cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Multi-particle systems in quantum spacetime and a novel challenge for center-of-mass motion
Creators: name: Amelino-Camelia, Giovanni
name: Astuti, Valerio
name: Palmisano, Michelangelo
name: Ronco, Michele
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In recent times there has been considerable interest in scenarios for quantum gravity in which particle kinematics is affected nonlinearly by the Planck scale, with encouraging results for the phenomenological prospects, but also some concerns that the nonlinearities might produce pathological properties for composite/multiparticle systems. We here focus on kinematics in the $κ$-Minkowski noncommutative spacetime, the quantum spacetime which has been most studied from this perspective, and compare the implications of the alternative descriptions of the total momentum of a multiparticle system which have been so far proposed. We provide evidence suggesting that priority should be given to defining the total momentum as the standard linear sum of the momenta of the particles composing the system. We also uncover a previously unnoticed feature concerning some (minute but conceptually important) effects on center-of-mass motion due to properties of the motion of the constituents relative to the center of mass.
Thin Shell Wormhole in Heterotic String Theory
Creators: name: Rahaman, F.
name: Kalam, M.
name: Chakraborti, S.
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Using 'Cut and Paste' technique, we develop a thin shell wormhole in heterotic string theory. We determine the surface stresses, which are localized in the shell, by using Darmois-Israel formalism. The linearized stability of this thin wormhole is also analyzed.
description: 12 pages, 2 figures, Accepted in Int. J. Mod. Phys. D
Investigation of the presence of charge order in magnetite by measurement of the spin wave spectrum
Creators: name: McQueeney, R. J.
name: Yethiraj, M.
name: Montfrooij, W.
name: Gardner, J. S.
name: Metcalf, P.
name: Honig, J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Inelastic neutron scattering results on magnetite (Fe3O4) show a large splitting in the acoustic spin wave branch, producing a 7 meV gap midway to the Brillouin zone boundary at q = (0,0,1/2) and E = 43 meV. The splitting occurs below the Verwey transition temperature, where a metal-insulator transition occurs simultaneously with a structural transformation, supposedly caused by the charge ordering on the iron sublattice. The wavevector (0,0,1/2) corresponds to the superlattice peak in the low symmetry structure. The dependence of the magnetic superexchange on changes in the crystal structure and ionic configurations that occur below the Verwey transition affect the spin wave dispersion. To better understand the origin of the observed splitting, we have constructed a series of Heisenberg models intended to reproduce the pairwise variation of the magnetic superexchange arising from both small crystalline distortions and charge ordering. We find that none of the models studied predicts the observed splitting, whose origin may arise from charge-density wave formation or magnetoelastic coupling.
description: 62 pages, 17 figures, submitted to Phys. Rev. B
Astro-quark matter: a challenge facing astroparticle physics
Creators: name: Xu, Renxin
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Quark matter both in terrestrial experiment and in astrophysics is briefly reviewed. Astrophysical quark matter could appear in the early Universe, in compact stars, and as cosmic rays. Emphasis is put on quark star as the nature of pulsars. Possible astrophysical implications of experiment-discovered sQGP are also concisely discussed.
description: 14 pages, 4 figures and 1 table; talk presented at CosPA2007 (International Symposium on Cosmology and Particle Astrophysics, Taipei, Nov. 13-15, 2007)
Electronic Aharonov-Bohm Effect Induced by Quantum Vibrations
Creators: name: Shekhter, R. I.
name: Gorelik, L. Y.
name: Glazman, L. I.
name: Jonson, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Mechanical displacements of a nanoelectromechanical system (NEMS) shift the electron trajectories and hence perturb phase coherent charge transport through the device. We show theoretically that in the presence of a magnetic feld such quantum-coherent displacements may give rise to an Aharonov-Bohm-type of effect. In particular, we demonstrate that quantum vibrations of a suspended carbon nanotube result in a positive nanotube magnetoresistance, which decreases slowly with the increase of temperature. This effect may enable one to detect quantum displacement fluctuations of a nanomechanical device.
description: 4 pages, 3 figures
Maximizing Store Revenues using Tabu Search for Floor Space Optimization
Creators: name: Xu, Jiefeng
name: Gul, Evren
name: Lim, Alvin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: Neural and Evolutionary Computing (cs.NE)
subject: Optimization and Control (math.OC)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics
subject: G.m
subject: 90C59, 90C90

description: Floor space optimization is a critical revenue management problem commonly encountered by retailers. It maximizes store revenue by optimally allocating floor space to product categories which are assigned to their most appropriate planograms. We formulate the problem as a connected multi-choice knapsack problem with an additional global constraint and propose a tabu search based meta-heuristic that exploits the multiple special neighborhood structures. We also incorporate a mechanism to determine how to combine the multiple neighborhood moves. A candidate list strategy based on learning from prior search history is also employed to improve the search quality. The results of computational testing with a set of test problems show that our tabu search heuristic can solve all problems within a reasonable amount of time. Analyses of individual contributions of relevant components of the algorithm were conducted with computational experiments.
Two novel classes of solvable many-body problems of goldfish type with constraints
Creators: name: Calogero, Francesco
name: Gomez-Ullate, David
Publisher: name: arXiv
Year: 2007
Subjects: subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: Two novel classes of many-body models with nonlinear interactions "of goldfish type" are introduced. They are solvable provided the initial data satisfy a single constraint (in one case; in the other, two constraints): i. e., for such initial data the solution of their initial-value problem can be achieved via algebraic operations, such as finding the eigenvalues of given matrices or equivalently the zeros of known polynomials. Entirely isochronous versions of some of these models are also exhibited: i.e., versions of these models whose nonsingular solutions are all completely periodic with the same period.
description: 30 pages, 2 figures
Critical behavior of the three-dimensional bond-diluted Ising spin glass: Finite-size scaling functions and Universality
Creators: name: Jorg, Thomas
Publisher: name: arXiv
Year: 2006
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We study the three-dimensional (3D) bond-diluted Edwards-Anderson (EA) model with binary interactions at a bond occupation of 45% by Monte Carlo (MC) simulations. Using an efficient cluster MC algorithm we are able to determine the universal finite-size scaling (FSS) functions and the critical exponents with high statistical accuracy. We observe small corrections to scaling for the measured observables. The critical quantities and the FSS functions indicate clearly that the bond-diluted model for dilutions above the critical dilution p*, at which a spin glass (SG) phase appears, lies in the same universality class as the 3D undiluted EA model with binary interactions. A comparison with the FSS functions of the 3D site-diluted EA model with Gaussian interactions at a site occupation of 62.5% gives very strong evidence for the universality of the SG transition in the 3D EA model.
description: Revised version. 10 pages, 9 figures, 2 tables
Gender Equality Act 2020 (Vic) Research Brief
Creators: name: Stewart, Rebecca
Publisher: name: Monash University
Year: 2021
Subjects: subject: Sociology
subject: FOS: Sociology

description: With approximately 65 per cent of Australians aged 15 years and over employed or actively seeking employment, workplaces have significant social influence as key settings in the community where individuals spend the majority of their adult lives (Australian Bureau of Statistics, 2018). Whilst Australia has made progress in recent years, the Workplace Gender Equality Agency’s most recent scorecard demonstrate just how much more needs to be done to address gender-based gaps in terms of representation, remuneration and flexibility in the workplace (Workplace Gender Equality Agency, 2020). This Research Brief reflects on the purpose and reporting requirements of the Gender Equality Act 2020 (Vic) including the role of the Public Sector Gender Equality Commissioner tasked with monitoring its ongoing implementation. The Brief also outlines the obligations and reporting requirements under the Act, which commenced on 31 March 2021.
Understanding Fundamental Tradeoffs in Nanomechanical Resonant Sensors
Creators: name: Demir, Alper
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Nanomechanical resonators are used as high performance detectors in a variety of applications such as mass spectrometry and atomic force microscopy. Initial emphasis in nanomechanical resonant sensor research was on increasing the sensitivity to the level of a single molecule, atom and beyond. On the other hand, there are applications where the speed of detection is crucial, prompting recent works that emphasize sensing schemes with improved time resolution. We first develop a general modeling framework encompassing all resonator tracking schemes currently in use, by extending recent previous work. We then explore the fundamental trade-offs between accuracy and speed in three resonant sensor architectures, namely the feedback-free open-loop approach, positive-feedback based self-sustaining oscillator, and negative-feedback based frequency-locked loop scheme. We comparatively analyze them in a unified manner, clarify some misconceptions that seem to exist in the literature, and unravel their speed versus accuracy characteristics.
description: 14 pages, 10 figures
title: Explosive spalling of concrete under fire load - A review of spalling theory development
Creators: name: Kirnbauer, Johannes
name: Bund, Anna-Laura
name: Robisson, Agathe
Publisher: name: TU Wien
Year: 2023
Subjects: concrete
spalling
fire load
permeability
moisture

description: In this work, we will present the most important findings and events concerning the explosive spalling of concrete since its first written account in 1854. As explosive spalling is a very complex process, essential knowledge about the basics of this phenomenon will be discussed. When concrete is heated, it undergoes numerous physical and chemical modifications. Over the years various theories and models have been developed to describe explosive spalling but leave gaps in understanding the leading causes of this phenomenon. Spalling is considered to be a result of a combination of thermo-mechanical and thermo-hydro changes which trigger the formation of cracks. The theories still considered plausible today will be described in more detail and underline the topic complexity. Today, spalling of concrete due to fire is still topical due to the development of alternative binder systems and additives that may change the microstructure of concrete which therefore may show a different behavior under high temperatures.
Weak deflection angle of black-bounce traversable wormholes using Gauss-Bonnet theorem in the dark matter medium
Creators: name: Övgün, Ali
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, we first use the optical metrics of black-bounce traversable wormholes to calculate the Gaussian curvature. Then we use the Gauss-Bonnet theorem to obtain the weak deflection angle of light from the black-bounce traversable wormholes. Then we investigate the effect of dark matter medium on weak deflection angle using the Gauss-Bonnet theorem. We show how weak deflection angle of wormhole is affected by the bounce parameter $a$. Using the Gauss-bonnet theorem for calculating weak deflection angle shows us that light bending can be thought as a global and topological effect.
description: 8 pages. Accepted for publication in Turkish Journal of Physics
Η ανάπλαση του ελληνικού πολιτικού συστήματος: από τη Συμφωνία της Βάρκιζας ως το δημοψήφισμα για την επιστροφή του Γεωργίου Β’ (1945 - 1946)»
Creators: name: Καράτσαλης, Γεώργιος–Κωνσταντίνος Πολυβίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Μεγάλη Βρετανία
Γεώργιος Β’
Συμφωνία Βάρκιζας
Great Britain
George II of Greece
Varkiza Agreement

description: Αντικείμενο μελέτης της παρούσας εργασίας αποτελεί η διαδικασία αναμόρφωσης του πολιτικού συστήματος στη μετακατοχική Ελλάδα. Χρονική περίοδο μελέτης ορίζουμε το διάστημα που μεσολαβεί από την υπογραφή της Συμφωνίας της Βάρκιζας (12 Φεβρουαρίου 1945) μέχρι το δημοψήφισμα που διενεργήθηκε για την επάνοδο του βασιλιά Γεωργίου Β’ και την επιστροφή του στην Ελλάδα (1 και 27 Σεπτεμβρίου 1946). Επιλέγουμε τη χρονική οριοθέτηση αυτή, καθώς θεωρούμε ότι, με τη Συμφωνία της Βάρκιζας ετίθεντο, θεωρητικά τουλάχιστον, τα θεμέλια της ειρήνευσης της χώρας και ανοιγόταν η προοπτική ομαλής αναδιάταξης των πολιτικών πραγμάτων, τόσο εξαιτίας της επισυμβείσας στρατιωτικής ήττας των αριστερών δυνάμεων, κατά τη δεκεμβριανή σύγκρουση, όσο και των υποχρεώσεων που αναλάμβανε ο αστικός πολιτικός κόσμος ως απόρροια των συμφωνηθέντων, οι οποίες, όμως, κατέληξαν «κενό γράμμα», ενώ το δημοψήφισμα του 1946 αποτελεί, κατά τη γνώμη μας, το χρονικό σημείο κατά το οποίο έχουν δρομολογηθεί οι πολιτικές εξελίξεις και έχει προκύψει, έστω και σιωπηρά, ως μονόδρομος η εμφύλια σύγκρουση. Η εργασία επιχειρεί να σκιαγραφήσει τόσο τις δομές άσκησης εξουσίας, όσο και τις αρχές από τις οποίες διέπονταν αυτές, ταυτοχρόνως, όμως, να καταδείξει και τη διαλεκτική σχέση αλληλεξάρτησης και συνδιαμόρφωσης που δημιουργήθηκε μεταξύ αυτών των δομών και των αρχών.
description: The aim of this dissertation is to study the process of reforming the political system in post – war Greece. The signing of the Varkiza Agreement (12 February 1945) constitutes the starting point of the period in question, while the closing point is the referendum that was carried out for the return of King George II in Greece (1 and 27 September 1946). We chose this time span, as we consider that the Varkiza Agreement laid, at least typically, the foundations of peace in the country. In addition, the prospects of the smooth reform of the domestic politics were created, firstly due to fact that the Left formations were beaten in the collision of December and secondly because of the obligations undertaken by the civil political world as an outcome of the Varkiza Agreement, even though they ended up as a meaningless piece of paper. On the other hand, the referendum of 1946 constitutes, from our point of view, the time when the political developments had already commenced and at the same time civil war has become a one way street, though silently. The dissertation aims to sketch on the one hand the structures of authority and on the other hand the principals that run through them, but at the same time to outline the dialectical relation of interdependence and mutual forming that was created between those structures and those principles.
Quantum Knitting
Creators: name: Garnerone, S.
name: Marzuoli, A.
name: Rasetti, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We analyze the connections between the mathematical theory of knots and quantum physics by addressing a number of algorithmic questions related to both knots and braid groups. Knots can be distinguished by means of `knot invariants', among which the Jones polynomial plays a prominent role, since it can be associated with observables in topological quantum field theory. Although the problem of computing the Jones polynomial is intractable in the framework of classical complexity theory, it has been recently recognized that a quantum computer is capable of approximating it in an efficient way. The quantum algorithms discussed here represent a breakthrough for quantum computation, since approximating the Jones polynomial is actually a `universal problem', namely the hardest problem that a quantum computer can efficiently handle.
description: 29 pages, 5 figures; to appear in Laser Journal
Non-volatile reconfigurable integrated photonics enabled by broadband low-loss phase change material
Creators: name: Fang, Zhuoran
name: Zheng, Jiajiu
name: Saxena, Abhi
name: Whitehead, James
name: Chen, Yueyang
name: Majumdar, Arka
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Phase change materials (PCMs) have long been used as a storage medium in rewritable compact disk and later in random access memory. In recent years, the integration of PCMs with nanophotonic structures has introduced a new paradigm for non-volatile reconfigurable optics. However, the high loss of the archetypal PCM Ge2Sb2Te5 in both visible and telecommunication wavelengths has fundamentally limited its applications. Sb2S3 has recently emerged as a wide-bandgap PCM with transparency windows ranging from 610nm to near-IR. In this paper, the strong optical phase modulation and low optical loss of Sb2S3 are experimentally demonstrated for the first time in integrated photonic platforms at both 750nm and 1550nm. As opposed to silicon, the thermo-optic coefficient of Sb2S3 is shown to be negative, making the Sb2S3-Si hybrid platform less sensitive to thermal fluctuation. Finally, a Sb2S3 integrated non-volatile microring switch is demonstrated which can be tuned electrically between a high and low transmission state with a contrast over 30dB. Our work experimentally verified the prominent phase modification and low loss of Sb2S3 in wavelength ranges relevant for both solid-state quantum emitter and telecommunication, enabling potential applications such as optical field programmable gate array, post-fabrication trimming, and large-scale integrated quantum photonic network.
Geographies of displacement : gender, culture and power in UNHCR refugee camps, Kenya
Creators: name: Hyndman, M. Jennifer
Publisher: name: University of British Columbia
Year: 2009

description: The end of the Cold War marks a period of human displacement greater in scale than any other this century. The number of refugees in 1995 numbered over 16 million; a conservative estimate of internally displaced persons (IDPs) in the same year was 26 million. Approximately 36% of the worlds' refugees and half of all IDPs are located in continental Africa, suggesting an uneven world geography of forced migration. This research analyzes the 'safe spaces' where displaced people seek protection from threats of persecution and violence. In particular, it examines the major humanitarian organization providing assistance to involuntary migrants, the Office of the United Nations High Commissioner for Refugees (UNHCR), both at its headquarters in Geneva and in the context of refugee camps administered by the agency in Kenya. As resettlement targets in countries like Canada, the U.S., and Australia decline, many states hosting large numbers of refugees are less interested in allowing refugees to integrate or settle locally. In the case of Kenya, most refugees have the choice between returning home on a voluntary basis or staying in the camps. A few are resettled abroad and many more seek unofficial livelihoods beyond the borders of the camps. Questions of legal status, social and spatial segregation, and camp management constitute the major themes of this study. The legal framework which defines refugee status and entitlements originated after the Second World War and has, with few exceptions, become increasing irrelevant to crises of displacement in African locations. Ad hoc measures on the part of UNHCR to accommodate refugees who fall outside the 1951 definition have been flexible but insufficient. Camps have become more permanent, suspending refugees in 'safe spaces' without many political, social, cultural, and economic rights. The organization of the camps is scrutinized in detail for its relation to colonial administrations, the impact of its design and operations for refugee women and men, and the correspondence of UNHCR policy to practice in the field. The research contributes to the practice, politics, theory, and geography of humanitarian responses to human displacement.
Ερμηνευτική προσέγγιση και προβληματικές του εγκλήματος της υπόθαλψης εγκληματία
Creators: name: Παπαγεωργίου, Φωτεινή Χρήστου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: υπόθαλψη
έγκλημα
fomentation
crime

description: Στο ενδέκατο κεφάλαιο (ΙΑ΄) του Ειδικού Μέρους του Ποινικού Κώδικα, που τιτλοφορείται «εγκλήματα σχετικά με την απονομή της δικαιοσύνης» συναντάμε μεταξύ άλλων στη διάταξη του άρθρου 231 ΠΚ το έγκλημα της υποθάλψεως εγκληματία. Παρόλο που από κοινωνιολογική σκοπιά, η υπόθαλψη εγκληματία ως πράξη συνιστά κατ’ ουσίαν ενέργεια ή παράλειψη αλληλεγγύης προς τον συνάνθρωπο, το φυγά, τον καταδιωκόμενο, το δραπέτη, εντούτοις η έννομη τάξη και το Κράτος Δικαίου «ενοχλούνται» από την τέλεσή της, επιλέγοντας την τιμωρία της δια της τυποποίησης της σε διάταξη νόμου. Ο τρόπος που τυποποιείται στον Ποινικό Κώδικα, ως και η τέλεσή του στην πράξη πυροδότησε διάλογο μεταξύ επιστημονικής κοινότητας και δικαστικών λειτουργών για πλείστα θεωρητικά ζητήματα με έντονη ωστόσο πρακτική εφαρμογή. Η ορθή τους προσέγγιση από τον εφαρμοστή του δικαίου παρά τις ακανθώδεις πτυχές τους με γνώμονα τις γενικές απαρέγκλιτης αξίας αρχές του Κράτους Δικαίου, του Συντάγματος, ως και του Ποινικού Δικαίου αποτελεί προαπαιτούμενο για πλείστες ορθές καταδίκες και δίκαιες αθωώσεις. Προς την κατεύθυνση αυτή, αναγκαία κρίνεται μία συμπληρωματική επαναδιατύπωση της διατάξεως από τον νομοθέτη ή η ένταξή της στο αντίστοιχο κεφάλαιο του εννόμου αγαθού, που προστατεύει, προσπάθειες που θα επέλυαν οριστικά μ’ αυτόν τον τρόπο διφορούμενα ζητήματα.
description: In the eleventh chapter of the special part of Penal Code, entitled “crimes related to the administration of justice” find in the article number 231 of Penal Code the crime of fomentation of criminal. Although from an sociological aspect, the fomentation of criminal consists of an action or a failure of solidarity with our neighbors, with the figutive, persecuted or the runaway, however the legal system and the rule of law “annoyed’’of the commission of this action, selecting its punishment with the adoption of a statutory provision. The mode of standardization in the Penal Code of the crime of fomentation of criminal and on the other hand its commission in practice sparked a debate between scientific community and judges about many theoretical issues with a great practical application simultaneously. Despite their controversial aspects, their correct approach of the practitioners of the law in accordance with the general principles of the Rule of Law, of the Constitution and of Penal and Criminal Law are a prerequisite for proper convictions and fair acquittals. In this direction, is necessary an additional reformulation of the provision by the legislator or its inclusion in the relevant chapter of the legal right that protects in Penal Code. Only with this way, ambiguous issues concerning the crime of fomentation of criminal will be solved.
Second harmonic generation and X-ray diffraction studies of pretransitional region in relaxor K(1-x) LixTaO3
Creators: name: Yokota, Hiroko
name: Uesu, Yoshiaki
name: Malibert, Charlotte
name: Kiat, Jean-Michel
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Optical second-harmonic-generation(SHG) observations and precise X-ray diffraction experiments have been performed on quantum paraelectrics KTaO3 (KTO) and relaxor K(1-x)LixTaO3 with x=3% (KLT-3) and 7% (KLT-7). It is found in KLT-3 and KLT-7 that a pretransitional region exists between two characteristic temperatures Td and Tp (
description: 31 pages, 10 figures
Pressure-induced magnetism in iron-based superconductors $A$Fe$_2$As$_2$ ($A=$ K, Cs, Rb)
Creators: name: Khasanov, Rustem
name: Guguchia, Zurab
name: Morenzoni, Elvezio
name: Baines, Chris
name: Wang, Aifeng
name: Chen, Xianhui
name: Bukowski, Zbigniew
name: Tafti, Fazel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The magnetic properties of iron-based superconductors $A$Fe$_2$As$_2$ ($A=$K, Cs, and Rb), which are characterized by the V-shaped dependence of the critical temperature ($T_{\rm c}$) on pressure ($P$) were studied by means of the muon spin rotation/relaxation technique. In all three systems studied the magnetism was found to appear for pressures slightly below the critical one ($P_{\rm c}$), i.e. at pressure where $T_{\rm c}(P)$ changes the slope. Rather than competing, magnetism and superconductivity in $A$Fe$_2$As$_2$ are coexisting at $P\gtrsim P_{\rm c}$ pressure region. Our results support the scenario of a transition from one pairing state to another, with different symmetries on either side of $P_{\rm c}$.
description: 7 pages, 3 figures
Matrix product states and exactly solvable spin 1/2 Heisenberg chains with nearest neighbor interactions
Creators: name: Asoudeh, M.
name: Karimipour, V.
name: Sadrolashrafi, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Using the matrix product formalism, we introduce a two parameter family of exactly solvable $xyz$ spin 1/2 Heisenberg chains in magnetic field (with nearest neighbor interactions) and calculate the ground state and correlation functions in compact form. The ground state has a very interesting property: all the pairs of spins are equally entangled with each other. Therefore it is possible to engineer long-range entanglement in experimentally realizable spin systems on the one hand and study more closely quantum phase transition in such systems on the other.
description: 4 pages, RevTex, references added, improved presentation, typos fixed
Supernova X-Ray Database (SNaX) Updated to Ensure Long-term Stability
Creators: name: Nisenoff, Alexandra
name: Dwarkadas, Vikram V.
name: Ross, Mathias C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The Supernova X-Ray Database (SNaX) was established a few years ago to make X-ray data on supernovae (SNe) publicly available via an elegant searchable web interface. The database has recently been updated to PhP7, had security updates done, and moved to a new server, ensuring its long-term stability. We urge astronomers to continue to download the data as needed for their work. Those with X-ray data on SNe are requested to upload it to the database via the easily fillable spreadsheet, making it accessible to everyone.
description: 3 pages, 1 figure. Published in the Research Notes of the American Astronomical Society. Just a small reminder to astronomers to use the database for X-ray data on SNe, and to upload your data on X-ray SNe to the database
Grothendieck's constant and local models for noisy entangled quantum states
Creators: name: Acin, Antonio
name: Gisin, Nicolas
name: Toner, Benjamin
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We relate the nonlocal properties of noisy entangled states to Grothendieck's constant, a mathematical constant appearing in Banach space theory. For two-qubit Werner states $ρ^W_p=p \proj{ψ^-}+(1-p){\one}/{4}$, we show that there is a local model for projective measurements if and only if $p \le 1/K_G(3)$, where $K_G(3)$ is Grothendieck's constant of order 3. Known bounds on $K_G(3)$ prove the existence of this model at least for $p \lesssim 0.66$, quite close to the current region of Bell violation, $p \sim 0.71$. We generalize this result to arbitrary quantum states.
description: 6 pages, 1 figure
Nineteenth-century archaeology and the retrieval of the past : Carlyle, Scott, Bulwer-Lytton, Pater, and Haggard
Creators: name: Malley, Shawn Cameron
Publisher: name: University of British Columbia
Year: 2009

description: "Nineteenth-Century Archaeology and the Retrieval of the Past: Carlyle, Scott, Bulwer-Lytton, Pater, and Haggard" shows that the recovery, analysis, and interpretation of material history was a model for investigating, re-creating, and reinventing the past in Thomas Carlyle's "Past and Present" (1843), Walter Scott's "The Antiquary" (1816), Edward Bulwer-Lytton's "The Last Days of Pompeii" (1834), Walter Pater's "The Renaissance" (1873) and "Greek Studies" (1895), and H. Rider Haggard's "She". (1887). Through the self-conscious use of archaeological language and methodology, the authors of these fictional and nonfiction texts composed what I term "narratives of continuity," in which the retrieval of artifacts is a tangible means of drawing connections between past and present. These narratives illustrate teleological interpretations of history espoused by archaeologists, who themselves sought prefigurements of modern culture as they studied archaeological records. This thesis in part examines philosophic, scientific, and political thought underlying the penchant in these texts to link past and present as a means of sustaining historical identity and thereby validating present institutions. To the Victorians, archaeology was an authenticating medium for the material consolidation of tradition. The archaeological themes and language in these texts have a counterpart in their form. Devices such as editorial "framing" and narrative "stratification" contribute to the sense of text as archaeological site. These texts are "sites" for the recovery and substantiation of the past. They also chart developments in archaeology over the course of the nineteenth century. The archaeological trope evolves with archaeology's maturation from amateur antiquarianism (reflected in Scott's 1816 novel The Antiquary) to the first glimpses of professional and scientific archaeology at the end of the century depicted in Haggard's "She" (1887). Narratives of continuity, moreover, emanate from several fields of Victorian archaeology. The writings of Carlyle, Scott, Bulwer-Lytton, Pater, and Haggard depict a range of archaeological activity spanning domestic excavation to foreign archaeology in the Middle East, Egypt, Greece, Italy, and South Africa.
Complementary local-global approach for phonon mode connectivities
Creators: name: Gan, Chee Kwan
name: Ong, Zhun-Yong
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Sorting and assigning phonon branches (e.g., longitudinal acoustic) of phonon modes is important for characterizing the phonon bands of a crystal and the determination of phonon properties such as the Grüneisan parameter and group velocity. To do this, the phonon band indices (including the longitudinal and transverse acoustic) have to be assigned correctly to all phonon modes across a path or paths in the Brillouin zone. As our solution to this challenging problem, we propose a computationally efficient and robust two-stage hybrid method that combines two approaches with their own merits. The first is the perturbative approach in which we connect the modes using degenerate perturbation theory. In the second approach, we use numerical fitting based on least-squares fits to circumvent local connectivity errors at or near exact degenerate modes. The method can be easily generalized to other condensed matter problems involving Hermitian matrix operators such as electronic bands in tight-binding Hamiltonians or in a standard density-functional calculation, and photonic bands in photonic crystals.
description: 6 figures, 7 pages
A second-order identity for the Riemann tensor and applications
Creators: name: Mantica, Carlo Alberto
name: Molinari, Luca Guido
Publisher: name: arXiv
Year: 2008
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53B20, 53B21

description: A second-order differential identity for the Riemann tensor is obtained, on a manifold with symmetric connection. Several old and some new differential identities for the Riemann and Ricci tensors descend from it. Applications to manifolds with Recurrent or Symmetric structures are discussed. The new structure of K-recurrency naturally emerges from an invariance property of an old identity by Lovelock.
description: 16 pages
The characteristic polarized radio continuum distribution of cluster spiral galaxies
Creators: name: Vollmer, B.
name: Soida, M.
name: Beck, R.
name: Urbanik, M.
name: Chyzy, K.
name: Otmianowska-Mazur, K.
name: Kenney, J.
name: van Gorkom, J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Deep observations of 6cm polarized radio continuum emission of 8 Virgo spiral galaxies are presented. All galaxies show strongly asymmetric distributions of polarized intensity with elongated ridges located in the outer galactic disk. Such features are not found in existing observations of polarized radio continuum emission of field spiral galaxies, where the distribution of 6cm polarized intensity is generally relatively symmetric and strongest in the interarm regions. We therefore conclude that most Virgo spiral galaxies and most probably the majority of cluster spiral galaxies show asymmetric distributions of polarized radio continuum emission due to their interaction with the cluster environment. The polarized continuum emission is sensitive to compression and shear motions in the plane of the sky and thus contains important information about velocity distortions caused by these interactions.
description: 5 pages, 1 figure, A&A accepted as a letter
Dynamic phase transitions in electromigration-induced step bunching
Creators: name: Popkov, Vladislav
name: Krug, Joachim
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Electromigration-induced step bunching in the presence of sublimation or deposition is studied theoretically in the attachment-limited regime. We predict a phase transition as a function of the relative strength of kinetic asymmetry and step drift. For weak asymmetry the number of steps between bunches grows logarithmically with bunch size, whereas for strong asymmetry at most a single step crosses between two bunches. In the latter phase the emission and absorption of steps is a collective process which sets in only above a critical bunch size and/or step interaction strength.
description: 4 pages, 4 figures
Dark energy from vacuum entanglement
Creators: name: Lee, Jae-Weon
name: Lee, Jungjai
name: Kim, Hyeong-Chan
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We suggest that vacuum entanglement energy associated with the entanglement entropy of the universe is the origin of dark energy. The observed properties of dark energy can be explained by using the nature of entanglement energy without modification of gravity or exotic matter. From the number of degrees of freedom in the standard model, we obtain the equation of state parameter $ω^0_Λ\simeq -0.93$ and $d\simeq 0.95$ for the holographic dark energy, which are consistent with current observational data at the 95% confidence level.
description: to be published in JCAP
Bright Optical Eigenmode with about 1 nm $^3$ Volume
Creators: name: Li, Wancong
name: Zhou, Qiang
name: Zhang, Pu
name: Chen, Xue-Wen
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Concentrating optical field in an eigenmode with a tiny volume is vitally important for light-matter interactions at the fundamental level and underpins new technologies. In the past decades, researchers have investigated various approaches to shrink light and so far managed to reduce the volume of optical eigenmodes, under the quantum-optical definition, down to several ten nm3. Here we report on the discovery, characterization and engineering of a class of extremely localized eigenmodes that are resonances of atomistic protrusions on a metallic host nanoparticle and feature quantum-optical mode volumes of below 1 nm3. We theoretically demonstrate that these extremely localized modes can be made bright with radiation efficiencies reaching 30% and provide up to 4x10^7 times intensity enhancement. The existence of bright eigenmodes with the volume comparable to a photon emitter foresees exciting new optical physics, such as ultrastrong coupling with single optical emitters, angstrom-resolution optical imaging, and atomic-scale single-molecule photochemistry.
CAMP: Cost-Aware Multiparty Session Protocols
Creators: name: Castro-Perez, David
name: Yoshida, Nobuko
Publisher: name: arXiv
Year: 2020
Subjects: subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences

description: This paper presents CAMP, a new static performance analysis framework for message-passing concurrent and distributed systems, based on the theory of multiparty session types (MPST). Understanding the run-time performance of concurrent and distributed systems is of great importance for the identification of bottlenecks and optimisation opportunities. In the message-passing setting, these bottlenecks are generally communication overheads and synchronisation times. Despite its importance, reasoning about these intensional properties of software, such as performance, has received little attention, compared to verifying extensional properties, such as correctness. Behavioural protocol specifications based on sessions types capture not only extensional, but also intensional properties of concurrent and distributed systems. CAMP augments MPST with annotations of communication latency and local computation cost, defined as estimated execution times, that we use to extract cost equations from protocol descriptions. CAMP is also extendable to analyse asynchronous communication optimisation built on a recent advance of session type theories. We apply our tool to different existing benchmarks and use cases in the literature with a wide range of communication protocols, implemented in C, MPI-C, Scala, Go, and OCaml. Our benchmarks show that, in most of the cases, we predict an upper-bound on the real execution costs with < 15% error.
description: Accepted at OOPSLA'20
Διατύπωση σχεδίου οργάνωσης της κυκλοφορίας με χρήση μακροσκοπικού υποδείγματος προσομοίωσης
Creators: name: Κοσμοπούλου, Σοφία Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Υποδείγματα
Προσομοίωση
Λεωφορειολωρίδα
Models
Simulation
Bus lane

description: Η παρούσα διπλωματική εργασία επικεντρώνεται στην μελέτη του μακροσκοπικού μοντέλου VISUM και στην εφαρμογή του σε τμήμα της ανατολικής Θεσσαλονίκης. Το δίκτυο της περιοχής μελέτης κωδικοποιήθηκε με την εισαγωγή πραγματικών δεδομένων προσφοράς και ζήτησης και διερευνήθηκε εκτενώς ο καταμερισμός στο δίκτυο των μετακινήσεων κατά την πρωινή ώρα αιχμής. Σε πειραματικό επίπεδο μελετώνται τα αποτελέσματα της εφαρμογής των αλγορίθμων στατικού καταμερισμού που παρέχει το VISUM στην προσπάθεια εύρεσης εκείνου που αποδίδει πιστότερα τις κυκλοφοριακές συνθήκες της περιοχής μελέτης, ενώ κατά το στάδιο της μελέτης εφαρμογής δύο προτεινόμενα εναλλακτικά σενάρια που περιλαμβάνουν μέτρα με κύριο άξονα την απόδοση προτεραιότητας στα μέσα μαζικής μεταφοράς, συγκρίνονται μεταξύ τους και με το μοντέλο της υφιστάμενης κατάστασης για την εξαγωγή συμπερασμάτων ως προς την ικανοποιητικότερη δέσμη μέτρων βελτίωσης των κυκλοφοριακών συνθηκών της πόλης.
description: The present thesis focuses on the examination of the macroscopic simulation model Visum and its implementation in a section of eastern Thessaloniki. The road network of the study area is being encoded by means of actual data of supply and demand, extensively researching the stage of the traffic assignment, during morning peak hour. The experimental phase of the thesis examines the outcomes of the application of the five different assignment algorithms that Visum provides concerning static assignment, in the midst of the attempt to find which is the one provides the most reliable results compared to real traffic conditions. Subsequently, the case study of the thesis proposes two alternative scenarios which include regulatory measures and practices of improving traffic conditions in the area. They principally aim at prioritizing mass public transport. Under these circumstances, two new models are structured, which are compared to each other and to the initial model of the current traffic conditions. This extensive comparison leads to conclusions concerning a set of measures to improve traffic conditions in the city.
Quantum molecular dynamics simulations for the nonmetal-to-metal transition in fluid helium
Creators: name: Kietzmann, Andre
name: Holst, Bastian
name: Redmer, Ronald
name: Desjarlais, Michael P.
name: Mattsson, Thomas R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We have performed quantum molecular dynamics simulations for dense helium to study the nonmetal-to-metal transition at high pressures. We present new results for the equation of state and the Hugoniot curve in the warm dense matter region. The optical conductivity is calculated via the Kubo-Greenwood formula from which the dc conductivity is derived. The nonmetal-to-metal transition is identified at about 1 g/ccm. We compare with experimental results as well as with other theoretical approaches, especially with predictions of chemical models.
description: 4 pages, 5 figures
Estimation of heavy tails in optical non-linear processes
Creators: name: Rácz, Éva
name: Ruppert, László
name: Filip, Radim
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In optical non-linear processes rogue waves can be observed, which can be mathematically described by heavy-tailed distributions. These distributions are special due to the fact that the probability of registering extremely high intensities is significantly higher than for the exponential distribution, which is most commonly observed in statistical and quantum optics. The current manuscript gives a practical overview of the generic statistics toolkit concerning heavy-tailed distributions and proposes methods to deal with issues specific to non-linear optics. We take a closer look at supercontinuum generation, where rogue waves were already observed. We propose modifications to the Hill estimator to deal with detector saturation as well as corrections introduced by pumping the process by bright squeezed vacuum. The suggested methodology facilitates statistically reliable observation of heavy-tailed distribution in non-linear optics, nanooptics, atomic, solid-state processes and optomechanics.
description: 19 pages, 10 figures
Real time robot arm collision detection and path planning
Creators: name: Toth, Erik
Publisher: name: Zenodo
Year: 2023

description: Collaborative robots are intended to create a manufacturing workplace where humans can share a commonplace with the machines and work together. Unfortunately, most workplaces have yet to allow real collaboration between them. In most cases, even collaborative robots are isolated from human contact because of safety requirements. Furthermore, there is a protective stop in place if a collision happens so the worker will not be injured. However, this will cause the robot to stop which in turn stops the whole line and a restart will be needed. This means a loss in production. One way to solve this problem is to alert the human part that a collision will happen so that they can move out of the robot’s way. Another way is to create a system that can detect obstacles and can recreate the path of the robotic arm in real time so that it avoids possible collisions. In this work, I will create a solution that contains both systems. An XR device will help the human worker by showing the robot’s movement in advance. This way one can see where the machine intends to move in the next second and can move out of the way. This AR device will be responsible for scanning the worker’s hands in real-time based on which collisions can be predicted. The robotic arm’s path will be recreated by mathematically modeling the environment and fitting polynomials, parametric curves, and splines on it so that the most efficient route is found that avoids the obstacle. The expected result of my thesis is a technology that enables true collaboration between humans and robots by minimizing or even eliminating the risks.