cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
title: Keeping up with the Max Plancks? Germany’s quest for university excellence and the role of public research institutes in doctoral education
Creators: name: Bünstorf, Guido
name: König, Johannes
name: Otto, Anne
Publisher: name: KOBRA Universität Kassel
Year: 2024
Subjects: subject: doctoral education
subject: public research organizations
subject: STEM Ph.D.graduates
subject: career outcomes
subject: industry-trained Ph.D.s
classificationCode: 370
subject: 370
classificationCode: Deutschland
subject: Deutschland
classificationCode: Promotion
subject: Promotion
classificationCode: Doktorand
subject: Doktorand
classificationCode: Bildung
subject: Bildung
classificationCode: Forschungsinstitut
subject: Forschungsinstitut
classificationCode: Berufslaufbahn
subject: Berufslaufbahn

description:
Doctoral education is a crucial stage in the academic socialization of early-career researchers. Prior research has shown that career paths and activities of Ph.D.s are shaped by the universities and departments in which they were trained. To widen this focus, we analyze the role of public research organizations (PROs) and private-sector firms as organizational employment contexts of doctoral education. The empirical context of our study is Germany, where PROs and firms employ large numbers of doctoral candidates and provide the organizational environment for their dissertation research. Utilizing a novel process-generated dataset that covers about 40,000 STEM Ph.D.s who graduated from 1995 to 2011, we find that Ph.D.s employed at PROs during doctoral education are more likely to stay in academia than their university-employed peers. Despite extensive policy efforts that sought to strengthen the research performance of German universities, doctoral candidates employed at basic research-oriented PROs had the strongest cross-cohort increase in their post-graduation academic employment share. This group also experienced the most pronounced fall in the share of high post-graduation income owners. Industry-employed doctoral candidates are unlikely to migrate to the academic sector and have the highest likelihood of obtaining high post-graduation incomes.
The Wide-field High-resolution Infrared TElescope (WHITE)
Creators: name: Burgarella, D.
name: Roux, B. Le
name: Langlois, M.
name: Moretto, G.
name: Fusco, T.
name: Ferrari, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The Wide-field High-resolution Infrared TElescope (WHITE) will be dedicated in the first years of its life to carrying out a few (well focused in terms of science objectives and time) legacy surveys. WHITE would have an angular resolution of ~0.3'' homogeneous over ~0.7 sq. deg. in the wavelength range 1 - 5 um, which means that we will very efficiently use all the available observational time during night time and day time. Moreover, the deepest observations will be performed by summing up shorter individual frames. We will have a temporal information that can be used to study variable objects. The three key science objectives of WHITE are : 1) A complete survey of the Magellanic Clouds to make a complete census of young stellar objects in the clouds and in the bridge and to study their star formation history and the link with the Milky Way. The interaction of the two clouds with our Galaxy might the closest example of a minor merging event that could be the main driver of galaxy evolution in the last 5 Gyrs. 2) The building of the first sample of dusty supernovae at z<1.2 in the near infrared range (1-5 um) to constrain the equation of state from these obscured objects, study the formation of dust in galaxies and build the first high resolution sample of high redshift galaxies observed in their optical frame 3) A very wide weak lensing survey over that would allow to estimate the equation of state in a way that would favourably compete with space projects.
description: Invited talk to the 2nd ARENA Conference : "The Astrophysical Science Cases at Dome C" Potsdam 17-21 September, 2007
Influence of density and release properties of UCx targets on the fission product yields at ALTO
Creators: name: Guillot, Julien
name: Roussière, Brigitte
name: Tusseau-Nenez, Sandrine
name: Grebenkov, Denis S.
name: Ignacio, Maxime
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: To study the influence of the structural properties of UCx targets on their release properties, several types of targets using different precursors (carbon and uranium) were synthesized, characterized, irradiated and heated leading to the determination of the released fractions of eight elements. In this article, the production rates of these targets are estimated under the use conditions at ALTO, i.e. with targets bombarded by an electron beam (10 μA, 50 MeV). We have simulated the fission number produced using the FLUKA code. Then, we have determined the release efficiency as a function of the half-life of the isotopes using average diffusion coefficients deduced for the elements studied previously. Finally, we compare the production rates obtained from the various targets and conclude that the target must be adapted to the element studied. It is crucial to find in each case the best compromise between the target density and the release efficiency.
description: 11 pages, 5 figures, 1 table
Efficient numerical simulation of granular matter using the Bottom-To-Top Reconstruction method
Creators: name: Schwager, Thomas
name: Poeschel, Thorsten
Publisher: name: arXiv
Year: 2006
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The numerical simulation of granular systems of even moderate size is a challenging computational problem. In most investigations, either Molecular Dynamics or Event-driven Molecular Dynamics is applied. Here we show that in certain cases, mainly (but not exclusively) for static granular packings, the Bottom-to-top Reconstruction method allows for the efficient simulation of very large systems. We apply the method to heap formation, granular flow in a rotating cylinder and to structure formation in nano-powders. We also present an efficient implementation of the algorithm in C++, including a benchmark.
description: 8 pages, 15 figures
A note on knot fertility
Creators: name: Ito, Tetsuya
Publisher: name: arXiv
Year: 2020
Subjects: subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 57K10

description: We show that a knot whose minimum crossing number $c(K)$ is even and greater than $30$ is not fertile; there exists a knot $K'$ with crossing number less than $c$ such that $K'$ is not obtained from a minimum crossing number diagram of $K$ by suitably changing the over-under information.
description: 3 pages, no figures
Reachability in Controlled Markovian Quantum Systems: An Operator-Theoretic Approach
Creators: name: Ende, Frederik vom
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: Functional Analysis (math.FA)
subject: Optimization and Control (math.OC)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: In quantum systems theory one of the fundamental problems boils down to: Given an initial state, which final states can be reached by the dynamic system in question? Formulated in the framework of bilinear control systems, the evolution shall be governed by an inevitable Hamiltonian drift term, finitely many control Hamiltonians allowing for (at least) piecewise constant control amplitudes, plus a (possibly bang-bang switchable) noise term in Kossakowski-Lindblad form. Now assuming switchable coupling of finite-dimensional systems to a thermal bath of arbitrary temperature, the core problem of reachability boils down to studying points in the standard simplex amenable to two types of controls that can be used interleaved: Permutations within the simplex, and contractions by a dissipative one-parameter semigroup. We illustrate how the solutions of the core problem pertain to the reachable set of the original controlled Markovian quantum system. This allows us to show that for global as well as local switchable coupling to a temperature-zero bath one can generate every quantum state from every initial state up to arbitrary precision. Moreover we present an inclusion for non-zero temperatures as a consequence of our results on d-majorization. Then we consider infinite-dimensional open quantum-dynamical systems following a unital Kossakowski-Lindblad master equation extended by controls. Here the drift Hamiltonian can be arbitrary, the finitely many control Hamiltonians are bounded, and the switchable noise term is generated by a single compact normal operator. Via new majorization results of ours, we show that such bilinear quantum control systems allow to approximately reach any target state majorized by the initial one, as up to now only has been known in finite-dimensional analogues.
description: PhD Thesis, 264 pages. Based on arXiv:1712.01023, arXiv:1804.00918, arXiv:1808.06898, arXiv:1902.03085, arXiv:1905.01224, arXiv:1906.00758, arXiv:1911.01061, arXiv:2004.05613
MS/MS-based computational tools for large-scale metabolite annotation - SGMS School 2022
Creators: name: Allard, Pierre-Marie
Publisher: name: Zenodo
Year: 2022
Subjects: computational mass spectrometry
metabolomics
knowledge graphs

description: Presentation for the SGMS 2022 School. https://www.sgms.ch/sgms/education/sgms-school-2022.php
GABRIELA : a new detector array for gamma-ray and conversion electron spectroscopy of transfermium elements
Creators: name: Hauschild, K.
name: Yeremin, A. V.
name: Lopez-Martens, A.
name: Dorvaux, O.
name: Belozerov, A. V.
name: Briancon, C.
name: Chelnokov, M. L.
name: Chepigin, V. I.
name: Garcia-Santamaria, S. A.
name: Gorshkov, V. A.
name: Hanappe, F.
name: Kabachenko, A. P.
name: Korichi, A.
name: Malyshev, O. N.
name: Oganessian, Yu. Ts.
name: Popeko, A. G.
name: Rowley, N.
name: Shutov, A. V.
name: Stuttge, L.
name: Svirikhin, A. I.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: With the aid of the Geant4 Monte Carlo simulation package a new detection system has been designed for the focal plane of the recoil separator VASSILISSA situated at the Flerov Laboratory of Nuclear Reactions, JINR, Dubna. GABRIELA (Gamma Alpha Beta Recoil Investigations with the Electromagnetic Analyser VASSILISSA) has been optimised to detect the arrival of reaction products and their subsequent radioactive decays involving the emission of alpha- and beta-particles, fission fragments, gamma- and X-rays, and conversion electrons. The new detector system is described and the results of the first commissioning experiments are presented.
description: 24 pages, Submitted to NIM A
Nearly hypo structures and compact Nearly Kähler 6-manifolds with conical singularities
Creators: name: Fernández, Marisa
name: Ivanov, Stefan
name: Muñoz, Vicente
name: Ugarte, Luis
Publisher: name: arXiv
Year: 2006
Subjects: subject: Differential Geometry (math.DG)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 53C25

description: We prove that any totally geodesic hypersurface $N^5$ of a 6-dimensional nearly Kähler manifold $M^6$ is a Sasaki-Einstein manifold, and so it has a hypo structure in the sense of \cite{ConS}. We show that any Sasaki-Einstein 5-manifold defines a nearly Kähler structure on the sin-cone $N^5\times\mathbb R$, and a compact nearly Kähler structure with conical singularities on $N^5\times [0,π]$ when $N^5$ is compact thus providing a link between Calabi-Yau structure on the cone $N^5\times [0,π]$ and the nearly Kähler structure on the sin-cone $N^5\times [0,π]$. We define the notion of {\it nearly hypo} structure that leads to a general construction of nearly Kähler structure on $N^5\times\mathbb R$. We determine {\it double hypo} structure as the intersection of hypo and nearly hypo structures and classify double hypo structures on 5-dimensional Lie algebras with non-zero first Betti number. An extension of the concept of nearly Kähler structure is introduced, which we refer to as {\it nearly half flat} SU(3)-structure, that leads us to generalize the construction of nearly parallel $G_2$-structures on $M^6\times\mathbb R$ given in \cite{BM}. For $N^5=S^5\subset S^6$ and for $N^5=S^2 \times S^3\subset S^3 \times S^3$, we describe explicitly a Sasaki-Einstein hypo structure as well as the corresponding nearly Kähler structures on $N^5\times\mathbb R$ and $N^5\times [0,π]$, and the nearly parallel $G_2$-structures on $N^5\times\mathbb R^2$ and $(N^5\times [0,π])\times [0,π]$.
description: 28 pages, new four figures, references added, final version to appear in the Journal of the London. Math. Soc
Ανάπτυξη εφαρμογής ανάκτησης πληροφορίας με βάση τη γεωγραφική θέση του χρήστη
Creators: name: Γιαννακάκη, Ελένη Ιωάννη
name: Βαρυπάτης, Ευάγγελος
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: εφαρμογή για κινητά τηλέφωνα
γεωγραφική θέση
ανάκτηση πληροφορίας
κοινωνικά δίκτυα
mobile application android
GPS
retrieve information
facebook-social network

description: Αντικείμενο της παρούσας διπλωματικής εργασίας είναι η σχεδίαση και ανάπτυξη μιας εφαρμογής για κινητά τηλέφωνα, η οποία δίνει τη δυνατότητα στους χρήστες της να δέχονται μηνύματα deals και events που βρίσκονται στη περιοχή τους και είναι χρήστες του κοινωνικού δικτύου facebook. Επίσης μπορούν να δημιουργούν μηνύματα καθώς και deals και events αν είναι διαχειριστές μιας facebook-page. Για την ανάπτυξη αυτής της εφαρμογής χρησιμοποιήθηκαν δικτυακές υπηρεσίες που επιτρέπουν την επικοινωνία μεταξύ φορητών συσκευών και ενός κεντρικού εξυπηρετητή.
description: The subject of this thesis is to design and develop a mobile application, which enables users to receive messages, deals and events that are in their area and are users of the social network facebook. They can also create messages. If a user managers a facebook-page, then he can also create deals and events. To develop this application used network services that allow communication between mobile devices and a central server.
description: Σε συνεργασία με το τμήμα Λογιστικής και Χρηματοοικονομικής (Πανεπιστήμιο Μακεδονίας)
Mean field theory and Monte Carlo simulation of Phase transitions and Magnetic Properties of a tridimensional Fe7S8 Compound
Creators: name: Benyoussef, S.
name: Amraoui, Y. EL
name: Ez-Zahraouy, H.
name: Mezzane, D.
name: Kutnjak, Z.
name: Luk'yanchuk, I. A.
name: Marssi, M. EL
Publisher: name: arXiv
Year: 2020
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The structural, electronic and magnetic properties of Fe7S8 material have been studied within the framework of the ab-initio calculations, the mean field approximation (MFA) and Monte Carlo simulation (MCS). Our study shows that two forms of the iron atoms, Fe2+ with spin S=2, and Fe3+ with spin σ=5/2 are the most probable configurations. A mixed Ising model with ferromagnetic spin coupling between Fe2+ and Fe3+ ions and between Fe3+ and Fe3+ ions, and with antiferromagnetic spin coupling between Fe2+ ions of adjacent layers has been used to study the magnetic properties of this compound. We demonstrated that the magnetic phase transition can be either of the first or of the second order, depending on the value of the exchange interaction and crystal field. The presence of vacancies in every second iron layer leads to incomplete cancellation of magnetic moments, hence to the emergence of the ferrimagnetism. Anomalies in the magnetization behavior have been found and compared with the experimental results.
description: 18 pages, 14 Figures, 4 Tables
On the Development of Effective Field Theory
Creators: name: Weinberg, Steven
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: This is a lightly edited version of the talk given on September 30, 2020 to inaugurate the international seminar series {\it All Things EFT}. It reviews some of the early history of effective field theories, and concludes with a discussion of the implications of effective field theory for future discovery.
description: 12 pages
Polarization simulations of stellar wind bow shock nebulae. II. The case of dust scattering
Creators: name: Shrestha, Manisha
name: Neilson, Hilding R.
name: Hoffman, Jennifer L.
name: Ignace, Richard
name: Fullard, Andrew G.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We study the polarization produced by scattering from dust in a bow shock-shaped region of enhanced density surrounding a stellar source, using the Monte Carlo radiative transfer code SLIP. Bow shocks are structures formed by the interaction of the winds of fast-moving stars with the interstellar medium. Our previous study focused on the polarization produced in these structures by electron scattering; we showed that polarization is highly dependent on inclination angle and that multiple scattering changes the shape and degree of polarization. In contrast to electron scattering, dust scattering is wavelength-dependent, which changes the polarization behaviour. Here we explore different dust particle sizes and compositions and generate polarized spectral energy distributions for each case. We find that the polarization SED behaviour depends on the dust composition and grain size. Including dust emission leads to polarization changes with temperature at higher optical depth in ways that are sensitive to the orientation of the bow shock. In various scenarios and under certain assumptions, our simulations can constrain the optical depth and dust properties of resolved and unresolved bow shock-shaped scattering regions.Constraints on optical depth can provide estimates of local ISM density for observed bow shocks. We also study the impact of dust grains filling the region between the star and bow shock. We see that as the density of dust between the star and bow shock increases, the resulting polarization is suppressed for all the optical depth regimes.
description: 21 pages, accepted for publication in MNRAS
Μελέτη συμπληρωματικών τεχνικών έργων στα πλαίσια της διευθέτησης του χειμάρρου Μαϊστρου Αλεξανδρούπολης
Creators: name: Σταματάκη, Στυλιανή Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Διευθέτηση χειμάρρου
Τεχνικά έργα
Μελέτη προϋπολογισμού
River management
Technological works
Cost analysis

description: Η συντριπτική πλειοψηφία των υδάτινων ρευμάτων της χώρας μας (χείμαρροι, ποταμοί) εμφανίζει υδατοπαροχές με έντονη ετήσια μεταβλητότητα ενώ ένα επιπλέον δυσμενές χαρακτηριστικό των υδάτινων ρευμάτων της χώρας μας, ειδικότερα των χειμάρρων και των χειμαρροποτάμων, είναι οι αιφνίδιες πλημμυρικές υδατοπαροχές μετά από βροχοπτώσεις μεγάλης ραγδαιότητας, οι οποίες και έχουν καταστρεπτικές συνέπειες στις λεκάνες απορροής. Μέσα από το παραπάνω πλαίσιο, αναδεικνύεται η σπουδαιότητα εκτέλεσης υδροδυναμικών/ υδραυλικών έργων στο χώρο των λεκάνων απορροής. Πιο συγκεκριμένα, τα εν λόγω έργα αποτελούν βασικά έργα υποδομής, καθώς με την κατασκευή τους επιτυγχάνεται η μείωση της έντασης και της έκτασης των εμφανιζόμενων διαβρώσεων, αποσαθρώσεων και γεωκατακρημνισμάτων κάθε μορφής συνεισφέροντας με αυτό τον τρόπο στον έλεγχο της υποβάθμισης του ευρύτερου χώρου της λεκάνης απορροής, αποτρέποντας με τα κατάλληλα έργα την εμφάνιση πλημμυρικών φαινομένων ή τον περιορισμό των επιπτώσεων τους. Στόχος της παρούσας διπλωματικής εργασίας είναι η διευθέτηση του χειμάρρου Μαΐστρου, στην περιοχή της Αλεξανδρούπολης μέσα από το πρίσμα των αρχών των υδραυλικών έργων και της διαχείρισης των υδατικών πόρων. Πιο αναλυτικά, μελετάται η κατασκευή 2 καταβαθμών ελεύθερης υδατόπτωσης για την μείωση της κλίσεως του χειμάρρου σε προκαθορισμένες θέσεις , η ανύψωση στην ροή του νερού που προκαλείται από την παρουσία δυο γεφυρών κατάντη του χειμάρρου καθώς και η σύνταξη προϋπολογισμού για τις παραπάνω εργασίες σε επίπεδο προμελέτης και με βάση τα τιμολόγια του υπουργείου.
description: The vast majority of inland water bodies of Greece (streams, rivers) display water discharges of extreme annual variability. In addition to that, there is one adverse factor, for the streams and rivers, of the sudden flood discharge that streams present after rapid rainfall that cause catastrophic events on the watersheds. Due to that, there is a great need of constructing hydraulic/ hydronomic works in the area of the catchments. More specifically, these hydraulic works, are major in fracture projects and their construction, achieve the reducing of intensity and extent of emerging corrosion, erosion of all forms, preventing in that way the flooding phenomena or reducing their impacts. The aim of this thesis is the training of the stream Maistros in the area of Alexandroupolis through the prism of the principles of hydraulic works and water management. Specifically it studies the construction of two drop structures as well as the raise of the water flow that is caused by the presence of two bridges downstream of the torrent. At the end of the thesis, there is an estimation of the budget for the above hydraulic works of the preliminary designs of the works based on the price-list of the Ministry.
Infant gut immunity: A preliminary study of IgA associations with breastfeeding
Creators: name: Bridgman, Sarah L.; Konya, Theodore; Azad, Meghan B.; Sears, Malcolm R.; Becker, A. B.; Turvey, Stuart E.; Mandhane, P. J.; Subbarao, P.; Scott, James A.; Field, Catherine J.; Kozyrskyj, Anita L.
Publisher: name: University of Alberta Libraries
Year: 2016

Abstract
Kindergarten : discovered in the midst of Julia Kristeva’s two-sided sacred
Creators: name: McMillan, Kate
Publisher: name: University of British Columbia
Year: 2009

description: Well on my way toward compiling what I thought would be the theoretical groundwork for the writing of my major paper, I experienced what can only be described as an epiphany; a most unsettling turn of events which launched me in a completely unplanned-for direction. At once discombobulated and perfectly at home, I suddenly found myself in a space which enabled me to discuss what I have always felt, living, as I do, the passionate life of a teacher. All the ideas and feelings I hold so close to my heart were miraculously given not just a voice, but an entire musical score with parts for everyone. This wondrous symphony was made audible to me through the writings of Julia Kristeva; a citizen of the postmodern universe who also considers herself to be a foreigner and an exile. The drawing card for me was Kristeva's espousal of the notions of: One and Other; polyphonic vocalizing; an ever-changing and evolving space which defies reduction in a hierarchical sense; and the absolute necessity of acknowledging the existence of things abject and horrible. To me, Kristeva's unique take on the world transposes itself into a window that opens onto my Kindergarten class; providing me with a linguistic (in a Kristevan sense) framework in which to situate what had heretofore been impossible to express verbally. Uncomfortable with the fit a strict adherence to linear regulations produces, I have attempted to create a work that invites readers into a place of disruption, movement and discovery. Instead of chapters, a left-to-right progression and consecutively numbered pages, I have organized my thesis around the four notions of space ("Anaphora"), abjection ("Wandering at the Borders of the Speakable and the Visible"), humour ("Defying the Laws of Gravity"), and fixed narrative ('The Presence of Absence"). The notion of story-telling is an integral part of the whole project, thus the fairy tale beginnings to each section. Although the title page is located at the beginning of "Anaphora," this does not imply that this is the place to start; indeed, I hope that different readers will find their own entry points. As each section is encountered, the reader must unfold and open out the pages; a visual argument against the notion of a linear, fixed narrative being the only way in which to produce a work of academic merit. If, due to restrictions imposed by the Library, the copy of my thesis you are reading does not open out or contain some coloured pages and you would like to see the "real thing," please contact Dr. John Willinsky at the Department of Curriculum and Instruction.
Competing ferromagnetism in high temperature copper oxide superconductors
Creators: name: Kopp, Angela
name: Ghosal, Amit
name: Chakravarty, Sudip
Publisher: name: arXiv
Year: 2006
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The extreme variability of observables across the phase diagram of the cuprate high temperature superconductors has remained a profound mystery, with no convincing explanation of the superconducting dome. While much attention has been paid to the underdoped regime of the hole-doped cuprates because of its proximity to a complex Mott insulating phase, little attention has been paid to the overdoped regime. Experiments are beginning to reveal that the phenomenology of the overdoped regime is just as puzzling. For example, the electrons appear to form a Landau Fermi liquid, but this interpretation is problematic; any trace of Mott phenomena, as signified by incommensurate antiferromagnetic fluctuations, is absent, and the uniform spin susceptibility shows a ferromagnetic upturn. Here we show and justify that many of these puzzles can be resolved if we assume that competing ferromagnetic fluctuations are simultaneously present with superconductivity, and the termination of the superconducting dome in the overdoped regime marks a quantum critical point beyond which there should be a genuine ferromagnetic phase at zero temperature. We propose new experiments, and make new predictions, to test our theory and suggest that effort must be mounted to elucidate the nature of the overdoped regime, if the problem of high temperature superconductivity is to be solved. Our approach places competing order as the root of the complexity of the cuprate phase diagram.
description: The expanded published version with very minor differences
Using Spectral Submanifolds for Optimal Mode Selection in Model Reduction
Creators: name: Buza, Gergely
name: Jain, Shobhit
name: Haller, George
Publisher: name: arXiv
Year: 2020
Subjects: subject: Dynamical Systems (math.DS)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Model reduction of large nonlinear systems often involves the projection of the governing equations onto linear subspaces spanned by carefully-selected modes. The criteria to select the modes relevant for reduction are usually problem-specific and heuristic. In this work, we propose a rigorous mode-selection criterion based on the recent theory of Spectral Submanifolds (SSM), which facilitates a reliable projection of the governing nonlinear equations onto modal subspaces. SSMs are exact invariant manifolds in the phase space that act as nonlinear continuations of linear normal modes. Our criterion identifies critical linear normal modes whose associated SSMs have locally the largest curvature. These modes should then be included in any projection-based model reduction as they are the most sensitive to nonlinearities. To make this mode selection automatic, we develop explicit formulas for the scalar curvature of an SSM and provide an open-source numerical implementation of our mode-selection procedure. We illustrate the power of this procedure by accurately reproducing the forced-response curves on three examples of varying complexity, including high-dimensional finite element models.
Contrasting magnetism in VPS3 and CrI3 monolayers with the common honeycomb S = 3/2 spin lattice
Creators: name: Yang, Ke
name: Ning, Yueyue
name: Ma, Yaozhenghang
name: Zhou, Yuxuan
name: Wu, Hua
Publisher: name: arXiv
Year: 2025
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Two-dimensional (2D) magnetic materials are promising candidates for spintronics and quantum technologies. One extensively studied example is the ferromagnetic (FM) CrI$_3$ monolayer with the honeycomb Cr$^{3+}$ ($t_{2g}^3$, $S$ = 3/2) spin lattice, while VPS$_3$ has a same honeycomb $S$ = 3/2 spin lattice (V$^{2+}$, $t_{2g}^3$) but displays N$\acute{e}$el antiferromagnetism (AFM). In this work, we study the electronic structure and particularly the contrasting magnetism of VPS$_3$ and CrI$_3$ monolayers. We find that VPS$_3$ is a Mott-Hubbard insulator but CrI$_3$ is a charge-transfer insulator, and therefore their magnetic exchange mechanisms are essentially different. The first nearest-neighbor (1NN) direct $d$-$d$ exchange dominates in VPS$_3$, thus leading to a strong antiferromagnetic (AF) coupling. However, the formation of vanadium vacancies, associated with instability of the low-valence V$^{2+}$ ions, suppresses the AF coupling and thus strongly reduces the N$\acute{e}$el temperature ($T_{\text{N}}$) in line with the experimental observation. In contrast, our results reveal that the major 1NN $d$-$p$-$d$ superexchanges in CrI$_3$ via different channels give rise to competing FM and AF couplings, ultimately resulting in a weak FM coupling as observed experimentally. After revisiting several important superexchange channels reported in the literature, based on our MLWFs and tight-binding analyses, we note that some antiphase contributions must be subtly and simultaneously considered, and thus we provide a deeper insight into the FM coupling of CrI$_3$. Moreover, we identify and compare the major contributions to the magnetic anisotropy, i.e., a weak shape anisotropy in VPS$_3$ and a relatively strong exchange anisotropy in CrI$_3$.
description: 16 pages, 12 figures, 3 tables
Alfvenic Perturbations in a Sunspot Chromosphere Linked to Fractionated Plasma in the Corona
Creators: name: Baker, D.
name: Stangalini, M.
name: Valori, G.
name: Brooks, D. H.
name: To, A. S. H.
name: van Driel-Gesztelyi, L.
name: Demoulin, P.
name: Stansby, D.
name: Jess, D. B.
name: Jafarzadeh, S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In this study, we investigate the spatial distribution of highly varying plasma composition around one of the largest sunspots of solar cycle 24. Observations of the photosphere, chromosphere, and corona are brought together with magnetic field modelling of the sunspot in order to probe the conditions which regulate the degree of plasma fractionation within loop populations of differing connectivities. We find that in the coronal magnetic field above the sunspot umbra, the plasma has photospheric composition. Coronal loops rooted in the penumbra contain fractionated plasma, with the highest levels observed in the loops that connect within the active region. Tracing field lines from regions of fractionated plasma in the corona to locations of Alfvenic fluctuations detected in the chromosphere shows that they are magnetically linked. These results indicate a connection between sunspot chromospheric activity and observable changes in coronal plasma composition.
description: 14 pages, 6 figure, accepted by ApJ on 15 November 2020
Laser-noise-induced correlations and anti-correlations in Electromagnetically Induced Transparency
Creators: name: Cruz, L. S.
name: Felinto, D.
name: Gómez, J. G. Aguirre
name: Martinelli, M.
name: Valente, P.
name: Lezama, A.
name: Nussenzveig, P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: High degrees of intensity correlation between two independent lasers were observed after propagation through a rubidium vapor cell in which they generate Electromagnetically Induced Transparency (EIT). As the optical field intensities are increased, the correlation changes sign (becoming anti-correlation). The experiment was performed in a room temperature rubidium cell, using two diode lasers tuned to the $^{85}$Rb $D_2$ line ($λ= 780$nm). The cross-correlation spectral function for the pump and probe fields is numerically obtained by modeling the temporal dynamics of both field phases as diffusing processes. We explored the dependence of the atomic response on the atom-field Rabi frequencies, optical detuning and Doppler width. The results show that resonant phase-noise to amplitude-noise conversion is at the origin of the observed signal and the change in sign for the correlation coefficient can be explained as a consequence of the competition between EIT and Raman resonance processes.
description: Accepted for publication in EPJ D
Averaging Problem in Cosmology and Macroscopic Gravity
Creators: name: Zalaletdinov, Roustam
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The Averaging problem in general relativity and cosmology is discussed. The approach of macroscopic gravity to resolve the problem is presented. An exact cosmological solution to the equations of macroscopic gravity is given and its properties are discussed. Contents: 1. Introduction to General Relativity 2. General Relativity -> Relativistic Cosmology 3. Introduction to Relativistic Cosmology 4. Relativistic Cosmology -> Mathematical Cosmology 5. Averaging Problem in Relativistic Cosmology 6. History of the Averaging Problem 7. Averaging and FLRW Cosmologies 8. Averaging Problem in General Relativity 9. Macroscopic Gravity and General Relativity 10. Macroscopic Gravity and Cosmology 11. The System of Macroscopic Gravity Equations 12. An Exact Cosmological Solution
description: 23 pages, LaTeX
Maximizing the Expected Value of a Lottery Ticket: How to Sell and When to Buy
Creators: name: Kim, Allen
name: Skiena, Steven
Publisher: name: arXiv
Year: 2021
Subjects: subject: Discrete Mathematics (cs.DM)
subject: FOS: Computer and information sciences

description: Unusually large prize pools in lotteries like Mega Millions and Powerball attract additional bettors, which increases the likelihood that multiple winners will have to share the pool. Thus, the expected value of a lottery ticket decreases as the probability of collisions (two or more bettors with identical winning tickets) increase. We propose a way to increase the expected value of lottery tickets by minimizing collisions, while preserving the independent generation necessary in a distributed point-of-sales environment. Our approach involves partitioning the ticket space among different vendors and pairing them off to ensure no collisions among pairs. Our analysis demonstrates that this approach increases the expected value each ticket, without increasing the size of the prize pool. We also analyze when ticket sales have maximal expected value, and show that they provide positive returns when the jackpot is between \$775.2 million and \$1.67 billion dollars.
Is Bell's theorem relevant to quantum mechanics? On locality and non-commuting observables
Creators: name: Matzkin, A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Bell's theorem is a statement by which averages obtained from specific types of statistical distributions must conform to a family of inequalities. These models, in accordance with the EPR argument, provide for the simultaneous existence of quantum mechanically incompatible quantities. We first recall several contradictions arising between the assumption of a joint distribution for incompatible observables and the probability structure of quantum-mechanics, and conclude that Bell's theorem is not expected to be relevant to quantum phenomena described by non-commuting observables, irrespective of the issue of locality. Then, we try to disentangle the locality issue from the existence of joint distributions by introducing two models accounting for the EPR correlations but denying the existence of joint distributions. We will see that these models do not need to resort explicitly to non-locality: the first model relies on conservation laws for ensembles, and the second model on an equivalence class by which different configurations lead to the same physical predictions.
description: Extended with new material
Experimental evidence on the development of scale invariance in the internal structure of self-affine aggregates
Creators: name: Horowitz, C. M.
name: Pasquale, M. A.
name: Albano, E. V.
name: Arvia, A. J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: It is shown that an alternative approach for the characterization of growing branched patterns consists of the statistical analysis of frozen structures, which cannot be modified by further growth, that arise due to competitive processes among neighbor growing structures. Scaling relationships applied to these structures provide a method to evaluate relevant exponents and to characterize growing systems into universality classes. The analysis is applied to quasi-two-dimensional electrochemically formed silver branched patterns showing that the size distribution of frozen structures exhibits scale invariance. The measured exponents, within the error bars, remind us those predicted by the Kardar-Parisi-Zhang equation.
description: 11 pages, 4 figures
Closure of the entanglement gap at quantum criticality: The case of the Quantum Spherical Model
Creators: name: Wald, Sascha
name: Arias, Raul
name: Alba, Vincenzo
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The study of entanglement spectra is a powerful tool to detect or elucidate universal behaviour in quantum many-body systems. We investigate the scaling of the entanglement (or Schmidt) gap $δξ$, i.e., the lowest laying gap of the entanglement spectrum, at a two-dimensional quantum critical point. We focus on the paradigmatic quantum spherical model, which exhibits a second-order transition, and is mappable to free bosons with an additional external constraint. We analytically show that the Schmidt gap vanishes at the critical point, although only logarithmically. For a system on a torus and the half-system bipartition, the entanglement gap vanishes as $π^2/\ln(L)$, with $L$ the linear system size. The entanglement gap is nonzero in the paramagnetic phase and exhibits a faster decay in the ordered phase. The rescaled gap $δξ\ln(L)$ exhibits a crossing for different system sizes at the transition, although logarithmic corrections prevent a precise verification of the finite-size scaling. Interestingly, the change of the entanglement gap across the phase diagram is reflected in the zero-mode eigenvector of the spin-spin correlator. At the transition quantum fluctuations give rise to a non-trivial structure of the eigenvector, whereas in the ordered phase it is flat. We also show that the vanishing of the entanglement gap at criticality can be qualitatively but not quantitatively captured by neglecting the structure of the zero-mode eigenvector.
description: 20 pages, 13 figures
Σχέσεις κράτους-εκκλησίας στη Σερβία, O Νόμος περί εκκλησιών και θρησκευτικών κοινοτήτων
Creators: name: Dukic, Dalibor Branko (Τζούκιτς, Ντάλιμπορ)
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Κράτος
Εκκλησία
Σερβία
State
Church
Serbia

description: Σκοπός της μεταπτυχιακής εργασίας είναι η λεπτομερής ανάλυση των σχέσεων του κράτους με τις εκκλησίες και θρησκευτικές κοινότητες στη Σερβία, με βάση το Νόμο περί εκκλησιών και θρησκευτικών κοινοτήτων. Ο νέος Νόμος περί εκκλησιών και θρησκευτικών κοινοτήτων που ψηφίστηκε το 2006 συμπλήρωσε το νομοθετικό κενό που υπήρχε στη σερβική νομοθεσία για πολλά χρόνια. Χάρη σε αυτόν, το σύστημα της συνεργασίας κράτους με θρησκευτικές οργανώσεις έγινε ο ακρογωνιαίος λίθος για τη μελλοντική ανάπτυξη των σχέσεων αυτών. Ο στόχος της εργασίας δεν ήταν απλά η περιγραφή της ισχύουσας νομοθεσίας, αλλά η παρουσίαση όλης της προβληματικής και διάφορων θέσεων και επιχειρημάτων που αναπτύχθηκαν γύρω από το θέμα των σχέσεων του σερβικού κράτους με διάφορες εκκλησίες και θρησκευτικές κοινότητες.
description: The aim of the thesis is the detailed analysis of state-church relations in Serbia, with emphasis on the Law on Churches and Religious Communities. The new Law on Churches and Religious Communities of 2006 resolves many controversial issues in this deregulated field lasting for many years. Due to the new Law, the principle of co-operation became the cornerstone for the further development of relations among the State, Churches and Religious Communities. The aim of this work was not only the description of the current legislation, but the presentation of the whole problem and the various positions and arguments developed around the issue of relations among the Serbian state and various churches and religious communities.
The Invariant Symplectic Action and Decay for Vortices
Creators: name: Ziltener, Fabian
Publisher: name: arXiv
Year: 2006
Subjects: subject: Symplectic Geometry (math.SG)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 53D20, 35B40

description: The (local) invariant symplectic action functional $\A$ is associated to a Hamiltonian action of a compact connected Lie group $\G$ on a symplectic manifold $(M,ω)$, endowed with a $\G$-invariant Riemannian metric $_M$. It is defined on the set of pairs of loops $(x,ξ):S^1\to M\x\Lie\G$ for which $x$ satisfies some admissibility condition. I prove a sharp isoperimetric inequality for $\A$ if $_M$ is induced by some $ω$-compatible and $\G$-invariant almost complex structure $J$, and, as an application, an optimal result about the decay at $\infty$ of symplectic vortices on the half-cylinder $[0,\infty)\x S^1$.
description: 20 pages. Final version. (I shortened the version # 3 a lot.) Accepted for publication by J. Symplectic Geom
The elliptic scattering theory of the 1/2-XYZ and higher order Deformed Virasoro Algebras
Creators: name: Fioravanti, Davide
name: Rossi, Marco
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Bound state excitations of the spin 1/2-XYZ model are considered inside the Bethe Ansatz framework by exploiting the equivalent Non-Linear Integral Equations. Of course, these bound states go to the sine-Gordon breathers in the suitable limit and therefore the scattering factors between them are explicitly computed by inspecting the corresponding Non-Linear Integral Equations. As a consequence, abstracting from the physical model the Zamolodchikov-Faddeev algebra of two $n$-th elliptic breathers defines a tower of $n$-order Deformed Virasoro Algebras, reproducing the $n=1$ case the usual well-known algebra of Shiraishi-Kubo-Awata-Odake \cite{SKAO}.
description: Latex version, 13 pages
Re-thinking the spaces of production : re-writing studio practices as fragmented text
Creators: name: Mastri, Rosa
Publisher: name: University of British Columbia
Year: 2009

description: As educators and researchers, how can we challenge the conventions of pedagogical practices and traditional art production expectations in the studio ? Art educational research has invited into play a revamping of traditional research 'inquiries' that suggests we, as researchers and art educators, re-think issues deemed important in improving instruction as we move into the next century. This study uses feminist and postmodern critical theories to re-frame the inquiry and in turn questions its own inquiry. By juxtaposing narratives of past art students' studio experiences with those occurring in this re-search space, an analogy is drawn between 'where we produce', that is, within the parameters of preconceived constructs -studio, academia, classrooms - to understand the meanings of 'spaces of production'. Central to this project is the concept of spaces in which the process of production occurs; that is, the spaces between 'the idea and the object' of students' experiences of learning in post secondary art studios along with those in which educational re-search occurs. It is vital that we challenge notions held taut about the production practices of re-searching, so that research issues and methods do not simply replicate past production sites but enter to invent varied points of view. The evolving 'fragmented' text includes: narratives of past art production and studio experiences shared by two female participants and myself as post fine arts students; the experiences I, as researcher, entered in the spaces of production of this so called 're-search'; feminist and postmodern critiques; and examples of contemporary artistic practices. As a result, a space to challenge conventionalities about re-searching and art studio practices is opened. A re-working/re-sculpting of the conventional 're-search' text is performed.
Periodicity and the determinant bundle
Creators: name: Melrose, Richard
name: Rochon, Frédéric
Publisher: name: arXiv
Year: 2006
Subjects: subject: Differential Geometry (math.DG)
subject: K-Theory and Homology (math.KT)
subject: FOS: Mathematics

description: The infinite matrix `Schwartz' group $G^{-\infty}$ is a classifying group for odd K-theory and carries Chern classes in each odd dimension, generating the cohomology. These classes are closely related to the Fredholm determinant on $G^{-\infty}.$ We show that while the higher (even, Schwartz) loop groups of $G^{-\infty},$ again classifying for odd K-theory, do \emph{not} carry multiplicative determinants generating the first Chern class, `dressed' extensions, corresponding to a star product, do carry such functions. We use these to discuss Bott periodicity for the determinant bundle and the eta invariant. In so doing we relate two distinct extensions of the eta invariant, to self-adjoint elliptic operators and to elliptic invertible suspended families and show that the corresponding $τ$ invariant is a determinant in this sense.