significantly improve disaster management beyond informing the public, and emphasizes the importance of different roles that social media can play in management, monitoring, modeling and mitigation of natural and human-caused extreme disasters. In the proposed approach Social Media users are viewed as human sensors that are deployed in the field, and their posts are considered to be sensor observations, thus different social media outlets all together form a Human Sensor Network. We utilized the human sensor observations, as boundary value forcings, to show improved geophysical model forecasts of extreme disaster events when combined with other scientific data such as satellite observations and sensor measurements. Several recent extreme disasters are presented as use case scenarios. In the case of the Deepwater Horizon oil spill disaster of 2010 that devastated the Gulf of Mexico, the research demonstrates how social media data from Flickr can be used as a boundary forcing condition of GNOME oil spill plume forecast model, and results in an order of magnitude forecast improvement.  In the case of Hurricane Sandy NY/NJ landfall impact of 2012, we demonstrate how the model forecasts, when combined with social media data in a single framework, can be used for near real-time forecast validation, damage assessment and disaster management. Owing to inherent uncertainties in the weather forecasts, the NOAA operational surge model only forecasts the worst-case scenario for flooding from any given hurricane. Geolocated and time-stamped Instagram photos and tweets allow near real-time assessment of the surge levels at different locations, which can validate model forecasts, give timely views of the actual levels of surge, as well as provide an upper bound beyond which the surge did not spread.  Additionally, we developed AsonMaps--a crisis-mapping tool that combines dynamic model forecast outputs with social media observations and physical measurements to define the regions of event impacts.
Reference Advice for Word Sense Disambiguation
Creators: name: Johnson, Benjamin Luke
Publisher: name: Maryland Shared Open Access Repository
Year: 2013
Subjects: Anaphora Resolution
NLP
NLU
Reference Resolution
Word sense disambiguation

description: Much of the world's knowledge is encoded in natural language.  Accessing this information would be invaluable for applications such as agent systems, question answering, the semantic web, expert systems, and many more.  However, language is very ambiguous -- each word in a natural language utterance can have a variety of meanings.  Word sense disambiguation is the task of determining the dictionary (or lexical) sense of each word in a context.  Knowing which sense a word represents allows us to ascertain its meaning. In this work, we introduce a new resource for WSD processing: reference advice.  Reference advice uses reference resolution methods to infer potential meanings of referring expressions, such as 'he', 'she,' 'this,' 'it' and many more.  We present a method for creating reference advice, and incorporating that advice into WSD processing.  We also develop several system configurations which act as points of comparison for evaluation. Lastly, we discuss the impact of the success of reference advice in supporting WSD processing.  We explore a shift away from pipeline text processing architectures, wherein each processing component feeds its results downstream until a final processing component presents a solution.  We discuss how our system represents a step toward text processing architectures where each processing component is able to provide input to many other processing components, not just those components that are rigidly positioned downstream.
Revisiting the Local Star-Forming Galaxies Observed in the HETDEX Pilot Survey
Creators: name: Shinn, Jong-Ho
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: I have reanalyzed the data obtained for local ($z<0.15$) star-forming galaxies during the pilot survey for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX)---called the HETDEX Pilot Survey (HPS)---which uses an integral-field-unit spectrograph and covers $\sim3500-5800$ $\unicode{x212B}$ at $\sim5$ $\unicode{x212B}$ resolution. I have newly determined the gas metallicities, $12 + \text{log(O/H)}$, following the Bayesian analysis scheme of the previous study, but dealing carefully with the uncertainty of strong-line calibration, performing reproducibility tests with mock data, and monitoring the convergence of the Markov-Chain Monte Carlo (MCMC) sampling. From the mock-data tests, I found that the nebular emission-line color excess $E(B-V)$ can be overestimated by as much as 2-$σ$ or more, although the metallicity can recover the input value to within 1-$σ$. The new metallicity estimates on the HPS data are from well-converged MCMC samples (effective sample sizes $>$ 2000), and they are higher than the previous estimates by $\sim$2-$σ$. Using the HPS data, I also showed that the MCMC sampling can have the statistical accuracy as poor as the one near the iteration start if done without convergence monitoring. The overestimation of $E(B-V)$ indicates the overestimation of the star-formation rates (SFRs) in the previous study, which can be as much as a factor of five. This finding undermines the previous suggestion of a hitherto-unknown galaxy population based on the locations of galaxies in the mass-SFR plane. I found that the independent determination of $E(B-V)$ using either H$β$-H$γ$ or H$α$-H$β$ line pair is ideal for the analysis of forthcoming HETDEX data, but it requires additional cost.
description: 19 pages, 15 figures, MNRAS in press, online supplementary data included in the source file
Quantum Phase Estimation Algorithm with Gaussian Spin States
Creators: name: Pezzè, Luca
name: Smerzi, Augusto
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum phase estimation (QPE) is one of the most important subroutines in quantum computing. In general applications, current QPE algorithms either suffer an exponential time overload or require a set of - notoriously quite fragile - GHZ states. These limitations have prevented so far the demonstration of QPE beyond proof-of-principles. Here we propose a new QPE algorithm that scales linearly with time and is implemented with a cascade of Gaussian spin states (GSS). GSS are renownedly resilient and have been created experimentally in a variety of platforms, from hundreds of ions up to millions of cold/ultracold neutral atoms. We show that our protocol achieves a QPE sensitivity overcoming previous bounds, including those obtained with GHZ states, and is robustly resistant to several sources of noise and decoherence. Our work paves the way toward realistic quantum advantage demonstrations of the QPE, as well as applications of atomic squeezed states for quantum computation.
description: 9 pages, 3 figures, supplementary information not included, comment are welcome
MACHOs in dark matter haloes
Creators: name: Holopainen, Janne
name: Flynn, Chris
name: Knebe, Alexander
name: Gill, Stuart P.
name: Gibson, Brad K.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Using eight dark matter haloes extracted from fully-self consistent cosmological N-body simulations, we perform microlensing experiments. A hypothetical observer is placed at a distance of 8.5 kpc from the centre of the halo measuring optical depths, event durations and event rates towards the direction of the Large Magellanic Cloud. We simulate 1600 microlensing experiments for each halo. Assuming that the whole halo consists of MACHOs, f = 1.0, and a single MACHO mass is m_M = 1.0 Msun, the simulations yield mean values of tau = 4.7^{+5.0}_{-2.2} 10^{-7} and Gamma = 1.6^{+1.3}_{-0.6} 10^{-6} events/star/year. We find that triaxiality and substructure can have major effects on the measured values so that tau and Gamma values of up to three times the mean can be found. If we fit our values of tau and Gamma to the MACHO collaboration observations (Alcock et al. 2000), we find f = 0.23^{+0.15}_{-0.13} and m_M = 0.44^{+0.24}_{-0.16}. Five out of the eight haloes under investigation produce f and m_M values mainly concentrated within these bounds.
description: 15 pages, 12 figures, accepted to MNRAS
Shell-models of RMHD turbulence and the heating of solar coronal loops
Creators: name: Buchlin, E.
name: Velli, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A simplified non-linear numerical model for the development of incompressible magnetohydrodynamics (MHD) in the presence of a strong magnetic field B0 and stratification, nicknamed Shell-Atm, is presented. In planes orthogonal to the mean field, the non-linear incompressible dynamics is replaced by 2D shell-models for the complex variables u and b, allowing one to reach large Reynolds numbers while at the same time carrying out sufficiently long time integrations to obtain a good statistics at moderate computational cost. The shell-models of different planes are coupled by Alfven waves propagating along B0. The model may be applied to open or closed magnetic field configurations where the axial field dominates and the plasma pressure is low; here we apply it to the specific case of a magnetic loop of the solar corona heated via turbulence driven by photospheric motions, and we use statistics for its analysis. The Alfven waves interact non-linearly and form turbulent spectra in the directions perpendicular and, via propagation, also parallel to the mean field. A heating function is obtained, and is shown to be intermittent; the average heating is consistent with values required for sustaining a hot corona, and is proportional to the aspect ratio of the loop to the power -1.5; characteristic properties of heating events are distributed as power-laws. Cross-correlations show a delay of dissipation compared to energy content.
description: 12 pages, 16 figures, accepted for publication in ApJ
Handbook of normal frames and coordinates
Creators: name: Iliev, Bozhidar Z.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Differential Geometry (math.DG)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 53-02, 53B05, 53B99, 53C05, 53C80, 53C99, 53Z05, 57R55, 81Q99, 83C99, 57R25

description: The main subject of the book is an up-to-date and in-depth survey of the theory of normal frames and coordinates in differential geometry. The book can be used as a reference manual, review of the existing results and introduction to some new ideas and developments. In the book can be found practically all existing essential results and methods concerning normal frames and coordinates. Most of the results are represented in full detail with full, in some cases new, proofs. All classical results are expanded and generalized in various directions. Theorems of existence, uniqueness and, possibly, holonomicity of the normal frames and coordinates are proved; mostly, the proofs are constructive and some their parts can be used independently for other tasks. Besides published results, their extensions and generalizations, the book contains completely new results which appear for the first time.
description: 462 LaTeX pages. For other publications on the same topic, view the "publication" pages at http://theo.inrne.bas.bg/~bozho/
Structure and position-dependent properties of inhomogeneous suspensions of responsive colloids
Creators: name: Lin, Yi-Chen
name: Rotenberg, Benjamin
name: Dzubiella, Joachim
Publisher: name: arXiv
Year: 2020
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Responsive particles, such as biomacromolecules or hydrogels, display a broad and polymodal distribution of conformations and have thus the ability to change their properties (e.g, size, shape, charge density, etc.) substantially in response to external fields or to their local environment (e.g., mediated by cosolutes or pH). Here, we discuss the basic statistical mechanics for a model of responsive colloids (RCs) by introducing an additional property degree of freedom as a collective variable in a formal coarse-graining procedure. The latter leads to an additional one-body term in the coarse-grained (CG) free energy, defining a single-particle property distribution for an individual polydisperse RC. We argue that in the equilibrium thermodynamic limit such a CG system of RCs behaves like a conventional polydisperse system of non-responsive particles. We then illustrate the action of external fields, which impose local (position-dependent) property distributions leading to non-trivial effects on the spatial one-body property and density profiles, even for an ideal (non-interacting) gas of RCs. We finally apply density functional theory in the local density approximation (LDA-DFT) to discuss the effects of particle interactions for specific examples of i) a suspension of RCs in an external field linear in both position and property, ii) a suspension of RCs with highly localized properties (sizes) confined between two walls, and iii) a two-component suspension where an inhomogeneously distributed (non-responsive) cosolute component, as found, e.g., in the studies of osmolyte- or salt-induced collapse/swelling transitions of thermosensitive polymers, modifies the local properties and density of the RC liquid.
description: 31 pages, 5 figures, accepted in Phys. Rev. E
Monte Carlo simulation of joint density of states in one-dimensional Lebwohl-Lasher model using Wang-Landau algorithm
Creators: name: Mukhopadhyay, Kisor
name: Ghoshal, Nababrata
name: Roy, Soumen Kumar
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Monte Carlo simulation using the Wang-Landau algorithm has been performed in an one-dimensional Lebwohl-Lasher model. Both one-dimensional and two-dimensional random walks have been carried out. The results are compared with the exact results which are available for this model.
description: 17 pages, 7 figures, To appear in Physics Letters A
Realization of AlSb in the double layer honeycomb structure: a robust new class of two-dimensional material
Creators: name: Qin, Le
name: Zhang, Zhi-Hao
name: Jiang, Zeyu
name: Fan, Kai
name: Zhang, Wen-Hao
name: Tang, Qiao-Yin
name: Xia, Hui-Nan
name: Meng, Fanqi
name: Zhang, Qinghua
name: Gu, Lin
name: West, Damien
name: Zhang, Shengbai
name: Fu, Ying-Shuang
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Exploring new two-dimensional (2D) van der Waals (vdW) systems is at the forefront of materials physics. Here, through molecular beam epitaxy on graphene-covered SiC(0001), we report successful growth of AlSb in the double-layer honeycomb (DLHC) structure, a 2D vdW material which has no direct analogue to its 3D bulk and is predicted kinetically stable when freestanding. The structural morphology and electronic structure of the experimental 2D AlSb are characterized with spectroscopic imaging scanning tunneling microscopy and cross-sectional imaging scanning transmission electron microscopy, which compare well to the proposed DLHC structure. The 2D AlSb exhibits a bandgap of 0.93 eV versus the predicted 1.06 eV, which is substantially smaller than the 1.6 eV of bulk. We also attempt the less-stable InSb DLHC structure; however, it grows into bulk islands instead. The successful growth of a DLHC material here opens the door for the realization of a large family of novel 2D DLHC traditional semiconductors with unique excitonic, topological, and electronic properties.
description: 21 pages, 6 figures
Pseudopotential-based full zone k.p technique for indirect bandgap semiconductors: Si, Ge, diamond and SiC
Creators: name: Bulutay, C.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: The $k \cdot p$ is a versatile technique that describes the semiconductor band structure in the vicinity of the bandgap. The technique can be extended to full Brillouin zone by including more coupled bands into consideration. For completeness, a detailed formulation is provided where the associated $k \cdot p$ parameters are extracted from the local empirical pseudopotential method in the form of band edge energies and generalized momentum matrix elements. We demonstrate the systematic improvement of the technique with the proper choice of the band edge states for the group-IV indirect bandgap semiconductors: Si, Ge, diamond and SiC of the 3C cubic phase. The full zone agreement is observed to span an energy window of more than 20 eV for Si, and 40 eV for the diamond with the 15-band pseudopotential-based $k \cdot p$ approach.
description: 8 pages, 6 figures, requires fizik.cls (included)
Effects of modal energy scattering and friction on the resonance mitigation with an impact absorber
Creators: name: Theurich, Timo
name: Gross, Johann
name: Krack, Malte
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: A linear vibration absorber can be tuned to effectively suppress the resonance of a particular vibration mode. It relies on the targeted energy transfer into the absorber within a narrow and fixed frequency band. Nonlinear energy sinks (NES) have a similar working principle. They are effective in a much wider frequency band but generally only in a limited range of excitation levels. To design NES, their working principle must be thoroughly understood. We consider a particular type of NES, a small mass undergoing impacts and dry friction within a cavity of a base structure (vibro-impact NES or impact absorber). The nonlinear dynamic regimes under near-resonant forcing and resulting operating ranges are first revisited. We then investigate how off-resonant vibration modes and dissipation via impacts and dry friction contribute to the vibration suppression. Moreover, we assess the effectiveness of the impact absorber for suppressing multiple resonances in comparison to a linear tuned vibration absorber (LTVA) and a pure friction damper with the same mass.
Optimal navigation strategies for microswimmers on curved manifolds
Creators: name: Piro, Lorenzo
name: Tang, Evelyn
name: Golestanian, Ramin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Mathematical Physics (math-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Finding the fastest path to a desired destination is a vitally important task for microorganisms moving in a fluid flow. We study this problem by building an analytical formalism for overdamped microswimmers on curved manifolds and arbitrary flows. We show that the solution corresponds to the geodesics of a Randers metric, which is an asymmetric Finsler metric that reflects the irreversible character of the problem. Using the example of a spherical surface, we demonstrate that the swimmer performance that follows this "Randers policy" always beats a more direct policy. A study of the shape of isochrones reveals features such as self-intersections, cusps, and abrupt nonlinear effects. Our work provides a link between microswimmer physics and geodesics in generalizations of general relativity.
Letter from the Manager of the Royal Bank of Canada in Vernon, B.C., to Frank A. Hewer, January 18, 1909
Creators: name: Canada, Royal Bank Of
Publisher: name: The University of British Columbia
Year: 2017

description: Letter to Frank Hewer from the manager of the Royal Bank of Canada in Vernon, B.C., dated January 18, 1909, regarding legal papers pertaining to the Ranche, with reference to N. (Northcote) Caesar, G. Alers Hankey, and Mr. Hallett.
Euclidean solutions in Einstein-Yang-Mills-dilaton theory
Creators: name: Brihaye, Y.
name: Radu, E.
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present arguments for the existence of a new type of solutions of the Euclidean Einstein-Yang-Mills-dilaton theory in $d=4$ dimensions. Possesing nonvanishing nonabelian charges, these nonselfdual configurations have no counterparts on the Lorentzian section. They provide, however, new saddle points in the Euclidean path integral.
description: 11 pages, 6 figures, discussion extended, figure clarified
Optical polarizer/isolator based on a rectangular waveguide with helical grooves
Creators: name: Shvets, Gennady
Publisher: name: arXiv
Year: 2006
Subjects: subject: Optics (physics.optics)
subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: A chirality-based approach to making a one-way waveguide that can be used as an optical isolator or a polarizer is described. The waveguide is rectangular, and chirality is introduced by making slanted rectangular grooves on the waveguide walls. Chirality of the waveguide manifests as a strong circular dichroism, and is responsible for transmitting one circular polarization of light and reflecting the other. Optical isolation of the propagating circular polarization is accomplished when the chiral waveguide is placed in front of a non-chiral optical device. Even the crudest implementations of chirality are shown to exhibit significant circular dichroism.
description: 10pages,2 figs
Determination of the propagator in QED3 by spectral function
Creators: name: Hoshino, Yuichi
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: To study the infrared behaviour of the propagator, exponentiation of the lowest order spectral function has been known.We show this method is helpful in super renormalizable theory with dimension-full coupling constant.In the 1/N approximation anomalous dimension is independent of $N$,which plays an important role for confinement and pair condensation.
description: 6 pages Latex,2 figures.introduction is modified.mistakes in equations are corrected.figure captions are corrected
The supersymmetric solutions and extensions of ungauged matter-coupled N=1,d=4 supergravity
Creators: name: Ortin, Tomas
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We find the most general supersymmetric solutions of ungauged N=1,d=4 supergravity coupled to an arbitrary number of vector and chiral supermultiplets, which turn out to be essentially pp-waves and strings. We also introduce magnetic 1-forms and their supersymmetry transformations and 2-forms associated to the isometries of the scalar manifold and their supersymmetry transformations. Only the latter can couple to BPS objects (strings), in agreement with our results.
description: Some misprints and citations corrected
Omega attenuation in nuclei
Creators: name: Muehlich, P.
name: Mosel, U.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We study inclusive omega photoproduction in nuclei and propose a measurement of the nuclear transparency ratio as a means to learn about the in-medium properties of the omega meson. To this end we are using the semi-classical coupled-channel BUU transport approach that allows for a consistent treatment of all nuclear effects. The conditions of our calculations are chosen such as to match the setup of existing experimental facilities at ELSA or MAMI C. We show that the observables (total production cross section and transparency) indeed are sensitive to the omega N interaction in the nuclear medium.
description: 21 pages, 11 figures, submitted to Nuclear Physics A
Overcoming Thermo-Optical Dynamics in Broadband Nanophotonic Sensing
Creators: name: Wang, Mingkang
name: Perez-Morelo, Diego J.
name: Aksyuk, Vladimir
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Advances in integrated photonics open exciting opportunities for batch-fabricated optical sensors using high quality factor nanophotonic cavities to achieve ultra-high sensitivities and bandwidths. The sensitivity improves with higher optical power, however, localized absorption and heating within a micrometer-scale mode volume prominently distorts the cavity resonances and strongly couples the sensor response to thermal dynamics, limiting the sensitivity and hindering the measurement of broadband time-dependent signals. Here, we derive a frequency-dependent photonic sensor transfer function that accounts for thermo-optical dynamics and quantitatively describes the measured broadband optomechanical signal from an integrated photonic atomic-force-microscopy nanomechanical probe. Using this transfer function, the probe can be operated in the high optical power, strongly thermo-optically nonlinear regime, reaching a sensitivity of $\approx$ 0.4 fm/Hz$^{1/2}$, an improvement of $\approx 10\times$ relative to the best performance in the linear regime. Counterintuitively, we discover that higher transduction gain and sensitivity are obtained with lower quality factor optical modes for low signal frequencies. Not limited to optomechanical transducers, the derived transfer function is generally valid for describing small-signal dynamic response of a broad range of technologically important photonic sensors subject to the thermo-optical effect.
A General Information Theoretical Proof for the Second Law of Thermodynamics
Creators: name: Zhang, Qi-Ren
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We show that the conservation and the non-additivity of the information, together with the additivity of the entropy make the entropy increase in an isolated system. The collapse of the entangled quantum state offers an example of the information non-additivity. Nevertheless, the later is also true in other fields, in which the interaction information is important. Examples are classical statistical mechanics, social statistics and financial processes. The second law of thermodynamics is thus proven in its most general form. It is exactly true, not only in quantum and classical physics but also in other processes, in which the information is conservative and non-additive.
description: 4 pages
Essays on Chinese Rural Development
Creators: name: Shi, Xinjie
Publisher: name: The Australian National University
Year: 2019

description: This thesis is comprised of four research papers focusing on Chinese rural development issues. Using panel data from a survey conducted by the Research Centre for Rural Economy, the first two papers focus on rural-urban migration. The first paper (Chapter 2) examines the impact of rural-urban migration on agricultural (labour) productivity and finds that the lost-labour effect is greater than the compensating effect of off-farm income, resulting in a negative net impact of rural-urban migration on agricultural productivity. The second paper (Chapter 3) assesses the impact of rural-urban migration on the health status of migrants in China using an IV strategy, and finds that, contrary to earlier studies (that used flawed econometric techniques), migration actually worsens health, and especially for individuals who migrate continuously and stay in cities for a longer period. The two main mechanisms identified are (i) an income effect that makes migration beneficial for health, and (ii) a dominating industry effect that is negatively associated with health due to exposure to dangerous working environments. In the third paper (Chapter 4), drawing on pooled data from two waves (2013 and 2015) of the China Health and Retirement Longitudinal Survey (CHARLS), I use Regression Discontinuity to identify the impact of the new rural pension scheme on land reallocation and show how this is linked to labor reallocation in response to the program. I show a significant increase in the amount of land rented out arising from the pension scheme, which is associated with an increase in the number of migrants among adult children. This, in turn, reduces the number of workers for farming and also helps to relax credit constraints. Despite the labour and land reallocation, I find no welfare and well-being gains for the elderly and their families. Utilising the China Labour-force Dynamics Survey (CLDS) 2014, the fourth paper (Chapter 5) explores the role of 'inequality of opportunity' in individual earnings in rural China - that is, the share of overall inequality that can be attributed to 'circumstantial' factors over which individuals have no control, including family background, gender, ethnic minority status and region of birth. After finding an alarmingly high share of inequality of opportunity in overall earnings inequality (at 20.4%), I then examine the role of 'effort' in determining individual earnings, showing that key effort variables (such as off-farm employment and own education) are related to circumstances in ways that compound inequality of opportunity, rather than alleviating it.
Magnetoresistance behavior of a ferromagnetic shape memory alloy: Ni_1.75Mn_1.25Ga
Creators: name: Banik, S.
name: Rawat, R.
name: Mukhopadhyay, P. K.
name: Ahuja, B. L.
name: Chakrabarti, Aparna
name: Paulose, P. L.
name: Singh, S.
name: Singh, A. K.
name: Pandey, D.
name: Barman, S. R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A negative-positive-negative switching behavior of magnetoresistance (MR) with temperature is observed in a ferromagnetic shape memory alloy Ni_1.75Mn_1.25Ga. In the austenitic phase between 300 and 120 K, MR is negative due to s-d scattering. Curiously, below 120K MR is positive, while at still lower temperatures in the martensitic phase, MR is negative again. The positive MR cannot be explained by Lorentz contribution and is related to a magnetic transition. Evidence for this is obtained from ab initio density functional theory, a decrease in magnetization and resistivity upturn at 120 K. Theory shows that a ferrimagnetic state with anti-ferromagnetic alignment between the local magnetic moments of the Mn atoms is the energetically favoured ground state. In the martensitic phase, there are two competing factors that govern the MR behavior: a dominant negative trend up to the saturation field due to the decrease of electron scattering at twin and domain boundaries; and a weaker positive trend due to the ferrimagnetic nature of the magnetic state. MR exhibits a hysteresis between heating and cooling that is related to the first order nature of the martensitic phase transition.
description: 17 pages, 5 figures. Accepted in Phys. Rev. B
Virtual machine design and high-level implementation languages
Creators: name: Lin, Yi
Publisher: name: The Australian National University
Year: 2018
Subjects: subject: QA76.9.V5 L56 2013
subject: Virtual computer systems
subject: Programming languages (Electronic computers)

description: System programming tasks such as implementing language virtual machines (VMs), are, by convention, associated with low-level programming languages, such as C/C++. Low-level programming languages provide efficient semantics to directly access hardware resources, thus are naturally a good choice for system programming. However, there are two trends in system programming that are questioning this convention, challenging the ruling role of low-level languages in this field. On one hand, increasing hardware complexity requires languages to provide abstraction over complicated and diverse architectures. On the other hand, software size and complexity is also increasing as hardware evolves, leaving security, correctness and productivity as an even bigger challenge. Thus, efforts have been made to use higher-level languages to perform system programming in order to improve safety, productivity and correctness, as well as to maintain competitive performance. Research has confirmed the feasibility and performance of implementing language virtual machines in high-level languages. The idea is novel and compelling. However, it leaves a trail of software engineering challenges, such as unclear VM/ application context and poor portability, which may in return hamper the benefits that come with high-level languages. My thesis is that imposing clearly defined constraints on code structure, context transition, and language features addresses important software engineering pitfalls that arise when using high-level languages to design and implement flexible and efficient virtual machines. This thesis is divided into two parts, each addressing a major software engineering pitfall in the area of system programming with high-level languages: 1) clarifying VM/ application interdependencies both statically (reflected by code structure and annotations) and dynamically (maintained as run-time information) with very low overhead; and 2) defining a restricted language called RJava, a restricted but still expressive subset of Java suitable for implementing VM components where portability and bootstrapping are major concerns. Two key factors of system programming with high-level languages that former research paid great attention to are expressiveness of high-level languages and performance, while they paid less attention to software engineering concerns. This thesis focuses on two of the software engineering pitfalls, and shows that they can be fixed while preserving both expressiveness and performance. This thesis should help those designing new virtual machines and help improve existing ones, and so encourage the implementation of virtual machines in high-level languages.
Ferromagnetic and superconducting instabilities in graphite
Creators: name: Kopelevich, Y.
name: Moehlecke, S.
name: da Silva, R. R.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We review our recent work on magnetic properties of graphite and related carbon materials. The results demonstrate that a structural disorder, topological defects, as well as adsorbed foreign atoms can be responsible for the occurrence of both ferromagnetic and superconducting patches in graphitic structures.
description: 21 pages including 18 figures
A boundary version of Cartan-Hadamard and applications to rigidity
Creators: name: Lafont, J. -F.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Geometric Topology (math.GT)
subject: Differential Geometry (math.DG)
subject: Group Theory (math.GR)
subject: FOS: Mathematics

description: In this paper, we prove a version of the classical Cartan-Hadamard theorem for negatively curved manifolds, of dimension $n\neq 5$, with non-empty totally geodesic boundary. More precisely, if $M_1^n,M_2^n$ are any two such manifolds, we show that (1) $\partial ^\infty \tilde M_1^n$ is homeomorphic to $\partial ^\infty \tilde M_2^n$, and (2) $\tilde M_1^n$ is homeomorphic to $\tilde M_2^n$. As a sample application, we show that simple, thick, negatively curved P-manifolds of dimension $\geq 6$ are topologically rigid. We include some straightforward consequences of topological rigidity (diagram rigidity, weak co-Hopf property, and Nielson realization problem).
description: 16 pages
Renyi Dimension and Gaussian Filtering
Creators: name: Loring, Terry A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 28A80; 28A78

description: Consider the partition function S(ε) associated in theory of Renyi dimension to a finite Borel measure μon Euclidean d-space. This partion function S(ε) is the sum of the q-th powers of the measure applied to a partition of d-space into d-cubes of width ε. We further Guerin's investigation of the relation between this partition function and the Lebesgue Lp norm (Lq norm) of the convolution of μagainst an approximate identity of Gaussians. We prove a Lipschitz-type esimate on the partition function. This bound on the partition function leads to results regarding the computation of Renyi dimension. It also shows that the partion function is of O-regular variation. We find situtations where one can or cannot replace the partition function by a discrete version. We discover that the slopes of the least-square best fit linear approximations to the partion function cannot always be used to calculate upper and lower Renyi dimension.
description: Better abstract. Very minor changes in the rest of the paper