cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Resolvent criteria for similarity to a normal operator with spectrum on a curve
Creators: name: Dritschel, Michael A.
name: Estévez, Daniel
name: Yakubovich, Dmitry
Publisher: name: arXiv
Year: 2017
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 47A10 (Primary) 47B15, 47A60 (Secondary)

description: We give some new criteria for a Hilbert space operator with spectrum on a smooth curve to be similar to a normal operator, in terms of pointwise and integral estimates of the resolvent. These results generalize criteria of Stampfli, Van Casteren and Naboko, and answer several questions posed by Stampfli. The main tools are from our recent results on dilation to the boundary of the spectrum, along with the Dynkin functional calculus for smooth functions, which is based on pseudoanalytic continuation.
description: 22 pages
Bounds on the rise of total cross section from LHC7 and LHC8 data
Creators: name: Fagundes, D. A.
name: Menon, M. J.
name: Silva, P. V. R. G.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Recent measurements of the proton-proton total cross section $σ_{tot}$ at 7 and 8 TeV by the TOTEM and ATLAS Collaborations are characterized by some discrepant values: the TOTEM data suggest a rise of the cross section with the energy faster than the ATLAS data. Attempting to quantify these different behaviors, we develop new analytical fits to $σ_{tot}$ and $ρ$ data from $pp$ and $\bar{p}p$ scattering in the energy region 5 GeV - 8 TeV. The dataset comprises all the accelerator data below 7 TeV and we consider three ensembles by adding: either only the TOTEM data (T), or only the ATLAS data (A), or both sets (T+A). For the purposes, we use our previous RRPL$γ$ parametrization for $σ_{tot}(s)$, consisting of two Reggeons (RR), one critical Pomeron (P) and a leading log-raised-to-gamma (L$γ$) contribution (with $γ$ as a free fit parameter), analytically connected to $ρ(s)$ through singly-subtracted derivative dispersion relations and energy scale fixed at the physical threshold. The data reductions with ensembles T and A present good agreement with the experimental data analyzed and cannot be distinguished on statistical grounds. The quality of the fit is not as good with ensemble T+A. The fit results provide $γ\sim 2.3 \pm 0.1$ (T), $2.0 \pm 0.2$ (A), $2.1 \pm 0.2$ (T+A), with $χ^2/\mathrm{DOF} \sim 1.07$ (T), $1.09$ (A), $1.14$ (T+A), suggesting extrema bounds for $γ$ given by 1.8 and 2.4. Fits with $γ= 2$ (fixed) are also developed and discussed.
description: 14 pages, 3 figures, 6 tables, one appendix added (discussing some TOTEM data at 8 TeV), minor corrections, few comments added. Matches version accepted for publication in Nucl. Phys. A
Exploring the efficacy and limitations of shock-cooling models: new analysis of Type II supernovae observed by the Kepler mission
Creators: name: Rubin, Adam
name: Gal-Yam, Avishay
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Modern transient surveys have begun discovering and following supernovae (SNe) shortly after first light---providing systematic measurements of the rise of Type II SNe. We explore how analytic models of early shock-cooling emission from core-collapse SNe can constrain the progenitor's radius, explosion velocity, and local host extinction. We simulate synthetic photometry in several realistic observing scenarios and, assuming the models describe the typical explosions well, find that ultraviolet observations can constrain the progenitor's radius to a statistical uncertainty of $\pm10-15\%$, with a systematic uncertainty of $\pm 20\%$. With these observations the local host extinction ($A_V$) can be constrained to a factor of two and the shock velocity to $\pm 5\%$ with a systematic uncertainty of $\pm 10\%$. We also re-analyze the SN light curves presented in Garnavich et al. (2016) and find that KSN 2011a can be fit by a blue supergiant model with a progenitor radius of $R_s < 7.7 + 8.8 {\rm (stat)} + 1.9 {\rm (sys)}R_\odot$, while KSN 2011d can be fit with a red supergiant model with a progenitor radius of $R_s = 111_{-21 {\rm (stat)}}^{+89 {\rm (stat)}} \phantom{}_{-1{\rm (sys)}}^{+49 {\rm (sys)}}$. Our results do not agree with those of Garnavich et al. (2016). Moreover, we re-evaluate their claims and find that there is no statistically significant evidence for a shock breakout flare in the light curve of KSN 2011d.
description: Accepted to ApJ
Solving the Navier-Lame Equation in Cylindrical Coordinates Using the Buchwald Representation: Some Parametric Solutions with Applications
Creators: name: Sakhr, Jamal
name: Chronik, Blaine A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Physics (math-ph)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: Using a separable Buchwald representation in cylindrical coordinates, we show how under certain conditions the coupled equations of motion governing the Buchwald potentials can be decoupled and then solved using well-known techniques from the theory of PDEs. Under these conditions, we then construct three parametrized families of particular solutions to the Navier-Lame equation in cylindrical coordinates. In this paper, we specifically construct solutions having 2pi-periodic angular parts. These particular solutions can be directly applied to a fundamental set of linear elastic boundary value problems in cylindrical coordinates and are especially suited to problems involving one or more physical parameters. As an illustrative example, we consider the problem of determining the response of a solid elastic cylinder subjected to a time-harmonic surface pressure that varies sinusoidally along its axis, and we demonstrate how the obtained parametric solutions can be used to efficiently construct an exact solution to this problem. We also briefly consider applications to some related forced-relaxation type problems.
description: Two typos corrected; full citations added
Femtosecond laser inscription of Bragg grating waveguides in bulk diamond
Creators: name: Bharadwaj, V.
name: Courvoisier, A.
name: Fernandez, T. T.
name: Ramponi, R.
name: Galzerano, G.
name: Nunn, J.
name: Booth, M. J.
name: Osellame, R.
name: Eaton, S. M.
name: Salter, P. S.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences
subject: J.2
subject: 00A79, 81Q37, 78A60

description: Femtosecond laser writing is applied to form Bragg grating waveguides in the diamond bulk. Type II waveguides are integrated with a single pulse point-by-point periodic laser modification positioned towards the edge of the waveguide core. These photonic devices, operating in the telecommunications band, allow for simultaneous optical waveguiding and narrowband reflection from a 4th order grating. This fabrication technology opens the way towards advanced 3D photonic networks in diamond for a range of applications.
description: 4 Pages, 5 figures
Revisiting the VOS model for monopoles
Creators: name: Sousa, Lara
name: Avelino, Pedro P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We revisit the physical properties of global and local monopoles and discuss their implications in the dynamics of monopole networks. In particular, we review the Velocity-dependent One-Scale (VOS) model for global and local monopoles and propose physically motivated changes to its equations. We suggest a new form for the acceleration term of the evolution equation of the root-mean-squared velocity and show that, with this change, the VOS model is able to describe the results of radiation and matter era numerical simulations of global monopole networks with a single value of the acceleration parameter $k$, thus resolving the tension previously found in the literature. We also show that the fact that the energy of global monopoles is not localized within their cores affects their dynamics and, thus, the Hubble damping terms in the VOS equations. We study the ultra-relativistic linear scaling regime predicted by the VOS equations and demonstrate that it cannot be attained either on radiation or matter eras and, thus, cannot arise from the cosmological evolution of a global monopole network. We also briefly discuss the implications of our findings for the VOS model for local monopoles.
description: 8 pages, 2 figures
Quantum Identities for the Action
Creators: name: Gozzi, E.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we derive various identities involving the {\it action} functional which enters the path-integral formulation of quantum mechanics. They provide some kind of generalisations of the Ehrenfest theorem giving correlations between powers of the action and its functional derivatives.
description: 4 pages, few parts deleted
Testing backreaction effects with observational Hubble parameter data
Creators: name: Cao, Shu-Lei
name: Teng, Huan-Yu
name: Yu, Hao-Ran
name: Wan, Hao-Yi
name: Zhang, Tong-Jie
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In order to explore the generic properties of a backreaction model for explaining the accelerated expansion of the Universe, we exploit two metrics to describe the late time Universe. Since the standard FLRW metric cannot precisely describe the late time Universe on small scales, the template metric with an evolving curvature parameter $κ_{\mathcal{D}}(t)$ is employed. However, we doubt the validity of the prescription for $κ_{\mathcal{D}}$, which motivates us apply observational Hubble parameter data (OHD) to constrain parameters in dust cosmology. First, for FLRW metric, by getting best-fit constraints of $Ω^{\mathcal{D}_0}_m = 0.25^{+0.03}_{-0.03}$, $n = 0.02^{+0.69}_{-0.66}$, and $H_{\mathcal{D}_0} = 70.54^{+4.24}_{-3.97}\ {\rm km \ s^{-1} \ Mpc^{-1}}$, the evolutions of parameters are explored. Second, in template metric context, by marginalizing over $H_{\mathcal{D}_0}$ as a prior of uniform distribution, we obtain the best-fit values of $n=-1.22^{+0.68}_{-0.41}$ and ${Ω_{m}^{\mathcal{D}_{0}}}=0.12^{+0.04}_{-0.02}$. Moreover, we utilize three different Gaussian priors of $H_{\mathcal{D}_0}$, which result in different best-fits of $n$, but almost the same best-fit value of ${Ω_{m}^{\mathcal{D}_{0}}}\sim0.12$. Also, the absolute constraints without marginalization of parameter are obtained: $n=-1.1^{+0.58}_{-0.50}$ and ${Ω_{m}^{\mathcal{D}_{0}}}=0.13\pm0.03$. With these constraints, the evolutions of the effective deceleration parameter $q^{\mathcal{D}}$ indicate that the backreaction can account for the accelerated expansion of the Universe without involving extra dark energy component in the scaling solution context. Nevertheless, the results also verify that the prescription of $κ_{\mathcal{D}}$ is insufficient and should be improved.
description: 11 pages, 9 figures
Operator Spreading in Random Unitary Circuits
Creators: name: Nahum, Adam
name: Vijay, Sagar
name: Haah, Jeongwan
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Random quantum circuits yield minimally structured models for chaotic quantum dynamics, able to capture for example universal properties of entanglement growth. We provide exact results and coarse-grained models for the spreading of operators by quantum circuits made of Haar-random unitaries. We study both 1+1D and higher dimensions, and argue that the coarse-grained pictures carry over to operator spreading in generic many-body systems. In 1+1D, we demonstrate that the out-of-time-order correlator (OTOC) satisfies a biased diffusion equation, which gives exact results for the spatial profile of the OTOC, and the butterfly speed $v_{B}$. We find that in 1+1D the `front' of the OTOC broadens diffusively, with a width scaling in time as $t^{1/2}$. We address fluctuations in the OTOC between different realizations of the random circuit, arguing that they are negligible in comparison to the broadening of the front. Turning to higher D, we show that the averaged OTOC can be understood exactly via a remarkable correspondence with a classical droplet growth problem. This implies that the width of the front of the averaged OTOC scales as $t^{1/3}$ in 2+1D and $t^{0.24}$ in 3+1D (KPZ exponents). We support our analytic argument with simulations in 2+1D. We point out that, in a lattice model, the late time shape of the spreading operator is in general not spherical. However when full spatial rotational symmetry is present in 2+1D, our mapping implies an exact asymptotic form for the OTOC in terms of the Tracy-Widom distribution. For an alternative perspective on the OTOC in 1+1D, we map it to the partition function of an Ising-like model. As a result of special structure arising from unitarity, this partition function reduces to a random walk calculation which can be performed exactly. We also use this mapping to give exact results for entanglement growth in 1+1D circuits.
description: 29 pages, 16 figures. v2: new appendix on 'mean field'
Exceptional Points in Random-Defect Phonon Lasers
Creators: name: Lü, H.
name: Özdemir, S. K.
name: Nori, Franco
name: Kuang, L. -M.
name: Jing, H.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Intrinsic defects in optomechanical devices are generally viewed to be detrimental for achieving coherent amplification of phonons, and great care has thus been exercised in fabricating devices and materials with no (or a minimal number of) defects. Contrary to this view, here we show that, by surpassing an exceptional point (EP), both the mechanical gain and the phonon number can be enhanced despite increasing defect losses. This counterintuitive effect, well described by an effective non-Hermitian phonon-defect model, provides a mechanical analog of the loss-induced purely optical lasing. This opens the way to operating random-defect phonon devices at EPs.
description: 9 pages, 6 figures
Michael Davitt and Antisemitism in ireland
Creators: name: Fay, Peter
Publisher: name: Stanford Digital Repository
Year: 2024
Subjects: subject: Michael Davitt
subject: Irish Nationalism
subject: Antisemitism
subject: Jewish Community in ireland
subject: 19th Century Ireland
subject: Dreyfus Affair
subject: Boer War (1899-1902)
subject: Humanitarianism
subject: Irish History
subject: Zionism

description: This thesis explores the complex relationship between Irish nationalism and antisemitism through the lens of Michael Davitt's life and works. Although Ireland has been portrayed as relatively tolerant towards Jews, particularly when compared to other European countries, this thesis questions that narrative by examining instances of antisemitism within Irish society from the late 19th to early 20th centuries. Michael Davitt, a prominent Irish nationalist, offers a unique perspective on this issue. Despite his support for Jewish causes and opposition to antisemitic actions, Davitt was not immune to the prejudices of his time, as demonstrated by his views on events like the Dreyfus Affair and the Boer War. The thesis delves into Davitt’s early life, his education in England, and the experiences that shaped his broader humanitarianism and his specific stance towards the Jewish community in Ireland. By examining Davitt's public and private writings, this work sheds light on the contradictions in his views and the broader context of Irish antisemitism within the nationalist movement.
Yet another family of diagonal metrics for de Sitter and anti-de Sitter spacetimes
Creators: name: Podolsky, Jiri
name: Hruska, Ondrej
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we present and analyze a new class of coordinate representations of de Sitter and anti-de Sitter spacetimes for which the metrics are diagonal and (typically) static and axially symmetric. Contrary to the well-known forms of these fundamental geometries, that usually correspond to a 1+3 foliation with the 3-space of a constant spatial curvature, the new metrics are adapted to a 2+2 foliation, and are warped products of two 2-spaces of constant curvature. This new class of (anti-)de Sitter metrics depends on the value of cosmological constant Lambda and two discrete parameters +1,0,-1 related to the curvature of the 2-spaces. The class admits 3 distinct subcases for Lambda>0 and 8 subcases for Lambda<0. We systematically study all these possibilities. In particular, we explicitly present the corresponding parametrizations of the (anti-)de Sitter hyperboloid, visualize the coordinate lines and surfaces within the global conformal cylinder, investigate their mutual relations, present some closely related forms of the metrics, and give transformations to standard de Sitter and anti-de Sitter metrics. Using these results, we also provide a physical interpretation of B-metrics as exact gravitational fields of a tachyon.
description: 44 pages, 26 figures: final extended version published in Phys. Rev. D. It contains 5 more pages and 2 new figures on physical application - exact gravitational field of a tachyon moving in the (anti-)de Sitter spacetime. This paper was selected in June 2017 as Phys. Rev. D "EDITORS' SUGGESTION"
Krake-PyCOMPSs-demo
Creators: name: Thiem, Patrick
Publisher: name: Zenodo
Year: 2022

description: These files mainly show log data of the Krake stateful migration process of the PyCOMPSs demo application. Most COMPSs related log files are empty because no error occurred during the execution. In addition there is the PyCOMPSs application manifest file which was used in Krake to schedule the application.
Good Features to Correlate for Visual Tracking
Creators: name: Gundogdu, Erhan
name: Alatan, A. Aydin
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: During the recent years, correlation filters have shown dominant and spectacular results for visual object tracking. The types of the features that are employed in these family of trackers significantly affect the performance of visual tracking. The ultimate goal is to utilize robust features invariant to any kind of appearance change of the object, while predicting the object location as properly as in the case of no appearance change. As the deep learning based methods have emerged, the study of learning features for specific tasks has accelerated. For instance, discriminative visual tracking methods based on deep architectures have been studied with promising performance. Nevertheless, correlation filter based (CFB) trackers confine themselves to use the pre-trained networks which are trained for object classification problem. To this end, in this manuscript the problem of learning deep fully convolutional features for the CFB visual tracking is formulated. In order to learn the proposed model, a novel and efficient backpropagation algorithm is presented based on the loss function of the network. The proposed learning framework enables the network model to be flexible for a custom design. Moreover, it alleviates the dependency on the network trained for classification. Extensive performance analysis shows the efficacy of the proposed custom design in the CFB tracking framework. By fine-tuning the convolutional parts of a state-of-the-art network and integrating this model to a CFB tracker, which is the top performing one of VOT2016, 18% increase is achieved in terms of expected average overlap, and tracking failures are decreased by 25%, while maintaining the superiority over the state-of-the-art methods in OTB-2013 and OTB-2015 tracking datasets.
description: Accepted version of IEEE Transactions on Image Processing
Time dependence of entanglement entropy on the fuzzy sphere
Creators: name: Sabella-Garnier, Philippe
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We numerically study the behaviour of entanglement entropy for a free scalar field on the noncommutative ("fuzzy") sphere after a mass quench. It is known that the entanglement entropy before a quench violates the usual area law due to the non-local nature of the theory. By comparing our results to the ordinary sphere, we find results that, despite this non-locality, are compatible with entanglement being spread by ballistic propagation of entangled quasi-particles at a speed no greater than the speed of light. However, we also find that, when the pre-quench mass is much larger than the inverse of the short-distance cutoff of the fuzzy sphere (a regime with no commutative analogue), the entanglement entropy spreads faster than allowed by a local model.
description: 1+14 pages, 8 figures v2: References added, matches published version
Cosmic evolution of stellar quenching by AGN feedback: clues from the Horizon-AGN simulation
Creators: name: Beckmann, R. S.
name: Devriendt, J.
name: Slyz, A.
name: Peirani, S.
name: Richardson, M. L. A.
name: Dubois, Y.
name: Pichon, C.
name: Chisari, N. E.
name: Kaviraj, S.
name: Laigle, C.
name: Volonteri, M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The observed massive end of the galaxy stellar mass function is steeper than its predicted dark matter halo counterpart in the standard $Λ$CDM paradigm. In this paper, we investigate the impact of active galactic nuclei (AGN) feedback on star formation in massive galaxies. We isolate the impact of AGNs by comparing two simulations from the HORIZON suite, which are identical except that one also includes super massive black holes (SMBH), and related feedback models. This allows us to cross-identify individual galaxies between simulations and quantify the effect of AGN feedback on their properties, including stellar mass and gas outflows. We find that massive galaxies ($ \rm M_{*} \geq 10^{11} M_\odot $) are quenched by AGN feedback to the extent that their stellar masses decrease by up to 80% at $z=0$. SMBHs affect their host halo through a combination of outflows that reduce their baryonic mass, particularly for galaxies in the mass range $ \rm 10^9 M_\odot \leq M_{*} \leq 10^{11} M_\odot $, and a disruption of central gas inflows, which limits in-situ star formation. As a result, net gas inflows onto massive galaxies, $ \rm M_{*} \geq 10^{11} M_\odot $, drop by up to 70%. We measure a redshift evolution in the stellar mass ratio of twin galaxies with and without AGN feedback, with galaxies of a given stellar mass showing stronger signs of quenching earlier on. This evolution is driven by a progressive flattening of the $\rm M_{\rm SMBH}-M_* $ relation with redshift, particularly for galaxies with $\rm M_{*} \leq 10^{10} M_\odot $. $\rm M_{\rm SMBH}/M_*$ ratios decrease over time, as falling average gas densities in galaxies curb SMBH growth.
description: 19 pages, 16 figures, matches accepted version
Automatic Model Based Dataset Generation for Fast and Accurate Crop and Weeds Detection
Creators: name: Di Cicco, Maurilio
name: Potena, Ciro
name: Grisetti, Giorgio
name: Pretto, Alberto
Publisher: name: arXiv
Year: 2016
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Selective weeding is one of the key challenges in the field of agriculture robotics. To accomplish this task, a farm robot should be able to accurately detect plants and to distinguish them between crop and weeds. Most of the promising state-of-the-art approaches make use of appearance-based models trained on large annotated datasets. Unfortunately, creating large agricultural datasets with pixel-level annotations is an extremely time consuming task, actually penalizing the usage of data-driven techniques. In this paper, we face this problem by proposing a novel and effective approach that aims to dramatically minimize the human intervention needed to train the detection and classification algorithms. The idea is to procedurally generate large synthetic training datasets randomizing the key features of the target environment (i.e., crop and weed species, type of soil, light conditions). More specifically, by tuning these model parameters, and exploiting a few real-world textures, it is possible to render a large amount of realistic views of an artificial agricultural scenario with no effort. The generated data can be directly used to train the model or to supplement real-world images. We validate the proposed methodology by using as testbed a modern deep learning based image segmentation architecture. We compare the classification results obtained using both real and synthetic images as training data. The reported results confirm the effectiveness and the potentiality of our approach.
description: To appear in IEEE/RSJ IROS 2017
Quantum mechanical study of high-order harmonic generation from HeH$^{2+}$ molecule in homogeneous and plasmonic-enhanced laser Fields
Creators: name: Safaei, Nehzat
Publisher: name: arXiv
Year: 2017
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: High-order harmonic generation (HHG) from molecular ion HeH$^{2+}$ in two initial states of $1sσ$ (ground state) and $2pσ$ (first excited state) is investigated theoretically, in homogeneous and plasmonic-enhanced laser fields. The electron ionization and the enhancement of HHG yield in ground and first excited states, as the initial states, is studied and a strong orientation effect for ionization of electron in $2pσ$ state is discovered, that it can be used to reach a longer lifetime for the electron in the first excited state, which is responsible for the enhancement in HHG yield, during the high harmonic emission. In order to investigate effect of plasmonic field on the cutoff position of HHG spectra, first the enhancement of laser field in a nano-antennae is calculated and then the interaction of the enhanced field with HeH$^{2+}$ molecule is studied by solving the time-dependent Schrödinger equation. According to the results, when HeH$^{2+}$ molecule, in the initial state of $2pσ$, is irradiated by plasmonic polarized laser field, with the polarization normal to the molecular axis, the HHG yield and cutoff position enhance while the excited state has a long lifetime during the HHG process.
description: 6 pages, 6 figures
Bewusste geometrische Gestaltung bei Homo heidelbergensis?
Creators: name: Richter, Jürgen
Publisher: name: Archäologisches Korrespondenzblatt
Year: 2022

description: Beim Faustkeil von Bad Salzuflen (Kr. Lippe) handelt es sich wohl um eines der ältesten – wenn nicht das älteste – Artefakte, das bisher in Ostwestfalen bzw. ganz Westfalen zutage kam. Der Einzelfund dieses komplex gearbeiteten Faustkeils dient als Anlass dafür, eine standardisierte Form der Arbeitsschrittanalyse vorzustellen, die eine genaue Charakterisierung der technologischen Eigenheiten und der Rezeptur des Faustkeils ermöglicht. Es handelt sich um einen symmetrischen, plan-konvex formüberarbeiteten Faustkeil der Gruppe »biface-outil« mit Arbeitskanten für die Funktionen Spitze/Schneiden, Schaben und Trennen. Das geometrische Konzept des Faustkeils kombiniert zwei verschiedene Körper: einen Spitzenteil in der Form einer aufgeschnittenen (halben) Pyramide und einen Basisteil in der Form eines plattigen Quaders oder Zylinders. Zur Überbrückung der beiden Körper wurden eigens zwei alternierende Verdünnungsschläge angelegt, die vermuten lassen, dass die geometrische Konzeption dem Hersteller bewusst war. Nach formenkundlichen und technologischen Vergleichen entstand der Faustkeil wahrscheinlich vor 350 000-300 000 Jahren und gibt damit Einblick in die konzeptuellen und technischen Fähigkeiten der spätesten Vertreter des Homo heidelbergensis, nahe dem zeitlichen Übergang zu den frühen Neandertalern. Wenn die Datierungshypothese für diesen ohne stratigraphischen Kontext aufgefundenen Faustkeil richtig ist, handelt es sich um eines der seltenen Zeugnisse des Acheuléens in Mitteleuropa. Zugleich zeigt der Faustkeil den Einsatz eines technologischen Gestaltungsmittels, das auf die bewusste Wahrnehmung eines geometrischen Problems schließen lässt.
description: Archäologisches Korrespondenzblatt, Bd. 43 Nr. 1 (2013): Archäologisches Korrespondenzblatt
Markov Chain Monte Carlo technics applied to Parton Distribution Functions determination: proof of concept
Creators: name: Gbedo, Yémalin Gabin
name: Mangin-Brinet, Mariane
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present a new procedure to determine Parton Distribution Functions (PDFs), based on Markov Chain Monte Carlo (MCMC) methods. The aim of this paper is to show that we can replace the standard $χ^2$ minimization by procedures grounded on Statistical Methods, and on Bayesian inference in particular, thus offering additional insight into the rich field of PDFs determination. After a basic introduction to these technics, we introduce the algorithm we have chosen to implement -- namely Hybrid (or Hamiltonian) Monte Carlo. This algorithm, initially developed for Lattice QCD, turns out to be very interesting when applied to PDFs determination by global analyses; we show that it allows to circumvent the difficulties due to the high dimensionality of the problem, in particular concerning the acceptance. A first feasibility study is performed and presented, which indicates that Markov Chain Monte Carlo can successfully be applied to the extraction of PDFs and of their uncertainties.
description: 17 pages, 9 figures. Published in Phys. Rev. D
Multilevel rejection sampling for approximate Bayesian computation
Creators: name: Warne, David J.
name: Baker, Ruth E.
name: Simpson, Matthew J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computation (stat.CO)
subject: FOS: Computer and information sciences
subject: 62F15, 65C05

description: Likelihood-free methods, such as approximate Bayesian computation, are powerful tools for practical inference problems with intractable likelihood functions. Markov chain Monte Carlo and sequential Monte Carlo variants of approximate Bayesian computation can be effective techniques for sampling posterior distributions in an approximate Bayesian computation setting. However, without careful consideration of convergence criteria and selection of proposal kernels, such methods can lead to very biased inference or computationally inefficient sampling. In contrast, rejection sampling for approximate Bayesian computation, despite being computationally intensive, results in independent, identically distributed samples from the approximated posterior. An alternative method is proposed for the acceleration of likelihood-free Bayesian inference that applies multilevel Monte Carlo variance reduction techniques directly to rejection sampling. The resulting method retains the accuracy advantages of rejection sampling while significantly improving the computational efficiency.
An exponential integrator for the drift-kinetic model
Creators: name: Crouseilles, Nicolas
name: Einkemmer, Lukas
name: Prugger, Martina
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Numerical Analysis (math.NA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We propose an exponential integrator for the drift-kinetic equation in cylindrical geometry. This approach removes the CFL condition from the linear part of the system (which is often the most stringent requirement in practice) and treats the remainder explicitly using Arakawa's finite difference scheme. The present approach is mass conservative, up to machine precision, and significantly reduces the computational effort per time step. In addition, we demonstrate the efficiency of our method by performing numerical simulations in the context of the ion temperature gradient instability. In particular, we find that our numerical method can take time steps comparable to what has been reported in the literature for the (predominantly used) splitting approach. In addition, the proposed numerical method has significant advantages with respect to conservation of energy and efficient higher order methods can be obtained easily. We demonstrate this by investigating the performance of a fourth order implementation.
Geometric vector potentials from non-adiabatic spin dynamics
Creators: name: Baltanás, J. P.
name: Saarikoski, H.
name: Reynoso, A. A.
name: Frustaglia, D.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose a theoretical framework that captures the geometric vector potential emerging from the non-adiabatic spin dynamics of itinerant carriers subject to arbitrary magnetic textures. Our approach results in a series of constraints on the geometric potential and the non-adiabatic geometric phase associated with it. These constraints play a decisive role when studying the geometric spin phase gathered by conducting electrons in ring interferometers under the action of in-plane magnetic textures, allowing a simple characterization of the topological transition recently reported by Saarikoski et al. [Phys. Rev. B 91, 241406(R) (2015)] in Ref. 1.
description: Accepted for publication in Physical Review B (updated version, 6 pages, 1 figure)
Periods and factors of weak model sets
Creators: name: Keller, Gerhard
name: Richard, Christoph
Publisher: name: arXiv
Year: 2017
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 52C23, 37A25, 37B10, 37B50

description: There is a renewed interest in weak model sets due to their connection to $\mathcal B$-free systems, which emerged from Sarnak's program on the Möbius disjointness conjecture. Here we continue our recent investigation [arXiv:1511.06137] of the extended hull ${\mathcal M}^{\scriptscriptstyle G}_{\scriptscriptstyle W}$, a dynamical system naturally associated to a weak model set in an abelian group $G$ with relatively compact window $W$. For windows having a nowhere dense boundary (this includes compact windows), we identify the maximal equicontinuous factor of ${\mathcal M}^{\scriptscriptstyle G}_{\scriptscriptstyle W}$ and give a sufficient condition when ${\mathcal M}^{\scriptscriptstyle G}_{\scriptscriptstyle W}$ is an almost 1:1 extension of its maximal equicontinuous factor. If the window is measurable with positive Haar measure and is almost compact, then the system ${\mathcal M}^{\scriptscriptstyle G}_{\scriptscriptstyle W}$ equipped with its Mirsky measure is isomorphic to its Kronecker factor. For general nontrivial ergodic probability measures on ${\mathcal M}^{\scriptscriptstyle G}_{\scriptscriptstyle W}$, we provide a kind of lower bound for the Kronecker factor. All relevant factor systems are natural $G$-actions on quotient subgroups of the torus underlying the weak model set. These are obtained by factoring out suitable window periods. Our results are specialised to the usual hull of the weak model set, and they are also interpreted for ${\mathcal B}$-free systems.
The origin of the Ultraluminous X-ray Sources
Creators: name: Wiktorowicz, Grzegorz
name: Sobolewska, Małgorzata
name: Lasota, Jean-Pierre
name: Belczynski, Krzysztof
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Recently, several ultraluminous X-ray (ULX) sources were shown to host a neutron star (NS) accretor. We perform a suite of evolutionary calculations which show that, in fact, NSs are the dominant type of ULX accretor. Although black holes (BH) dominate early epochs after the star-formation burst, NSs outweigh them after a few 100 Myr and may appear as late as a few Gyr after the end of the star formation episode. If star formation is a prolonged and continuous event (i.e., not a relatively short burst), NS accretors dominate ULX population at any time in solar metallicity environment, whereas BH accretors dominate when the metallicity is sub-solar. Our results show a very clear (and testable) relation between the companion/donor evolutionary stage and the age of the system. A typical NS ULX consists of a $\sim1.3\,M_\odot$ NS and $\sim1.0\,M_\odot$ Red Giant. A typical BH ULX consist of a $\sim8\,M_\odot$ BH and $\sim6\,M_\odot$ main-sequence star. Additionally, we find that the very luminous ULXs ($L_X\gtrsim10^{41}$ erg/s) are predominantly BH systems ($\sim9\,M_\odot$) with Hertzsprung gap donors ($\sim2\,M_\odot$). Nevertheless, some NS ULX systems may also reach extremely high X-ray luminosities ($\gtrsim10^{41}$ erg/s).
description: 7 pages, 14 figures, published in ApJ
Long and Short Memory in Economics: Fractional-Order Difference and Differentiation
Creators: name: Tarasov, Vasily E.
name: Tarasova, Valentina V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Economics (econ.GN)
subject: Mathematical Finance (q-fin.MF)
subject: Statistical Finance (q-fin.ST)
subject: FOS: Economics and business
subject: 91B02, 26A33

description: Long and short memory in economic processes is usually described by the so-called discrete fractional differencing and fractional integration. We prove that the discrete fractional differencing and integration are the Grunwald-Letnikov fractional differences of non-integer order d. Equations of ARIMA(p,d,q) and ARFIMA(p,d,q) models are the fractional-order difference equations with the Grunwald-Letnikov differences of order d. We prove that the long and short memory with power law should be described by the exact fractional-order differences, for which the Fourier transform demonstrates the power law exactly. The fractional differencing and the Grunwald-Letnikov fractional differences cannot give exact results for the long and short memory with power law, since the Fourier transform of these discrete operators satisfy the power law in the neighborhood of zero only. We prove that the economic processes with the continuous time long and short memory, which is characterized by the power law, should be described by the fractional differential equations.
description: 6 pages, PDF
Barjols, entreposage d'accessoires et de costumes pour la fête de la saint Marcel à l'arrière du studio photographique de Marius Fabre
Creators: name: Musée National Des Arts Et Traditions Populaires (Paris)
name: Centre D'ethnologie Française
Publisher: name: École des Hautes Études en Sciences Sociales; Institut  interdisciplinaire d'anthropologie du contemporain (Paris); Laboratoire d'anthropologie et d'histoire de l'institution de la culture (Paris)
Year: 2024

Abstract
Dirac dispersion generates large Nernst effect in Weyl semimetals
Creators: name: Watzman, Sarah J.
name: McCormick, Timothy M.
name: Shekhar, Chandra
name: Wu, Shu-Chun
name: Sun, Yan
name: Prakash, Arati
name: Felser, Claudia
name: Trivedi, Nandini
name: Heremans, Joseph P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Weyl semimetals expand research on topologically protected transport by adding bulk Berry monopoles with linearly dispersing electronic states and topologically robust, gapless surface Fermi arcs terminating on bulk node projections. Here, we show how the Nernst effect, combining entropy with charge transport, gives a unique signature for the presence of Dirac bands. The Nernst thermopower of NbP (maximum of 800 microV K-1 at 9 T, 109 K) exceeds its conventional thermopower by a hundredfold and is significantly larger than the thermopower of traditional thermoelectric materials. The Nernst effect has a pronounced maximum near T_M=90 +/- 20 K=mu_0/kB (mu_0 is chemical potential at T=0 K). A self-consistent theory without adjustable parameters shows that this results from electrochemical potential pinning to the Weyl point energy at T>=TM, driven by charge neutrality and Dirac band symmetry. Temperature and field dependences of the Nernst effect, an even function of the charge polarity, result from the intrinsically bipolar nature of the Weyl fermions. Through this study, we offer an understanding of the temperature dependence of the position of the electrochemical potential vis-a-vis the Weyl point, and we show a direct connection between topology and the Nernst effect, a potentially robust experimental tool for investigating topological states and the chiral anomaly.
Real-Time Control for Autonomous Racing Based on Viability Theory
Creators: name: Liniger, Alexander
name: Lygeros, John
Publisher: name: arXiv
Year: 2017
Subjects: subject: Systems and Control (eess.SY)
subject: Robotics (cs.RO)
subject: Optimization and Control (math.OC)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: In this paper we consider autonomous driving of miniature race cars. The viability kernel is used to efficiently generate finite look-ahead trajectories that maximize progress while remaining recursively feasible with respect to static obstacles (e.g., stay inside the track). Together with a low-level model predictive controller, this method makes real-time autonomous racing possible. The viability kernel computation is based on space discretization. To make the calculation robust against discretization errors, we propose a novel numerical scheme based on game theoretical methods, in particular the discriminating kernel. We show that the resulting algorithm provides an inner approximation of the viability kernel and guarantees that, for all states in the cell surrounding a viable grid point, there exists a control that keeps the system within the kernel. The performance of the proposed control method is studied in simulation where we determine the effects of various design choices and parameters and in experiments on an autonomous racing set-up maintained at the Automatic Control Laboratory of ETH Zurich. Both simulation and experimental results suggest that the more conservative approximation using the discriminating kernel results in safer driving style at the cost of a small increase in lap time.
description: 26 pages, 11 figures
$Φ$-meson--nucleus bound states
Creators: name: Cobos-Martínez, J. J.
name: Tsushima, K.
name: Krein, G.
name: Thomas, A. W.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: $ϕ$-meson--nucleus bound state energies and absorption widths are calculated for seven selected nuclei by solving the Klein-Gordon equation with complex optical potentials. Essential input for the calculations, namely the medium-modified $K$ and $\overline{K}$ meson masses, as well as the density distributions in nuclei, are obtained from the quark-meson coupling model. The attractive potential for the $ϕ$-meson in the nuclear medium originates from the in-medium enhanced $K\overline{K}$ loop in the $ϕ$-meson self-energy. The results suggest that the $ϕ$-meson should form bound states with all the nuclei considered. However, the identification of the signal for these predicted bound states will need careful investigation because of their sizable absorption widths.
description: To appear in Physical Review C; 8 pages, 5 figures. arXiv admin note: text overlap with arXiv:1706.02688
Rotational deviations and invariant pseudo-foliations for periodic point free torus homeomorphisms
Creators: name: Kocsard, Alejandro
name: Pereira-Rodrigues, Fernanda
Publisher: name: arXiv
Year: 2017
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 37E45, 37E30

description: This article deals with directional rotational deviations for non-wandering periodic point free homeomorphisms of the 2-torus which are homotopic to the identity. We prove that under mild assumptions, such a homeomorphism exhibits uniformly bounded rotational deviations in some direction if and only it leaves invariant a pseudo-foliation, a notion which is a slight generalization of classical one-dimensional foliations. To get these results, we introduce a novel object called $\tildeρ$-centralized skew-product and their associated stable sets at infinity.
description: 22 pages. Corrected version after referee report. Published in Mathematische Zeitschrift
Antenna Arrays for Line-of-Sight Massive MIMO: Half Wavelength is not Enough
Creators: name: Pinchera, Daniele
name: Migliore, Marco Donald
name: Schettino, Fulvio
name: Panariello, Gaetano
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: The aim of this paper is to analyze the array synthesis for 5 G massive MIMO systems in the line-of-sight working condition. The main result of the numerical investigation performed is that non-uniform arrays are the natural choice in this kind of application. In particular, by using non-equispaced arrays, we show that it is possible to achieve a better average condition number of the channel matrix and a significantly higher spectral efficiency. Furthermore, we verify that increasing the array size is beneficial also for circular arrays, and we provide some useful rules-of-thumb for antenna array design for massive MIMO applications. These results are in contrast to the widely-accepted idea in the 5 G massive MIMO literature, in which the half-wavelength linear uniform array is universally adopted.
description: updated version of the paper, that now includes additional results on the spectral efficiency