cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
MHz-rate semi-device-independent quantum random number generators based on unambiguous state discrimination
Creators: name: Brask, Jonatan Bohr
name: Martin, Anthony
name: Esposito, William
name: Houlmann, Raphael
name: Bowles, Joseph
name: Zbinden, Hugo
name: Brunner, Nicolas
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: An approach to quantum random number generation based on unambiguous quantum state discrimination (USD) is developed. We consider a prepare-and-measure protocol, where two non-orthogonal quantum states can be prepared, and a measurement device aims at unambiguously discriminating between them. Because the states are non-orthogonal, this necessarily leads to a minimal rate of inconclusive events whose occurrence must be genuinely random and which provide the randomness source that we exploit. Our protocol is semi-device-independent in the sense that the output entropy can be lower bounded based on experimental data and few general assumptions about the setup alone. It is also practically relevant, which we demonstrate by realising a simple optical implementation achieving rates of 16.5 Mbits/s. Combining ease of implementation, high rate, and real-time entropy estimation, our protocol represents a promising approach intermediate between fully device-independent protocols and commercial QRNGs.
description: 9 pages, 6 figures
Multipolar moments of weak lensing signal around clusters. Weighing filaments in harmonic space
Creators: name: Gouin, C.
name: Gavazzi, R.
name: Codis, S.
name: Pichon, C.
name: Peirani, S.
name: Dubois, Y.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Context. Upcoming weak lensing surveys such as Euclid will provide an unprecedented opportunity to quantify the geometry and topology of the cosmic web, in particular in the vicinity of lensing clusters. Aims. Understanding the connectivity of the cosmic web with unbiased mass tracers, such as weak lensing, is of prime importance to probe the underlying cosmology, seek dynamical signatures of dark matter, and quantify environmental effects on galaxy formation. Methods. Mock catalogues of galaxy clusters are extracted from the N-body PLUS simulation. For each cluster, the aperture multipolar moments of the convergence are calculated in two annuli (inside and outside the virial radius). By stacking their modulus, a statistical estimator is built to characterise the angular mass distribution around clusters. The moments are compared to predictions from perturbation theory and spherical collapse. Results. The main weakly chromatic excess of multipolar power on large scales is understood as arising from the contraction of the primordial cosmic web driven by the growing potential well of the cluster. Besides this boost, the quadrupole prevails in the cluster (ellipsoidal) core, while at the outskirts, harmonic distortions are spread on small angular modes, and trace the non-linear sharpening of the filamentary structures. Predictions for the signal amplitude as a function of the cluster-centric distance, mass, and redshift are presented. The prospects of measuring this signal are estimated for current and future lensing data sets. Conclusions. The Euclid mission should provide all the necessary information for studying the cosmic evolution of the connectivity of the cosmic web around lensing clusters using multipolar moments and probing unique signatures of, for example, baryons and warm dark matter.
description: Accepted for publication in A&A, 15 pages
Lorentz-symmetry test at Planck-scale suppression with nucleons in a spin-polarized $^{133}$Cs cold atom clock
Creators: name: Bars, H. Pihan-Le
name: Guerlin, C.
name: Lasseri, R. -D.
name: Ebran, J. -P.
name: Bailey, Q. G.
name: Bize, S.
name: Khan, E.
name: Wolf, P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Theory (nucl-th)
subject: Atomic Physics (physics.atom-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We introduce an improved model that links the frequency shift of the $^{133}\text{Cs}$ hyperfine Zeeman transitions $\vert F = 3, m_F> \longleftrightarrow \vert F = 4, m_F >$ to the Lorentz-violating Standard-Model Extension (SME) coefficients of the proton and neutron. The new model uses Lorentz transformations developed to second order in boost and additionally takes the nuclear structure into account, beyond the simple Schmidt model used previously in SME analyses, thereby providing access to both proton and neutron SME coefficients including the isotropic coefficient $\tilde{c}_{TT}$. Using this new model in a second analysis of the data delivered by the FO2 dual Cs/Rb fountain at Paris Observatory and previously analysed in arXiv:hep-ph/0601024v1, we improve by up to 12 orders of magnitude the present maximum sensitivities (see arXiv:0801.0287v9) on the $\tilde{c}_{Q}$, $\tilde{c}_{TJ}$ and $\tilde{c}_{TT}$ coefficients for the neutron and on the $\tilde{c}_{TT}$ coefficient for the proton, reaching respectively $10^{-20}$, $10^{-17}$, $10^{-13}$ and $10^{-15}$ GeV.
Destructive interference of direct and crossed Andreev pairing in a system of two nanowires coupled via an s-wave superconductor
Creators: name: Reeg, Christopher
name: Klinovaja, Jelena
name: Loss, Daniel
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We consider a system of two one-dimensional nanowires coupled via an $s$-wave superconducting strip, a geometry that is capable of supporting Kramers pairs of Majorana fermions. By performing an exact analytical diagonalization of a tunneling Hamiltonian describing the proximity effect (via a Bogoliubov transformation), we show that the excitation gap of the system varies periodically on the scale of the Fermi wavelength in the limit where the interwire separation is shorter than the superconducting coherence length. Comparing with the excitation gaps in similar geometries containing only direct pairing, where one wire is decoupled from the superconductor, or only crossed Andreev pairing, where each nanowire is considered as a spin-polarized edge of a quantum Hall state, we find that the gap is always reduced, by orders of magnitude in certain cases, when both types of pairing are present. Our analytical results are further supported by numerical calculations on a tight-binding lattice. Finally, we show that treating the proximity effect by integrating out the superconductor using the bulk Green's function does not reproduce the results of our exact diagonalization.
description: 5 pages, 3 figures + 17 pages, 5 figures supplemental material
A local weighted Axler-Zheng theorem in $\mathbb{C}^n$
Creators: name: Cuckovic, Zeljko
name: Sahutoglu, Sonmez
name: Zeytuncu, Yunus E.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Complex Variables (math.CV)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics

description: The well-known Axler-Zheng theorem characterizes compactness of finite sums of finite products of Toeplitz operators on the unit disk in terms of the Berezin transform of these operators. Subsequently this theorem was generalized to other domains and appeared in different forms, including domains in $\mathbb{C}^n$ on which the $\overline{\partial}$-Neumann operator $N$ is compact. In this work we remove the assumption on $N$, and we study weighted Bergman spaces on smooth bounded pseudoconvex domains. We prove a local version of the Axler-Zheng theorem characterizing compactness of Toeplitz operators in the algebra generated by symbols continuous up to the boundary in terms of the behavior of the Berezin transform at strongly pseudoconvex points. We employ a Forelli-Rudin type inflation method to handle the weights.
description: Minor editorial changes, to appear in Pacific J. Math
An analogue of big q-Jacobi polynomials in the algebra of symmetric functions
Creators: name: Olshanski, Grigori
Publisher: name: arXiv
Year: 2017
Subjects: subject: Combinatorics (math.CO)
subject: Classical Analysis and ODEs (math.CA)
subject: Probability (math.PR)
subject: Quantum Algebra (math.QA)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics

description: The main result of the paper is a construction of a five-parameter family of new bases in the algebra of symmetric functions. These bases are inhomogeneous and share many properties of systems of orthogonal polynomials on an interval of the real line. This means, in particular, that the algebra of symmetric functions is embedded into the algebra of continuous functions on a certain compact space Omega, and under this realization, our bases turn into orthogonal bases of weighted Hilbert spaces corresponding to certain probability measures on Omega. These measures are of independent interest --- they are an infinite-dimensional analogue of the multidimensional q-Beta distributions. Our construction uses the big q-Jacobi polynomials and an extension of the Knop-Okounkov-Sahi multivariate interpolation polynomials to the case of infinite number of variables.
description: v2: a number of typos fixed
Displaced Photon Signal from a Light Scalar in Minimal Left-Right Symmetric Model
Creators: name: Dev, P. S. Bhupal
name: Mohapatra, Rabindra N.
name: Zhang, Yongchao
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: We point out that in the minimal left-right realization of TeV scale seesaw for neutrino masses, the neutral scalar from the right-handed $SU(2)_R$ breaking sector could be much lighter than the right-handed scale. We discuss for the first time the constraints on this particle from low-energy flavor observables, find that the light scalar is necessarily long-lived. We show that it can be searched for at the LHC via displaced signals of a collimated photon jet, and can also be tested in current and future high-intensity experiments. In contrast to the unique diphoton signal (and associated jets) in the left-right case, a generic beyond Standard Model light scalar decays mostly to leptons or jets. Thus, the diphoton channel proposed here provides a new avenue to test the left-right framework and reveal the underlying neutrino mass generation mechanism.
description: 9 pages, 3 figures, 2 tables, minor changes, version to appear in PRD
Local analogues of high-redshift star-forming galaxies: integral field spectroscopy of green peas
Creators: name: Lofthouse, Emma K.
name: Houghton, Ryan C. W.
name: Kaviraj, Sugata
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We use integral field spectroscopy, from the SWIFT and Palm3K instruments, to perform a spatially-resolved spectroscopic analysis of four nearby highly star-forming `green pea' (GP) galaxies, that are likely analogues of star-forming systems at z~2.5-3. By studying emission-line maps in H$α$, [NII]$λλ$6548,6584 and [SII]$λ$$λ$6716,6731, we explore the kinematic morphology of these systems and constrain properties such as gas-phase metallicities, electron densities and gas-ionization mechanisms. Two of our GPs are rotationally-supported while the others are dispersion-dominated systems. The rotationally-supported galaxies both show evidence for recent or ongoing mergers. However, given that these systems have intact disks, these interactions are likely to have low mass ratios (i.e. minor mergers), suggesting that the minor-merger process may be partly responsible for the high SFRs seen in these GPs. Nevertheless, the fact that the other two GPs appear morphologically undisturbed suggests that mergers (including minor mergers) are not necessary for driving the high star formation rates in such galaxies. We show that the GPs are metal-poor systems (25-40 per cent of solar) and that the gas ionization is not driven by AGN in any of our systems, indicating that AGN activity is not co-eval with star formation in these starbursting galaxies.
description: 10 pages, 16 figures, published in MNRAS
Are LIGO's Black Holes Made From Smaller Black Holes?
Creators: name: Fishbach, Maya
name: Holz, Daniel E.
name: Farr, Ben
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: One proposed formation channel for stellar mass black holes (BHs) is through hierarchical mergers of smaller BHs. Repeated mergers between comparable mass BHs leave an imprint on the spin of the resulting BH, since the final BH spin is largely determined by the orbital angular momentum of the binary. We find that for stellar mass BHs forming hierarchically the distribution of spin magnitudes is universal, with a peak at $a \sim 0.7$ and little support below $a \sim 0.5$. We show that the spin distribution is robust against changes to the mass ratio of the merging binaries, the initial spin distribution of the first generation of BHs, and the number of merger generations. While we assume an isotropic distribution of initial spin directions, spins that are preferentially aligned or antialigned do not qualitatively change our results. We also consider a "cluster catastrophe" model for BH formation in which we allow for mergers of arbitrary mass ratios and show that this scenario predicts a unique spin distribution that is similar to the universal distribution derived for major majors. We explore the ability of spin measurements from ground-based gravitational-wave (GW) detectors to constrain hierarchical merger scenarios. We apply a hierarchical Bayesian mixture model to mock GW data and argue that the fraction of BHs that formed through hierarchical mergers will be constrained with $\mathcal{O}(100)$ LIGO binary black hole detections, while with $\mathcal{O}(10)$ detections we could falsify a model in which all component BHs form hierarchically.
description: Minor edits to match journal version
Energy Dissipation in Hamiltonian Chains of Rotators
Creators: name: Cuneo, Noé
name: Eckmann, Jean-Pierre
name: Wayne, C. Eugene
Publisher: name: arXiv
Year: 2017
Subjects: subject: Dynamical Systems (math.DS)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We discuss, in the context of energy flow in high-dimensional systems and Kolmogorov-Arnol'd-Moser (KAM) theory, the behavior of a chain of rotators (rotors) which is purely Hamiltonian, apart from dissipation at just one end. We derive bounds on the dissipation rate which become arbitrarily small in certain physical regimes, and we present numerical evidence that these bounds are sharp. We relate this to the decoupling of non-resonant terms as is known in KAM problems.
Management system for the SND experiments
Creators: name: Korol, A.
name: Pugachev, K.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Human-Computer Interaction (cs.HC)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: A new management system for the SND detector experiments (at VEPP-2000 collider in Novosibirsk) is developed. We describe here the interaction between a user and the SND databases. These databases contain experiment configuration, conditions and metadata. The new system is designed in client-server architecture. It has several logical layers corresponding to the users roles. A new template engine is created. A web application is implemented using Node.js framework. At the time the application provides: showing and editing configuration; showing experiment metadata and experiment conditions data index; showing SND log (prototype).
description: 6 pages, 3 figures; INSTR17 conference
"Non-cold" dark matter at small scales: a general approach
Creators: name: Murgia, Riccardo
name: Merle, Alexander
name: Viel, Matteo
name: Totzauer, Maximilian
name: Schneider, Aurel
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Structure formation at small cosmological scales provides an important frontier for dark matter (DM) research. Scenarios with small DM particle masses, large momenta or hidden interactions tend to suppress the gravitational clustering at small scales. The details of this suppression depend on the DM particle nature, allowing for a direct link between DM models and astrophysical observations. However, most of the astrophysical constraints obtained so far refer to a very specific shape of the power suppression, corresponding to thermal warm dark matter (WDM), i.e., candidates with a Fermi-Dirac or Bose-Einstein momentum distribution. In this work we introduce a new analytical fitting formula for the power spectrum, which is simple yet flexible enough to reproduce the clustering signal of large classes of non-thermal DM models, which are not at all adequately described by the oversimplified notion of WDM. We show that the formula is able to fully cover the parameter space of sterile neutrinos (whether resonantly produced or from particle decay), mixed cold and warm models, fuzzy dark matter, as well as other models suggested by effective theory of structure formation (ETHOS). Based on this fitting formula, we perform a large suite of N-body simulations and we extract important nonlinear statistics, such as the matter power spectrum and the halo mass function. Finally, we present first preliminary astrophysical constraints, based on linear theory, from both the number of Milky Way satellites and the Lyman-$α$ forest. This paper is a first step towards a general and comprehensive modeling of small-scale departures from the standard cold DM model.
description: 26 pages, 12 figures, 4 tables
Opening Session, Open Data and Open Knowledge Workshop, 2023
Creators: name: Group on Earth Observations
Publisher: name: GEO Knowledge Hub
Year: 2023

description: This Knowledge Resource corresponds to the Opening Session during Open Knowledge Workshop 2023, Geneva, Switzerland.
The 1st GEO Open Data Open Knowledge workshop (ODOK) was held at the WMO Building, Geneva (Switzerland), from 15th to 16th June 2023. The workshop was organized by the Data Working Group, GEOSS Platform Team, and GEO Knowledge Hub Team with the support of the GEO Secretariat and the GEO Community.
Being a workshop widely supported by the GEO community, in two days of the event, ODOK counted 17 sessions (Thematic and practical), totalizing 38 hours of content. To fill these sessions, 95 speakers from 76 different organizations from 5 continents participated .
With this large amount of available content, ODOK created the perfect atmosphere for sharing content and knowledge related to Open Data and Open Knowledge practices. As a result, ODOK had approximately 400 participants, 193 in person and nearly 200 online.
Presentations
Introduction

Presentation 1: Outlining objectives of the workshop (Yana Gevorgyan - GEO Secretariat Director)
Presentation 2: How open data enhances support to field operations (Thao Ton That Whelan - International Committee for the Red Cross)
Presentation 3: Benefit and Value of Open data and Open knowledge (Einar Bjorgo - UNOSAT)
Presentation 4: Special guest intervention (Slawosz Uznanski - ESA Astronaut)
Presentation 5: Indigenous Knowledge (Diana Mastracci - Indigenous Alliance)
What is Open Knowledge for GEO and the importance for Regional GEOs ?

Presentation 6: GEO Towards Open Knowledge (Marie-Francoise Voidrot - OGC)
Presentation 7: AOGEO (GU Xingfa - AOGEO)
Presentation 8: AMERIGEO (Angelica Gutierrez - AMERIGEO)
Presentation 9: EUROGEO (Jean Dusart - EUROGEO)
Presentation 10: AFRIGEO (Phoebe Oduor - AFRIGEO)
Statistical Analysis of Astrometric Errors for the Most Productive Asteroid Surveys
Creators: name: Vereš, Peter
name: Farnocchia, Davide
name: Chesley, Steven R.
name: Chamberlin, Alan B.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We performed a statistical analysis of the astrometric errors for the major asteroid surveys. We analyzed the astrometric residuals as a function of observation epoch, observed brightness and rate of motion, finding that astrometric errors are larger for faint observations and some stations improved their astrometric quality over time. Based on this statistical analysis we develop a new weighting scheme to be used when performing asteroid orbit determination. The proposed weights result in ephemeris predictions that can be conservative by a factor as large as 1.5. However, the new scheme is more robust with respect to outliers and better handles faint detections.
description: 25 pages, 11 figures, 5 tables
Constructing a neutron star in G2-QCD
Creators: name: Hajizadeh, Ouraman
name: Maas, Axel
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Lattice (hep-lat)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The inner structure of neutron stars is still an open question. To make progress and understand the qualitative impact of gauge interactions on the neutron star structure we study neutron stars in a modified version of QCD. In this modification the gauge group of QCD is replaced by the exceptional Lie group G$_2$, which has neutrons and is accessible at finite density in lattice calculations. Using an equation of state constructed from lattice calculations we determine the mass-radius-relation for a neutron star in this theory using the Tolman-Oppenheimer-Volkoff equation. The results exhibit an influence of the non-trivial interactions on the mass-radius relation. However, the masses of the quarks are found to have little influence. We also give density profiles and the phase structure inside the neutron star. If the results carry over to full QCD, much of the internal structure of neutron stars could already be inferred from a precise measurement of the mass-radius relation.
description: (23 pages, 32 figures), Improved presentation, version to appear in European Physical Journal A
A Low-Complexity Approach to Distributed Cooperative Caching with Geographic Constraints
Creators: name: Avrachenkov, Konstantin
name: Goseling, Jasper
name: Serbetci, Berksan
Publisher: name: arXiv
Year: 2017
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We consider caching in cellular networks in which each base station is equipped with a cache that can store a limited number of files. The popularity of the files is known and the goal is to place files in the caches such that the probability that a user at an arbitrary location in the plane will find the file that she requires in one of the covering caches is maximized. We develop distributed asynchronous algorithms for deciding which contents to store in which cache. Such cooperative algorithms require communication only between caches with overlapping coverage areas and can operate in asynchronous manner. The development of the algorithms is principally based on an observation that the problem can be viewed as a potential game. Our basic algorithm is derived from the best response dynamics. We demonstrate that the complexity of each best response step is independent of the number of files, linear in the cache capacity and linear in the maximum number of base stations that cover a certain area. Then, we show that the overall algorithm complexity for a discrete cache placement is polynomial in both network size and catalog size. In practical examples, the algorithm converges in just a few iterations. Also, in most cases of interest, the basic algorithm finds the best Nash equilibrium corresponding to the global optimum. We provide two extensions of our basic algorithm based on stochastic and deterministic simulated annealing which find the global optimum. Finally, we demonstrate the hit probability evolution on real and synthetic networks numerically and show that our distributed caching algorithm performs significantly better than storing the most popular content, probabilistic content placement policy and Multi-LRU caching policies.
description: 24 pages, 9 figures, presented at SIGMETRICS'17
The formation and coalescence sites of the first gravitational wave events
Creators: name: Schneider, Raffaella
name: Graziani, Luca
name: Marassi, Stefania
name: Spera, Mario
name: Mapelli, Michela
name: Alparone, Matteo
name: de Bennassuti, Matteo
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present a novel theoretical model to characterize the formation and coalescence sites of compact binaries in a cosmological context. This is based on the coupling between the binary population synthesis code SeBa with a simulation following the formation of a Milky Way-like halo in a well resolved cosmic volume of 4 cMpc, performed with the GAMESH pipeline. We have applied this technique to investigate when and where systems with properties similar to the recently observed LIGO/VIRGO events are more likely to form and where they are more likely to reside when they coalesce. We find that more than 70% of GW151226 and LVT151012-like systems form in galaxies with stellar mass M* > 10^8 Msun in the redshift range [0.06 - 3] and [0.14 - 11.3], respectively. All GW150914-like systems form in low-metallicity dwarfs with M* < 5 10^6 Msun at 2.4 < z < 4.2. Despite these initial differences, by the time they reach coalescence the observed events are most likely hosted by star forming galaxies with M* > 10^{10} Msun. Due to tidal stripping and radiative feedback, a non negligible fraction of GW150914-like candidates end-up in galaxies with properties similar to dwarf spheroidals and ultra-faint satellites.
description: 6 pages, 3 figures, accepted by MNRAS after minor changes to the original version
Walking the talk: investigating university-community partnerships through a critical service-learning program
Creators: name: Elamin, Madinah Janay
Publisher: name: No Publisher Supplied
Year: 2023

description: Service-learning experiences assist in developing students' knowledge, skillsets, and critical-thinking abilities in real-world settings. University faculty/staff often use service-learning programs to expose students to challenges and inequalities faced within the local community, particularly in neighboring urban areas. Students engage with the community with the aim of ameliorating issues such as inadequate education, understaffed/under-financed healthcare, and food insecurity. However, critics of traditional service-learning programs argue these initiatives benefit universities rather than community partners and often include white-centered and classist approaches to curriculum, reifying stereotypes, and discrimination rather than reducing it. Critical service-learning proponents argue that service-learning programs that are based on what community members identify as a need and that teach students to understand how inequity and power are central to dismantling structures of injustice and ,creating more authentic partnerships between universities and communities. However, much of the work in this area is theoretical, with few studies of what critical service learning looks like in action. In an effort to address this imbalance in the literature, this qualitative case study examined a service-learning program within a research university in Northeast State, and how this program enacted critical service-learning assumptions. Employing interviews, observations and document analysis, this study inquired into the meaning, purpose, and practices of the program from the viewpoint of faculty/staff, community partners, and students. It was found that the program embodies aspects of critical service-learning by using a funds of knowledge approach to ground its conceptualization, centering power and inequity through the delivery of program components, and by providing opportunities for multiple stakeholder engagement. This study offers concert suggestions for improving community engagement through service learning.
Dark Matter and Collider Studies in the Left-Right Symmetric Model with Vector-Like Leptons
Creators: name: Bahrami, Sahar
name: Frank, Mariana
name: Ghosh, Dilip Kumar
name: Ghosh, Nivedita
name: Saha, Ipsita
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In the context of a left-right symmetric model, we introduce one full generation of vectorlike lepton doublets (both left and right-handed) together with their mirror doublets. We show that the lightest vectorlike neutrino in the model is right-handed, and can serve as the dark matter candidate. We find that the relic density, as well as the direct and indirect DM detection bounds, are satisfied for a large range of the parameter space of the model. In accordance with the parameter space, we then explore the possibility of detecting signals of the model at both the LHC and the ILC, in the pair production of the associated vectorlike charged leptons which decay into final states including dark matter. A comprehensive analysis of signal and backgrounds shows that the signals at the ILC, especially with polarized beams are likely to be visible for light vectorlike leptons, even with low luminosity, rendering our model highly predictable and experimentally testable.
description: 43 pages, 13 captioned figures, 9 tables; comments added, references updated, typos are fixed, matches with journal version
Recovering the HII region size statistics from 21-cm tomography
Creators: name: Kakiichi, Koki
name: Majumdar, Suman
name: Mellema, Garrelt
name: Ciardi, Benedetta
name: Dixon, Keri L.
name: Iliev, Ilian T.
name: Jelic, Vibor
name: Koopmans, Leon V. E.
name: Zaroubi, Saleem
name: Busch, Philipp
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We introduce a novel technique, called "granulometry", to characterize and recover the mean size and the size distribution of HII regions from 21-cm tomography. The technique is easy to implement, but places the previously not very well defined concept of morphology on a firm mathematical foundation. The size distribution of the cold spots in 21-cm tomography can be used as a direct tracer of the underlying probability distribution of HII region sizes. We explore the capability of the method using large-scale reionization simulations and mock observational data cubes while considering capabilities of SKA1-low and a future extension to SKA2. We show that the technique allows the recovery of the HII region size distribution with a moderate signal-to-noise ratio from wide-field imaging ($\rm SNR\lesssim3$), for which the statistical uncertainty is sample variance dominated. We address the observational requirements on the angular resolution, the field-of-view, and the thermal noise limit for a successful measurement. To achieve a full scientific return from 21-cm tomography and to exploit a synergy with 21-cm power spectra, we suggest an observing strategy using wide-field imaging (several tens of square degrees) by an interferometric mosaicking/multi-beam observation with additional intermediate baselines (~2-4 km).
description: 19 pages, 19 figures, the version accepted in MNRAS
Made-to-measure modeling of observed galaxy dynamics
Creators: name: Bovy, Jo
name: Kawata, Daisuke
name: Hunt, Jason A. S.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Among dynamical modeling techniques, the made-to-measure (M2M) method for modeling steady-state systems is among the most flexible, allowing non-parametric distribution functions in complex gravitational potentials to be modeled efficiently using N-body particles. Here we propose and test various improvements to the standard M2M method for modeling observed data, illustrated using the simple setup of a one-dimensional harmonic oscillator. We demonstrate that nuisance parameters describing the modeled system's orientation with respect to the observer---e.g., an external galaxy's inclination or the Sun's position in the Milky Way---as well as the parameters of an external gravitational field can be optimized simultaneously with the particle weights. We develop a method for sampling from the high-dimensional uncertainty distribution of the particle weights. We combine this in a Gibbs sampler with samplers for the nuisance and potential parameters to explore the uncertainty distribution of the full set of parameters. We illustrate our M2M improvements by modeling the vertical density and kinematics of F-type stars in Gaia DR1. The novel M2M method proposed here allows full probabilistic modeling of steady-state dynamical systems, allowing uncertainties on the non-parametric distribution function and on nuisance parameters to be taken into account when constraining the dark and baryonic masses of stellar systems.
description: Code available at https://github.com/jobovy/simple-m2m
Electrically Induced, Non-Volatile, Metal Insulator Transition in a Ferroelectric Gated MoS$_2$ Transistor
Creators: name: Lu, Zhongyuan
name: Serrao, Claudy
name: Khan, Asif I.
name: Clarkson, James D.
name: Wong, Justin C.
name: Ramesh, Ramamoorthy
name: Salahuddin, Sayeef
Publisher: name: arXiv
Year: 2017
Subjects: subject: Applied Physics (physics.app-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We demonstrate an electrically induced, non-volatile, metal-insulator phase transition in a MoS$_2$ transistor. A single crystalline, epitaxially grown, PbZr$_{0.2}$Ti$_{0.8}$O$_3$ (PZT) was placed in the gate of a field effect transistor made of thin film MoS$_2$. When a gate voltage is applied to this ferroelectric gated transistor, a clear transition from insulator to metal and vice versa is observed. Importantly, when the gate voltage is turned off, the remnant polarization in the ferroelectric can keep the MoS$_2$ in its original phase, thereby providing a non-volatile state. Thus a metallic or insulating phase can be written, erased or retained simply by applying a gate voltage to the transistor.
Self-affine sets in analytic curves and algebraic surfaces
Creators: name: Feng, De-Jun
name: Käenmäki, Antti
Publisher: name: arXiv
Year: 2016
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics

description: We characterize analytic curves that contain non-trivial self-affine sets. We also prove that compact algebraic surfaces cannot contain non-trivial self-affine sets.
Preparing Greenberger-Horne-Zeilinger and $W$ states on a long-range Ising spin model by global controls
Creators: name: Chen, Jiahui
name: Zhou, Hui
name: Duan, Changkui
name: Peng, Xinhua
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Entanglement, a unique quantum resource with no classical counterpart, remains at the heart of quantum information. The Greenberger-Horne-Zeilinger (GHZ) and $W$ states are two inequivalent classes of multipartite entangled states which can not be transformed into each other by means of local operations and classic communication. In this paper, we present the methods to prepare the GHZ and $W$ states via global controls on a long-range Ising spin model. For the GHZ state, general solutions are analytically obtained for an arbitrary-size spin system, while for the $W$ state, we find a standard way to prepare the $W$ state that is analytically illustrated in three- and four-spin systems and numerically demonstrated for larger-size systems. The number of parameters required in the numerical search increases only linearly with the size of the system.
Direct Probe of Dark Energy through Gravitational Lensing Effect
Creators: name: He, Hong-Jian
name: Zhang, Zhen
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We show that gravitational lensing can provide a direct method to probe the nature of dark energy at astrophysical scales. For lensing system as an isolated astrophysical object, we derive the dark energy contribution to gravitational potential as a repulsive power-law term, containing a generic equation of state parameter $w$. We find that it generates $w$-dependent and position-dependent modification to the conventional light orbital equation of $w=-1$. With post-Newtonian approximation, we compute its direct effect for an isolated lensing system at astrophysical scales and find that the dark energy force can deflect the path of incident light rays. We demonstrate that the dark-energy-induced deflection angle $Δα_{DE}^{}\propto M^{(1+\frac{1}{3w})}$ (with $1+\frac{1}{3w}>0$), which increases with the lensing mass $M$ and consistently approaches zero in the limit $M \to 0$. This effect is distinctive because dark energy tends to diffuse the rays and generates concave lensing effect. This is in contrast to the conventional convex lensing effect caused by both visible and dark matter. Measuring such concave lensing effect can directly probe the existence and nature of dark energy. We estimate this effect and show that the current gravitational lensing experiments are sensitive to the direct probe of dark energy at astrophysical scales. For the special case $w=-1$, our independent study favors the previous works that the cosmological constant can affect light bending, although our prediction qualitatively and quantitatively differ from the literature, including our consistent realization of $Δα_{DE}\to 0$ (under $M \to 0$) at the leading order.
description: 30pp. JCAP final version. All conclusions un-changed. Refinements and references added. (This update is delayed due to author's traveling)
Non Volatile MoS$_{2}$ Field Effect Transistors Directly Gated By Single Crystalline Epitaxial Ferroelectric
Creators: name: Lu, Zhongyuan
name: Serrao, Claudy
name: Khan, Asif Islam
name: You, Long
name: Wong, Justin C.
name: Ye, Yu
name: Zhu, Hanyu
name: Zhang, Xiang
name: Salahuddin, Sayeef
Publisher: name: arXiv
Year: 2017
Subjects: subject: Applied Physics (physics.app-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We demonstrate non-volatile, n-type, back-gated, MoS$_{2}$ transistors, placed directly on an epitaxial grown, single crystalline, PbZr$_{0.2}$Ti$_{0.8}$O$_{3}$ (PZT) ferroelectric. The transistors show decent ON current (19 $μA/μ$m), high on-off ratio (10$^{7}$), and a subthreshold swing of (SS ~ 92 mV/dec) with a 100 nm thick PZT layer as the back gate oxide. Importantly, the ferroelectric polarization can directly control the channel charge, showing a clear anti-clockwise hysteresis. We have selfconsistently confirmed the switching of the ferroelectric and corresponding change in channel current from a direct time-dependent measurement. Our results demonstrate that it is possible to obtain transistor operation directly on polar surfaces and therefore it should be possible to integrate 2D electronics with single crystalline functional oxides.
Null-recurrence and transience of random difference equations in the contractive case
Creators: name: Alsmeyer, Gerold
name: Buraczewski, Dariusz
name: Iksanov, Alexander
Publisher: name: arXiv
Year: 2016
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: Given a sequence $(M_{k}, Q_{k})_{k\ge 1}$ of independent, identically distributed ran\-dom vectors with nonnegative components, we consider the recursive Markov chain $(X_{n})_{n\ge 0}$, defined by the random difference equation $X_{n}=M_{n}X_{n-1}+Q_{n}$ for $n\ge 1$, where $X_{0}$ is independent of $(M_{k}, Q_{k})_{k\ge 1}$. Criteria for the null-recurrence/transience are provided in the situation where $(X_{n})_{n\ge 0}$ is contractive in the sense that $M_{1}\cdot\ldots\cdot M_{n}\to 0$ a.s., yet occasional large values of the $Q_{n}$ overcompensate the contractive behavior so that positive recurrence fails to hold. We also investigate the attractor set of $(X_{n})_{n\ge 0}$ under the sole assumption that this chain is locally contractive and recurrent.
description: submitted for publication, 24 pages
Superconvergence of immersed finite volume methods for one-dimensional interface problems
Creators: name: Cao, Waixiang
name: Zhang, Xu
name: Zhang, Zhimin
name: Zou, Qingsong
Publisher: name: arXiv
Year: 2017
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: In this paper, we introduce a class of high order immersed finite volume methods (IFVM) for one-dimensional interface problems. We show the optimal convergence of IFVM in H1 and L2 norms. We also prove some superconvergence results of IFVM. To be more precise, the IFVM solution is superconvergent of order p+2 at the roots of generalized Lobatto polynomials, and the flux is superconvergent of order p+1 at generalized Gauss points on each element including the interface element. Furthermore, for diffusion interface problems, the convergence rates for IFVM solution at the mesh points and the flux at generalized Gaussian points can both be raised to 2p. These superconvergence results are consistent with those for the standard finite volume methods. Numerical examples are provided to confirm our theoretical analysis.
Reliable estimation of prediction uncertainty for physico-chemical property models
Creators: name: Proppe, Jonny
name: Reiher, Markus
Publisher: name: arXiv
Year: 2017
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: The predictions of parameteric property models and their uncertainties are sensitive to systematic errors such as inconsistent reference data, parametric model assumptions, or inadequate computational methods. Here, we discuss the calibration of property models in the light of bootstrapping, a sampling method akin to Bayesian inference that can be employed for identifying systematic errors and for reliable estimation of the prediction uncertainty. We apply bootstrapping to assess a linear property model linking the 57Fe Moessbauer isomer shift to the contact electron density at the iron nucleus for a diverse set of 44 molecular iron compounds. The contact electron density is calculated with twelve density functionals across Jacob's ladder (PWLDA, BP86, BLYP, PW91, PBE, M06-L, TPSS, B3LYP, B3PW91, PBE0, M06, TPSSh). We provide systematic-error diagnostics and reliable, locally resolved uncertainties for isomer-shift predictions. Pure and hybrid density functionals yield average prediction uncertainties of 0.06-0.08 mm/s and 0.04-0.05 mm/s, respectively, the latter being close to the average experimental uncertainty of 0.02 mm/s. Furthermore, we show that both model parameters and prediction uncertainty depend significantly on the composition and number of reference data points. Accordingly, we suggest that rankings of density functionals based on performance measures (e.g., the coefficient of correlation, r2, or the root-mean-square error, RMSE) should not be inferred from a single data set. This study presents the first statistically rigorous calibration analysis for theoretical Moessbauer spectroscopy, which is of general applicability for physico-chemical property models and not restricted to isomer-shift predictions. We provide the statistically meaningful reference data set MIS39 and a new calibration of the isomer shift based on the PBE0 functional.
description: 49 pages, 9 figures, 7 tables
ACE2 overexpression mediates spatial distribution of pathologic features in acute kidney injury
Creators: name: Emathinger, Jacqueline
name: Robertson, Joshua A.
name: Nelson, Jonathan W.
name: Hagen, Matthew W.
name: Andeen, Nicole K.
name: Kung, Vanderlene L.
Publisher: name: Oregon Health and Science University
Year: 2023
Subjects: subject: Angiotensin-Converting Enzyme 2
subject: Acute Kidney Injury
subject: Pathology
subject: Renal ischemia reperfusion injury

description: Acute kidney injury (AKI) is a widespread health problem, with increased incidence among hospitalized patients. The most common cause of AKI is ischemic injury, which targets the proximal tubule causing damage to kidney structure and function. Within ischemic AKI, overactivation of the renin angiotensin system (RAS) can drive pathologic changes. Angiotensin converting enzyme 2 (ACE2) is an integral part of the RAS and is highly expressed along the brush border of the proximal tubule (PT), where it acts to enzymatically degrade angiotensin II (AngII) and extinguish its effects. While several studies have examined the protective role ACE2 plays within chronic kidney disease and hypertension, less is known about ACE2 in acute injury. Here, we hypothesize that ACE2 overexpression is protective against AKI through local AngII metabolism and promotes recovery of renal function after AKI.
Correlated wounded hot spots in proton-proton interactions
Creators: name: Albacete, Javier L.
name: Petersen, Hannah
name: Soto-Ontoso, Alba
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We investigate the effect of non-trivial spatial correlations between proton constituents, considered in this work to be gluonic hot spots, on the initial conditions of proton-proton collisions from ISR to LHC energies, i.e. $\sqrt s\!=\!52.6,7000,13000$ GeV. The inclusion of these correlations is motivated by their fundamental role in the description of a recently observed new feature of $pp$ scattering at $\sqrt s\!=\!7$ TeV, the hollowness effect. Our analysis relies on a Monte-Carlo Glauber approach including fluctuations in the hot spot positions and their entropy deposition in the transverse plane. We explore both the energy dependence and the effect of spatial correlations on the number of wounded hot spots, their spatial distribution and the eccentricities, $\varepsilon_n$, of the initial state geometry of the collision. In minimum bias collisions we find that the inclusion of short range repulsive correlations between the hot spots reduces the value of the eccentricity ($\varepsilon_2$) and the triangularity ($\varepsilon_3$). In turn, upon considering only the events with the highest entropy deposition i.e. the ultra-central ones, the probability of having larger $\varepsilon_{2,3}$ increases significantly in the correlated scenario. Finally, the eccentricities show a quite mild energy dependence.
description: Manuscript restructured and extended to include a centrality study and probability distributions instead of averages . Accepted for publication in Phys. Rev. C