cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The mirage of scientific productivity and how women are left behind: the Colombian case
Creators: name: López-Aguirre, Camilo
name: Farías, Diana
Publisher: name: Taylor & Francis
Year: 2022
Subjects: Biotechnology
Cancer
Science Policy

description: Equity, diversity and inclusion (EDI) in the workforce are paramount for the betterment of the scientific endeavor. Colombia is a country with great scientific potential, but also multiple long-lasting socioeconomical difficulties. Here, we provide a quantitative analysis of the temporal trajectories of gender parity in scientific publishing in Colombia. Data was dissected based on education level, researcher’s rank and research area, in order to elucidate differential patterns of scientific publishing. We controlled for gender-based differences in number of researchers by quantifying per capita scientific productivity. Our results show widespread gender disparity in scientific publishing persistent across time. Gender-based differences in per capita scientific publishing indicate that gender disparity persists even after controlling for differences in the number of researchers. Temporal trajectories revealed a decrease in women publishing in the medical sciences and a widening of the per capita publishing gender gap. Women senior researchers and women researchers with doctoral degrees had the lowest publishing participation within their group, suggesting access to postgraduate education or entering the workforce in themselves do not prevent women from being underrepresented. We highlight the need to understand the problem of underrepresentation in science and possible ways to address it beyond increasing the number of women researchers.
Accurate high-harmonic spectra from time-dependent two-particle reduced density matrix theory
Creators: name: Lackner, Fabian
name: Březinová, Iva
name: Sato, Takeshi
name: Ishikawa, Kenichi L.
name: Burgdörfer, Joachim
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The accurate description of the non-linear response of many-electron systems to strong-laser fields remains a major challenge. Methods that bypass the unfavorable exponential scaling with particle number are required to address larger systems. In this paper we present a fully three-dimensional implementation of the time-dependent two-particle reduced density matrix (TD-2RDM) method for many-electron atoms. We benchmark this approach by a comparison with multi-configurational time-dependent Hartree-Fock (MCTDHF) results for the harmonic spectra of beryllium and neon. We show that the TD-2RDM is very well-suited to describe the non-linear atomic response and to reveal the influence of electron-correlation effects.
description: 14 pages, 10 figures
Microwave-Induced Oscillations in the Magnetocapacitance: Direct Evidence for Non-equilibrium Occupation of Electronic States
Creators: name: Dorozhkin, S. I.
name: Kapustin, A. A.
name: Umansky, V.
name: von Klitzing, K.
name: Smet, J. H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: In a two-dimensional electron system, microwave radiation may induce giant resistance oscillations. Their origin has been debated controversially and numerous mechanisms based on very different physical phenomena have been invoked. However none of them have been unambiguously experimentally identified, since they produce similar effects in transport studies. The capacitance of a two-subband system is sensitive to a redistribution of electrons over energy states, since it entails a shift of the electron charge perpendicular to the plane. In such a system microwave induced magnetocapacitance oscillations have been observed. They can only be accounted for by an electron distribution function oscillating with energy due to Landau quantization, one of the quantum mechanisms proposed for the resistance oscillations.
description: submitted to Phys.Rev.Lett., corresponding author S. I. Dorozhkin
Proper Motion of the Draco Dwarf Galaxy from Subaru Suprime-Cam Data
Creators: name: Casetti-Dinescu, Dana I.
name: Girard, Terrence M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We have measured the absolute proper motion of the Draco dwarf spheroidal galaxy using Subaru Suprime-Cam images taken at three epochs, with time baselines of 4.4 and 7 years. The magnitude limit of the proper-motion study is i=25, thus allowing for thousands of background galaxies and Draco stars to be used to perform extensive astrometric tests and to derive the correction to an inertial reference frame. The derived proper motion is (mu_alpha, mu_delta) =(-0.284 +- 0.047, -0.289 +-0.041) mas/yr. This motion implies an orbit that takes Draco to a pericenter of $\sim 20$ kpc; a somewhat disruptive orbit suggesting that tides might account for the rising velocity-dispersion profile of Draco seen in line-of-sight velocity studies. The orbit is only marginally consistent with Draco's membership to the vast polar structure of Galactic satellites, in contrast to a recent HST proper-motion measurement that finds alignment very likely. Our study is a test case to demonstrate that deep imaging with mosaic cameras of appropriate resolution can be used for high-accuracy, ground-based proper-motion measurement. As a useful by-product of the study, we also identify two faint brown-dwarf candidates in the foreground field.
description: accepted for publication in MNRAS
Detecting dimensional crossover and finite Hilbert space through entanglement entropies
Creators: name: Garagiola, Mariano
name: Cuestas, Eloisa
name: Pont, Federico M.
name: Serra, Pablo
name: Osenda, Omar
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The information content of the two-particle one- and two-dimensional Calogero model is studied using the von Neumann and Rényi entropies. The one-dimensional model is shown to have non-monotonic entropies with finite values in the large interaction strength limit. On the other hand, the von Neumann entropy of the two-dimensional model with isotropic confinement is a monotone increasing function of the interaction strength which diverges logarithmically. By considering an anisotropic confinement in the two-dimensional case we show that the one-dimensional behavior is eventually reached when the anisotropy increases. The crossover from two to one dimensions is demonstrated using the harmonic approximation and it is shown that the von Neumann divergence only occurs in the isotropic case. The Rényi entropies are used to highlight the structure of the model spectrum. In particular, it is shown that these entropies have a non-monotonic and non-analytical behavior in the neighborhood of the interaction strength parameter values where the Hilbert space and, consequently, the spectrum of the reduced density matrix are both finite.
description: in press, Physical Review A
Random walks and branching processes in correlated Gaussian environment
Creators: name: Aurzada, Frank
name: Devulder, Alexis
name: Guillotin-Plantard, Nadine
name: Pène, Françoise
Publisher: name: arXiv
Year: 2016
Subjects: subject: Probability (math.PR)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 60G50, 60G22, 60G10, 60G15

description: We study persistence probabilities for random walks in correlated Gaussian random environment first studied by Oshanin, Rosso and Schehr. From the persistence results, we can deduce properties of critical branching processes with offspring sizes geometrically distributed with correlated random parameters. More precisely, we obtain estimates on the tail distribution of its total population size, of its maximum population, and of its extinction time.
On the structure of Bethe vectors
Creators: name: Fuksa, J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: The structure of Bethe vectors for generalised models associated with the XXX- and XXZ-type R-matrix is investigated. The Bethe vectors in terms of two--component and multi--component models are described. Consequently, their structure in terms of local variables and operators is provided. This, as a consequence, proves the equivalence of coordinate and algebraic Bethe ansatzes for the Heisenberg XXX and XXZ spin chains.
description: 13 pages
Construction of two-bubble solutions for the energy-critical NLS
Creators: name: Jendrej, Jacek
Publisher: name: arXiv
Year: 2016
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We construct pure two-bubbles for the energy-critical focusing nonlinear Schrödinger equation in space dimension $N \geq 7$. The constructed solution is global in (at least) one time direction and approaches a superposition of two stationary states both centered at the origin, with the ratio of their length scales converging to $0$. One of the bubbles develops at scale $1$, whereas the length scale of the other converges to $0$ at rate $|t|^{-\frac{2}{N-6}}$. The phases of the two bubbles form the right angle.
description: 33 pages
Maximizing Investment Value of Small-Scale PV in a Smart Grid Environment
Creators: name: Every, Jeremy
name: Li, Li
name: Guo, Youguang G.
name: Dorrell, David G.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optimization and Control (math.OC)
subject: Artificial Intelligence (cs.AI)
subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Determining the optimal size and orientation of small-scale residential based PV arrays will become increasingly complex in the future smart grid environment with the introduction of smart meters and dynamic tariffs. However consumers can leverage the availability of smart meter data to conduct a more detailed exploration of PV investment options for their particular circumstances. In this paper, an optimization method for PV orientation and sizing is proposed whereby maximizing the PV investment value is set as the defining objective. Solar insolation and PV array models are described to form the basis of the PV array optimization strategy. A constrained particle swarm optimization algorithm is selected due to its strong performance in non-linear applications. The optimization algorithm is applied to real-world metered data to quantify the possible investment value of a PV installation under different energy retailers and tariff structures. The arrangement with the highest value is determined to enable prospective small-scale PV investors to select the most cost-effective system.
description: To appear the proceedings of the 5th International Conference for Renewable Energy Research and Applications (ICRERA2016), Birmingham, United Kingdom. 6 pages. 3 figures
Spin-orbit scattering in superconducting nanoparticles
Creators: name: Alhassid, Y.
name: Nesterov, K. N.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We review interaction effects in chaotic metallic nanoparticles. Their single-particle Hamiltonian is described by the proper random-matrix ensemble while the dominant interaction terms are invariants under a change of the single-particle basis. In the absence of spin-orbit scattering, the non-trivial invariants consist of a pairing interaction, which leads to superconductivity in the bulk, and a ferromagnetic exchange interaction. Spin-orbit scattering breaks spin-rotation invariance and when it is sufficiently strong, the only dominant nontrivial interaction is the pairing interaction. We discuss how the magnetic response of discrete energy levels of the nanoparticle (which can be measured in single-electron tunneling spectroscopy experiments) is affected by such pairing correlations and how it can provide a signature of pairing correlations. We also consider the spin susceptibility of the nanoparticle and discuss how spin-orbit scattering changes the signatures of pairing correlations in this observable.
description: 10 pages, 6 figures, submitted for a special volume of Fortschritte der Physik (Progress of Physics), dedicated to the conference on Frontiers of Quantum and Mesoscopic Thermodynamics (FQMT15)
Interaction-induced insulating state in thick multilayer graphene
Creators: name: Nam, Youngwoo
name: Ki, Dong-Keun
name: Koshino, Mikito
name: McCann, Edward
name: Morpurgo, Alberto F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Close to charge neutrality, the low-energy properties of high-quality suspended devices based on atomically thin graphene layers are determined by electron-electron interactions. Bernal-stacked layers, in particular, have shown a remarkable even-odd effect with mono- and tri-layers remaining gapless conductors, and bi- and tetra-layers becoming gapped insulators. These observations $-$at odds with the established notion that (Bernal) trilayers and thicker multilayers are semi-metals$-$ have resulted in the proposal of a physical scenario leading to a surprising prediction, namely that even-layered graphene multilayers remain insulating irrespective of their thickness. Here, we present data from two devices that conform ideally to this hypothesis, exhibiting the behavior expected for Bernal-stacked hexa and octalayer graphene. Despite their large thickness, these multilayers are insulating for carrier density |n|<2-3x10$^{10}$cm$^{-2}$, possess an energy gap of approximately 1.5 meV at charge neutrality (in virtually perfect agreement with what is observed in bi and tetra layer graphene) and exhibit the expected integer quantum Hall effect. These findings indicate the soundness of our basic insights on the effect of electron interactions in Bernal graphene multilayers, show that graphene multilayers exhibit unusual and interesting physics that remains to be understood, and pose ever more pressing questions as to the microscopic mechanisms behind the semimetallic behavior of bulk graphite.
description: 22 pages, 6 figures, To appear in 2D Materials
Intersection patterns of finite sets and of convex sets
Creators: name: Frick, Florian
Publisher: name: arXiv
Year: 2016
Subjects: subject: Combinatorics (math.CO)
subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 05C15, 52A35

description: The main result is a common generalization of results on lower bounds for the chromatic number of r-uniform hypergraphs and some of the major theorems in Tverberg-type theory, which is concerned with the intersection pattern of faces in a simplicial complex when continuously mapped to Euclidean space. As an application we get a simple proof of a generalization of a result of Kriz for certain parameters. This specializes to a short and simple proof of Kneser's conjecture. Moreover, combining this result with recent work of Mabillard and Wagner we show that the existence of certain equivariant maps yields lower bounds for chromatic numbers. We obtain an essentially elementary proof of the result of Schrijver on the chromatic number of stable Kneser graphs. In fact, we show that every neighborly even-dimensional polytope yields a small induced subgraph of the Kneser graph of the same chromatic number. We furthermore use this geometric viewpoint to give tight lower bounds for the chromatic number of certain small subhypergraphs of Kneser hypergraphs.
description: 13 pages
Deep Retinal Image Understanding
Creators: name: Maninis, Kevis-Kokitsi
name: Pont-Tuset, Jordi
name: Arbeláez, Pablo
name: Van Gool, Luc
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: This paper presents Deep Retinal Image Understanding (DRIU), a unified framework of retinal image analysis that provides both retinal vessel and optic disc segmentation. We make use of deep Convolutional Neural Networks (CNNs), which have proven revolutionary in other fields of computer vision such as object detection and image classification, and we bring their power to the study of eye fundus images. DRIU uses a base network architecture on which two set of specialized layers are trained to solve both the retinal vessel and optic disc segmentation. We present experimental validation, both qualitative and quantitative, in four public datasets for these tasks. In all of them, DRIU presents super-human performance, that is, it shows results more consistent with a gold standard than a second human annotator used as control.
description: MICCAI 2016 Camera Ready
Hourglass dispersion and resonance of magnetic excitations in the superconducting state of the single-layer cuprate HgBa2CuO4+δ near optimal doping
Creators: name: Chan, M. K.
name: Tang, Y.
name: Dorow, C. J.
name: Jeong, J.
name: Mangin-Thro, L.
name: Veit, M. J.
name: Ge, Y.
name: Abernathy, D. L.
name: Sidis, Y.
name: Bourges, P.
name: Greven, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We use neutron scattering to study magnetic excitations near the antiferromagnetic wave vector in the underdoped single-layer cuprate HgBa2CuO4+δ (superconducting transition temperature Tc ~ 88 K, pseudogap temperature T* ~ 220 K). The response is distinctly enhanced below T* and exhibits a Y-shaped dispersion in the pseudogap state, whereas the superconducting state features an X-shaped (hourglass) dispersion and a further resonance-like enhancement. A large spin gap of about 40 meV is observed in both states. This phenomenology is reminiscent of that exhibited by bilayer cuprates. The resonance spectral weight, irrespective of doping and compound, scales linearly with the putative binding energy of a spin-exciton described by an itinerant-spin formalism.
description: 6 pages, 3 figures
Joint multifractal analysis based on wavelet leaders
Creators: name: Jiang, Zhi-Qiang
name: Yang, Yan-Hong
name: Wang, Gang-Jin
name: Zhou, Wei-Xing
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Finance (q-fin.ST)
subject: FOS: Economics and business

description: Mutually interacting components form complex systems and the outputs of these components are usually long-range cross-correlated. Using wavelet leaders, we propose a method of characterizing the joint multifractal nature of these long-range cross correlations, a method we call joint multifractal analysis based on wavelet leaders (MF-X-WL). We test the validity of the MF-X-WL method by performing extensive numerical experiments on the dual binomial measures with multifractal cross correlations and the bivariate fractional Brownian motions (bFBMs) with monofractal cross correlations. Both experiments indicate that MF-X-WL is capable to detect the cross correlations in synthetic data with acceptable estimating errors. We also apply the MF-X-WL method to the pairs of series from financial markets (returns and volatilities) and online worlds (online numbers of different genders and different societies) and find an intriguing joint multifractal behavior.
description: 11 pages and 5 figures. arXiv admin note: text overlap with arXiv:1610.09519
Bottomonium-like states: physics case for energy scan above the $B\bar{B}$ threshold at Belle-II
Creators: name: Bondar, A. E.
name: Mizuk, R. V.
name: Voloshin, M. B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The Belle-II experiment is expected to collect large data samples at the $Υ(4S)$ and $Υ(5S)$ resonances to study primarily $B$ and $B_s$ mesons. We discuss what other data above the $B\bar{B}$ threshold are of interest. We propose to perform a high-statistics energy scan from the $B\bar{B}$ threshold up to the highest possible energy, and to collect data at the $Υ(6S)$ and at higher mass states if they are found in the scan. We emphasize the interest in increasing the maximal energy from 11.24\,GeV to 11.5 - 12\,GeV in the future. These data are needed for investigation of bottomonium and bottomonium-like states.
description: 11 pages, 2 figures
Cholera forecast for Dhaka, Bangladesh, with the 2016 El Niño
Creators: name: Martinez, Pamela P.
name: Reiner, Robert C.
name: Roy, Manojit
name: Cash, Benjamin A.
name: Yunus, Md.
name: Faruque, A. S. G.
name: Huq, Sayeeda
name: King, Aaron A.
name: Pascual, Mercedes
Publisher: name: arXiv
Year: 2016
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: A substantial body of work supports a teleconnection between the El Niño Southern Oscillation (ENSO) and cholera incidence in Bangladesh. In particular, high positive anomalies during the winter (Dec-Feb) in Sea Surface Temperatures (SST) in the Tropical Pacific have been shown to exacerbate the seasonal outbreak of cholera following the monsoons from Aug to Nov, and climate studies have indicated a role of regional precipitation over Bangladesh in mediating this long-distance effect. Thus, the current strong El Niño has the potential to significantly increase cholera risk this year in Dhaka, Bangladesh, where the last five years have experienced low seasons of the disease. To examine this possibility and produce a forecast for the city, we considered two models for the transmission dynamics of cholera: a statistical model previously developed for the disease in this region, and a process-based model presented here that includes the effect of SST anomalies in the force of infection and is fitted to extensive cholera surveillance record between 1995 and 2010. Prediction accuracy was evaluated with 'out-of-fit' data from the same surveillance efforts, by comparing the total number of cholera cases observed for the season to those predicted by model simulations 8 to 12 months ahead, starting in January each year. Encouraged by accurate forecasts for the low risk of cholera for this period, we then generated a prediction for this coming season. An increase above the third quantile in cholera cases is expected for the period of Aug - Dec 2016 with 92% and 87% probability respectively for the two models. This alert warrants the preparedness of the public health system. We discuss the possible limitations of our approach, including variations in the impact of El Niño events, and the importance of this large, warm event for further informing an early-warning system for cholera in Dhaka
Properties of Supersonic Evershed Downflows
Creators: name: Pozuelo, Sara Esteban
name: Rubio, Luis R. Bellot
name: Rodriguez, Jaime de la Cruz
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We study supersonic Evershed downflows in a sunspot penumbra by means of high spatial resolution spectropolarimetric data acquired in the Fe I 617.3 nm line with the CRISP instrument at the Swedish 1-m Solar Telescope. Physical observables, such as Dopplergrams calculated from line bisectors and Stokes V zero-crossing wavelengths, and Stokes V maps in the far red wing, are used to find regions where supersonic Evershed downflows may exist. We retrieve the LOS velocity and the magnetic field vector in these regions using two-component inversions of the observed Stokes profiles with the help of the SIR code. We follow these regions during their lifetime to study their temporal behavior. Finally, we carry out a statistical analysis of the detected supersonic downflows to characterize their physical properties. Supersonic downflows are contained in compact patches moving outward, which are located in the mid and outer penumbra. They are observed as bright, roundish structures at the outer end of penumbral filaments that resemble penumbral grains. The patches may undergo fragmentations and mergings during their lifetime, even some of them are recurrents. Supersonic downflows are associated with strong and rather vertical magnetic fields with a reversed polarity compared to that of the sunspot. Our results suggest that downflows returning back to the solar surface with supersonic velocities are abruptly stopped in dense deep layers and produce a shock. Consequently, this shock enhances the temperature and is detected as a bright grain in the continuum filtergrams, which could explain the existence of outward moving grains in the mid and outer penumbra.
description: 15 pages, 16 figures. Accepted for publication in ApJ. Movies are available at http://dubshen.astro.su.se/~sara
Expansion of the spectrum in the weak disorder regime for random operators in continuum space
Creators: name: Borisov, Denis
name: Hoecker-Escuti, Francisco
name: Veselic, Ivan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: Probability (math.PR)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We study the spectrum of random ergodic Schroedinger-type operators in the weak disorder regime. We give upper and lower bounds on how much the spectrum expands at its bottom for very general perturbations. The background operator is assumed to be a periodic elliptic differential operator on R^d, not necessarily of second order.
Cordel literature and health education: a scoping review protocol
Creators: name: Costa, André Albuquerque Meneses
name: Sthefane Gomes Feitosa
name: De Oliveira, Denis Francisco Gonçalves
Publisher: name: Open Science Framework
Year: 2023
Subjects: subject: Education
subject: Arts and Humanities
subject: Medicine and Health Sciences
subject: health education
subject: scoping review
subject: Cordel literature

description: This review aims to answer the question: Has Cordel Literature been used in health education?
Direct Detection of sub-GeV Dark Matter with Scintillating Targets
Creators: name: Derenzo, Stephen
name: Essig, Rouven
name: Massari, Andrea
name: Soto, Adrían
name: Yu, Tien-Tien
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We describe a novel search for MeV-to-GeV-mass dark matter, in which the dark matter scatters off electrons in a scintillating target. The excitation and subsequent de-excitation of the electron produces one or more photons, which could be detected with an array of cryogenic low-noise photodetectors, such as transition edge sensors (TES) or microwave kinetic inductance devices (MKID). Scintillators may have distinct advantages over other experiments searching for a low ionization signal from sub-GeV DM. First, the detection of one or a few photons may be technologically easier. Second, since no electric field is required to detect the photons, there may be far fewer dark counts mimicking a DM signal. We discuss various target choices, but focus on calculating the expected dark matter-electron scattering rates in three scintillating crystals, sodium iodide (NaI), cesium iodide (CsI), and gallium arsenide (GaAs). Among these, GaAs has the lowest band gap (1.52 eV) compared to NaI (5.9 eV) or CsI (6.4 eV), allowing it to probe dark matter masses possibly as low as ~0.5 MeV, compared to ~1.5 MeV with NaI or CsI. We compare these scattering rates with those expected in silicon (Si) and germanium (Ge). The proposed experimental concept presents an important complementary path to existing efforts, and its potential advantages may make it the most sensitive direct-detection probe of DM down to MeV masses.
description: 5 pages + 8 pages of supplementary materials & references, 5 figures, 3 tables
Stress-induced magnetic domain selection reveals a conical ground state for the multiferroic phase of Mn2GeO4
Creators: name: White, J. S.
name: Honda, T.
name: Sibille, R.
name: Gauthier, N.
name: Dmitriev, V.
name: Strässle, Th.
name: Niedermayer, Ch.
name: Kimura, T.
name: Kenzelmann, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: At ambient pressure (P) and below 5.5 K, olivine-type Mn2GeO4 hosts a multiferroic (MF) phase where a multicomponent, i.e., multi-k magnetic order generates spontaneous ferromagnetism and ferroelectricity (FE) along the c axis. Under high P the FE disappears above 6 GPa, yet the P evolution of the magnetic structure remained unclear based on available data. Here we report high P single crystal neutron diffraction experiments in theMF phase at T = 4.5 K.We observe clearly that the incommensurate spiral component of the magnetic order responsible for FE varies little with P up to 5.1 GPa. With support from high P synchrotron x-ray diffraction measurements at room temperature (T), the P driven suppression of FE is proposed to occur as a consequence of a crystal structure transition away from the olivine structure. In addition, in the low T neutron scattering experiments an emergent nonhydrostatic P component, i.e., a uniaxial stress, leads to the selection of certain multi-k domains. We use this observation to deduce a double-k conical magnetic structure for the ambient P ground state, this being a key ingredient for a model description of the MF phase.
Cooperon condensation and intra-valley pairing states in honeycomb Dirac systems
Creators: name: Tsuchiya, Shunji
name: Goryo, Jun
name: Arahata, Emiko
name: Sigrist, Manfred
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Motivated by recent developments in the experimental study of superconducting graphene and transition metal dichalcogenides, we investigate superconductivity of the Kane-Mele (KM) model with short-range attractive interactions on the two-dimensional honeycomb lattice. We show that intra-valley spin-triplet pairing arises from nearest-neighbor (NN) attractive interaction and the intrinsic spin-orbit coupling. We demonstrate this in two independent approaches: We study superconducting instability driven by condensation of Cooperons, which are in-gap bound states of two conduction electrons, within the $T$-matrix approximation and also study the superconducting ground state within the mean-field theory. We find that Cooperons with antiparallel spins condense at the $K$ and $K'$ points. This leads to the emergence of an intra-valley spin-triplet pairing state belonging to the irreducible representation A$_1$ of the point group $C_{6v}$. The fact that this pairing state has opposite chirality for $K$ and $K'$ identifies this state as a "helical" valley-triplet state, the valley-analog to the $^3$He-B phase in two dimension. Because of the finite center of mass momentum of Cooper pairs, the pair amplitude in NN bonds exhibits spatial modulation on the length scale of lattice constant, such that this pairing state may be viewed as a pair-density wave state. We find that the pair amplitude spontaneously breaks the translational symmetry and exhibits a $p$-Kekulé pattern. We also discuss the selection rule for pairing states focusing the characteristic band structure of the KM model and the Berry phase effects to the emergence of the intra-valley pairing state.
description: 14 pages, 12 figures, 1 table
Optimizing phonon scattering by nanoprecipitates in lead chalcogenides
Creators: name: Yang, Xiaolong
name: Carrete, Jesús
name: Wang, Zhao
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We calculate the thermal conductivity of PbTe and PbS with seven different types of nanoprecipitates using an ab-initio-based Boltzmann transport approach. We find that precipitates with realistic size distributions can reduce the thermal conductivity well below the predictions of theoretical models assuming a single precipitate size.We explore the question of how to tune this distribution to reduce the thermal conductivity even further. The predicted minimum value is strongly correlated with the phonon spectrum of the host material and with the mass density difference between the host and the inclusions.
Systematic Magnus-based approach for suppressing leakage and non-adiabatic errors in quantum dynamics
Creators: name: Ribeiro, Hugo
name: Baksic, Alexandre
name: Clerk, Aashish A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present a systematic, perturbative method for correcting quantum gates to suppress errors that take the target system out of a chosen subspace. It addresses the generic problem of non-adiabatic errors in adiabatic evolution and state preparation, as well as general leakage errors due to spurious couplings to undesirable states. The method is based on the Magnus expansion: by correcting control pulses, we modify the Magnus expansion of an initially-given, imperfect unitary in such a way that the desired evolution is obtained. Applications to adiabatic quantum state transfer, superconducting qubits and generalized Landau-Zener problems are discussed.
description: 24 pages, 10 figures, 1 table
Sub-kpc ALMA imaging of compact star-forming galaxies at z~2.5: revealing the formation of dense galactic cores in the progenitors of compact quiescent galaxies
Creators: name: Barro, G.
name: Kriek, M.
name: Pérez-González, P. G.
name: Trump, J. R.
name: Koo, D. C.
name: Faber, S. M.
name: Dekel, A.
name: Primack, J. R.
name: Guo, Y.
name: Kocevski, D. D.
name: Muñoz-Mateos, J. C.
name: Rujoparkarn, W.
name: Sheth, K.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present spatially-resolved Atacama Large Millimeter/sub-millimeter Array (ALMA) 870 $μ$m dust continuum maps of six massive, compact, dusty star-forming galaxies (SFGs) at $z\sim2.5$. These galaxies are selected for their small rest-frame optical sizes ($r_{\rm e, F160W}\sim1.6$ kpc) and high stellar-mass densities that suggest that they are direct progenitors of compact quiescent galaxies at $z\sim2$. The deep observations yield high far-infrared (FIR) luminosities of L$_{\rm IR}=10^{12.3-12.8}$ L$_{\odot}$ and star formation rates (SFRs) of SFR$=200-700$ M$_{\odot}$yr$^{-1}$, consistent with those of typical star-forming "main sequence" galaxies. The high-spatial resolution (FWHM$\sim$0.12"-0.18") ALMA and HST photometry are combined to construct deconvolved, mean radial profiles of their stellar mass and (UV+IR) SFR. We find that the dusty, nuclear IR-SFR overwhelmingly dominates the bolometric SFR up to $r\sim5$ kpc, by a factor of over 100$\times$ from the unobscured UV-SFR. Furthermore, the effective radius of the mean SFR profile ($r_{\rm e, SFR}\sim1$ kpc) is $\sim$30% smaller than that of the stellar mass profile. The implied structural evolution, if such nuclear starburst last for the estimated gas depletion time of $Δt=\pm100$ Myr, is a 4$\times$ increase of the stellar mass density within the central 1 kpc and a 1.6$\times$ decrease of the half-mass radius. This structural evolution fully supports dissipation-driven, formation scenarios in which strong nuclear starbursts transform larger, star-forming progenitors into compact quiescent galaxies.
description: Accepted to ApJ Letters
Successful Entrapment of Carbon Dots within Flexible Free-Standing Transparent Mesoporous Organic-Inorganic Silica Hybrid Films for Photonic Applications
Creators: name: Vassilakopoulou, Anastasia
name: Georgakilas, Vasilios
name: Vainos, Nikolaos
name: Koutselas, Ioannis
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Other Condensed Matter (cond-mat.other)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The effective entrapment of Carbon dots (CDs) into a polymer-silica hybrid matrix, formed as free standing transparent flexible films, is presented. CDs of 3 nm mean size with strong photoluminescence are embedded into a silica matrix during the sol-gel procedure, using tetraethylorthosilicate and F127 triblock copolymer as the structure directing agent under acidic conditions. The final hybrid nanostructure forms free standing transparent films that show high flexibility and long term stable CDs luminescence indicating the protective character of the hybrid matrix. It is crucial that the photoluminescence of the hybrid's CDs is not seriously affected after thermal treatment at 550C for 30min. Moreover, the herein reported hybrid is demonstrated to be suitable for the fabrication of advanced photonic structures using soft lithography process due to its low shrinkage and distortion upon drying.
description: 24 pages, 9 figures
Entropic properties of $D$-dimensional Rydberg systems
Creators: name: Toranzo, I. V.
name: Puertas-Centeno, D.
name: Dehesa, J. S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The fundamental information-theoretic measures (the Rényi $R_{p}[ρ]$ and Tsallis $T_{p}[ρ]$ entropies, $p>0$) of the highly-excited (Rydberg) quantum states of the $D$-dimensional ($D>1$) hydrogenic systems, which include the Shannon entropy ($p \to 1$) and the disequilibrium ($p = 2$), are analytically determined by use of the strong asymptotics of the Laguerre orthogonal polynomials which control the wavefunctions of these states. We first realize that these quantities are derived from the entropic moments of the quantum-mechanical probability $ρ(\vec{r})$ densities associated to the Rydberg hydrogenic wavefunctions $Ψ_{n,l,\{μ\}}(\vec{r})$, which are closely connected to the $\mathfrak{L}_{p}$-norms of the associated Laguerre polynomials. Then, we determine the ($n\to\infty$)-asymptotics of these norms in terms of the basic parameters of our system (the dimensionality $D$, the nuclear charge and the hyperquantum numbers $(n,l,\{μ\}$) of the state) by use of recent techniques of approximation theory. Finally, these three entropic quantities are analytically and numerically discussed in terms of the basic parameters of the system for various particular states.
Asymptotic analysis for fiber drawing processes
Creators: name: Hanevy, Niall
name: O'KIELY, DOIREANN
Publisher: name: University of Limerick
Year: 2023
Subjects: Mathematical sciences

description: In fiber drawing, axial tension is applied to long, thin viscous threads to increase their length and consequently reduce their cross-sectional area. This process is used to manufacture rods and threads of glass and polymer such as optical fibers and filaments for textiles. Drawing is described mathematically using the Trouton model for extensional flow in a long, narrow cylinder. This leading-order description gives simple expressions for fiber radius and one-dimensional axial velocity in the long, slender limit. In this paper we determine the next-order corrections, showing that they can be an order of magnitude larger than previously assumed.
A Hybrid Algorithm of Fast Invariant Imbedding and Doubling-Adding Methods for Efficient Multiple Scattering Calculations
Creators: name: Kawabata, Kiyoshi
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: An efficient hybrid numerical method for multiple scattering calculations is proposed. We use the well established doubling--adding method to find the reflection function of the lowermost homogeneous slab comprising the atmosphere of our interest. This reflection function provides the initial value for the fast invariant imbedding method of Sato et al., (1977), with which layers are added until the final reflection function of the entire atmosphere is obtained. The execution speed of this hybrid method is no slower than one half of that of the doubling-adding method, probably the fastest algorithm available, even in the most unsuitable cases for the fast invariant imbedding method. The efficiency of the proposed method increases rapidly with the number of atmospheric slabs and the optical thickness of each slab. For some cases, its execution speed is approximately four times faster than the doubling--adding method. This work has been published in NAIS Journal (ISSN 1882-9392) Vol. 7, 5-16 (2012).
description: 12 pages, 6 figures, a commemorative paper dedicated to late Prof. Sueo Ueno
Decameter Stationary Type IV Burst in Imaging Observations on the 6th of September 2014
Creators: name: Koval, Artem
name: Stanislavsky, Aleksander
name: Chen, Yao
name: Feng, Shiwei
name: Konovalenko, Aleksander
name: Volvach, Yaroslav
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: First-of-its-kind radio imaging of decameter solar stationary type IV radio burst has been presented in this paper. On 6 September 2014 the observations of type IV burst radio emission have been carried out with the two-dimensional heliograph based on the Ukrainian T-shaped radio telescope (UTR-2) together with other telescope arrays. Starting at 09:55 UT and throughout 3 hours, the radio emission was kept within the observational session of UTR-2. The interesting observation covered the full evolution of this burst, "from birth to death". During the event lifetime, two C-class solar X-ray flares with peak times 11:29 UT and 12:24 UT took place. The time profile of this burst in radio has a double-humped shape that can be explained by injection of energetic electrons, accelerated by the two flares, into the burst source. According to the heliographic observations we suggest the burst source was confined within a high coronal loop, which was a part of a relatively slow coronal mass ejection. The latter has been developed for several hours before the onset of the event. Through analyzing about 1.5 million of heliograms (3700 temporal frames with 4096 images in each frame that correspond to the number of frequency channels) the radio burst source imaging shows a fascinating dynamical evolution. Both space-based (GOES, SDO, SOHO, STEREO) data and various ground-based instrumentation (ORFEES, NDA, RSTO, NRH) records have been used for this study.
Using Dust as Probes to Determine Sheath Extent and Structure
Creators: name: Douglass, Angela
name: Land, Victor
name: Qiao, Ke
name: Matthews, Lorin
name: Hyde, Truell
Publisher: name: arXiv
Year: 2016
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Two in-situ experimental methods are presented in which dust particles are used to determine the extent of the sheath and gain information about the time-averaged electric force profile within a RF plasma sheath. These methods are advantageous because they are not only simple and quick to carry out, but they also can be performed using standard dusty plasma experimental equipment. In the first method, dust particles are tracked as they fall through the plasma toward the lower electrode. These trajectories are then used to determine the electric force on the particle as a function of height as well as the extent of the sheath. In the second method, dust particle levitation height is measured across a wide range of RF voltages. Similarities were observed between the two experiments, but in order to understand the underlying physics behind these observations, the same conditions were replicated using a self-consistent fluid model. Through comparison of the fluid model and experimental results, it is shown that the particles exhibiting a levitation height that is independent of RF voltage indicate the sheath edge - the boundary between the quasineutral bulk plasma and the sheath. Therefore, both of these simple and inexpensive, yet effective, methods can be applied across a wide range of experimental parameters in any ground-based RF plasma chamber to gain useful information regarding the sheath, which is needed for interpretation of dusty plasma experiments.
description: 10 pages, 7 figures
Face-on accretion onto a protoplanetary disc
Creators: name: Wijnen, T. P. G.
name: Pols, O. R.
name: Pelupessy, F. I.
name: Zwart, S. Portegies
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Globular clusters (GCs) are known to harbor multiple stellar populations. To explain these observations Bastian et al. suggested a scenario in which a second population is formed by the accretion of enriched material onto the low-mass stars in the initial GC population. The idea is that the low-mass, pre-main sequence stars sweep up gas expelled by the massive stars of the same generation into their protoplanetary disc as they move through the GC core. We perform simulations with 2 different smoothed particle hydrodynamics codes to investigate if a low-mass star surrounded by a protoplanetary disc can accrete the amount of enriched material required in this scenario. We focus on the gas loading rate onto the disc and star as well as on the lifetime of the disc. We find that the gas loading rate is a factor of 2 smaller than the geometric rate, because the effective cross section of the disc is smaller than its surface area. The loading rate is consistent for both codes, irrespective of resolution. The disc gains mass in the high resolution runs, but loses angular momentum on a time scale of 10^4 yrs. Two effects determine the loss of (specific) angular momentum in our simulations: 1) continuous ram pressure stripping and 2) accretion of material with no azimuthal angular momentum. Our study and previous work suggest that the former, dominant process is mainly caused by numerical rather than physical effects, while the latter is not. The latter process causes the disc to become more compact, increasing the surface density profile at smaller radii. The disc size is determined in the first place by the ram pressure when the flow first hits the disc. Further evolution is governed by the decrease in the specific angular momentum of the disc. We conclude that the size and lifetime of the disc are probably not sufficient to accrete the amount of mass required in Bastian et al.'s scenario.
description: Accepted for publication in A&A, 15 pages, 5 figures, 4 tables