cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Black Lives Matter in Wikipedia: Collaboration and Collective Memory around Online Social Movements
Creators: name: Twyman, Marlon
name: Keegan, Brian C.
name: Shaw, Aaron
Publisher: name: arXiv
Year: 2016
Subjects: subject: Social and Information Networks (cs.SI)
subject: Computers and Society (cs.CY)
subject: Human-Computer Interaction (cs.HC)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences
subject: H.5.3; K.4.2

description: Social movements use social computing systems to complement offline mobilizations, but prior literature has focused almost exclusively on movement actors' use of social media. In this paper, we analyze participation and attention to topics connected with the Black Lives Matter movement in the English language version of Wikipedia between 2014 and 2016. Our results point to the use of Wikipedia to (1) intensively document and connect historical and contemporary events, (2) collaboratively migrate activity to support coverage of new events, and (3) dynamically re-appraise pre-existing knowledge in the aftermath of new events. These findings reveal patterns of behavior that complement theories of collective memory and collective action and help explain how social computing systems can encode and retrieve knowledge about social movements as they unfold.
description: 14 pages
MPEC 2023-R208 : 2023 RM9
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2023 RM9

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Diffusion Quantum Monte Carlo Study of Martensitic Phase Transition: The Case of Phosphorene
Creators: name: Reeves, Kyle G.
name: Yao, Yi
name: Kanai, Yosuke
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Recent technical advances in dealing with finite-size errors make quantum Monte Carlo methods quite appealing for treating extended systems in electronic structure calculations, especially when commonly-used density functional theory (DFT) methods might not be satisfactory. We present a theoretical study of martensitic phase transition of a two-dimensional phosphorene by employing diffusion Monte Carlo (DMC) approach to investigate the energetics of this phase transition. The DMC calculation supports DFT prediction of having a rather diffusive barrier that is characterized by having two transition states, in addition to confirming that the so-called black and blue phases of phosphorene are essentially degenerate. At the same time, the calculation shows the importance of treating correlation energy accurately for describing the energy changes in the martensitic phase transition, as is already widely appreciated for chemical bond formation/dissociation. Building on the atomistic characterization of the phase transition process, we also discuss how mechanical strain influences the stabilities of the two phases of phosphorene.
description: 12 pages, 6 figures
MPEC 2023-R209 : 2023 RN9
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2023 RN9

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
The asteroseismic potential of TESS: exoplanet-host stars
Creators: name: Campante, T. L.
name: Schofield, M.
name: Kuszlewicz, J. S.
name: Bouma, L.
name: Chaplin, W. J.
name: Huber, D.
name: Christensen-Dalsgaard, J.
name: Kjeldsen, H.
name: Bossini, D.
name: North, T. S. H.
name: Appourchaux, T.
name: Latham, D. W.
name: Pepper, J.
name: Ricker, G. R.
name: Stassun, K. G.
name: Vanderspek, R.
name: Winn, J. N.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: New insights on stellar evolution and stellar interiors physics are being made possible by asteroseismology. Throughout the course of the Kepler mission, asteroseismology has also played an important role in the characterization of exoplanet-host stars and their planetary systems. The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will be performing a near all-sky survey for planets that transit bright nearby stars. In addition, its excellent photometric precision, combined with its fine time sampling and long intervals of uninterrupted observations, will enable asteroseismology of solar-type and red-giant stars. Here we develop a simple test to estimate the detectability of solar-like oscillations in TESS photometry of any given star. Based on an all-sky stellar and planetary synthetic population, we go on to predict the asteroseismic yield of the TESS mission, placing emphasis on the yield of exoplanet-host stars for which we expect to detect solar-like oscillations. This is done for both the target stars (observed at a 2-min cadence) and the full-frame-image stars (observed at a 30-min cadence). A similar exercise is also conducted based on a compilation of known host stars. We predict that TESS will detect solar-like oscillations in a few dozen target hosts (mainly subgiant stars but also in a smaller number of F dwarfs), in up to 200 low-luminosity red-giant hosts, and in over 100 solar-type and red-giant known hosts, thereby leading to a threefold improvement in the asteroseismic yield of exoplanet-host stars when compared to Kepler's.
description: Accepted for publication in ApJ; 31 pages, 12 figures
MPEC 2023-R210 : 2023 RO9
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2023 RO9

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
A numerical investigation of wind accretion in persistent Supergiant X-ray Binaries I - Structure of the flow at the orbital scale
Creators: name: Mellah, I. El
name: Casse, F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Classical Supergiant X-ray Binaries host a neutron star orbiting a supergiant OB star and display persistent X-ray luminosities of 10$^{35}$ to 10$^{37}$ erg/s. The stellar wind from the massive companion is believed to be the main source of matter accreted by the compact object. With this first paper, we introduce a ballistic model to characterize the structure of the wind at the orbital scale as it accelerates, from the stellar surface to the vicinity of the accretor. Thanks to the parametrization we retained and the numerical pipeline we designed, we can investigate the supersonic flow and the subsequent observables as a function of a reduced set of characteristic numbers and scales. We show that the shape of the permanent flow is entirely determined by the mass ratio, the filling factor, the Eddington factor and the $α$-force multiplier which drives the stellar wind acceleration. Provided scales such as the orbital period are known, we can trace back the observables to evaluate the mass accretion rates, the accretion mechanism, the shearing of the inflow and the stellar parameters. We confront our model to three persistent Supergiant X-ray Binaries (Vela X-1, IGR J18027-2016, XTE J1855-026) and discuss the likelihood of wind-formed accretion discs around the accretors in each case, further investigated in a following paper.
Experimental demonstration of spontaneous chirality in a nonlinear microresonator
Creators: name: Cao, Qi-Tao
name: Wang, He-Ming
name: Dong, Chun-Hua
name: Jing, Hui
name: Liu, Rui-Shan
name: Chen, Xi
name: Ge, Li
name: Gong, Qihuang
name: Xiao, Yun-Feng
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Chirality is an important concept that describes the asymmetry property of a system, which usually emerges spontaneously due to mirror symmetry breaking. Such spontaneous chirality manifests predominantly as parity breaking in modern physics, which has been studied extensively, for instance, in Higgs physics, double-well Bose-Einstein condensates, topological insulators and superconductors. In the optical domain, spontaneous chiral symmetry breaking has been elusive experimentally, especially for micro- and nano-photonics which demands multiple identical subsystems, such as photonic nanocavities, meta-molecules and other dual-core settings. Here, for the first time, we observe spontaneous emergence of a chiral field in a single ultrahigh-Q whispering- gallery microresonator. This counter-intuitive effect arises due to the inherent Kerr nonlinearity-modulated coupling between clockwise (CW) and counterclockwise (CCW) propagating waves. At an ultra-weak input threshold of a few hundred microwatts, the initial chiral symmetry is broken spontaneously, and the CW-to-CCW output ratio reaches 20:1. The spontaneous chirality in microresonator holds great potential in studies of fundamental physics and applied photonic devices.
description: 6 pages, 4 figures
Molecular dynamics-based refinement of nanodiamond size measurements obtained with dynamic light scattering
Creators: name: Koniakhin, S. V.
name: Eliseev, I. E.
name: Terterov, I. N.
name: Shvidchenko, A. V.
name: Eidelman, E. D.
name: Dubina, M. V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The determination of particle size by dynamic light scattering uses the Stokes-Einstein relation, which can break down for nanoscale objects. Here we employ a molecular dynamics simulation of fully solvated 1-5 nm carbon nanoparticles for the refinement of the experimental data obtained for nanodiamonds in water by using dynamic light scattering. We performed molecular dynamics simulations in differently sized boxes and calculated nanoparticles diffusion coefficients using the velocity autocorrelation function and mean-square displacement. We found that the predictions of the Stokes-Einstein relation are accurate for nanoparticles larger than 3 nm while for smaller nanoparticles the diffusion coefficient should be corrected and different boundary conditions should be taken into account.
description: 5 pages, 5 figures, 1 table
Hysteretic phenomena in GFET: general theory and experiment
Creators: name: Kurchak, Anatolii I.
name: Morozovska, Anna N.
name: Strikha, Maksym V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We propose a general theory for the analytical description of versatile hysteretic phenomena in a graphene field effect transistor (GFET) allowing for the existence of the external dipoles on graphene free surface and the localized states at the graphene-surface interface. We demonstrated that the absorbed dipole molecules (e.g. dissociated or highly polarized water molecules) can cause hysteretic form of carrier concentration as a function of gate voltage and corresponding dependence of graphene conductivity in GFET on the substrate of different types, including the most common SiO2 and ferroelectric ones. It was shown that the increase of the gate voltage sweeping rate leads to the complete vanishing of hysteresis for GFET on SiO2 substrate, as well as for GFET on ferroelectric substrate for applied electric fields E less than the critical value Ec. For E>Ec the crossover from the hysteresis to antihysteresis takes place. These results well correlate with the available experimental data up to the quantitative agreement. Proposed model takes into consideration the carriers trapping from the graphene channel by the interface states and describes the antihysteresis in GFET on PZT substrate well enough. Obtained results clarify the fundamental principles of GFET operation as well as can be directly applied to describe the basic characteristics of advanced nonvolatile ultra-fast memory devices using GFET on versatile substrates.
description: main paper : 28 pages, 10 figures, supplementary materials with 3 figures
On the Atomic Cluster Expansion: interatomic potentials and beyond
Creators: name: Ortner, Christoph
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The Atomic Cluster Expansion (ACE) [R. Drautz, Phys. Rev. B, 99:014104 (2019)] provides a systematically improvable, universal descriptor for the environment of an atom that is invariant to permutation, translation and rotation. ACE is being used extensively in newly emerging interatomic potentials based on machine learning. This commentary discusses the ACE framework and its potential impact.
description: 5 pages
Electronics lab instructors' approaches to troubleshooting instruction
Creators: name: Dounas-Frazer, Dimitri R.
name: Lewandowski, H. J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: In this exploratory qualitative study, we describe instructors' self-reported practices for teaching and assessing students' ability to troubleshoot in electronics lab courses. We collected audio data from interviews with 20 electronics instructors from 18 institutions that varied by size, selectivity, and other factors. In addition to describing participants' instructional practices, we characterize their perceptions about the role of troubleshooting in electronics, the importance of the ability to troubleshoot more generally, and what it means for students to be competent troubleshooters. One major finding of this work is that, while almost all instructors in our study said that troubleshooting is an important learning outcome for students in electronics lab courses, only half of instructors said they directly assessed students' ability to troubleshoot. Based on our findings, we argue that there is a need for research-based instructional materials that attend to both cognitive and non-cognitive aspects of troubleshooting proficiency. We also identify several areas for future investigation related to troubleshooting instruction in electronics lab courses.
description: 17 pages, 1 table; Submitted to Phys. Rev. Phys. Educ. Res
Super-de Sitter and alternative super-Poincaré symmetries
Creators: name: Tolstoy, V. N.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It is well-known that de Sitter Lie algebra $\mathfrak{o}(1,4)$ contrary to anti-de Sitter one $\mathfrak{o}(2,3)$ does not have a standard $\mathbb{Z}_2$-graded superextension. We show here that the Lie algebra $\mathfrak{o}(1,4)$ has a superextension based on the $\mathbb{Z}_2\times\mathbb{Z}_2$-grading. Using the standard contraction procedure for this superextension we obtain an {\it alternative} super-Poincaré algebra with the $\mathbb{Z}_2\times\mathbb{Z}_2$-grading.
description: 10 pages, X. International Workshop LIE THEORY AND ITS APPLICATIONS IN PHYSICS, (Varna, Bulgaria, 2013)
Fast Spherical Quasiconformal Parameterization of Genus-0 Closed Surfaces with Application to Adaptive Remeshing
Creators: name: Choi, Gary Pui-Tung
name: Man, Mandy Hiu-Ying
name: Lui, Lok Ming
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computational Geometry (cs.CG)
subject: Graphics (cs.GR)
subject: Differential Geometry (math.DG)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: In this work, we are concerned with the spherical quasiconformal parameterization of genus-0 closed surfaces. Given a genus-0 closed triangulated surface and an arbitrary user-defined quasiconformal distortion, we propose a fast algorithm for computing a spherical parameterization of the surface that satisfies the prescribed distortion. The proposed algorithm can be effectively applied to adaptive surface remeshing for improving the visualization in computer graphics and animations. Experimental results are presented to illustrate the effectiveness of our algorithm.
Time reversal of ultrasound in granular media
Creators: name: Harazi, Maxime
name: Yang, Yougu
name: Fink, Mathias
name: Tourin, Arnaud
name: Jia, Xiaoping
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Time reversal (TR) focusing of ultrasound in granular packings is experimentally investigated. Pulsed elastic waves transmitted from a compressional or shear transducer source are measured by a TR mirror, reversed in time and back-propagated. We find that TR of ballistic coherent waves onto the source position is very robust regardless driving amplitude but provides poor spatial resolution. By contrast, the multiply scattered coda waves offer a finer TR focusing at small amplitude by a lens effect. However, at large amplitude, these TR focusing signals decrease significantly due to the vibration-induced rearrangement of the contact networks, leading to the breakdown of TR invariance. Our observations reveal that granular acoustics is in between particle motion and wave propagation in terms of sensitivity to perturbations. These laboratory experiments are supported by numerical simulations of elastic wave propagation in disordered 2D percolation networks of masses and springs, and should be helpful for source location problems in natural processes.
description: 15 pages, 6 figures
Signatures of an annular Fermi sea
Creators: name: Jo, Insun
name: Liu, Yang
name: Pfeiffer, L. N.
name: West, K. W.
name: Baldwin, K. W.
name: Shayegan, M.
name: Winkler, R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report Shubnikov-de Haas oscillations measurements revealing experimental signatures of an annular Fermi sea that develops near the energy band edge of the excited subband of two-dimensional holes confined in a wide GaAs quantum well. As we increase the hole density, when the Fermi level reaches the excited subband edge, the low-field magnetoresistance traces show a sudden emergence of new oscillations at an unexpectedly large frequency whose value does $\textit{not}$ correspond to the (negligible) density of holes in the excited subband. There is also a sharp and significant increase in zero-field resistance near this onset of subband occupation. Guided by numerical energy dispersion calculations, we associate these observations with the unusual shape of the excited subband dispersion which results in a "ring of extrema" at finite wavevectors and an annular Fermi sea. Such a dispersion and Fermi sea have long been expected from energy band calculations in systems with strong spin-orbit interaction but their experimental signatures have been elusive.
description: 5 pages, 4 figures
Patterns of patterns of synchronization: Noise induced attractor switching in rings of coupled nonlinear oscillators
Creators: name: Emenheiser, Jeffrey
name: Chapman, Airlie
name: Pósfai, Márton
name: Crutchfield, James P.
name: Mesbahi, Mehran
name: D'Souza, Raissa M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Following the long-lived qualitative-dynamics tradition of explaining behavior in complex systems via the architecture of their attractors and basins, we investigate the patterns of switching between qualitatively distinct trajectories in a network of synchronized oscillators. Our system, consisting of nonlinear amplitude-phase oscillators arranged in a ring topology with reactive nearest neighbor coupling, is simple and connects directly to experimental realizations. We seek to understand how the multiple stable synchronized states connect to each other in state space by applying Gaussian white noise to each of the oscillators' phases. To do this, we first identify a set of locally stable limit cycles at any given coupling strength. For each of these attracting states, we analyze the effect of weak noise via the covariance matrix of deviations around those attractors. We then explore the noise-induced attractor switching behavior via numerical investigations. For a ring of three oscillators we find that an attractor-switching event is always accompanied by the crossing of two adjacent oscillators' phases. For larger numbers of oscillators we find that the distribution of times required to stochastically leave a given state falls off exponentially, and we build an attractor switching network out of the destination states as a coarse-grained description of the high-dimensional attractor-basin architecture.
Heralded single excitation of atomic ensemble via solid-state-based telecom photon detection
Creators: name: Ikuta, Rikizo
name: Kobayashi, Toshiki
name: Matsuki, Kenichiro
name: Miki, Shigehito
name: Yamashita, Taro
name: Terai, Hirotaka
name: Yamamoto, Takashi
name: Koashi, Masato
name: Mukai, Tetsuya
name: Imoto, Nobuyuki
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Telecom photonic quantum networks with matter quantum systems enable a rich variety of applications, such as a long distance quantum cryptography and one-way quantum computing. Preparation of a heralded single excitation (HSE) in an atomic ensemble by detecting a telecom wavelength photon having a correlation with the atomic excitation is an important step. Such a system has been demonstrated with a quantum frequency conversion (QFC) to telecom wavelength employing a Rb atomic cloud. However the limited wavelength selection prevents the next step. Here we for the first time demonstrate HSE with a solid-state-based QFC and a detector for a telecom wavelength that will have a great advantage of the utility of mature telecom technologies. We unambiguously show that the demonstrated HSE indicates a non-classical statistics by the direct measurement of the autocorrelation function.
description: 8 pages, 4 figures
Context-aware Event Forecasting via Graph Disentanglement
Creators: name: Ma, Yunshan
name: Ye, Chenchen
name: Wu, Zijian
name: Wang, Xiang
name: Cao, Yixin
name: Chua, Tat-Seng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences
subject: I.2.4

description: Event forecasting has been a demanding and challenging task throughout the entire human history. It plays a pivotal role in crisis alarming and disaster prevention in various aspects of the whole society. The task of event forecasting aims to model the relational and temporal patterns based on historical events and makes forecasting to what will happen in the future. Most existing studies on event forecasting formulate it as a problem of link prediction on temporal event graphs. However, such pure structured formulation suffers from two main limitations: 1) most events fall into general and high-level types in the event ontology, and therefore they tend to be coarse-grained and offers little utility which inevitably harms the forecasting accuracy; and 2) the events defined by a fixed ontology are unable to retain the out-of-ontology contextual information. To address these limitations, we propose a novel task of context-aware event forecasting which incorporates auxiliary contextual information. First, the categorical context provides supplementary fine-grained information to the coarse-grained events. Second and more importantly, the context provides additional information towards specific situation and condition, which is crucial or even determinant to what will happen next. However, it is challenging to properly integrate context into the event forecasting framework, considering the complex patterns in the multi-context scenario. Towards this end, we design a novel framework named Separation and Collaboration Graph Disentanglement (short as SeCoGD) for context-aware event forecasting. Since there is no available dataset for this novel task, we construct three large-scale datasets based on GDELT. Experimental results demonstrate that our model outperforms a list of SOTA methods.
description: KDD 2023, 9 pages, 7 figures, 4 tables
Dispersive wave propagation in two-dimensional rigid periodic blocky materials with elastic interfaces
Creators: name: Bacigalupo, Andrea
name: Gambarotta, Luigi
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Dispersive waves in two-dimensional blocky materials with periodic microstructure made up of equal rigid units having polygonal centro-symmetric shape with mass and gyroscopic inertia, connected each other through homogeneous linear interfaces, have been analysed. The acoustic behavior of the resulting discrete Lagrangian model has been obtained through a Floquet-Bloch approach. From the resulting eigenproblem derived by the Euler-Lagrange equations for harmonic wave propagation, two acoustic branches and an optical branch are obtained in the frequency spectrum. A micropolar continuum model to approximate the Lagrangian model has been derived based on a second-order Taylor expansion of the generalized macro-displacement field. The constitutive equations of the equivalent micropolar continuum have been obtained, with the peculiarity that the positive definiteness of the second-order symmetric tensor associated to the curvature vector is not guaranteed and depends both on the ratio between the local tangent and normal stiffness and on the block shape. The same results has been obtained through an extended Hamiltonian derivation of the equations of motion for the equivalent continuum that is related to the Hill-Mandel macro homogeneity condition. Moreover, it is shown that the hermitian matrix governing the eigenproblem of harmonic wave propagation in the micropolar model is exact up to the second order in the norm of the wave vector with respect to the same matrix from the discrete model. To appreciate the acoustic behavior of some relevant blocky materials and to understand the reliability and the validity limits of the micropolar continuum model, some blocky patterns have been analysed: rhombic and hexagonal assemblages and running bond masonry.
Current noise enhancement: channel mixing and possible nonequilibrium phonon backaction in atomic-scale Au junctions
Creators: name: Stevens, Loah A.
name: Zolotavin, Pavlo
name: Chen, Ruoyu
name: Natelson, Douglas
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report measurements of the bias dependence of the Fano factor in ensembles of atomic-scale Au junctions at 77 K. Previous measurements of shot noise at room temperature and low biases have found good agreement of the Fano factor with the expectations of the Landauer- Büttiker formalism, while enhanced Fano factors have been observed at biases of hundreds of mV [R. Chen et al., Sci. Rep. 4, 4221 (2014)]. We find even stronger enhancement of shot noise at 77 K with an "excess" Fano factor up to ten times the low bias value. We discuss the observed ensemble Fano factor bias dependence in terms of candidate models. The results are most consistent with either a bias-dependent channel mixing picture or a model incorporating noise enhancement due to current-driven, nonequilibrium phonon populations, though a complete theoretical treatment of the latter in the ensemble average limit is needed.
description: 25 pages, six figures + supporting information; to appear in J. Phys. Condens. Matt
Front structure and dynamics in dense colonies of motile bacteria: Role of active turbulence
Creators: name: Chatterjee, Rayan
name: Joshi, Abhijeet A.
name: Perlekar, Prasad
Publisher: name: arXiv
Year: 2016
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Chaotic Dynamics (nlin.CD)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences

description: We study the spreading of a bacterial colony undergoing turbulent like collective motion. We present two minimalistic models to investigate the interplay between population growth and coherent structures arising from turbulence. Using Direct Numerical Simulation (DNS) of the proposed models we find that turbulence has two prominent effects on the spatial growth of the colony: (a) the front speed is enhanced, and (b) the front gets crumpled. Both these effects, which we highlight by using statistical tools, are markedly different in our two models. We also show that the crumpled front structure and the passive scalar fronts in random flows are related in certain regimes.
description: 9 pages, 8 figures
Combining Fully Convolutional and Recurrent Neural Networks for 3D Biomedical Image Segmentation
Creators: name: Chen, Jianxu
name: Yang, Lin
name: Zhang, Yizhe
name: Alber, Mark
name: Chen, Danny Z.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Segmentation of 3D images is a fundamental problem in biomedical image analysis. Deep learning (DL) approaches have achieved state-of-the-art segmentation perfor- mance. To exploit the 3D contexts using neural networks, known DL segmentation methods, including 3D convolution, 2D convolution on planes orthogonal to 2D image slices, and LSTM in multiple directions, all suffer incompatibility with the highly anisotropic dimensions in common 3D biomedical images. In this paper, we propose a new DL framework for 3D image segmentation, based on a com- bination of a fully convolutional network (FCN) and a recurrent neural network (RNN), which are responsible for exploiting the intra-slice and inter-slice contexts, respectively. To our best knowledge, this is the first DL framework for 3D image segmentation that explicitly leverages 3D image anisotropism. Evaluating using a dataset from the ISBI Neuronal Structure Segmentation Challenge and in-house image stacks for 3D fungus segmentation, our approach achieves promising results comparing to the known DL-based 3D segmentation approaches.
The decay of Hopf solitons in the Skyrme model
Creators: name: Foster, David
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: It is understood that the Skyrme model has a topologically interesting baryonic excitation which can model nuclei. So far no stable knotted solutions, of the Skyrme model, have been found. Here we investigate the dynamics of Hopf solitons decaying to the vacuum solution in the Skyrme model. In doing this we develop a matrix-free numerical method to identify the minimum eigenvalue of the Hessian of the corresponding energy functional. We also show that as the Hopf solitons decay, they emit a cloud of isospinning radiation.
description: 10 pages, 12 images
Estimation of Mass of Compact Object in H 1743-322 from 2010 and 2011 Outbursts using TCAF Solution and Spectral Index - QPO Frequency Correlation
Creators: name: Molla, Aslam Ali
name: Chakrabarti, Sandip K.
name: Debnath, Dipak
name: Mondal, Santanu
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The well known black hole candidate H~1743-322 exhibited temporal and spectral variabilities during several outbursts. Daily variation of the accretion rates and the flow geometry change on a daily basis during each of the outbursts could be understood very well using the recent implementation of two component advective flow (TCAF) solution of the viscous transonic flow equations as an additive table model in XSPEC. This has dramatically improved our understanding about the accretion flow dynamics. Most interestingly, the solution allows to treat mass of the black hole candidate as a free parameter and there mass could be estimated from spectral fits. In this paper, we fit the data of two successive outbursts of H~1743-322 in 2010 and 2011 and studied evolutions of accretion flow parameters, such as, two component (Keplerian and sub-Keplerian) accretion rates, shock location (i.e., size of the Compton cloud), etc. We assume that the model Normalization remains the same accross the states in both these outbursts. We use this to estimate mass of the black hole and found that it comes out in the range of $9.25-12.86 M_\odot$. For the sake of comparison, we also estimated mass using Photon index vs. QPO frequency correlation method which turns out to be $11.65 \pm 0.67 M_\odot$ using GRO J1655-40 as reference source. Combining these two estimates, the most probable mass of the compact object becomes $11.21^{+1.65}_{-1.96} M_\odot$.
description: 16 Pages, 9 Figues and 4 Appendix Tables (Accepted for Publication in ApJ)
Dark matter, light mediators, and the neutrino floor
Creators: name: Dent, James B.
name: Dutta, Bhaskar
name: Newstead, Jayden L.
name: Strigari, Louis E.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We analyze future direct data matter detection experiments using Effective Field Theory (EFT) operators with light, $\lesssim 100$ MeV mass mediators. We compare the nuclear recoil energy spectra from these operators to the predicted high energy solar neutrino spectrum. A set of operators that generate spectra similar to the neutrino background is identified, however this set is distinct from those that mimic the neutrino background for heavy, $\gtrsim 100$ MeV mass mediators. We outline a general classification scheme based on momentum dependence of the dark matter-nucleus interaction to determine how strong the discovery limit for a given operator saturates in the presence of the neutrino background. Our results highlight the benefit of considering a general theoretical framework regarding dark matter, and motivate continued experimental progress towards lower nuclear recoil energy thresholds.
description: 4 pages, 2 figures
Are we ready for spray-on carbon nanotubes?
Creators: name: Maynard, Andrew D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: Earlier this year, British sculptor, Anish Kapoor was given exclusive rights to use a new spray-on carbon nanotube-based paint. The material, produced by UK-based Surrey NanoSystems and marketed as Vantablack S-VIS, can be applied to a range of surfaces, and absorbs well over 99% of the light that falls onto it. It is claimed to be the world's blackest paint, and there is growing interest in its use in works of art and high-end consumer products. It's easy to see the appeal of Vantablack S-VIS. Apart from technical applications where stray reflections need to be suppressed, this is a material that potentially enables manufacturers and artists to give their products a unique aesthetic edge. Yet, having worked on carbon nanotube safety for some years, I was intrigued to see the material in a spray-paint designed to coat objects that people may possibly come into contact with. It was, after all, only a few years ago that journalists were asking if carbon nanotubes were the next asbestos. And while this is unlikely, concerns over the possible health impacts of the material persist.
description: 7 pages, Commentary for Nature Nanotechnology
Stability of the graviton Bose-Einstein condensate in the brane-world
Creators: name: Casadio, Roberto
name: da Rocha, Roldao
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We consider a solution of the effective four-dimensional Einstein equations, obtained from the general relativistic Schwarzschild metric through the principle of Minimal Geometric Deformation (MGD). Since the brane tension can, in general, introduce new singularities on a relativistic Eötvös brane model in the MGD framework, we require the absence of observed singularities, in order to constrain the brane tension. We then study the corresponding Bose-Einstein condensate (BEC) gravitational system and determine the critical stability region of BEC MGD stellar configurations. Finally, the critical stellar densities are shown to be related with critical points of the information entropy.
description: 7 pages, 4 figures
XPS and DFT study of pulsed Bi-implantation of bulk and thin-films of ZnO - the role of oxygen imperfections
Creators: name: Zatsepin, D. A.
name: Boukhvalov, D. W.
name: Gavrilov, N. V.
name: Kurmaev, E. Z.
name: Zhidkov, I. S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: An atomic and electronic structure of the bulk and thin-film morphologies of ZnO were modified using pulsed Bi-ion implantation (1x1017 cm-2 fluence, 70 min exposure under Bi-ion beam, EBi+ = 30 keV, pulsed ion-current density of not more than 0.8 mA/cm2 with a repetition rate of 12.5 Hz). The final samples were qualified by X-ray photoelectron core-level and valence band mapping spectroscopy applying ASTM materials science standard. The spectroscopy data obtained was discussed on the basis of DFT-models for Bi-embedding into ZnO host-matrices. It was established that in the case of direct Bi-impurities insertion into the employed ZnO-host for both studied morphologies neither the only "pure" Bi2O3-like phase nor the only "pure" Bi-metal will be preferable to appear as a secondary phase. An unfavorability of the large cluster agglomeration of Bi-impurities in ZnO-hosts has been shown and an oxygen 2s electronic states pleomorphizm was surely established.
description: 20 pages, 8 figures, 2 tables, accepted to Appl. Surf. Sci
A benchmark of the He-like triplet for ions with $6\leq Z\leq 14$ in Maxwellian and non-Maxwellian plasmas
Creators: name: Rodríguez, Y.
name: Gatuzz, E.
name: Bautista, M. A.
name: Mendoza, C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: After an extensive assessment of the effective collision strengths available to model the He-like triplet of C V, N VI, O VII, Ne IX, Mg XI and Si XIII in collisionally dominated plasmas, new accurate effective collision strengths are reported for Ne IX. The uncertainty intervals of the density and temperature diagnostics due to the atomic data errors are also determined for both Maxwell-Boltzmann and $κ$ electron-energy distributions. It is shown that these uncertainty bands limit the temperature range where the temperature line-ratio diagnostic can be applied and its effectiveness to discern the electron-energy distribution type. These findings are benchmarked with Chandra and XMM-Newton spectra of stellar coronae and with tokamak measurements.
description: Accepted for publication in MNRAS. 14 pages, 9 figures and 9 tables
A new approach to representations of $3$-Lie algebras and abelian extensions
Creators: name: Liu, Jiefeng
name: Makhlouf, Abdenacer
name: Sheng, Yunhe
Publisher: name: arXiv
Year: 2016
Subjects: subject: Representation Theory (math.RT)
subject: Mathematical Physics (math-ph)
subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: In this paper, we introduce the notion of generalized representation of a $3$-Lie algebra, by which we obtain a generalized semidirect product $3$-Lie algebra. Moreover, we develop the corresponding cohomology theory. Various examples of generalized representations of 3-Lie algebras and computation of 2-cocycles of the new cohomology are provided. Also, we show that a split abelian extension of a 3-Lie algebra is isomorphic to a generalized semidirect product $3$-Lie algebra. Furthermore, we describe general abelian extensions of 3-Lie algebras using Maurer-Cartan elements.
description: 17 pages
The mean light curves of the Mira-type stars in the H- and K-bands
Creators: name: Kudashkina, L. S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: For nine Mira-type stars (o Cet, R Leo, S Car, U Her, X Oph, R Aql, RR Aql, S Ori, S Scl,) and one semi-regular star (L2 Pup), the mean light curves have been obtained. The initial values of the brightness (observations) were fitted by a trigonometric polynomial of the statistically optimal order. The Fourier coefficients and the additional parameters (degree of the trigonometric polynomial, amplitude of the brightness, the maximal slope of ascending and descending branch, semi-amplitudes and initial epochs for the brightness maximum (minimum magnitude) of each harmonic contribution, etc., were given in the tables reported earlier (Kudashkina, 2015). In this study, we have received several interesting correlations between these parameters in the bands H and K. It was particularly noted the anomalous position on the figures of the star X Oph. The mean light curves of the investigated stars are commonly symmetric in the near infrared region (H and K).
description: 7 pages, 6 figures
Holographic Beam Mapping of the CHIME Pathfinder Array
Creators: name: Berger, Philippe
name: Newburgh, Laura B.
name: Amiri, Mandana
name: Bandura, Kevin
name: Cliche, Jean-Francois
name: Connor, Liam
name: Deng, Meiling
name: Denman, Nolan
name: Dobbs, Matt
name: Fandino, Mateus
name: Gilbert, Adam J.
name: Good, Deborah
name: Halpern, Mark
name: Hanna, David
name: Hincks, Adam D.
name: Hinshaw, Gary
name: Hofer, Carolin
name: Johnson, Andre M.
name: Landecker, Tom L.
name: Masui, Kiyoshi W.
name: Parra, Juan Mena
name: Oppermann, Niels
name: Pen, Ue-Li
name: Peterson, Jeffrey B.
name: Recnik, Andre
name: Robishaw, Timothy
name: Shaw, J. Richard
name: Siegel, Seth
name: Sigurdson, Kris
name: Smith, Kendrick
name: Storer, Emilie
name: Tretyakov, Ian
name: Van Gassen, Kwinten
name: Vanderlinde, Keith
name: Wiebe, Donald
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder radio telescope is currently surveying the northern hemisphere between 400 and 800 MHz. By mapping the large scale structure of neutral hydrogen through its redshifted 21 cm line emission between $z \sim 0.8-2.5$ CHIME will contribute to our understanding of Dark Energy. Bright astrophysical foregrounds must be separated from the neutral hydrogen signal, a task which requires precise characterization of the polarized telescope beams. Using the DRAO John A. Galt 26 m telescope, we have developed a holography instrument and technique for mapping the CHIME Pathfinder beams. We report the status of the instrument and initial results of this effort.
description: 16 pages, 9 figures. Submitted to Proc. SPIE, Astronomical Telescopes + Instrumentation (2016)
UGC 3672: An unusual merging triplet of gas-rich galaxies in the Lynx-Cancer void
Creators: name: Chengalur, Jayaram N.
name: Pustilnik, S. A.
name: Egorova, E. S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present HI 21cm and optical observations of UGC 3672 which is located near the centre of the nearby Lynx-Cancer void. We find that UGC 3672 consists of an approximately linearly aligned triplet of gas rich dwarfs with large scale velocity continuity along the triplet axis. The faintest component of the triplet is extremely gas-rich (MHI/LB ~ 17) and also extremely metal deficient (12+log(O/H) ~ 7.0). The metallicity of this dwarf is close to the 'floor' observed in star forming galaxies. Low resolution HI images show that the galaxy triplet is located inside a common HI envelope, with fairly regular, disk like kinematics. At high angular resolution however, the gas is found to be confined to several filamentary tidal tails and bridges. The linear alignment of the galaxies, along with the velocity continuity that we observe, is consistent with the galaxies lying along a filament. We argue that the location of this highly unusual system in an extremely low density environment is not a coincidence, but is a consequence of structure formation proceeding more slowly and also probing smaller scales than in regions with average density. Our observations also indicate that wet mergers of galaxies flowing along filaments is a possible pathway for the formation of gas rich disks. The UGC 3672 system provides an interesting opportunity to study the kind of interactions typical between high redshift extremely gas rich unevolved small systems that lie at base of the hierarchical galaxy formation model.
description: 12 pages, 8 figures, accepted for publication in MNRAS
A new analytic method with a convergence-control parameter for solving nonlinear problems
Creators: name: Zhang, Xiaolong
name: Liang, Songxin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Numerical Analysis (math.NA)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 34E10, 35B20, 76M45

description: In this paper, a new analytic method with a convergence-control parameter $c$ is first proposed. The parameter $c$ is used to adjust and control the convergence region and rate of the resulting series solution. It turns out that the convergence region and rate can be greatly enlarged by choosing a proper value of $c$. Furthermore, a numerical approach for finding the optimal value of the convergence-control parameter is given. At the same time, it is found that the traditional Adomian decomposition method is only a special case of the new method. The effectiveness and applicability of the new technique are demonstrated by several physical models including nonlinear heat transfer problems, nano-electromechanical systems, diffusion and dissipation phenomena, and dispersive waves. Moreover, the ideas proposed in this paper may offer us possibilities to greatly improve current analytic and numerical techniques.
description: 15page,7figures