cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Hinge Spin Polarization in Magnetic Topological Insulators Revealed by Resistance Switch
Creators: name: Perez-Piskunow, Pablo M.
name: Roche, Stephan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We report on the possibility to detect hinge spin polarization in magnetic topological insulators by resistance measurements. By implementing a three-dimensional model of magnetic topological insulators into a multi-terminal device with ferromagnetic contacts near the top surface, local spin features of the chiral edge modes are unveiled. We find local spin polarization at the hinges that inverts sign between top and bottom surfaces. At the opposite edge, the topological state with inverted spin polarization propagates in the reverse direction. Large resistance switch between forward and backward propagating states is obtained, driven by the matching between the spin polarized hinges and the ferromagnetic contacts. This feature is general to the ferromagnetic, antiferromagnetic and canted-antiferromagnetic phases, and enables the design of spin-sensitive devices, with the possibility of reversing the hinge spin polarization of the currents.
description: Main: 6 pages, 4 figures. Supplemental Material: 3 pages, 5 figures
Coupling Light to Higher Order Transverse Modes of a Near-Concentric Optical Cavity
Creators: name: Utama, Adrian Nugraha
name: Chow, Chang Hoong
name: Nguyen, Chi Huan
name: Kurtsiefer, Christian
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Optical cavities in the near-concentric regime have near-degenerate transverse modes; the tight focusing transverse modes in this regime enable strong coupling with atoms. These features provide an interesting platform to explore multi-mode interaction between atoms and light. Here, we use a spatial light modulator (SLM) to shape the phase of an incoming light beam to match several Laguerre-Gaussian (LG) modes of a near-concentric optical cavity. We demonstrate coupling efficiency close to the theoretical prediction for single LG modes and well-defined combinations of them, limited mainly by imperfections in the cavity alignment.
description: 12 pages, 7 figures
Theorising the informant: the epistemic space of Bengal and the codification of Hindu law 1772-1800
Creators: name: Dodson, Michael S.
Publisher: name: University of British Columbia
Year: 2009

description: This thesis attempts to interpret the events surrounding the codification and implementation of Hindu law in late eighteenth century Bengal, under the government of the East India Company. The first chapter provides the necessary framework of historical facts for this interpretation; it consists primarily of a narrative of events such as the implementation of structural changes to the judicature, and the collection and translation of "laws" from the Hindu normative treatises, the dharmasastra, in Company sponsored legal digests. The second chapter provides the basic theoretical framework through which these events are interpreted, by first discussing the utilisation of discourse theory by Edward Said in Orientalism, and then by considering subsequent refinements to his approach. I argue for a conception of epistemic space as constituted by objects of knowledge, variously inscribed by divergent discourses. Further, each discourse is seen to be connected with non-discursive factors through the enunciation of individual members of various knowledge communities. Two separate and competing discourses are then described, the first wielded by orientalists and East India Company officials, in a justification of Company rule in India, and the second deployed by Hindu pandits in the compilation of dharmasastra nibandhas. Each discourse is seen to be derived in large part from pre-existing philosophical frameworks peculiar to the members of these two different knowledge communities. The legal, colonial discourse of the orientalists is informed largely by notions of "civil society" and "civil justice," while the "traditional" discourse of the pandits is influenced principally by the philosophical methodologies of mvmdmsa and nyaya, and the concept of dharma. Utilising the concept of "hybridity" as developed by Homi Bhabha, I argue that the pandits of late eighteenth century Bengal refused the demands of colonial discourse, and thereby colonialism itself, by not accepting the "civilise-ational" requirements it imposed upon the legal project.
Particle acoustic detection in gravitational wave aluminum resonant antennas
Creators: name: Buonomo, B.
name: Coccia, E.
name: D'Antonio, S.
name: Monache, G. Delle
name: Di Gioacchino, D.
name: Fafone, V.
name: Ligi, C.
name: Marini, A.
name: Mazzitelli, G.
name: Modestino, G.
name: Panella, S.
name: Pizzella, G.
name: Quintieri, L.
name: Roccella, S.
name: Ronga, F.
name: Tripodi, P.
name: Valente, P.
Publisher: name: arXiv
Year: 2005
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The results on cosmic rays detected by the gravitational antenna NAUTILUS have motivated an experiment (RAP) based on a suspended cylindrical bar, which is made of the same aluminum alloy as NAUTILUS and is exposed to a high energy electron beam. Mechanical vibrations originate from the local thermal expansion caused by warming up due to the energy lost by particles crossing the material. The aim of the experiment is to measure the amplitude of the fundamental longitudinal vibration at different temperatures. We report on the results obtained down to a temperature of about 4 K, which agree at the level of about 10% with the predictions of the model describing the underlying physical process.
description: RAP experiment, 16 pages, 7 figures
Real time multibody modeling and simulation of a scaled bogie test rig
Creators: name: Shrestha, Sundar
name: Spiryagin, Maksym
name: Wu, Qing
Publisher: name: arXiv
Year: 2020
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: In wheel rail adhesion studies, most of the test rigs used are simplified designs such as a single wheel or wheelset, but the results may not be accurate. Alternatively, representing the complex system by using a full vehicle model provides accurate results but may incur complexity in design. To trade off accuracy over complexity, a bogie model can be the optimum selection. Furthermore, only a real time model can replicate its physical counterpart in the time domain. Developing such a model requires broad expertise and appropriate software and hardware. A few published works are available which deal with real time modeling. However, the influence of the control system has not been included in those works. To address these issues, a real-time scaled bogie test rig including the control system is essential. Therefore, a 1:4 scaled bogie roller rig is developed to study the adhesion between wheel and roller contact. To compare the performances obtained from the scaled bogie test rig and to expand the test applications, a numerical simulation model of that scaled bogie test rig is developed using Gensys multibody software. This model is the complete model of the test rig which delivers more precise results. To exactly represent the physical counterpart system in the time domain, a real-time scaled bogie test rig (RT SBTR) is developed after four consecutive stages. Then, to simulate the RT-SBTR to solve the internal state equations and functions representing the physical counterpart system in equal or less than actual time, the real-time simulation environment is prepared in two stages. To such end, the computational time improved from 4 times slower than real time to 2 times faster than real time. Finally, the real time scaled bogie model is also incorporated with the braking control system which slightly reduces the computational performances without affecting real time capability.
description: 14 pages, 18 figures, journal paper
Performance Modeling of Streaming Kernels and Sparse Matrix-Vector Multiplication on A64FX
Creators: name: Alappat, Christie L.
name: Laukemann, Jan
name: Gruber, Thomas
name: Hager, Georg
name: Wellein, Gerhard
name: Meyer, Nils
name: Wettig, Tilo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Performance (cs.PF)
subject: Hardware Architecture (cs.AR)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: The A64FX CPU powers the current number one supercomputer on the Top500 list. Although it is a traditional cache-based multicore processor, its peak performance and memory bandwidth rival accelerator devices. Generating efficient code for such a new architecture requires a good understanding of its performance features. Using these features, we construct the Execution-Cache-Memory (ECM) performance model for the A64FX processor in the FX700 supercomputer and validate it using streaming loops. We also identify architectural peculiarities and derive optimization hints. Applying the ECM model to sparse matrix-vector multiplication (SpMV), we motivate why the CRS matrix storage format is inappropriate and how the SELL-C-sigma format with suitable code optimizations can achieve bandwidth saturation for SpMV.
description: 6 pages, 5 figures, 3 tables
The deformed Hermitian-Yang-Mills equation on almost Hermitian manifolds
Creators: name: Huang, Liding
name: Zhang, Jiaogen
name: Zhang, Xi
Publisher: name: arXiv
Year: 2020
Subjects: subject: Differential Geometry (math.DG)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: In this paper, we consider the deformed Hermitian-Yang-Mills equation on closed almost Hermitian manifolds. In the case of hypercritical phase, we derive a priori estimates under the existence of an admissible $\mathcal{C}$-subsolution. As an application, we prove the existence of solutions for the deformed Hermitian-Yang-Mills equation under the condition of existence of a supersolution.
MIDDLE TRIASSIC PLATFORM AND BASIN EVOLUTION OF THE SOUTHERN BAKONY MOUNTAINS (TRANSDANUBIAN RANGE, HUNGARY)
Creators: name: BUDAI, TAMÁS
name: VÖRÖS, ATTILA
Publisher: name: Università degli Studi di Milano
Year: 2006

description: Middle Triassic history of the Southern Bakony Mts. is outlined on the base of horizontal and vertical facies changes of the formations. During the Pelsonian (Balatonicus Chron) the evolution of the basins and platforms was determined basically by synsedimentary tectonics. The Felsõörs basin of the Balaton Highland opened due to the block-faulting of the Bithynian carbonate ramp (Megyehegy Dolomite). Above the drowning blocks „halfgraben” basins were formed (Felsõörs Formation), while isolated platforms developed on the uplifted ones in the middle part of the Balaton Highland and on the Veszprém plateau (Tagyon Formation). Due to the relative sea-level fall in the early Illyrian, the platforms became subaerially exposed and karstified. As a consequence of the late Illyrian tectonic subsidence (manifested by neptunian dykes) the central platform of the Balaton Highland has been drowned (Camunum Subchron). On the contrary, the Anisian platform of the Veszprém plateau was totally flooded only during the latest Illyrian (Reitzi Subchron) due to eustatic sea-level rise. It was followed by a short highstand period (Secedensis Chron), characterised by the first progradation of the Budaörs platform on the Veszprém plateau and highstand shedding in the basins and on the submarine high (Vászoly Limestone) in the centre of the Balaton Highland basin. Due to the following rapid sea-level rise, carbonate sedimentation continued in eupelagic basin from the Fassanian (Buchenstein Formation). At the beginning of the late Longobardian highstand period (Regoledanus Chron) the Budaörs platform intensively prograded from the Veszprém plateau to the southwest, causing highstand shedding in the Balaton Highland basin (Füred Limestone).
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 112, No 3
Computing nearest stable matrix pairs
Creators: name: Gillis, Nicolas
name: Mehrmann, Volker
name: Sharma, Punit
Publisher: name: Technische Universität Berlin
Year: 2017
Subjects: subject: 510 Mathematik
subject: dissipative Hamiltonian system
subject: distance to stability
subject: convex optimization

description: In this paper, we study the nearest stable matrix pair problem: given a square matrix pair (E,A), minimize the Frobenius norm of (∆E,∆A) such that (E+\∆E,A+∆A) is a stable matrix pair. We propose a reformulation of the problem with a simpler feasible set byintroducing dissipative Hamiltonian (DH) matrix pairs: A matrix pair (E,A) is DH if A=(J-R)Q with skew-symmetric J, positive semidefinite R, and an invertible Q such that Q^TE is positive semidefinite. This reformulation has a convex feasible domain onto which it is easy to project. This allows us to employ a fast gradient method to obtain a nearby stable approximation of a given matrix pair.
An exceptional symmetry algebra for the 3D Dirac-Dunkl operator
Creators: name: Langlois-Rémillard, Alexis
name: Oste, Roy
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: Representation Theory (math.RT)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We initiate the study of an algebra of symmetries for the 3D Dirac-Dunkl operator associated with the Weyl group of the exceptional root system $G_2$. For this symmetry algebra, we give both an abstract definition and an explicit realisation. We then construct ladder operators, using an intermediate result we prove for the Dirac-Dunkl symmetry algebra associated with arbitrary finite reflection group acting on a three-dimensional space.
description: 7 pages; to be published in Springer Proceedings in Mathematics & Statistics
PECULIAR PRESERVATION OF A JUVENILE PACHYPLEUROSAURID FROM BESANO (ITALY)
Creators: name: RENESTO, SILVIO
Publisher: name: Università degli Studi di Milano
Year: 2006

description: A small pachypleurosaurid collected in the Besano area of Italy, is described. A comparative analysis of size and proportions with other pachipleurosaurids suggest it represents a juvenile specimen of Neusticosaurus pusillus. The specimen represents a peculiar taphonomic case: the centra of the dorsal vertebrae are clustered together in the pectoral area while the rest of the trunk is virtually undisturbed, suggesting that disarticulation of dorsal vertebral elements may have occurred before decay of integumental soft parts, possibly before the carcass reached the bottom of the basin.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 112, No 3
NEW LADINIAN AMMONOIDS FROM MT. SVILAJA (EXTERNAL DINARIDES, CROATIA)
Creators: name: BALINI, MARCO
name: JURKOVSEK, BOGDAN
name: KOLAR-JURKOVSEK, TEA
Publisher: name: Università degli Studi di Milano
Year: 2006

description: A small collection of Ladinian ammonoids from Mt. Svilaja (External Dinarides) is here described for the first time. The ammonoids were collected from a thick succession, which yielded in its lower part the classic Lower Triassic ammonoid faunas of Muæ, known since the XIX century. The collection comes from an interval yielding conodonts of the hungaricus Assemblage zone, and is composed of leiostraca (Proarcestes) and trachyostraca ammonoids. The latter consists of the new genus Alkaites, and the new species A. dinaricus, Detoniceras svilajanus and Argolites trinodosus. Alkaites n. gen. is characterised by involute coiling, v-shaped ventral side and five spiral rows of nodes. D. svilajanus n. sp. is distinguished by flat ventral side, and four rows of nodes with peculiar ratio 1:1:2:2 between perimbilical,1st lateral, 2nd lateral, and ventrolateral nodes. A. trinodosus n. sp. is characterised from any other species of Argolites by three rows of nodes. At the present the new genus Alkaites and the three new species are known only from the study area. The dating of the new taxa is done by indirect correlations based on the distribution of Detoniceras and Argolites in other sections of the Southern Alps, as well as on the calibration of the hungaricus Assemblage zone with the ammonoid standard scale. The inferred age is Gredleri Zone (Lower Ladinian).
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 112, No 3
Wideband Monitoring Observations of PSR J1803-3002A in the Globular Cluster NGC 6522
Creators: name: Zhang, Lei
name: Manchester, Richard N.
name: Cameron, Andrew D.
name: Hobbs, George
name: Li, Di
name: Dai, Shi
name: Zhi, Qijun
name: Zhu, Zonghong
name: Wang, Jingbo
name: Toomey, Lawrence
name: Feng, Yi
name: Wang, Shuangqiang
name: Zhang, Songbo
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We report the first wideband monitoring observations of PSR J1803-3002A, a relatively bright millisecond pulsar in the globular cluster NGC 6522 with a spin period of 7.1 ms and no known binary companion. These observations were performed using the Parkes 64-m radio telescope with the Ultra-Wideband Low (UWL) receiver system, which covers 704 to 4032 MHz. We confirm that PSR J1803-3002A is an isolated millisecond pulsar located near the cluster center and probe the emission properties of the pulsar over the wide observed band. The mean pulse profile consists of three components, with the outer components becoming more prominent at higher frequencies, and a mean spectral index for the pulsed emission of -1.66+/-0.07 over the observed band. The fractional linear and circular polarization increase with increasing frequency, which is unusual for pulsars. We determine a Faraday rotation measure of -107+/-6 rad m-2 for the pulsar. PSR J1803-3002A is a distant pulsar in the Galactic plane, but there is no evidence of pulse broadening due to interstellar scattering in our observations. These results demonstrate the power of ultra-wideband receiving and signal processing systems.
PLANT FOSSIL REMAINS FROM THE RHAETIAN OF SHEMSHAK FORMATION,NARGES-CHAL AREA, ALBORZ, NE IRAN
Creators: name: VAEZ-JAVADI, FATEMEH
Publisher: name: Università degli Studi di Milano
Year: 2006

description: The Shemshak Formation is well-exposed in Narges-Chal area, East Alborz. It contains abundant well-preserved plant megafossils belonging to twenty two taxa of various orders viz., Equisetales, Marattiales, Filicales, Pteridospermales, Bennettitales, Ginkgoales, and Coniferales. Based on the occurrence of Equisetites conicus, Scytophyllum persicum, Otozamites ashtarensis, Pterophyllum bavieri, Pterophyllum tietzei, Zamites persica, Nilssoniopteris musafolia and Baiera muensteriana a Rhaetian age is suggested for this assemblage.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 112, No 3
The volume operator for singly polarized gravity waves with planar or cylindrical symmetry
Creators: name: Neville, Donald E.
Publisher: name: arXiv
Year: 2005
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: A previous paper constructed a kinematic basis for spin networks with planar or cylindrical symmetry and arbitrary polarization. This paper imposes a constraint which limits the gravitational wave to a single polarization. The spectrum of the constraint contains a physically reasonable number of zero eigenvalues, and the zero eigenvectors can be constructed explicitly. Commutation of the constraint with the Hamiltonian is expected to lead to a further constraint. This new constraint is not investigated in this paper, but I argue it will be non-local, relating states at two or more neighboring vertices.
description: Expanded discussion of outlook for future research, in last three paragraphs. Corrected the typo in eq. (3). 12 pages
Momentum distribution function and short-range correlations of the warm dense electron gas -- ab initio quantum Monte Carlo results
Creators: name: Hunger, Kai
name: Schoof, Tim
name: Dornheim, Tobias
name: Bonitz, Michael
name: Filinov, Alexey
Publisher: name: arXiv
Year: 2021
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: In a classical plasma the momentum distribution, $n(k)$, decays exponentially, for large $k$, and the same is observed for an ideal Fermi gas. However, when quantum and correlation effects are relevant simultaneously, an algebraic decay, $n_\infty(k)\sim k^{-8}$ has been predicted. This is of relevance for cross sections and threshold processes in dense plasmas that depend on the number of energetic particles. Here we present extensive \textit{ab initio} results for the momentum distribution of the nonideal uniform electron gas at warm dense matter conditions. Our results are based on first principle fermionic path integral Monte Carlo (CPIMC) simulations and clearly confirm the $k^{-8}$ asymptotic. This asymptotic behavior is directly linked to short-range correlations which are analyzed via the on-top pair distribution function (on-top PDF), i.e. the PDF of electrons with opposite spin. We present extensive results for the density and temperature dependence of the on-top PDF and for the momentum distribution in the entire momentum range.
Traduction et hospitalité : essai sur la tradition orale autochtone et le pluralisme juridique canadien
Creators: name: Lemieux, René
Publisher: name: Université d'Ottawa / University of Ottawa
Year: 2019
Subjects: traduction
Delgamuukw
tradition orale autochtone
pluralisme juridique
droit canadien
droit autochtone

description: La thèse a pour point de départ d’arrêt Delgamuukw (1997) qui évoque la possibilité d’admettre en cour des récits oraux autochtones à titre de preuve. Le discours sur cette nouveauté juridique est ici un prétexte à une réflexion sur ce qui passe et ce qui ne passe pas entre la tradition juridique autochtone et le droit colonial canadien. En grande partie, il s’agit, pour prendre une métaphore psychanalytique, d’allonger le droit colonial canadien sur un divan et de l’écouter discourir sur la représentation qu’il se donne des récits oraux autochtones, lesquels se constituent très souvent comme des ordres juridiques autochtones en confrontation ouverte avec la souveraineté de l’État canadien. La méthode proposée pour analyser ce discours est tirée pour une bonne part des études de la traduction, aussi appelées traductologie. Le premier chapitre vise à définir la problématique des enjeux autochtones à l’intérieur du pluralisme juridique au Canada en analysant les lieux des ordres juridiques autochtones au Canada, dans une perspective à la fois juridique et politique. Le deuxième chapitre examine une série de dichotomies conceptuels évoquées par le discours juridique canadien – l’oralité et l’écriture, le témoignage et la preuve, le fond et la forme – pour à chaque fois montrer la manière avec laquelle le droit s’affirme par l’exclusion d’une altérité. Finalement, l’objectif de la thèse est de montrer que les rapports entre le droit colonial canadien et les ordres juridiques autochtones s’organisent comme des apories – ou indécidables –, et ces apories travaillent en retour les concepts juridiques par lesquels le droit se raconte.
PDE Eigenvalue Iterations with Applications in Two-dimensional Photonic Crystals
Creators: name: Altmann, Robert
name: Froidevaux, Marine
Publisher: name: Technische Universität Berlin
Year: 2018
Subjects: subject: 510 Mathematik
subject: nonlinear eigenvalue problem
subject: photonic crystals
subject: inverse power
subject: Newton iteration

description: The first part of this paper is devoted to the approximative solution of linear and Hermitian eigenvalue problems where the differential operator satisfies a Garding inequality. For this, known iterative schemes for the matrix case such as the inverse power or Arnoldi method are extended to the infinite-dimensional case. This formally allows one to apply different spatial discretizations in each iteration step and thus, justifies the use of adaptive methods. The second part considers eigenvalue problems as they appear in two-dimensional models of photonic crystals for the computation of band-gaps. If the permittivity of the material is frequency-dependent, then this leads to a nonlinear eigenvalue problem. For this, we consider two strategies. First, a linearization combined with the application of the inverse power method and second, a direct application of Newton's iteration.
Kaluza-Klein black hole with negatively curved extra dimensions in string generated gravity models
Creators: name: Maeda, Hideki
name: Dadhich, Naresh
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We obtain a new exact black-hole solution in Einstein-Gauss-Bonnet gravity with a cosmological constant which bears a specific relation to the Gauss-Bonnet coupling constant. The spacetime is a product of the usual 4-dimensional manifold with a $(n-4)$-dimensional space of constant negative curvature, i.e., its topology is locally ${\ma M}^n \approx {\ma M}^4 \times {\ma H}^{n-4}$. The solution has two parameters and asymptotically approximates to the field of a charged black hole in anti-de Sitter spacetime. The most interesting and remarkable feature is that the Gauss-Bonnet term acts like a Maxwell source for large $r$ while at the other end it regularizes the metric and weakens the central singularity.
description: 4 pages, 2 figures, final version to appear in Physical Review D as a rapid communication
Exciton-trion dynamics of a single molecule in a radio-frequency cavity
Creators: name: Doležal, Jiří
name: Canola, Sofia
name: Merino, Pablo
name: Švec, Martin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Charged optical excitations (trions) generated by charge carrier injection are crucial for emerging optoelectronic technologies as they can be produced and manipulated by electric fields. Trions and neutral excitons can be efficiently induced in single molecules by means of tip-enhanced spectromicroscopic techniques. However, little is known of the exciton-trion dynamics at single molecule level as this requires methods permitting simultaneous sub-nanometer and sub-nanosecond characterization. Here, we investigate exciton-trion dynamics by phase fluorometry, combining radio-frequency modulated scanning tunnelling luminescence with time-resolved single photon detection. We generate excitons and trions in single Zinc Phthalocyanine (ZnPc) molecules on NaCl/Ag(111), determine their dynamics and trace the evolution of the system in the picosecond range with atomic resolution. In addition, we explore dependence of effective lifetimes on bias voltage and propose a conversion of neutral excitons into trions via charge capture as the primary mechanism of trion formation.
Arithmetical Foundations A
Creators: name: Pfender, Michael
Publisher: name: Technische Universität Berlin
Year: 2018
Subjects: subject: 510 Mathematik
subject: research exposition
subject: arithmetical foundations
subject: free variables
subject: Hilbert’s infinite hotel
subject: Natural Numbers Object N

description: Free-variables categorical cartesian theories: Interpretation of free variables as identitic maps or projections. Iteration, full schema of primitive recursion, Hilbert's infnite hotel, Algebra and order on the Natural Numbers Object N.
Recent twists in twisted light: A perspective on optical vortices from dielectric metasurfaces
Creators: name: Piccardo, Marco
name: Ambrosio, Antonio
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Optical vortices are the electromagnetic analogue of fluid vortices studied in hydrodynamics. In both cases the traveling wavefront, either made of light or fluid, is twisted like a corkscrew around its propagation axis - an analogy that inspired also the first proposition of the concept of optical vortex. Even though vortices are one of the most fundamental topological excitations in nature, they are rarely found in their electromagnetic form in natural systems, for the exception of energetic sources in astronomy, such as pulsars, quasars and black holes. Mostly optical vortices are artificially created in the laboratory by a rich variety of approaches. Here we provide our perspective on a technology that shook-up optics in the last decade - metasurfaces, planar nanostructured metamaterials - with a specific focus on its use for molding and controlling optical vortices.
Catalogs of Wide Binaries and their Impact on Galactic Astronomy
Creators: name: Chaname, Julio
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Wide binaries, particularly in large numbers and as free from selection biases as possible, constitute a largely overlooked tool for studying the Galaxy. The goal of this review is to highlight the potential inherent to large samples of field wide binaries for research on problems as varied as star formation in the early Galaxy, the nature of halo dark matter, the evolution of the stellar halo, new geometric distances, metallicities, masses, and ages of field stars and white dwarfs, and much more. Using the Revised NLTT as an illustrative example, I review the main steps in the assembly of a large catalog of wide binaries useful for multiple applications. The capability of cleanly separating between the Galactic disk and halo populations using good colors and proper motions is emphasized. The critical role of large surveys for research on wide binaries as well as for the better understanding of the Galaxy in general is stressed throughout. Finally, I point out the potential for assembling new samples of wide binaries from available proper-motion surveys, and report on current efforts of using the SDSS towards this goal.
description: 9 pages, 4 figures; Invited talk in IAU Symposium 240 "Binary Stars as Critical Tests and Tools in Contemporary Astrophysics" (Prague, 22-25 August 2006), Bill Hartkopf, Ed Guinan & Petr Harmanec, eds
New Effects in Gravitational Waves and Memory
Creators: name: Bieri, Lydia
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We find new effects for gravitational waves and memory in asymptotically-flat spacetimes of slow decay. In particular, we derive growing magnetic memory for these general systems. These effects do not arise in spacetimes resulting from data with fast decay towards infinity, including data that is stationary outside a compact set. The new results are derived for the Einstein vacuum as well as for the Einstein-fluid equations describing neutrino radiation, where the neutrino distribution falls off slowly towards infinity. Moreover, they hold for other matter and energy fields coupled to the Einstein equations as long as the data obey corresponding decay laws and other conditions are fulfilled. The magnetic memory occurs naturally in the Einstein vacuum regime of pure gravitation, and in the Einstein-matter systems satisfying the aforementioned conditions. As a main new effect, we find that there is diverging magnetic memory sourced by the magnetic part of the curvature. In the most extreme case, the magnetic memory, in addition, features a curl term from the neutrino cloud, growing at the same rate. Electric memory is diverging as well, sourced by the electric part of the curvature tensor and the corresponding energy-momentum component. Shear (news) adds to the electric memory. Moreover, a multitude of lower order terms contribute to both electric and magnetic memory. Further, we identify a range of decay rates for asymptotically-flat spacetimes for which the new effects occur but with different leading order behavior. The new effects are expected to be seen in current and future gravitational wave detectors. They have an abundance of applications of which we mention a few in this paper. Applications include exploring gravitational wave sources of the above types, detecting dark matter via gravitational waves and other areas of physics.
description: reference added in introduction. arXiv admin note: substantial text overlap with arXiv:2010.07418
The Nuclear Physics of Hyperfine Structure in Hydrogenic Atoms
Creators: name: Friar, J. L.
name: Payne, G. L.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The theory of QED corrections to hyperfine structure in light hydrogenic atoms and ions has recently advanced to the point that the uncertainty of these corrections is much smaller than 1 part per million (ppm), while the experiments are even more accurate. The difference of the experimental results and the corresponding QED theory is due to nuclear effects, which are primarily the result of the finite nuclear charge and magnetization distributions. This difference varies from tens to hundreds of ppm. We have calculated the dominant nuclear component of the 1s hyperfine interval for deuterium, tritium and singly ionized helium, using a unified approach with modern second-generation potentials. The calculated nuclear corrections are within 3% of the experimental values for deuterium and tritium, but are roughly 20% discrepant for helium. The nuclear corrections for the trinucleon systems can be qualitatively understood by invoking SU(4) symmetry.
description: 12 pages, 1 figure, latex - submitted to Physics Letters B
Dispatches from Second Empire Paris: Walter Benjamin, Michel Foucault, and urban modernity
Creators: name: Duckworth, Grant
Publisher: name: University of British Columbia
Year: 2009

description: In this thesis, I examine the socio-spatial transformations which occurred in metropolitan Paris during the Second Empire (1852-1870). Although the reign of Napoleon III only lasted seventeen years, it constitutes an important threshold in the history of France and the French capital. This was the age of imperialism, industrialism, commercialism, and science; a time when the emperor deliberately set out to modernize the country, its economy, and its cities. At the center of this aggressive modernization scheme was Paris. For decades, critics from all walks of life had been calling out for massive urban reforms. The chilling spectacle of political rebellion, growing concerns about the threat of contamination, mounting congestion, and urban decay, and the rise of mass consumerism were the primary forces behind the "strategic beautification" of Paris. The responsibility of modernizing the capital was delegated to Georges-Eugene Haussmann. Between his appointment in 1853 and his unceremonious departure in 1870, Haussmann turned the rabbit-warren network of filthy medieval corridors into an elaborate panorama of architectural splendours and magnificent boulevards. I argue that Haussmann's civic improvement scheme should be remembered as a grand Utopian experiment which produced its own share of failures. The historical philosophies of the Jewish intellectual Walter Benjamin and the French academic Michel Foucault inform much of the discussion. Both Benjamin and Foucault resided and worked in Paris but at different times and under completely different circumstances. For Benjamin, nineteenth-century Paris was a dreamworld of phantasmagoria, a City of Mirrors, and a labyrinth of reflecting images. Foucault, who never wrote about Paris specifically, was concerned with an entirely different set of questions. According to him, the major socio-spatial changes of the previous century were representative of institutionally sanctioned strategies of surveillance, discipline, normalization. Like Haussmann, the experience of living in the French capital had a profound effect on Benjamin's and Foucault's geographical imaginations. I argue that in order to understand Benjamin's and Foucault's ruminations on nineteenth-century notions of space, power, and, knowledge, it is important to first place those arguments in the context of their personal experiences, the urban geographies through which they moved, and the times that they belonged to. Thus, Paris is not simply an object of historical analysis, it is also a context for comparing and contrasting the intellectual thought of Benjamin and Foucault.
Searching for lepton number violating $Λ$ baryon decays mediated by GeV-scale Majorana neutrino with LHCb
Creators: name: Zhang, Guangshuai
name: Ma, Bo-Qiang
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider the lepton-number-violating processes in $Λ_b$/$Λ_c$ decays mediated by on-shell GeV-scale sterile neutrino. We calculate the branching ratio for the following processes: $Λ_b^{0} \rightarrow \mathcal{B}^+ μ^{-}μ^- π^+$, where $\mathcal{B}^+$ is $Λ_c^+$ or proton, and $Λ_c^{+} \rightarrow Λμ^{+}μ^+ π^-$, as function of the mass of the sterile neutrino $m_N$ and the heavy-light mixing coefficient of the extended Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix $|U_{μN}|^2$. The effect of finite detector size is included in our calculation. After comparing the theoretical effective branching ratio with the expected experimental ability of LHCb, we give the sensitivity upper bounds on $|U_{μN}|^2$ on the ($|U_{μN}|^2$-$m_N$) plane. These channels give comparable results with the bounds given by different search strategies (e.g., at Belle, NuTeV, DELPHI and BEBC) in the mass region $m_N \simeq$ 0.25 GeV - 4.5 GeV, and the limits are stronger in the mass range 2 GeV $
description: 10 pages, 4 figures
Liouville type results for periodic and almost periodic linear operators
Creators: name: Rossi, Luca
Publisher: name: arXiv
Year: 2008
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35B10; 35B15; 34C27; 35B05

description: We are concerned with some extensions of the classical Liouville theorem for bounded harmonic functions to solutions of more general equations. We deal with entire solutions of periodic and almost periodic parabolic equations including the elliptic framework as a particular case. We derive a Liouville type result for periodic operators as a consequence of a result for operators periodic in just one variable, which is new even in the elliptic case. More precisely, we show that if $c\leq0$ and $a_{ij}, b_i, c, f$ are periodic in the same space/time direction, with the same period, then any bounded solution $u$ of $$\partial_t u-a_{ij}(x,t)\partial_{ij}u-b_i(x,t)\partial_iu-c(x,t)u=f(x,t),\quad x\in\R^N,\ t\in\R,$$ is periodic in that direction. We then derive the following Liouville type result: if $c\leq0, f\equiv0$ and $a_{ij}, b_i, c$ are periodic in all the space/time variables, with the same periods, then the space of bounded solutions of the above equation has at most dimension one. In the case of the equation $\partial_t u-Lu=f(x,t)$, with $L$ periodic elliptic operator independent of $t$, the hypothesis $c\leq0$ can be weaken by requiring that the periodic principal eigenvalue of $-L$ is nonnegative. Instead, the periodicity assumption cannot be relaxed, because we explicitly exhibit an almost periodic function $b$ such that the space of bounded solutions of $u''+b(x)u'=0$ in $\R$ has dimension 2, and it is generated by the constant solution and a non-almost periodic solution. Next, a sufficient condition for any bounded solution to be almost periodicis derived. We also treat the case of periodic domains under either Dirichlet or Robin boundary conditions.
description: 27 pages, 1 figure
TOARCIAN NANNOBIOHORIZONS FROM LUSITANIAN BASIN (PORTUGAL)AND THEIR CALIBRATION AGAINST AMMONITE ZONES
Creators: name: PERILLI, NICOLA
name: VICTOR DUARTE, LUIS
Publisher: name: Università degli Studi di Milano
Year: 2006

description: The calcareous nannofossil content of the Toarcian succession, widespread in the Lusitanian Basin (Central Portugal), has been studied on the basis of a closely spaced sampling and a refined lithostratigraphic frame dated by ammonites. The almost continuous calcareous nannofossil record allows to calibrate the biohorizons and zone boundaries (NJ5/NJ6, NJ6/NJ7 NJ7/NJ8) with respect to the ammonite zones, and to characterize Toarcian nannofossil zones. The easily recognizable events include the LCO of Calcivascularis jansae (Levisoni Zone), the FOs of Carinolithus cantaluppii and Carinolithus superbus (Levisoni Zone), the FO of Discorhabdus striatus (Bifrons Zone), the AE of Lotharingius hauffii (Gradata Zone) and the FO of Watznaueria contracta (Aalensis Zone). The other events are helpful to increase the resolution, albeit they are defined by taxa with a low abundance and discontinuous occurrence. They comprise the LOs of Biscutum grande and Biscutum finchii (Levisoni Zone) and the FOs of Discorhabdus criotus (Gradata Zone), Retecapsa incompta (Bonarelli Zone) and Triscutum sullivanii (Speciosum Zone). Both biohorizons and zone boundaries are compared with previous findings from the Basque-Cantabrian area and Iberian Range (Spain) as well as from NW Europe and Italy/S France.
description: Rivista italiana di Paleontologia e Stratigrafia, Vol 112, No 3
Isoparametric surfaces in 3-dimensional de Sitter space and anti-de Sitter space
Creators: name: Liu, Huili
name: Zhao, Guosong
Publisher: name: Technische Universität Berlin
Year: 1999
Subjects: subject: 510 Mathematik
subject: isoparametric surface
subject: de Sitter space
subject: anti-de Sitter space
subject: principal curvature

description: A spacelike surface $M$ in 3-dimensional de Sitter space $\mathbb{S}^3_1$ or 3-dimensional anti-de Sitter space $\mathbb{H}^3_1$ is called isoparametric, if $M$ has constant principle curvatures. A timelike surface is called isoparametric, if its minimal polynomial of the shape operator is constant. In this paper, we determine the spacelike isoparametric surfaces and the timelike isoparametric surfacesx in $\mathbb{S}^3_1$ and $\mathbb{H}^3_1$.
Spacelike Ricci Inheritance Vectors in a Model of String Cloud and String Fluid Stress Tensor
Creators: name: Baysal, H.
name: Yilmaz, I.
Publisher: name: arXiv
Year: 2005
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the consequences of the existence of spacelike Ricci inheritance vectors (SpRIVs) parallel to $x^a$ for model of string cloud and string fluid stress tensor in the context of general relativity. Necessary and sufficient conditions are derived for a spacetime with a model of string cloud and string fluid stress tensor to admit a SpRIV and a SpRIV which is also a spacelike conformal Killing vector (SpCKV). Also, some results are obtained.
description: 11 pages
Searching and characterizing young planets with the GAPS2 project
Creators: name: Biazzo, Katia
name: Baratella, Martina
name: Benatti, Serena
name: Carleo, Ilaria
name: Damasso, Mario
name: Desidera, Silvano
name: Mancini, Luigi
name: Team@INAF, On Behalf Of The GAPS-YO
Publisher: name: Zenodo
Year: 2021

description: Since 2012 the GAPS (Global Architecture of Planetary Systems) project at the Telescopio Nazionale Galileo (TNG) involves a large part of the Italian community working on exoplanetary science. In the first five years, the project was based on radial velocity (RV) surveys with the HARPS-N@TNG spectrograph and was focused on the search and characterization of planetary systems around stars with different properties. In 2017, thanks to the integration of GIARPS (GIANO-B & HARPS-N) at the TNG, the GAPS2 project started to explore the origin and the diversity of planetary systems adopting a twofold approach: the observation of planetary atmospheres and the detection/study of planets around young stars. The current literature suggests that we should expect a large fraction of hot Jupiters around very young stars with respect to the old ones, but the available statistic is poor and based on claimed detections still not confirmed by independent investigations. The observation of planets around young objects is therefore important because it allows us to study the ongoing planet formation, helping to investigate the role played by the formation sites, the migration mechanisms, and the orbit evolution.
Optimal robustness of port-Hamiltonian systems
Creators: name: Mehrmann, Volker
name: Van Dooren, Paul
Publisher: name: Technische Universität Berlin
Year: 2019
Subjects: subject: 510 Mathematik
subject: linear matrix inequality
subject: port-Hamiltonian system
subject: passivity
subject: robustness

description: We construct optimally robust port-Hamiltonian realizations of a given rational transfer function that represents a passive system. We show that the realization with a maximal passivity radius is a normalized port-Hamiltonian one. Its computation is linked to a particular solution of a linear matrix inequality that defines passivity of the transfer function, and we provide an algorithm to construct this optimal solution. We also consider the problem of finding the nearest passive system to a given non-passive one and provide a simple but suboptimal solution.
High local genetic diversity and low outcrossing rate in Caenorhabditis elegans natural populations
Creators: name: Barrière, Antoine
name: Félix, Marie-Anne
Publisher: name: arXiv
Year: 2005
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: Background: Caenorhabditis elegans is a major model system in biology, yet very little is known about its biology outside the laboratory. Especially, its unusual mode of reproduction with self-fertile hermaphrodites and facultative males raises the question of its frequency of outcrossing in natural populations. Results: We describe the first analysis of C. elegans individuals sampled directly from natural populations. C. elegans is found predominantly in the dauer stage and with a very low frequency of males compared with hermaphrodites. While C. elegans was previously shown to display a low worldwide genetic diversity, we find by comparison a surprisingly high local genetic diversity of C. elegans populations; this local diversity is contributed in great part by immigration of new alleles rather than by mutation. Our results on heterozygote frequency, male frequency and linkage disequilibrium furthermore show that selfing is the predominant mode of reproduction in C. elegans natural populations, yet that infrequent outcrossing events occur, at a rate of approximately 1%. Conclusions: Our results give a first insight in the biology of C. elegans in the natural populations. They demonstrate that local populations of C. elegans are genetically diverse and that a low frequency of outcrossing allows for the recombination of these locally diverse genotypes.