cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Predicting Music Relistening Behavior Using the ACT-R Framework
Creators: name: Reiter-Haas, Markus
name: Parada-Cabaleiro, Emilia
name: Schedl, Markus
name: Motamedi, Elham
name: Tkalcic, Marko
name: Lex, Elisabeth
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences

description: Providing suitable recommendations is of vital importance to improve the user satisfaction of music recommender systems. Here, users often listen to the same track repeatedly and appreciate recommendations of the same song multiple times. Thus, accounting for users' relistening behavior is critical for music recommender systems. In this paper, we describe a psychology-informed approach to model and predict music relistening behavior that is inspired by studies in music psychology, which relate music preferences to human memory. We adopt a well-established psychological theory of human cognition that models the operations of human memory, i.e., Adaptive Control of Thought-Rational (ACT-R). In contrast to prior work, which uses only the base-level component of ACT-R, we utilize five components of ACT-R, i.e., base-level, spreading, partial matching, valuation, and noise, to investigate the effect of five factors on music relistening behavior: (i) recency and frequency of prior exposure to tracks, (ii) co-occurrence of tracks, (iii) the similarity between tracks, (iv) familiarity with tracks, and (v) randomness in behavior. On a dataset of 1.7 million listening events from Last.fm, we evaluate the performance of our approach by sequentially predicting the next track(s) in user sessions. We find that recency and frequency of prior exposure to tracks is an effective predictor of relistening behavior. Besides, considering the co-occurrence of tracks and familiarity with tracks further improves performance in terms of R-precision. We hope that our work inspires future research on the merits of considering cognitive aspects of memory retrieval to model and predict complex user behavior.
description: Accepted for publication in RecSys'21 late-breaking results
M\o ller Operators and Hadamard States for Dirac Fields with MIT Boundary Conditions
Creators: name: Drago, Nicol\'O
name: Ginoux, Nicolas
name: Murro, Simone
Publisher: name: Deutsche Mathematiker-Vereinigung
Year: 2022

description: The aim of this paper is to prove the existence of Hadamard states for Dirac fields coupled with MIT boundary conditions on any globally hyperbolic manifold with timelike boundary once a suitable propagation of singularities theorem is assumed. To this avail, we consider particular pairs of weakly-hyperbolic symmetric systems coupled with admissible boundary conditions. We then prove the existence of an isomorphism between the solution spaces to the Cauchy problems associated with these operators - this isomorphism is in fact unitary between the spaces of $L^2$-initial data. In particular, we show that for Dirac fields with MIT boundary conditions, this isomorphism can be lifted to a $*$-isomorphism between the algebras of Dirac fields and that any Hadamard state can be pulled back along this $*$-isomorphism preserving the singular structure of its two-point distribution.
description: DOCUMENTA MATHEMATICA, Vol 27 (2022), p. 1693-1737
Møller operators and Hadamard states for Dirac fields with MIT boundary conditions
Creators: name: Drago, Nicolò
name: Ginoux, Nicolas
name: Murro, Simone
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: Primary 35L50, 58J45, 35Q41, Secondary 53C27, 53C50, 81T05

description: The aim of this paper is to prove the existence of Hadamard states for Dirac fields coupled with MIT boundary conditions on any globally hyperbolic manifold with timelike boundary. This is achieved by introducing a geometric Møller operator which implements a unitary isomorphism between the spaces of $L^2$ -initial data of particular symmetric systems we call weakly-hyperbolic and which are coupled with admissible boundary conditions. In particular, we show that for Dirac fields with MIT boundary conditions, this isomorphism can be lifted to a $*$-isomorphism between the algebras of Dirac fields and that any Hadamard state can be pulled back along this $*$-isomorphism preserving the singular structure of its two-point distribution.
description: 34 pages, 4 figures
Characterizing Pale Blue Dots In The Sky - Spectral Fingerprints From Earth To Super-Earth
Creators: name: Kaltenegger, Lisa
Publisher: name: Zenodo
Year: 2008
Subjects: Astronomical spectroscopy
HITRAN

description: There are many puzzle-pieces to assemble if we want to detect life, signs of life, or even conditions for life, on rocky exoplanets. What detectable signatures does life leave in a planetary atmosphere or on a planetary surface and what does HITRAN have to do with it? Future space missions will provide the pieces to solve this puzzle. In this talk we will look at the evidence that we are searching for, as well as what we are likely to get, and the challenges we face to define these pieces.
description: Session I: Astrophysics. June 22, 2008.
Tropical Teichmuller and Siegel spaces
Creators: name: Chan, Melody
name: Melo, Margarida
name: Viviani, Filippo
Publisher: name: arXiv
Year: 2012
Subjects: subject: Algebraic Geometry (math.AG)
subject: Combinatorics (math.CO)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics

description: In this paper, we present a unified study of the moduli space of tropical curves and Outer space which we link via period maps to the moduli space of tropical abelian varieties and the space of positive definite quadratic forms. Our work is a first step towards exhibiting Outer space and the space of positive definite quadratic forms as analogues of Teichmüller space and Siegel space, respectively, in tropical geometry. All these spaces and the maps among them are described within the category of ideal stacky fans, which we describe in detail.
description: 32 pages, final version, to appear in Contemporary Mathematics (Proceedings of the CIEM Workshop on tropical geometry)
Priomordial non-Gaussian features from DBI Galileon inflation
Creators: name: Choudhury, Sayantan
name: Pal, Supratik
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We have studied primordial non-Gaussian features from a model of potential driven single field DBI Galileon inflation. We have computed the bispectrum from the three point correlation function considering all possible cross correlation between scalar and tensor modes from the proposed setup. Further, we have computed the trispectrum from four point correlation function considering the contribution from contact interaction, scalar and graviton exchange diagrams in the in-in picture. Finally we have obtained the non-Gaussian consistency conditions from the four point correlator, which results in partial violation of the Suyama-Yamaguchi four-point consistency relation. This further leads to the conclusion that sufficient primordial non-Gaussianities can be obtained from DBI Galileon inflation.
description: 31 pages, Revision accepted by European Physical Journal C
ByzRev 03.2021.026: Hugh A. G. Houghton – David C. Parker (Hrsg.), Codex Zacynthius (Texts and Studies 21).
Creators: name: Zawadzki, Konrad F.
Publisher: name: The Byzantine Review
Year: 2021

description: Hugh A. G. Houghton – David C. Parker (Hrsg.), Codex Zacynthius (Texts and Studies 21). Piscataway, NJ: Gorgias Press 2020. XVII, 317 S. – ISBN: 978-1-4632-4107-0 (\$ 146.00
description: The Byzantine Review, Bd. 3 (2021)
Second-order, number-conserving description of non-equilibrium dynamics in finite-temperature Bose-Einstein condensates
Creators: name: Billam, T. P.
name: Mason, P.
name: Gardiner, S. A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: While the Gross--Pitaevskii equation is well-established as the canonical dynamical description of atomic Bose-Einstein condensates (BECs) at zero-temperature, describing the dynamics of BECs at finite temperatures remains a difficult theoretical problem, particularly when considering low-temperature, non-equilibrium systems in which depletion of the condensate occurs dynamically as a result of external driving. In this paper, we describe a fully time-dependent numerical implementation of a second-order, number-conserving description of finite-temperature BEC dynamics. This description consists of equations of motion describing the coupled dynamics of the condensate and non-condensate fractions in a self-consistent manner, and is ideally suited for the study of low-temperature, non-equilibrium, driven systems. The δ-kicked-rotor BEC provides a prototypical example of such a system, and we demonstrate the efficacy of our numerical implementation by investigating its dynamics at finite temperature. We demonstrate that the qualitative features of the system dynamics at zero temperature are generally preserved at finite temperatures, and predict a quantitative finite-temperature shift of resonance frequencies which would be relevant for, and could be verified by, future experiments.
description: 21 Pages, 6 Figures
Digital Water City
Creators: name: Gnirss, Regina
Publisher: name: Zenodo
Year: 2021

description: Digital Water City Die aktuellen Extremwetterereignisse führen zu überfluteten Straßen, verschmutzten Gewässern, überhitzten Innenstädte oder zu Wasserknappheit – besonders in Metropolen. Digitale Tools ermöglichen in Zeiten des Klimawandels ein effizienteres und nachhaltigeres Wassermanagement.
description: This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 820954.
Minimal hypersurfaces in manifolds of Ricci curvature bounded below
Creators: name: Ding, Qi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: In this paper, we study the angle estimate of distance functions from minimal hypersurfaces in manifolds of Ricci curvature bounded from below using Colding's method in [13]. With Cheeger-Colding theory, we obtain the Laplacian comparison for limits of distance functions from minimal hypersurfaces in the version of Ricci limit space. As an application, if a sequence of minimal hypersurfaces converges to a metric cone $CY\times\mathbb{R}^{n-k}(2\leq k\leq n)$ in a non-collapsing metric cone $CX\times\mathbb{R}^{n-k}$ obtained from ambient manifolds of almost nonnegative Ricci curvature, then we can prove a Frankel property for the cross section $Y$ of $CY$. Namely, $Y$ has only one connected component in $X$.
description: 31 pages
Gauge dependence of vacuum expectation values of gauge invariant operators from soft breaking of BRST symmetry. Example of Gribov-Zwanziger action
Creators: name: Lavrov, Peter M.
name: Reshetnyak, Alexander A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 81T13 81T10 81T08 81T70 58D30

description: We review the study of influence of the so-called soft BRST symmetry breaking within the Batalin-Vilkovisky (BV) formalism introduced in our papers [JHEP 1110 (2011) 043, arXiv:1108.4820 [hep-th], MPLA 27 (2012) 1250067, arXiv:1201.4720 [hep-th]] on gauge dependence of the effective action and vacuum expectation values of gauge invariant operators. We derive the Ward identities for generating functionals of Green's functions for a given theory with soft BRST symmetry breaking term being added to the quantum action and investigate theirs gauge dependence. It is strongly argued that gauge theories with a soft breaking of BRST symmetry are inconsistent within the BV formalism because of the gauge-dependence of $S$-matrix. The application to the Gribov-Zwanziger action (enlarging SU(N) Yang-Mills gauge theory by means of not gauge-invariant horizon function) for the one-parameter family of $R_ξ$ gauges with use of the new form of the Hermitian augmented Faddeev-Popov operator (being by Faddeev-Popov operator for transverse components of Yang--Mills fields) is considered.
description: 15 pages, Contribution in Proceedings of the 17-th International Seminar QUARKS-2012, Yaroslavl, Russia, 4-10 June, 2012, misprints, expression (71) corrected, added formulae, discussion on Gribov region in covariant gauges; two indices in Eq.(72) corrected
La réforme à travers l'écriture. Transmission de savoir historique et changement de mentalité historiographique entre le IXe et le XIIe siècle à la lumière de quelques considérations de sociologie textuelle
Creators: name: Tischler, Matthias M.
Publisher: name: Francia
Year: 2019

description: -
description: Francia, Bd. 33 Nr. 1 (2006)
Simple and Optimal Randomized Fault-Tolerant Rumor Spreading
Creators: name: Doerr, Benjamin
name: Doerr, Carola
name: Moran, Shay
name: Moran, Shlomo
Publisher: name: arXiv
Year: 2012
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: We revisit the classic problem of spreading a piece of information in a group of $n$ fully connected processors. By suitably adding a small dose of randomness to the protocol of Gasienic and Pelc (1996), we derive for the first time protocols that (i) use a linear number of messages, (ii) are correct even when an arbitrary number of adversarially chosen processors does not participate in the process, and (iii) with high probability have the asymptotically optimal runtime of $O(\log n)$ when at least an arbitrarily small constant fraction of the processors are working. In addition, our protocols do not require that the system is synchronized nor that all processors are simultaneously woken up at time zero, they are fully based on push-operations, and they do not need an a priori estimate on the number of failed nodes. Our protocols thus overcome the typical disadvantages of the two known approaches, algorithms based on random gossip (typically needing a large number of messages due to their unorganized nature) and algorithms based on fair workload splitting (which are either not {time-efficient} or require intricate preprocessing steps plus synchronization).
description: This is the author-generated version of a paper which is to appear in Distributed Computing, Springer, DOI: 10.1007/s00446-014-0238-z It is available online from http://link.springer.com/article/10.1007/s00446-014-0238-z This version contains some new results (Section 6)
Phytomedical investigation of Najas minor All. in the view of the chemical constituents
Creators: name: Topuzović, Marina D.
name: Radojević, Ivana D.
name: Dekić, Milan S.
name: Radulović, Niko S.
name: Vasić, Sava M.
name: Čomić, Ljiljana R.
name: Ličina, Braho Z.
Publisher: name: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund
Year: 2015
Subjects: Najas minor
antimicrobial
antibiofilm
total phenolic content
flavonoid and tannin content
volatile constituents

description: Plants are an abundant natural source of effective antibiotic compounds. Phytomedical investigations of certain plants haven't still been conducted. One of them is Najas minor (N. minor), an aquatic plant with confirmed allelopathy. Research conducted in this study showed the influence of water and ethyl acetate extracts of N. minor on microorganisms, in the view of chemical profiling of volatile constituents and the concentrations of total phenols, flavonoids and tannins. Antimicrobial activity was defined by determining minimum inhibitory and minimum microbicidal concentrations using microdilution method. Influence on bacterial biofilm formation was performed by tissue culture plate method. The total phenolics, flavonoids and condensed tannins were determined by Folin-Ciocalteu, aluminum chloride and butanol-HCl colorimetric methods. Chemical profiling of volatile constituents was investigated by GC and GC-MS. Water extract didn't have antimicrobial activity below 5000 µg/mL. Ethyl acetate extract has shown strong antimicrobial activity on G+ bacteria - Staphylococcus aureus PMFKGB12 and Bacillus subtilis (MIC < 78.13 µg/mL). The best antibiofilm activity was obtained on Escherichia coli ATCC25922 (BIC50 at 719 µg/mL). Water extract had higher yield. Ethyl acetate extract had a significantly greater amount of total phenolics, flavonoids and tannins. As major constituent hexahydrofarnesyl acetone was identified. The ethyl acetate extract effected only G+ bacteria, but the biofilm formation of G-bacteria was suppressed. There was a connection between those in vivo and in vitro effects against pathogenic bacterial biofilm formation. All of this points to a so far unexplored potential of N. minor.
description: EXCLI Journal; 14:Doc496; ISSN 1611-2156
Non-Fermi Liquid behavior at the Orbital Ordering Quantum Critical Point in the Two-Orbital Model
Creators: name: Lo, Ka Wai
name: Lee, Wei-Cheng
name: Phillips, Philip W.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The critical behavior of a two-orbital model with degenerate $d_{xz}$ and $d_{yz}$ orbitals is investigated by multidimensional bosonization. We find that the corresponding bosonic theory has an overdamped collective mode with dynamical exponent $z=3$, which appears to be a general feature of a two-orbital model and becomes the dominant fluctuation in the vicinity of the orbital-ordering quantum critical point. Since the very existence of this $z=3$ overdamped collective mode induces non-Fermi liquid behavior near the quantum critical point, we conclude that a two-orbital model generally has a sizable area in the phase diagram showing non-Fermi liquid behavior. Furthermore, we show that the bosonic theory resembles the continuous model near the d-wave Pomeranchuk instability, suggesting that orbital order in a two-orbital model is identical to nematic order in a continuous model. Our results can be applied to systems with degenerate $d_{xz}$ and $d_{yz}$ orbitals such as iron-based superconductors and bilayer strontium ruthenates Sr$_3$Ru$_2$O$_7$.
description: 5 pages, 2 figures
TeV Scale B-L model with a flat Higgs potential at the Planck scale -- in view of the hierarchy problem
Creators: name: Iso, Satoshi
name: Orikasa, Yuta
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The recent discovery of the Higgs-like particle at around 126 GeV has given us a big hint towards the origin of the Higgs potential. Especially the running quartic coupling vanishes near the Planck scale, which indicates a possible link between the physics in the electroweak and the Planck scales. Motivated by this and the hierarchy problem, we investigate a possibility that the Higgs has a flat potential at the Planck scale. In particular, we study the RG analysis of the B-L extension of the standard model with a classical conformality. The B-L symmetry is radiatively broken at the TeV scale via the Coleman-Weinberg mechanism. The electroweak symmetry breaking is triggered by a radiatively generated scalar mixing so that its scale 246 GeV is dynamically related with the B-L breaking scale at TeV. The Higgs boson mass is given at the border of the stability bound,which is lowered by a few GeV from the SM by the effect of the B-L gauge interaction.
description: 18 pages, 5 figures; report number changed
Electronic Structure and Stability of Cs$_{2}$TiX$_{6}$ and Cs$_{2}$ZrX$_{6}$ (X$=$Br,I) Vacancy Ordered Double Perovskites
Creators: name: Cucco, B.
name: Bouder, G.
name: Pedesseau, L.
name: Katan, C.
name: Even, J.
name: Kepenekian, M.
name: Volonakis, G.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Vacancy ordered halide perovskites have been extensively investigated as promising lead-free alternatives to halide perovskites for various opto-electronic applications. Among these Cs$_{2}$TiBr$_{6}$ has been reported as a stable absorber with interesting electronic and optical properties, such as a band-gap in the visible, and long carrier diffusion lengths. Yet, a thorough theoretical analysis of the exhibited properties is still missing in order to further assess its application potential from a materials design point of view. In this letter, we perform a detailed analysis for the established Ti-based compounds and investigate the less-known materials based on Zr. We discuss in details their electronic properties and band symmetries, highlight the similarity between the materials in terms of properties, and reveal limits for tuning electronic and optical properties within this family of vacancy ordered double perovskites that share the same electron configuration. We also show the challenges to compute accurate and meaningful quasi-particle corrections at GW level. Furthermore, we address their chemical stability against different decomposition reaction pathways, identifying stable regions for the formation of all materials, while probing their mechanical stability employing phonon calculations. We predict that Cs$_{2}$ZrI$_{6}$, a material practically unexplored to-date, shall exhibit a quasi-direct electronic band-gap well within the visible range, the smallest charge carrier effective masses within the Cs$_{2}$BX$_{6}$ (B=Ti,Zr; X=Br, I) compounds, and a good chemical stability.
Retrieving Cloud Effective Radius from GOES-13 Radiance Measurements
Creators: name: Nobrega, Thiago
name: Correia, Alexandre
name: Mendonça, Marina
name: Pugliesi, Andre
Publisher: name: Zenodo
Year: 2021

description: Abstract submitted to the XI Workshop on Lidar Measurements in Latin America, 19-22 October 2021, for a poster presentation.
Separating points through inclusions of $\mathcal O_\infty$
Creators: name: Kucerovsky, Dan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Operator Algebras (math.OA)
subject: FOS: Mathematics
subject: 46L05, 46L35

description: We define a basis property that an inclusion of C*-algebras $\mathcal O_\infty\subset A$ may have, and give various conditions for the property to hold. Some applications are considered. We also give a characterization of open projections in a corona algebra.
On counting centralizer subgroups of symmetric groups
Creators: name: Lu, Zhipeng
Publisher: name: arXiv
Year: 2019
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05A16

description: Let $S_{2m}$ be the symmetric group, $h=(1\ 2)(3\ 4)\cdots(2m-1\ 2m)$ and $H=C(h)$. We consider the structure of $gHg^{-1}\cap H$ for any $g\in S_{2m}$. We prove the permutations $g$ which makes $gHg^{-1}\cap H$ have size of polynomial in $m$ have density zero.
Fusion rules and complete reducibility of certain modules for affine Lie algebras
Creators: name: Adamovic, Drazen
name: Perse, Ozren
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Algebra (math.QA)
subject: Mathematical Physics (math-ph)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We develop a new method for obtaining branching rules for affine Kac-Moody Lie algebras at negative integer levels. This method uses fusion rules for vertex operator algebras of affine type. We prove that an infinite family of ordinary modules for affine vertex algebra of type A investigated in Adamović and O. Perše (2008) is closed under fusion. Then we apply these fusion rules on explicit bosonic realization of level -1 modules for the affine Lie algebra of type $A_{\ell-1}^{(1)}$, obtain a new proof of complete reducibility for these representations, and the corresponding decomposition for $\ell \ge 3$. We also obtain the complete reducibility of the associated level -1 modules for affine Lie algebra of type $C_{\ell}^{(1)}$. Next we notice that the category of $D_{2 \ell -1}^{(1)}$ modules at level $- 2 \ell +3 $ obtained in Perše (2012) has the isomorphic fusion algebra. This enables us to decompose certain $E_6 ^{(1)}$ and $F_4 ^{(1)}$--modules at negative levels.
description: 18 pages; final version, to appear in Journal of Algebra and Its Applications
Unidentified sources in the Fermi-LAT second source catalog: the case for DM subhalos
Creators: name: Zechlin, Hannes-S.
name: Horns, Dieter
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The Large Area Telescope (LAT) aboard the Fermi satellite allows us to study the high-energy gamma-ray sky with unprecedented sensitivity. However, the origin of 31% of the detected gamma-ray sources remains unknown. This population of unassociated gamma-ray sources may contain new object classes, among them sources of photons from self-annihilating or decaying non-baryonic dark matter. Fermi-LAT might be capable to detect up to a few of these dark matter subhalos as faint and moderately extended gamma-ray sources with a temporally steady high-energy emission. After applying corresponding selection cuts to the second year Fermi catalog 2FGL, we investigate 13 candidate objects in more detail including their multi-wavelength properties in the radio, infrared, optical, UV, and X-ray bands. For the gamma-ray band, we analyze both the 24-month and 42-month Fermi-LAT data sets. We probe the gamma-ray spectra for indications of a spectral cutoff, which singles out four sources of particular interest. We find all sources to be compatible with a point-source scenario. Multi-wavelength associations and, in particular, their infrared color-color data indicate no source to be compatible with a dark matter origin, and we find the majority of the candidates to probably originate from faint, high-frequency peaked BL Lac type objects. We discuss possibilities to further investigate source candidates and future prospects to search for dark matter subhalos.
description: 28 pages, 4 figures, 11 tables; v3: text as published in JCAP, v4: SWIFT-XRT analysis corrected (published as JCAP 02 (2015) E01)
Theory of overparametrization in quantum neural networks
Creators: name: Larocca, Martin
name: Ju, Nathan
name: García-Martín, Diego
name: Coles, Patrick J.
name: Cerezo, M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: The prospect of achieving quantum advantage with Quantum Neural Networks (QNNs) is exciting. Understanding how QNN properties (e.g., the number of parameters $M$) affect the loss landscape is crucial to the design of scalable QNN architectures. Here, we rigorously analyze the overparametrization phenomenon in QNNs with periodic structure. We define overparametrization as the regime where the QNN has more than a critical number of parameters $M_c$ that allows it to explore all relevant directions in state space. Our main results show that the dimension of the Lie algebra obtained from the generators of the QNN is an upper bound for $M_c$, and for the maximal rank that the quantum Fisher information and Hessian matrices can reach. Underparametrized QNNs have spurious local minima in the loss landscape that start disappearing when $M\geq M_c$. Thus, the overparametrization onset corresponds to a computational phase transition where the QNN trainability is greatly improved by a more favorable landscape. We then connect the notion of overparametrization to the QNN capacity, so that when a QNN is overparametrized, its capacity achieves its maximum possible value. We run numerical simulations for eigensolver, compilation, and autoencoding applications to showcase the overparametrization computational phase transition. We note that our results also apply to variational quantum algorithms and quantum optimal control.
description: 14+16 pages, 7+2 figures
Continuous slice functional calculus in quaternionic Hilbert spaces
Creators: name: Ghiloni, Riccardo
name: Moretti, Valter
name: Perotti, Alessandro
Publisher: name: arXiv
Year: 2012
Subjects: subject: Functional Analysis (math.FA)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Complex Variables (math.CV)
subject: Operator Algebras (math.OA)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 46S10, 47A60, 47C15, 30G35, 32A30, 81R15

description: The aim of this work is to define a continuous functional calculus in quaternionic Hilbert spaces, starting from basic issues regarding the notion of spherical spectrum of a normal operator. As properties of the spherical spectrum suggest, the class of continuous functions to consider in this setting is the one of slice quaternionic functions. Slice functions generalize the concept of slice regular function, which comprises power series with quaternionic coefficients on one side and that can be seen as an effective generalization to quaternions of holomorphic functions of one complex variable. The notion of slice function allows to introduce suitable classes of real, complex and quaternionic $C^*$--algebras and to define, on each of these $C^*$--algebras, a functional calculus for quaternionic normal operators. In particular, we establish several versions of the spectral map theorem. Some of the results are proved also for unbounded operators. However, the mentioned continuous functional calculi are defined only for bounded normal operators. Some comments on the physical significance of our work are included.
description: 71 pages, some references added. Accepted for publication in Reviews in Mathematical Physics
Lax--Oleinik formula on networks
Creators: name: Pozza, Marco
name: Siconolfi, Antonio
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35F21, 35R02, 35B51, 49L25

description: We provide a Lax-Oleinik-type representation formula for solutions of time-dependent Hamilton-Jacobi equations, posed on a network with a rather general geometry, under standard assumptions on the Hamiltonians. It depends on a given initial datum at $t=0$ and a flux limiter at the vertices, which both have to be assigned in order the problem to be uniquely solved. Previous results in the same direction are solely in the frame of junction, namely network with a single vertex. An important step to get the result is to define a suitable action functional and prove existence as well as Lipschitz-continuity of minimizers between two fixed points of the network in a given time, despite the fact that the integrand lacks convexity at the vertices.
description: 28 pages
Zum Stand der archäologischen Untersuchungen auf dem Weinberg in Hitzacker, Ldkr. Lüchow-Dannenberg
Creators: name: Saile, Thomas
Publisher: name: Nachrichten aus Niedersachsens Urgeschichte
Year: 2019

description: Nachrichten aus Niedersachsens Urgeschichte, Bd. 75 (2006): Nachrichten aus Niedersachsens Urgeschichte
Bounded vorticity for the 3D Ginzburg-Landau model and an isoflux problem
Creators: name: Román, Carlos
name: Sandier, Etienne
name: Serfaty, Sylvia
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 35Q56 (35J50 49K10 82D55)

description: We consider the full three-dimensional Ginzburg-Landau model of superconductivity with applied magnetic field, in the regime where the intensity of the applied field is close to the "first critical field" $H_{c_1}$ at which vortex filaments appear, and in the asymptotics of a small inverse Ginzburg-Landau parameter $\varepsilon$. This onset of vorticity is directly related to an "isoflux problem" on curves (finding a curve that maximizes the ratio of a magnetic flux by its length), whose study was initiated in [Román, C. On the First Critical Field in the Three Dimensional Ginzburg-Landau Model of Superconductivity. Commun. Math. Phys. 367, 317-349 (2019). https://doi.org/10.1007/s00220-019-03306-w] and which we continue here. By assuming a nondegeneracy condition for this isoflux problem, which we show holds at least for instance in the case of a ball, we prove that if the intensity of the applied field remains below $H_{c_1}+ C \log |\log \varepsilon|$, the total vorticity remains bounded independently of $\varepsilon$, with vortex lines concentrating near the maximizer of the isoflux problem, thus extending to the three-dimensional setting a two-dimensional result of [Sandier, E., Serfaty, S. Ginzburg-Landau minimizers near the first critical field have bounded vorticity. Cal Var 17, 17-28 (2003). https://doi.org/10.1007/s00526-002-0158-9]. We finish by showing an improved estimate on the value of $H_{c_1}$ in some specific simple geometries.
description: 50 pages, 4 figures
Betty Arndt, Andreas Strobl, gutingi - Vom Dorf zur Stadt
Creators: name: Gärtner, Tobias
Publisher: name: Nachrichten aus Niedersachsens Urgeschichte
Year: 2019

description: Rezension zu: Betty Arndt, Andreas Strobl, gutingi - Vom Dorf zur Stadt. Begleitband zur gleichnamigen Ausstellung in der Paulinerkirche in Göttingen vom 11. Juni bis 7. August 2005. Studien zur Geschichte der Stadt Göttingen 23. Göttingen: Vandenhoeck und Ruprecht 2005. 237 Seiten, zahlreiche überwiegend farbige Abbildungen; eine CD-Rom als Beilage. Kartoniert. ISBN 3-525-85426-9
description: Nachrichten aus Niedersachsens Urgeschichte, Bd. 75 (2006): Nachrichten aus Niedersachsens Urgeschichte
Analysis of the quantum Zeno effect for quantum control and computation
Creators: name: Dominy, Jason M.
name: Paz-Silva, Gerardo A.
name: Rezakhani, A. T.
name: Lidar, D. A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: Mathematical Physics (math-ph)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Within quantum information, many methods have been proposed to avoid or correct the deleterious effects of the environment on a system of interest. In this work, expanding on our earlier paper [G. A. Paz-Silva et al., Phys. Rev. Lett. 108, 080501 (2012), arXiv:1104.5507], we evaluate the applicability of the quantum Zeno effect as one such method. Using the algebraic structure of stabilizer quantum error correction codes as a unifying framework, two open-loop protocols are described which involve frequent non-projective (i.e., weak) measurement of either the full stabilizer group or a minimal generating set thereof. The effectiveness of the protocols is measured by the distance between the final state under the protocol and the final state of an idealized evolution in which system and environment do not interact. Rigorous bounds on this metric are derived which demonstrate that, under certain assumptions, a Zeno effect may be realized with arbitrarily weak measurements, and that this effect can protect an arbitrary, unknown encoded state against the environment arbitrarily well.
description: 19 pages, 1 figure
Fragmented deformations of primitive multiple curves
Creators: name: Drezet, J. -M.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14M05, 14B20

description: A primitive multiple curve is a Cohen-Macaulay irreducible projective curve Y that can be locally embedded in a smooth surface, and such that the associated reduced curve Y_red is smooth. The subject of this paper is the study of deformations of Y in curves with smooth irreducible components, when the number of components is maximal (it is then the multiplicity n of Y). We are particularly interested in deformations in n disjoint smooth irreducible components, which are called fragmented deformations. We describe them completely. We give also a characterization of primitive multiple curves having a fragmented deformation.
description: 40 pages, 1 figure
2D-QSAR study of some 2,5-diaminobenzophenone farnesyltransferase inhibitors by different chemometric methods
Creators: name: Ghanbarzadeh, Saeed
name: Ghasemi, Saeed
name: Shayanfar, Ali
name: Ebrahimi-Najafabadi, Heshmatollah
Publisher: name: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund
Year: 2015
Subjects: QSAR
multiple linear regression
artificial neural network
support vector machine

description: Quantitative structure activity relationship (QSAR) models can be used to predict the activity of new drug candidates in early stages of drug discovery. In the present study, the information of the ninety two 2,5-diaminobenzophenone-containing farnesyltranaferase inhibitors (FTIs) were taken from the literature. Subsequently, the structures of the molecules were optimized using Hyperchem software and molecular descriptors were obtained using Dragon software. The most suitable descriptors were selected using genetic algorithms-partial least squares and stepwise regression, where exhibited that the volume, shape and polarity of the FTIs are important for their activities. The two-dimensional QSAR models (2D-QSAR) were obtained using both linear methods (multiple linear regression) and non-linear methods (artificial neural networks and support vector machines). The proposed QSAR models were validated using internal validation method. The results showed that the proposed 2D-QSAR models were valid and they can be used for prediction of the activities of the 2,5-diaminobenzophenone-containing FTIs. In conclusion, the 2D-QSAR models (both linear and non-linear) showed good prediction capability and the non-linear models were exhibited more accuracy than the linear models.
description: EXCLI Journal; 14:Doc484; ISSN 1611-2156
Permanental fields, loop soups and continuous additive functionals
Creators: name: Jan, Yves Le
name: Marcus, Michael B.
name: Rosen, Jay
Publisher: name: arXiv
Year: 2012
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: A permanental field, $ψ=\{ψ(ν),ν\in {\mathcal{V}}\}$, is a particular stochastic process indexed by a space of measures on a set $S$. It is determined by a kernel $u(x,y)$, $x,y\in S$, that need not be symmetric and is allowed to be infinite on the diagonal. We show that these fields exist when $u(x,y)$ is a potential density of a transient Markov process $X$ in $S$. A permanental field $ψ$ can be realized as the limit of a renormalized sum of continuous additive functionals determined by a loop soup of $X$, which we carefully construct. A Dynkin-type isomorphism theorem is obtained that relates $ψ$ to continuous additive functionals of $X$ (continuous in $t$), $L=\{L_t^ν,(ν,t)\in {\mathcal{V}}\times R_+\}$. Sufficient conditions are obtained for the continuity of $L$ on ${\mathcal{V}}\times R_+$. The metric on ${\mathcal{V}}$ is given by a proper norm.
description: Published in at http://dx.doi.org/10.1214/13-AOP893 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Rational Blanchfield forms, S-equivalence, and null LP-surgeries
Creators: name: Moussard, Delphine
Publisher: name: arXiv
Year: 2012
Subjects: subject: Algebraic Topology (math.AT)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics

description: Null Lagrangian-preserving surgeries are a generalization of the Garoufalidis and Rozansky null-moves, that these authors introduced to study the Kricker lift of the Kontsevich integral, in the setting of pairs (M,K) composed of a rational homology sphere M and a null-homologous knot K in M. They are defined as replacements of null-homologous rational homology handlebodies of M\K by other such handlebodies with identical Lagrangian. A null Lagrangian-preserving surgery induces a canonical isomorphism between the rational Alexander modules of the involved pairs, which preserves the Blanchfield form. Conversely, we prove that a fixed isomorphism between rational Alexander modules which preserves the Blanchfield form can be realized, up to multiplication by a power of t, by a finite sequence of null Lagrangian-preserving surgeries. We also prove that such classes of isomorphisms can be realized by rational S-equivalences. In the case of integral homology spheres, we prove similar realization results for a fixed isomorphism between integral Alexander modules.
Música Pra Pensar. Rap E Identità Afrolusitana Nella Periferia Di Lisbona
Creators: name: Ranocchiari, Dario
Publisher: name: Zenodo
Year: 2015
Subjects: rap
performance
ethnicity
social identity
ethnography
hip hop
music
ethnomusicology
Chullage
Portugal
Lisboa

description: Tesi di laurea in etnomusicologia (a.a. 2004-2005) sull'uso della musica rap come catalizzatore identitario tra figli di migranti africani a Lisbona (Portogallo). In particolare, si centra sulla figura del rapper Chullage e sul lavoro dell'associazione Khapaz di Arrentela con i giovani di Arrentela (Grande Lisboa).
Status of state cyanoHAB outreach and monitoring efforts, United States
Creators: name: Hardy, F. Joan
name: Preece, Ellen
name: Backer, Lorraine
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Space Science
subject: Medicine
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Sociology
subject: FOS: Sociology
subject: Cancer
subject: Inorganic Chemistry
subject: FOS: Chemical sciences

description: Hardy FJ, Preece E, Backer L. 2021. Status of state cyanoHAB outreach and monitoring efforts, United States. Lake Reserv Manage. 37:246–260. A widespread effort is underway to improve awareness of cyanobacteria harmful algal blooms (cyanoHABs) across the United States using a variety of monitoring programs and public health outreach measures to protect people, pets, and livestock. To determine the status of cyanoHAB outreach and monitoring efforts, 2 questionnaires were distributed to health/environmental departments in 50 states and the District of Columbia (DC). One questionnaire focused on cyanoHAB exposure to humans from drinking water and the second targeted exposure through recreational activities. All states plus DC responded to the recreational survey; 46 states plus DC responded to the drinking water survey. All states except Alaska answered that microcystins were the cyanotoxins of greatest concern for recreational exposure; microcystins were also of greatest concern for drinking water with the exception of Utah (anatoxin-a in reservoirs was greatest concern) and Rhode Island (microcystins and anatoxin-a in reservoirs/ponds were greatest concern). Regional comparisons disclosed a lack of cyanoHAB programs in southern states relative to northern states that may be related to the higher percentage of water surface area in northern states. Interestingly, recreational outreach is more extensive than drinking water outreach (only 16 states reported having some type of drinking water outreach program, compared with 35 states with recreational outreach), and preferred outreach methods are websites and press releases. Additionally, respondents reported very limited funding for outreach and monitoring programs. Our results establish baseline information to help determine what future direction cyanoHAB outreach and monitoring programs can take at local, regional, and national levels.
Reinforcement Learning of Self Enhancing Camera Image and Signal Processing
Creators: name: Bajaj, Chandrajit
name: Wang, Yi
name: Yang, Yunhao
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Current camera image and signal processing pipelines (ISPs), including deep-trained versions, tend to apply a single filter that is uniformly applied to the entire image. This is despite the fact that most acquired camera images have spatially heterogeneous artifacts. This spatial heterogeneity manifests itself across the image space as varied Moire ringing, motion-blur, color-bleaching, or lens-based projection distortions. Moreover, combinations of these image artifacts can be present in small or large pixel neighborhoods, within an acquired image. Here, we present a deep reinforcement learning model that works in learned latent subspaces, and recursively improves camera image quality through a patch-based spatially adaptive artifact filtering and image enhancement. Our \textit{Recursive Self Enhancement Reinforcement Learning}(RSE-RL) model views the identification and correction of artifacts as a recursive self-learning and self-improvement exercise and consists of two major sub-modules: (i) The latent feature sub-space clustering/grouping obtained through variational auto-encoders enabling rapid identification of the correspondence and discrepancy between noisy and clean image patches. (ii) The adaptive learned transformation is controlled by a soft actor-critic agent that progressively filters and enhances the noisy patches using its closest feature distance neighbors of clean patches. Artificial artifacts that may be introduced in a patch-based ISP, are also removed through a reward-based de-blocking recovery and image enhancement. We demonstrate the self-improvement feature of our model by recursively training and testing on images, wherein the enhanced images resulting from each epoch provide a natural data augmentation and robustness to the RSE-RL training-filtering pipeline. Our method shows advantage for heterogeneous noise and artifact removal.
Disentangling L Dwarf Spectra: Making Sense Of The Tangled Mess
Creators: name: Cruz, Kelle
name: Núñez, Alejandro
Publisher: name: Zenodo
Year: 2012
Subjects: astronomy, spectroscopy, brown dwarfs

description: Poster describing new method for the analysis of L dwarf spectra.

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