cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Magnetic incommensurability and fluctuating charge density waves in the repulsive Hubbard model
Creators: name: Sherman, A
name: Schreiber, M
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Magnetic and charge susceptibilities of the two-dimensional repulsive Hubbard model are investigated applying a strong coupling diagram technique in which the expansion in powers of the hopping constants is used. For small lattices and high temperatures results are in agreement with Monte Carlo simulations. With the departure from half-filling $x$ the low-frequency magnetic susceptibility becomes incommensurate and the incommensurability parameter grows with $x$. The incommensurability, its dependence on frequency and on $x$ resemble experimental results in lanthanum cuprates. Also for finite $x$ sharp maxima appear in the static charge susceptibility. The maxima are finite which points to the absence of the long-range charge ordering (static stripes). However, for $x\approx 0.12$ the maxima are located near the momenta $(0,\pmπ/2)$, $(\pmπ/2,0)$. In this case an interaction of carriers with tetragonal distortions can stabilize stripes with the wavelength of four lattice spacings, as observed in the low-temperature tetragonal phase of cuprates. As follows from the obtained results, the magnetic incommensurability is not a consequence of the stripes.
description: 4 pages, 3 figures, manuscript for proceefings of LT25
Comments on "Privacy-Enhanced Federated Learning Against Poisoning Adversaries"
Creators: name: Schneider, Thomas
name: Suresh, Ajith
name: Yalame, Hossein
Publisher: name: arXiv
Year: 2024
Subjects: subject: Cryptography and Security (cs.CR)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: In August 2021, Liu et al. (IEEE TIFS'21) proposed a privacy-enhanced framework named PEFL to efficiently detect poisoning behaviours in Federated Learning (FL) using homomorphic encryption. In this article, we show that PEFL does not preserve privacy. In particular, we illustrate that PEFL reveals the entire gradient vector of all users in clear to one of the participating entities, thereby violating privacy. Furthermore, we clearly show that an immediate fix for this issue is still insufficient to achieve privacy by pointing out multiple flaws in the proposed system.
 Note: Although our privacy issues mentioned in Section II have been published in January 2023 (Schneider et. al., IEEE TIFS'23), several subsequent papers continued to reference Liu et al. (IEEE TIFS'21) as a potential solution for private federated learning. While a few works have acknowledged the privacy concerns we raised, several of subsequent works either propagate these errors or adopt the constructions from Liu et al. (IEEE TIFS'21), thereby unintentionally inheriting the same privacy vulnerabilities. We believe this oversight is partly due to the limited visibility of our comments paper at TIFS'23 (Schneider et. al., IEEE TIFS'23). Consequently, to prevent the continued propagation of the flawed algorithms in Liu et al. (IEEE TIFS'21) into future research, we also put this article to an ePrint.
description: Published at IEEE Transactions on Information Forensics and Security'23
Deep low-frequency observations with the Giant Metrewave Radio Telescope: a search for relic radio emission
Creators: name: Sirothia, S. K.
name: Saikia, D. J.
name: Ishwara-Chandra, C. H.
name: Kantharia, N. G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present deep multifrequency observations using the Giant Metrewave Radio Telescope at 153, 244, 610 and 1260 MHz of a field centered on J0916+6348, to search for evidence of fossil radio lobes which could be due to an earlier cycle of episodic activity of the parent galaxy, as well as halos and relics in clusters of galaxies. We do not find any unambiguous evidence of episodic activity in a list of 374 sources, suggesting that such activity is rare even in relatively deep low-frequency observations. We examine the spectra of all the sources by combining our observations with those from the Westerbork Northern Sky Survey, NRAO VLA Sky Survey and the Faint Images of the Radio Sky at Twenty-centimeters survey. Considering only those which have measurements at a minimum of three different frequencies, we find that almost all sources are consistent with a straight spectrum with a median spectral index, $α\sim$0.8 (S$(ν)\proptoν^{-α}$), which appears steeper than theoretical expectations of the injection spectral index. We identify 14 very steep-spectrum sources with $α\geq$1.3. We examine their optical fields and discuss the nature of some of these sources.
description: 7 figures and 2 tables, accepted for publication in MNRAS
The Chemical Enrichment History of the Small Magellanic Cloud and Its Gradients
Creators: name: Carrera, Ricardo
name: Gallart, Carme
name: Aparicio, Antonio
name: Costa, Edgardo
name: Méndez, Rene A.
name: Noël, Noelia E. D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present stellar metallicities derived from Ca II triplet spectroscopy in over 350 red giant branch stars in 13 fields distributed in different positions in the SMC, ranging from $\sim$1\arcdeg\@ to $\sim$4\arcdeg\@ from its center. In the innermost fields the average metallicity is [Fe/H] $\sim -1$. This value decreases when we move away towards outermost regions. This is the first detection of a metallicity gradient in this galaxy. We show that the metallicity gradient is related to an age gradient, in the sense that more metal-rich stars, which are also younger, are concentrated in the central regions of the galaxy.
description: 30 pages, 13 figures, accepted for publication in Astronomical Journal
Search for B0 -> K*+ K*-
Creators: name: The BABAR Collaboration
name: Aubert, B.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We report the results of a search for the decay B0 -> K*+ K*- with a sample of 454 +/- 5 million BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center. We obtain an upper limit at the 90% confidence level on the branching fraction for Br(B0 -> K*+ K*-) < 2.0 x 10^{-6}, assuming the decay is fully longitudinally polarized.
description: 8 pages, 9 postscript figures, accepted by Phys. Rev. D. (Rapid Communications)
Superconductivity in a quintuple-layer square-planar nickelate
Creators: name: Pan, Grace A.
name: Segedin, Dan Ferenc
name: LaBollita, Harrison
name: Song, Qi
name: Nica, Emilian M.
name: Goodge, Berit H.
name: Pierce, Andrew T.
name: Doyle, Spencer
name: Novakov, Steve
name: Carrizales, Denisse Córdova
name: N'Diaye, Alpha T.
name: Shafer, Padraic
name: Paik, Hanjong
name: Heron, John T.
name: Mason, Jarad A.
name: Yacoby, Amir
name: Kourkoutis, Lena F.
name: Erten, Onur
name: Brooks, Charles M.
name: Botana, Antia S.
name: Mundy, Julia A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Since the discovery of high-temperature superconductivity in the copper oxide materials, there have been sustained efforts to both understand the origins of this phase and discover new cuprate-like superconducting materials. One prime materials platform has been the rare-earth nickelates and indeed superconductivity was recently discovered in the doped compound Nd$_{0.8}$Sr$_{0.2}$NiO$_2$. Undoped NdNiO$_2$ belongs to a series of layered square-planar nickelates with chemical formula Nd$_{n+1}$Ni$_n$O$_{2n+2}$ and is known as the 'infinite-layer' ($n = \infty$) nickelate. Here, we report the synthesis of the quintuple-layer ($n = 5$) member of this series, Nd$_6$Ni$_5$O$_{12}$, in which optimal cuprate-like electron filling ($d^{8.8}$) is achieved without chemical doping. We observe a superconducting transition beginning at $\sim$13 K. Electronic structure calculations, in tandem with magnetoresistive and spectroscopic measurements, suggest that Nd$_6$Ni$_5$O$_{12}$ interpolates between cuprate-like and infinite-layer nickelate-like behavior. In engineering a distinct superconducting nickelate, we identify the square-planar nickelates as a new family of superconductors which can be tuned via both doping and dimensionality.
description: 21 pages, 4 figures
GW approximation with LSDA+U method and applications to NiO, MnO, and V$_2$O$_3$
Creators: name: Kobayashi, S.
name: Nohara, Y.
name: Yamamoto, S.
name: Fujiwara, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: A GW approximation (GWA) method named U+GWA is proposed, where we can start GWA with more localized wave functions obtained by the local spin-density approximation (LSDA)+U method. Then GWA and U+GWA are applied to MnO, NiO, and V$_2$O$_3$ in antiferromagnetic phase. The band gaps and energy spectra show an excellent agreement with the experimentally observed results and are discussed in details. The calculated width of d-bands of V$_2$O$_3$ is much narrower than that of the observed one which may be a mixture of t$_{2g}^2$ multiplet and single electron t$_{2g}$ level. GWA or U+GWA does not work also in the paramagnetic phase of V$_2$O$_3$ and the reason for thois is clarified. The method of the unique choice of on-site Coulomb interaction is discussed in details. The criterion for whether we should adopt GWA or U+GWA is discussed and is assessed with the help of the off-diagonal elements of the self-energy.
description: To appear in Phys. Rev. B
Levels of explainable artificial intelligence for human-aligned conversational explanations
Creators: name: Dazeley, Richard
name: Vamplew, Peter
name: Foale, Cameron
name: Young, Charlotte
name: Aryal, Sunil
name: Cruz, Francisco
Publisher: name: arXiv
Year: 2021
Subjects: subject: Artificial Intelligence (cs.AI)
subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: Over the last few years there has been rapid research growth into eXplainable Artificial Intelligence (XAI) and the closely aligned Interpretable Machine Learning (IML). Drivers for this growth include recent legislative changes and increased investments by industry and governments, along with increased concern from the general public. People are affected by autonomous decisions every day and the public need to understand the decision-making process to accept the outcomes. However, the vast majority of the applications of XAI/IML are focused on providing low-level `narrow' explanations of how an individual decision was reached based on a particular datum. While important, these explanations rarely provide insights into an agent's: beliefs and motivations; hypotheses of other (human, animal or AI) agents' intentions; interpretation of external cultural expectations; or, processes used to generate its own explanation. Yet all of these factors, we propose, are essential to providing the explanatory depth that people require to accept and trust the AI's decision-making. This paper aims to define levels of explanation and describe how they can be integrated to create a human-aligned conversational explanation system. In so doing, this paper will survey current approaches and discuss the integration of different technologies to achieve these levels with Broad eXplainable Artificial Intelligence (Broad-XAI), and thereby move towards high-level `strong' explanations.
description: 35 pages, 13 figures
On Ergodic Sum Capacity of Fading Cognitive Multiple-Access and Broadcast Channels
Creators: name: Zhang, Rui
name: Cui, Shuguang
name: Liang, Ying-Chang
Publisher: name: arXiv
Year: 2008
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: This paper studies the information-theoretic limits of a secondary or cognitive radio (CR) network under spectrum sharing with an existing primary radio network. In particular, the fading cognitive multiple-access channel (C-MAC) is first studied, where multiple secondary users transmit to the secondary base station (BS) under both individual transmit-power constraints and a set of interference-power constraints each applied at one of the primary receivers. This paper considers the long-term (LT) or the short-term (ST) transmit-power constraint over the fading states at each secondary transmitter, combined with the LT or ST interference-power constraint at each primary receiver. In each case, the optimal power allocation scheme is derived for the secondary users to achieve the ergodic sum capacity of the fading C-MAC, as well as the conditions for the optimality of the dynamic time-division-multiple-access (D-TDMA) scheme in the secondary network. The fading cognitive broadcast channel (C-BC) that models the downlink transmission in the secondary network is then studied under the LT/ST transmit-power constraint at the secondary BS jointly with the LT/ST interference-power constraint at each of the primary receivers. It is shown that D-TDMA is indeed optimal for achieving the ergodic sum capacity of the fading C-BC for all combinations of transmit-power and interference-power constraints.
description: To appear in IEEE Transactions on Information Theory
Sum rules for correlation functions of ionic mixtures in arbitrary dimension $d\geq 2$
Creators: name: Suttorp, L. G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The correlations in classical multi-component ionic mixtures with spatial dimension $d\geq 2$ are studied by using a restricted grand-canonical ensemble and the associated hierarchy equations for the correlation functions. Sum rules for the first few moments of the two-particle correlation function are derived and their dependence on $d$ is established. By varying $d$ continuously near $d=2$ it is shown how the sum rules for the two-dimensional mixture are related to those for mixtures at higher $d$.
description: 19 pages
Trees of definable sets over the p-adics
Creators: name: Halupczok, Immanuel
Publisher: name: arXiv
Year: 2008
Subjects: subject: Algebraic Geometry (math.AG)
subject: Logic (math.LO)
subject: FOS: Mathematics
subject: 11G25, 03C60, 11U09, 14B05, 14G20

description: To a definable subset of Z_p^n (or to a scheme of finite type over Z_p) one can associate a tree in a natural way. It is known that the corresponding Poincare series P(X) = \sum_i N_i X^i is rational, where N_i is the number of nodes of the tree at depth i. This suggests that the trees themselves are far from arbitrary. We state a conjectural, purely combinatorial description of the class of possible trees and provide some evidence for it. We verify that any tree in our class indeed arises from a definable set, and we prove that the tree of a definable set (or of a scheme) lies in our class in three special cases: under weak smoothness assumptions, for definable subsets of Z_p^2, and for one-dimensional sets.
description: 33 pages, 1 figure
An optically pumped iodine laser amplifier
Creators: name: Billing, Martyn Kenneth
Publisher: name: University of British Columbia
Year: 2010

description: The design process of an optically pumped amplifier for a CF₃I photodissoelation laser is described. In particular, a preamplifier is designed to amplify a 100 mJ laser pulse of 1 ns. duration which, by natural divergence, is contained in a beam of 2.5 cms diameter. Experimental studies of the sub-system of this preamplifier and the associated diagnostics are described. The operation of the preamplifier as part of the total laser system is discussed and suggestions are offered for the ongoing development of the device at the University of British Columbia.
A Screening Method for Power System Inertia Zones Identification
Creators: name: Prasad, {Rashmi
name: Vergara, Pedro P.
name: Padhy, Narayana Prasad
name: Dimitrovski, Robert
name: Lekić, Aleksandra
Publisher: name: arXiv
Year: 2024
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The heterogeneous distribution of frequency support from dispersed renewable generation sources results in varying inertia within the system. The effects of disturbances exhibit non-uniform variations contingent upon the disturbance's location and the affected region's topology and inertia. A screening method for inertia-zone identification is proposed considering the combination of network structure and generator inertia distribution that will aid in comprehending the response of nodes to disturbances. The nodes' dynamic nodal weight (DNW) is defined using maximal entropy random walk that defines each node's spreading power dynamics. Further, a modified weighted kmeans++ clustering technique is proposed using DNW to obtain the equivalent spatial points of each zone and the system to parameterize the inertia status of each zone. The impact of the proposed scheme is justified by simulating a modified IEEE 39 bus system with doubly-fed induction generator (DFIG) integration in the real-time digital simulator.
Anomalies, Horizons and Hawking radiation
Creators: name: Gangopadhyay, Sunandan
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Hawking radiation is obtained from the Reissner-Nordström blackhole with a global monopole and the Garfinkle-Horowitz-Strominger blackhole falling in the class of the most general spherically symmetric blackholes $(\sqrt{-g}\neq1)$, using only chiral anomaly near the event horizon and covariant boundary condition at the event horizon. The approach differs from the anomaly cancellation approach since apart from the covariant boundary condition, the chiral anomaly near the horizon is the only input to derive the Hawking flux.
description: minor corrections made, To appear in Euro. Phys. Letters
Properties of Classical and Quantum Jensen-Shannon Divergence
Creators: name: Briët, Jop
name: Harremoës, Peter
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Jensen-Shannon divergence (JD) is a symmetrized and smoothed version of the most important divergence measure of information theory, Kullback divergence. As opposed to Kullback divergence it determines in a very direct way a metric; indeed, it is the square of a metric. We consider a family of divergence measures (JD_alpha for alpha>0), the Jensen divergences of order alpha, which generalize JD as JD_1=JD. Using a result of Schoenberg, we prove that JD_alpha is the square of a metric for alpha lies in the interval (0,2], and that the resulting metric space of probability distributions can be isometrically embedded in a real Hilbert space. Quantum Jensen-Shannon divergence (QJD) is a symmetrized and smoothed version of quantum relative entropy and can be extended to a family of quantum Jensen divergences of order alpha (QJD_alpha). We strengthen results by Lamberti et al. by proving that for qubits and pure states, QJD_alpha^1/2 is a metric space which can be isometrically embedded in a real Hilbert space when alpha lies in the interval (0,2]. In analogy with Burbea and Rao's generalization of JD, we also define general QJD by associating a Jensen-type quantity to any weighted family of states. Appropriate interpretations of quantities introduced are discussed and bounds are derived in terms of the total variation and trace distance.
description: 13 pages, LaTeX, expanded contents, added references and corrected typos
The Computational and Latency Advantage of Quantum Communication Networks
Creators: name: Ferrara, Roberto
name: Bassoli, Riccardo
name: Deppe, Christian
name: Fitzek, Frank H. P.
name: Boche, Holger
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Theory (cs.IT)
subject: Quantum Physics (quant-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: This article summarises the current status of classical communication networks and identifies some critical open research challenges that can only be solved by leveraging quantum technologies. By now, the main goal of quantum communication networks has been security. However, quantum networks can do more than just exchange secure keys or serve the needs of quantum computers. In fact, the scientific community is still investigating on the possible use cases/benefits that quantum communication networks can bring. Thus, this article aims at pointing out and clearly describing how quantum communication networks can enhance in-network distributed computing and reduce the overall end-to-end latency, beyond the intrinsic limits of classical technologies. Furthermore, we also explain how entanglement can reduce the communication complexity (overhead) that future classical virtualised networks will experience.
description: 7 pages, 4 figures
Simultaneous packing and covering in sequence spaces
Creators: name: Swanepoel, Konrad J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Metric Geometry (math.MG)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 46B20 (primary), 52C17 (secondary)

description: We adapt a construction of Klee (1981) to find a packing of unit balls in $\ell_p$ ($1\leq p2^{1-1/p}$ covers the whole space. We show that the value $2^{1-1/p}$ is optimal.
description: 5 pages
Analysis and Modeling of the Hybrid Vessel's Electrical Power System
Creators: name: Mosselaar, Matthijs
name: Malbašić, Zoran
name: Fu, Aihui
name: Lekić, Aleksandra
Publisher: name: arXiv
Year: 2024
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: With the maritime industry poised on the cusp of a hybrid revolution, the design and analysis of advanced vessel systems have become paramount for engineers. This paper presents AC and DC electrical hybrid power system models in ETAP, the simulation software that can be adapted to engineer future hybrid vessels. These models are also a step towards a digital twin model that can help in troubleshooting and preventing issues, reducing risk and engineering time. The testing of the models is focused on time domain analysis, short-circuit currents, and protection \& coordination. The models are based on actual vessels and manufacturer parameters are used where available.
The dramatic size evolution of elliptical galaxies and the quasar feedback
Creators: name: Fan, L.
name: Lapi, A.
name: De Zotti, G.
name: Danese, L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Observations have evidenced that passively evolving massive galaxies at high redshift are much more compact than local galaxies with the same stellar mass. We argue that the observed strong evolution in size is directly related to the quasar feedback, which removes huge amounts of cold gas from the central regions in a Salpeter time, inducing an expansion of the stellar distribution. The new equilibrium configuration, with a size increased by a factor >~ 3, is attained after ~ 40 dynamical times, corresponding to ~ 2 Gyr. This means that massive galaxies observed at z >~ 1 will settle on the Fundamental Plane by z ~ 0.8-1. In less massive galaxies (M_star ~ 1 Gyr, the evolution for smaller galaxies is more difficult to perceive. Significant evolution of velocity dispersion is predicted for both small and large galaxies.
description: 4 pages, 2 figures, uses REVTeX4 + emulateapj.cls and apjfonts.sty. Accepted by ApJL
Polyamorie in der deutschsprachigen Presse 2007–2017
Creators: name: Ossmann, Stefan F.
Publisher: name: Österreichische Zeitschrift für Geschichtswissenschaften
Year: 2019

description: Österreichische Zeitschrift für Geschichtswissenschaften, Bd. 30 Nr. 1 (2019): Produzieren/Konsumieren – Prosumieren/Konduzieren
Echelle long-slit optical spectroscopy of evolved stars
Creators: name: Contreras, C. Sanchez
name: Sahai, R.
name: de Paz, A. Gil
name: Goodrich, R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present echelle long-slit optical spectra of a sample of objects evolving off the AGB, most of them in the pre-planetary nebula (pPN) phase, obtained with the ESI and MIKE spectrographs at Keck-II and Magellan-I, respectively. The total wavelength range covered with ESI (MIKE) is ~3900 to 10900 A (~3600 to 7200A). In this paper, we focus our analysis mainly on the Halpha profiles. Prominent Halpha emission is detected in half of the objects, most of which show broad Halpha wings (up to ~4000 km/s). In the majority of the Halpha-emission sources, fast, post-AGB winds are revealed by P-Cygni profiles. In ~37% of the objects Halpha is observed in absorption. In almost all cases, the absorption profile is partially filled with emission, leading to complex, structured profiles that are interpreted as an indication of incipient post-AGB mass-loss. All sources in which Halpha is seen mainly in absorption have F-G type central stars, whereas sources with intense Halpha emission span a larger range of spectral types from O to G. Shocks may be an important excitation agent of the close stellar surroundings for objects with late type central stars. Sources with pure emission or P Cygni Halpha profiles have larger J-K color excess than objects with Halpha mainly in absorption, which suggests the presence of warm dust near the star in the former. The two classes of profile sources also segregate in the IRAS color-color diagram in a way that intense Halpha-emitters have dust grains with a larger range of temperatures. (abridged)
description: 68 pages, 14 figures, accepted for publication in ApJS (abstract abridged)
The surface of (4) Vesta in visible light as seen by Dawn/VIR
Creators: name: Rousseau, B.
name: De Sanctis, M. C.
name: Raponi, A.
name: Ciarniello, M.
name: Ammannito, E.
name: Frigeri, A.
name: Carrozzo, F. G.
name: Tosi, F.
name: Scarica, P.
name: Fonte, S.
name: Raymond, C. A.
name: Russel, C. T.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We analyzed the surface of Vesta at visible wavelengths, using the data of the Visible and InfraRed mapping spectrometer (VIR) on board the Dawn spacecraft. We mapped the variations of various spectral parameters on the entire surface of the asteroid, and also derived a map of the lithology. We took advantage of the recent corrected VIR visible data to map the radiance factor at 550 nm, three color composites, two spectral slopes, and a band area parameter relative to the 930 nm crystal field signature in pyroxene. Using the howardite-eucrite-diogenite (HED) meteorites data as a reference, we derived the lithology of Vesta using the variations of the 930 nm and 506 nm (spin-forbidden) band centers observed in the VIR dataset. Our spectral parameters highlight a significant spectral diversity at the surface of Vesta. This diversity is mainly evidenced by impact craters and illustrates the heterogeneous subsurface and upper crust of Vesta. Impact craters also participate directly in this spectral diversity by bringing dark exogenous material to an almost entire hemisphere. Our derived lithology agrees with previous results obtained using a combination of infrared and visible data. We therefore demonstrate that it is possible to obtain crucial mineralogical information from visible wavelengths alone. In addition to the 506 nm band, we identified the 550 nm spin-forbidden one. As reported by a laboratory study for synthetic pyroxenes, we also do not observe any shift of the band center of this feature across the surface of Vesta, and thus across different mineralogies, preventing use of the 550 nm spin-forbidden band for the lithology derivation. Finally, the largest previously identified olivine rich-spot shows a peculiar behavior in two color composites but not in the other spectral parameters.
description: 23 pages, 11+7 figures
Multi-path entanglement of two photons
Creators: name: Rossi, A.
name: Vallone, G.
name: Chiuri, A.
name: De Martini, F.
name: Mataloni, P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present a novel optical device based on an integrated system of micro-lenses and single mode optical fibers. It allows to collect and direct into many modes two photons generated by spontaneous parametric down conversion. By this device multiqubit entangled states and/or multilevel qu-$d$it states of two photons, encoded in the longitudinal momentum degree of freedom, are created. The multi-path photon entanglement realized by this device is expected to find important applications in modern quantum information technology.
description: 4 pages, 3 figures, revtex, revised version
Andreev reflection in graphene nanoribbons
Creators: name: Rainis, Diego
name: Taddei, Fabio
name: Dolcini, Fabrizio
name: Polini, Marco
name: Fazio, Rosario
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study Andreev reflection in graphene nanoribbon/superconductor hybrid junctions. By using a tight-binding approach and the scattering formalism we show that finite-size effects lead to notable differences with respect to the bulk graphene case. At subgap voltages, conservation of pseudoparity, a quantum number characterizing the ribbon states, yields either a suppression of Andreev reflection when the ribbon has an even number of sites in the transverse direction or perfect Andreev reflection when the ribbon has an odd number of sites. In the former case the suppression of Andreev reflection induces an insulating behavior even when the junction is biased; electron conduction can however be restored by applying a gate voltage.
description: 6 pages, 6 figures
Akten der Konferenz "Phonetik und Phonologie im deutschsprachigen Raum (P&P14)"
Creators: name: Unknown
Publisher: name: Pustka, Elissa (Universität Wien)
Year: 2020
Subjects: Phonetik, Phonologie
University of Vienna, Vienna University Library
Universität Wien, Universitätsbibliothek Wien

description: Akten der Konferenz "Phonetik und Phonologie im deutschsprachigen Raum (P&P14)"
Polarization degrees of freedom in near-threshold photoproduction of omega mesons in the pi^0 gamma decay channel
Creators: name: Sarantsev, A. V.
name: Anisovich, A. V.
name: Nikonov, V. A.
name: Schmieden, H.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study polarization variables in the photoproduction of omega-mesons with subsequent omega to gamma pi^0 decay. Single and double polarization observables are calculated as a function of different final-state angles. Reaction models include pomeron (natural parity) and pi^0 (unnatural parity) exchange in the t-channel. In addition, the contribution of s-channel resonances is considered. The sensitivity of the polarization observables to the reaction dynamics is discussed.
description: 10 pages, 10 figures, explicit reference to sign of decay asymmetry added
title: Front Matter, Table of Contents, Preface, Conference Organization
Creators: name: Bramas, Quentin
name: Oshman, Rotem
name: Romano, Paolo
Publisher: name: Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Year: 2021
Subjects: subject: Front Matter
subject: Table of Contents
subject: Preface
subject: Conference Organization
subject: Theory of computation → Distributed computing models
subject: Theory of computation → Distributed algorithms
subject: Theory of computation → Concurrent algorithms
subject: Theory of computation → Data structures design and analysis
subject: Networks → Mobile networks
subject: Networks → Wireless access networks
subject: Networks → Ad hoc networks
subject: Computing methodologies → Distributed algorithms
subject: Security and privacy → Distributed systems security
subject: Information systems → Distributed storage
subject: Computer systems organization → Dependable and fault-tolerant systems and networks
subject: Software and its engineering → Distributed systems organizing principles

description: Front Matter, Table of Contents, Preface, Conference Organization
description: LIPIcs, Vol. 184, 24th International Conference on Principles of Distributed Systems (OPODIS 2020), pages 0:i-0:xvi
Magnetostatics and micromagnetics with physics informed neural networks
Creators: name: Kovacs, Alexander
name: Exl, Lukas
name: Kornell, Alexander
name: Fischbacher, Johann
name: Hovorka, Markus
name: Gusenbauer, Markus
name: Breth, Leoni
name: Oezelt, Harald
name: Praetorius, Dirk
name: Suess, Dieter
name: Schrefl, Thomas
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences
subject: I.6.3, I.6.5, I.2.6

description: Partial differential equations and variational problems can be solved with physics informed neural networks (PINNs). The unknown field is approximated with neural networks. Minimizing the residuals of the static Maxwell equation at collocation points or the magnetostatic energy, the weights of the neural network are adjusted so that the neural network solution approximates the magnetic vector potential. This way, the magnetic flux density for a given magnetization distribution can be estimated. With the magnetization as an additional unknown, inverse magnetostatic problems can be solved. Augmenting the magnetostatic energy with additional energy terms, micromagnetic problems can be solved. We demonstrate the use of physics informed neural networks for solving magnetostatic problems, computing the magnetization for inverse problems, and calculating the demagnetization curves for two-dimensional geometries.
description: 22 pages, 9 figures
Conductance of disordered graphene superlattice
Creators: name: Abedpour, N.
name: Esmailpour, Ayoub
name: Asgari, Reza
name: Tabar, M. Reza Rahimi
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We study the conductance of disordered graphene superlattices with short-range structural correlations. The system consists of electron- and hole-doped graphenes of various thicknesses, which fluctuate randomly around their mean value. The effect of the randomness on the probability of transmission through the system of various sizes is studied. We show that in a disordered superlattice the quasiparticle that approaches the barrier interface almost perpendicularly transmits through the system. The conductivity of the finite-size system is computed and shown that the conductance vanishes when the sample size becomes very large, whereas for some specific structures the conductance tends to a nonzero value in the thermodynamics limit.
description: 10 pages, 7 figures. Final version, to appear in Phys. Rev. B (2009)
Looking into the cradle of the grave: J22564-5910, a young post-merger hot subdwarf?
Creators: name: Vos, Joris
name: Pelisoli, Ingrid
name: Budaj, Jan
name: Reindl, Nicole
name: Schaffenroth, Veronika
name: Bobrick, Alexey
name: Geier, Stephan
name: Hermes, J. J.
name: Nemeth, Peter
name: Østensen, Roy
name: Reding, Joshua S.
name: Uzundag, Murat
name: Vuckovic, Maja
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present the discovery of J22564-5910, a new type of hot subdwarf (sdB) which shows evidence of gas present in the system and has shallow, multi-peaked hydrogen and helium lines which vary in shape over time. All observational evidence points towards J22564-5910 being observed very shortly after the merger phase that formed it. Using high-resolution, high signal-to-noise spectroscopy, combined with multi-band photometry, Gaia astrometry, and TESS light curves, we aim to interpret these unusual spectral features. The photometry, spectra and light curves are all analyzed, and their results are combined in order to support our interpretation of the observations: the likely presence of a magnetic field combined with gas features around the sdB. Based on the triple-peaked H lines, the magnetic field strength is estimated and, by using the shellspec code, qualitative models of gas configurations are fitted to the observations. All observations can either be explained by a magnetic field of ~650 kG which enables the formation of a centrifugal magnetosphere, or a non-magnetic hot subdwarf surrounded by a circumstellar gas disk/torus. Both scenarios are not mutually exclusive and both can be explained by a recent merger. J22564-5910 is the first object of its kind. It is a rapidly spinning sdB with gas still present in the system. It is the first post-merger star observed this early after the merger event, and as such is very valuable system to test merger theories. If the magnetic field can be confirmed, it is not only the first magnetic sdB, but it hosts the strongest magnetic field ever found in a pre-white dwarf object. Thus, it could represent the long-sought for immediate ancestor of strongly magnetic WDs.
description: 15 pages, 11 figures. Accepted for publication in A&A
Lithium intercalation in titanium disulfide
Creators: name: Dahn, Jeffery Raymond
Publisher: name: University of British Columbia
Year: 2010

description: The behaviour of Li/LiClO₄ ,PC/Li[sub x]TiS₂ electrochemical cells has been investigated. Electrolyte insertion(irreversible co-intercalation) occured in some Li[sub x]TiS₂ cathodes and was found to be dependent on the crystallite size of the cathode powder. In cases where electrolyte, insertion was small, the voltage as a function of state of discharge was found to agree with that reported by Thompson(1978). A neutron diffraction study on Li[sub x]TiS₂ with x = 0, .12, .33, .66 and 1.0 was performed. The location of the lithium atoms in the octahedral sites of the host TiS₂ lattice is established. The detailed crystal structure of Li₁TiS₂ is reported. No evidence for lithium ordering is observed in any of the samples at room temperature. Superlattice peaks were not detected at 106K for the Li.₃₃TiS₂ sample. The existence of three dimensional lithium ordering can be excluded by the data.
Spin-flip scattering in time-dependent transport through a quantum dot: Enhanced spin-current and inverse tunneling magnetoresistance
Creators: name: Perfetto, Enrico
name: Stefanucci, Gianluca
name: Cini, Michele
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study the effects of spin-flip scatterings on the time-dependent transport properties through a magnetic quantum dot attached to normal and ferromagnetic leads. The transient spin-dynamics as well as the steady-state tunneling magnetoresistance (TMR) of the system are investigated. The absence of a definite spin quantization axis requires the time-propagation of two-component spinors. We present numerical results in which the electrodes are treated both as one-dimensional tight-binding wires and in the wide-band limit approximation. In the latter case we derive a transparent analytic formula for the spin-resolved current, and transient oscillations damped over different time-scales are identified. We also find a novel regime for the TMR inversion. For any given strength of the spin-flip coupling the TMR becomes negative provided the ferromagnetic polarization is larger than some critical value. Finally we show how the full knowledge of the transient response allows for enhancing the spin-current by properly tuning the period of a pulsed bias.
description: 11 pages, 13 eps figures
Squeezed States and Affleck Dine Baryogenesis
Creators: name: Chaitanya, K. V. S. Shiv
name: Bambah, Bindu A
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Quantum fluctuations in the post inflationary Affleck-Dine baryogenesis model are studied. The squeezed states formalism is used to give evolution equations for the particle and anti-particle modes in the early universe. The role of expansion and parametric amplification of the quantum fluctuations on the baryon asymmetry produced is investigated.
description: 8 pages 9 figures
Gamma Ray Glow Observations at 20-km Altitude
Creators: name: Østgaard, N.
name: Christian, H. J.
name: Grove, J. E.
name: Sarria, D.
name: Mezentsev, A.
name: Kochkin, P.
name: Lehtinen, N.
name: Quick, M.
name: Al-Nussirat, S.
name: Wulf, E.
name: Genov, G.
name: Ullaland, K.
name: Marisaldi, M.
name: Yang, S.
name: Blakeslee, R. J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: In the spring of 2017 an ER-2 aircraft campaign was undertaken over continental United States to observe energetic radiation from thunderstorms and lightning. The payload consisted of a suite of instruments designed to detect optical signals, electric fields, and gamma rays from lightning. Starting from Georgia, USA, 16 flights were performed, for a total of about 70 flight hours at a cruise altitude of 20 km. Of these, 45 flight hours were over thunderstorm regions. An analysis of two gamma ray glow events that were observed over Colorado at 21:47 UT on 8May 2017 is presented.We explore the charge structure of the cloud system, as well as possible mechanisms that can produce the gamma ray glows. The thundercloud system we passed during the gamma ray glow observation had strong convection in the core of the cloud system. Electric field measurements combined with radar and radio measurements suggest an inverted charge structure, with an upper negative charge layer and a lower positive charge layer. Based on modeling results, we were not able to unambiguously determine the production mechanism. Possible mechanisms are either an enhancement of cosmic background locally (above or below 20 km) by an electric field below the local threshold or an enhancement of the cosmic background inside the cloud but then with normal polarity and an electric field well above the Relativistic Runaway Electron Avalanche threshold
The EAVI EMG/EEG Board: Hybrid physiological sensing
Creators: name: Tanaka, Atau
name: Fierro, David
name: Di Maggio, Francesco
name: Klang, Martin
name: Whitmarsh, Stephen
Publisher: name: arXiv
Year: 2024
Subjects: subject: Quantitative Methods (q-bio.QM)
subject: Signal Processing (eess.SP)
subject: FOS: Biological sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We present an update on the EAVI physiological interface, a wireless, microcontroller based hardware design for the acquisition of bioelectrical signals. The system has been updated to process electroencephalogram brain signals in addition to muscle electromyogram. The hardware/firmware system interfaces with host software carrying out feature extraction and signal processing. Recent advances in electronics have made physiological computing applications practical and feasible. However, there is a gap between high end biomedical equipment and consumer DIY solutions. The hardware design we present here bridges this gap, and combines a specialized biosignal acquisition chip mated with a general-purpose microcontroller. It is based on the Texas Instruments ADS129x family a single chip integrated solution for high quality biosignal amplification and digitization. It serves as analogue front end via programmable gain amplifiers to a 24bit delta-sigma analog-digital converter. The microcontroller is the STMicroelectronics STM32F427, a Cortex-M4 family microcontroller with floating point unit . In addition to EMG acquisition, the board includes a Kionix KX122 three-axis accelerometer. The TI and Kionix sensing chipts communicate with the ST microcontroller over an I2C digital serial bus. The board communicates with the host computer or rest of the music system wirelessly over Bluetooth LE 4.2 using an ST SPBTLE-1S transceiver. The board can also communicate over USB where it registers with the host as a class compliant audio and MIDI device. Audio and physiological signals are treated in the same signal processing chain using the OWL framework. The demo will show multichannel EMG, and single channel EEG. We call this hybridization ''ExG''. We will present documentation of the EAVI board used in the lab and on stage, in user studies with neuro-diverse musicians and trained instrumentalists, as well as in performance with the experimental all-female band, Chicks on Speed.
description: NIME 2023, NIME - New Interfaces for Musical Expression, May 2023, Mexico CIty, Mexico
Ratchet effect in frequency-modulated waveguide-coupled emitter arrays
Creators: name: Poddubny, Alexander N.
name: Golub, Leonid E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We study theoretically the spatial distribution of the polarizations in the array of resonant electromagnetic dipole emitters coupled to a one-dimensional waveguide. The ratchet effect manifests itself in the spatial asymmetry of the distribution of the emitter occupations along the array under symmetrical pumping from both sides. The occupation asymmetry is driven by the periodic modulation in time of the emitter resonance frequencies. We find numerically and analytically the optimal conditions for maximal asymmetry. We also demonstrate that the ratchet effect can be enhanced due to the formation of topological electromagnetic edge states, enabled by the frequency modulation. Our results apply to the classical structures with coupled resonators or arrays of semiconductor quantum wells as well as the quantum setups with waveguide-coupled natural or artificial atoms.
description: 7 pages, 5 figures
On empirical meaning of randomness with respect to a real parameter
Creators: name: V'yugin, Vladimir
Publisher: name: arXiv
Year: 2008
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences
subject: I.2.6

description: We study the empirical meaning of randomness with respect to a family of probability distributions $P_θ$, where $θ$ is a real parameter, using algorithmic randomness theory. In the case when for a computable probability distribution $P_θ$ an effectively strongly consistent estimate exists, we show that the Levin's a priory semicomputable semimeasure of the set of all $P_θ$-random sequences is positive if and only if the parameter $θ$ is a computable real number. The different methods for generating ``meaningful'' $P_θ$-random sequences with noncomputable $θ$ are discussed.
description: 14 pages