cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Destabilization of ferromagnetism by frustration and realization of a nonmagnetic Mott transition in the quarter-filled two-orbital Hubbard model
Creators: name: Kubo, Katsunori
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The two-orbital Hubbard model on a square lattice at quarter filling (electron number per site $n=1$) is investigated by the variational Monte Carlo method. For the variational wave function, we include short-range doublon-holon binding factors. We find that the energy of this wave function is lower than that of the density-density Jastrow wave function partially including long-range correlations used in a previous study. We introduce frustration to the model by the next-nearest-neighbor hopping $t'$ in addition to the nearest-neighbor hopping $t$. For $t'=0$, a ferromagnetic state with staggered orbital order occurs by increasing the Coulomb interaction $U$ before the Mott transition takes place. By increasing $t'$, the region of this ferromagnetic phase shrinks, and the Mott transition without magnetic order occurs.
description: 7 pages, 7 figures
Spin analog of the controlled Josephson charge current
Creators: name: Mandal, Sudhansu S.
name: Mukherjee, Soumya P.
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: We propose a controlled Josephson spin current across the junction of two non-centrosymmetric superconductors like CePt_3Si. The Josephson spin current arises due to direction dependent tunneling matrix element and different momentum dependent phases of the triplet components of the gap function. Its modulation with the angle ξbetween the noncentrosymmetric axes of two superconductors is proportional to \sin ξ. This particular dependence on ξmay find application of the proposed set-up in making a Josephson spin switch.
description: 4 pages, 1 figure; title is changed; article is rewritten
Construction of explicit symplectic integrators in general relativity. IV. Kerr black holes
Creators: name: Wu, Xin
name: Wang, Ying
name: Sun, Wei
name: Liu, Fuyao
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Chaotic Dynamics (nlin.CD)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences
subject: F.2.2; J.2
subject: 83-08, 85-08, 70Kxx

description: In previous papers, explicit symplectic integrators were designed for nonrotating black holes, such as a Schwarzschild black hole. However, they fail to work in the Kerr spacetime because not all variables can be separable, or not all splitting parts have analytical solutions as explicit functions of proper time. To cope with this difficulty, we introduce a time transformation function to the Hamiltonian of Kerr geometry so as to obtain a time-transformed Hamiltonian consisting of five splitting parts, whose analytical solutions are explicit functions of the new coordinate time. The chosen time transformation function can cause time steps to be adaptive, but it is mainly used to implement the desired splitting of the time transformed Hamiltonian. In this manner, new explicit symplectic algorithms are easily available. Unlike Runge Kutta integrators, the newly proposed algorithms exhibit good long term behavior in the conservation of Hamiltonian quantities when appropriate fixed coordinate time steps are considered. They are better than same order implicit and explicit mixed symplectic algorithms and extended phase space explicit symplectic like methods in computational efficiency. The proposed idea on the construction of explicit symplectic integrators is suitable for not only the Kerr metric but also many other relativistic problems, such as a Kerr black hole immersed in a magnetic field, a Kerr Newman black hole with an external magnetic field, axially symmetric core shell systems, and five dimensional black ring metrics.
description: 12pages,12figures
A Modified Villain Formulation of Fractons and Other Exotic Theories
Creators: name: Gorantla, Pranay
name: Lam, Ho Tat
name: Seiberg, Nathan
name: Shao, Shu-Heng
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We reformulate known exotic theories (including theories of fractons) on a Euclidean spacetime lattice. We write them using the Villain approach and then we modify them to a convenient range of parameters. The new lattice models are closer to the continuum limit than the original lattice versions. In particular, they exhibit many of the recently found properties of the continuum theories including emergent global symmetries and surprising dualities. Also, these new models provide a clear and rigorous formulation to the continuum models and their singularities. In appendices, we use this approach to review well-studied lattice models and their continuum limits. These include the XY-model, the $\mathbb{Z}_N$ clock-model, and various gauge theories in diverse dimensions. This presentation clarifies the relation between the condensed-matter and the high-energy views of these systems. It emphasizes the role of symmetries associated with the topology of field space, duality, and various anomalies.
description: 66 pages, 1 figure
Axion-dilaton cosmology, Ricci flows and integrable structures
Creators: name: Orlando, Domenico
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we study renormalization-group flows by deforming a class of conformal sigma-models. At leading order in $α'$, renormalization-group equations represent a Ricci flow. In the three-sphere background, the latter is described by the Halphen system, which is exactly solvable in terms of modular forms. The round sphere is found to be the unique perturbative infra-red fixed point at one loop order.
description: 2 pages, based on a talk given at the Cargese Summer School, May 22 to June 3, 2006
Ellipses of Constant Entropy in the XY Spin Chain
Creators: name: Franchini, F.
name: Its, A. R.
name: Jin, B. -Q.
name: Korepin, V. E.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Entanglement in the ground state of the XY model on the infinite chain can be measured by the von Neumann entropy of a block of neighboring spins. We study a double scaling limit: the size of the block is much larger then 1 but much smaller then the length of the whole chain. The entropy of the block has an asymptotic limit. We study this limiting entropy as a function of the anisotropy and of the magnetic field. We identify its minima at product states and its divergencies at the quantum phase transitions. We find that the curves of constant entropy are ellipses and hyperbolas and that they all meet at one point (essential critical point). Depending on the approach to the essential critical point the entropy can take any value between 0 and infinity. In the vicinity of this point small changes in the parameters cause large change of the entropy.
description: Revised Version, 20 pages, 8 figures, 1 table
Η προδικαστική προσφυγή ενώπιον της Αρχής Εξέτασης Προδικαστικών Προσφυγών
Creators: name: Πουλικίδου, Ιωάννα Θεόδωρου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Προδικαστική προσφυγή
Αρχή Εξέτασης Προδικαστικών Προσφυγών
Δημόσιες συμβάσεις
Preliminary Appeal
Authority for the Examination of Preliminary Appeals
Public procurements

description: Με την παρούσα εργασία σκοπείται η παρουσίαση της Αρχής Εξέτασης Προδικαστικών Προσφυγών και της προδικαστικής προσφυγής, καθώς και των ζητημάτων που έχουν ανακύψει στο πλαίσιο εφαρμογής του ν. 4412/2016 και των τροποποιήσεων που έχουν ήδη επέλθει σε αυτόν. Με τον ν. 4412/2016 αναδιαμορφώθηκε η έννομη προστασία στο προσυμβατικό στάδιο και προβλέφθηκε για πρώτη φορά η άσκηση προδικαστικής προσφυγής ενώπιον της Αρχής Εξέτασης Προδικαστικών Προσφυγών, δηλαδή, ενώπιον ενός ανεξαρτήτου οργάνου, εν αντιθέσει με τα προηγούμενα νομοθετήματα που προέβλεπαν την άσκηση προδικαστικής προσφυγής ενώπιον της αναθέτουσας αρχής. Πιο συγκεκριμένα, στο πρώτο κεφάλαιο της παρούσης εργασίας γίνεται αναφορά στην ΑΕΠΠ, στους λόγους που κατέστησαν αναγκαία την ίδρυσή της, στα χαρακτηριστικά της και στη νομική της φύση. Στο δε δεύτερο κεφάλαιο εξετάζεται η νομική φύση της προδικαστικής προσφυγής, οι προϋποθέσεις για την παραδεκτή άσκησή της, ο τρόπος εξέτασής της και οι αποφάσεις που εκδίδει η ΑΕΠΠ. Η τελευταία φαίνεται να ανταπεξέρχεται αποτελεσματικά στο έργο που της έχει ανατεθεί, πλην, όμως, υπάρχουν περιθώρια βελτίωσης, ώστε η προστασία των οικονομικών φορέων να είναι πληρέστερη και αποτελεσματικότερη
description: The purpose of my thesis is the presentation of the Authority for the Examination of Preliminary Appeals, the presentation of preliminary appeal and the issues which showed up during the application of law 4412/2016 and also the amendments of this particular law. With law 4412/2016 legal protection was reformed in the pre- contractual stage and for the first time the preliminary appeal was granted to Authority for the Examination of Preliminary Appeals, an independent institution, unlike the previous laws which defined that a preliminary appeal will be examined by the contracting authority. More specific, the first chapter of my thesis refers to the Authority for the Examination of Preliminary Appeals, the importance of its foundation, its attributes and its legal nature. The second chapter refers to the legal nature of preliminary appeal as well as to the conditions of admissions, how they are examined and the decisions of the Authority for the Examination of Preliminary Appeals. The Authority for the Examination of Preliminary Appeals seems to respond effectively to its assigned purpose. However, there is room for improvement, for the protection of economic operators to be better and more effective
Understanding the Effects of Systematics in Exoplanetary Atmospheric Retrievals
Creators: name: Ih, Jegug
name: Kempton, Eliza M. -R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Retrieval of exoplanetary atmospheric properties from their transmission spectra commonly assumes that the errors in the data are Gaussian and independent. However, non-Gaussian noise can occur due to instrumental or stellar systematics and merging discrete datasets. We investigate the effect of correlated noise and constrain the potential biases incurred in the retrieved posteriors. We simulate multiple noise instances of synthetic data and perform retrievals to obtain statistics of goodness-of-retrieval for varying noise models. We find that correlated noise allows for overfitting the spectrum, thereby yielding better goodness-of-fit on average but degrading the overall accuracy of retrievals. In particular, correlated noise can manifest as an apparent non-Rayleigh slope in the optical range, leading to an incorrect estimate of cloud/haze parameters. We also find that higher precision causes correlated results to be further off from the input values in terms of estimated errors. As such, we emphasize that caution must be taken in analyzing retrieved posteriors and that estimated parameter uncertainties are best understood as lower limits. Finally, we show that while correlated noise cannot be be reliably distinguished with HST observations, inferring its presence and strength may be possible with JWST observations.
description: 25 pages, 26 figures, Submitted to AJ
An Application of Reversible Entropic Dynamics on Curved Statistical Manifolds
Creators: name: Cafaro, Carlo
name: Ali, S. A.
name: Giffin, Adom
Publisher: name: arXiv
Year: 2007
Subjects: subject: Classical Physics (physics.class-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: Entropic Dynamics (ED) is a theoretical framework developed to investigate the possibility that laws of physics reflect laws of inference rather than laws of nature. In this work, a RED (Reversible Entropic Dynamics) model is considered. The geometric structure underlying the curved statistical manifold, M is studied. The trajectories of this particular model are hyperbolic curves (geodesics) on M. Finally, some analysis concerning the stability of these geodesics on M is carried out.
description: Presented at MaxEnt 2006, the 26th International Workshop on Bayesian Inference and Maximum Entropy Methods (July 8-13, 2006, Paris, France). This paper is slightly updated from the published version. This paper consists of 9 pages with 1 figure. Keywords: Inductive inference, information geometry, statistical manifolds, relative entropy
Η δεσμευτική δύναμη της δικαστικής ομολογίας ως έκφανση της συζητητικής αρχής
Creators: name: Σαμλίδης, Ελευθέριος Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Δικαστική ομολογία
Συζητητική αρχή
Απόδειξη
Judicial admission
Adversary system
Evidence

description: Η διπλωματική εργασία πραγματεύεται το αποδεικτικό μέσο της ομολογίας, όπως ρυθμίζεται στον Κώδικα Πολιτικής Δικονομίας. Προηγείται η καταγραφή των υποστηριζόμενων απόψεων σχετικά με τη νομική φύση της δικαστικής ομολογίας. Καταδεικνύεται η άμεση σύνδεση της με τη συζητητική αρχή, που αποτελεί τη δικονομική προέκταση της ιδιωτικής αυτονομίας που διέπει το ιδιωτικό ουσιαστικό δίκαιο και σε αντιδιαστολή με το ανακριτικό σύστημα και επιχειρείται η δικαιοπολιτική αποτίμηση των δύο συστημάτων από πλευράς δέσμευσης ή μη του δικαστή επί συμφωνίας των διαδίκων ως προς την αλήθεια ορισμένου ισχυρισμού. Ακολουθεί η κατ’ ιδίαν επεξεργασία των άρθρων του ΚΠολΔ για την ομολογία (352- 354). Οριοθετούνται οι περιπτώσεις ισχυρισμών που δεν καταλαμβάνονται από την δεσμευτική δύναμη της ομολογίας. Τέλος, σκιαγραφείται ο αναιρετικός έλεγχος της ομολογίας
description: This thesis deals with the admission as a means of proof, as regulated in the Greek Code of Civil Procedure. The views expressed on the legal nature of the judicial admission are preceded. The direct connection of the adversary system which in fact is the procedural extension of individual autonomy which is governing the private substantive law as opposed to the investigative system is demonstrated. Also an assessment of the two systems is made on whether the judge is bound by the agreement of the two parties over the truth of a claim. This is followed by the individual processing of the CCProc articles regarding the admission (352-354). The cases of claims not occupied by the binding force of the admission are delimited. Finally, issues of appeal regarding the admission are presented.
Attention-gated convolutional neural networks for off-resonance correction of spiral real-time MRI
Creators: name: Lim, Yongwan
name: Narayanan, Shrikanth S.
name: Nayak, Krishna S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Spiral acquisitions are preferred in real-time MRI because of their efficiency, which has made it possible to capture vocal tract dynamics during natural speech. A fundamental limitation of spirals is blurring and signal loss due to off-resonance, which degrades image quality at air-tissue boundaries. Here, we present a new CNN-based off-resonance correction method that incorporates an attention-gate mechanism. This leverages spatial and channel relationships of filtered outputs and improves the expressiveness of the networks. We demonstrate improved performance with the attention-gate, on 1.5 Tesla spiral speech RT-MRI, compared to existing off-resonance correction methods.
description: 8 pages, 4 figures, 1 table
A Light Mediator Relating Neutrino Reactions
Creators: name: Alikhanov, I.
name: Paschos, E. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The extension of the standard model with a multiplicative $U(1)_R$ factor is consistent with a light vector boson. In its simplest realization, only right-handed particles carry charges of the new group. In this model, there is a residual $τ_{3R}$ symmetry and one new coupling constant which correlates neutrino interactions. We compute new contributions to antineutrino$-$electron scattering and coherent scattering on nuclei, and compare them with the XENON1T result.
description: 14 pages, 5 figures. Matches published version
Observing the Time Evolution of the Multi-Component Nucleus of 3C\,84
Creators: name: Punsly, Brian
name: Nagai, Hiroshi
name: Savolainen, Tuomas
name: Orienti, Monica
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The advent of global mm-band Very Long Baseline Interferometry (VLBI) in recent years has finally revealed the morphology of the base of the two most prominent nearby, bright, extragalactic radio jets in M\,87 and 3C\,84. The images are quite surprising considering the predictions of jet theory and current numerical modeling. The jet bases are extremely wide compared to expectations and the nucleus of 3C\,84 is very complicated. It appears as a double in 86\,GHz observations with 50\,$μ$as resolution and a triple nucleus with 30\,$μ$as resolution with space-based VLBI by RadioAstron at 22\,GHz. What is even odder is that the double and triple are arranged along an east-west line that is approximately orthogonal to the north-south large scale jet on 150\,$μ$as $-$ 4\,mas scales. We explore the emergence of an (east-west) double nucleus in the lower resolution 43\,GHz Very Long Baseline Array (VLBA) imaging from August 2018 to April 2020. The double is marginally resolved. We exploit the east-west resolution associated with the longest baselines, $\sim 0.08$\,mas, to track a predominantly east-west separation speed of $\approx 0.086\pm 0.008$\,c. We estimate that the observed mildly relativistic speed persists over a de-projected distance of $\sim 1900-9800$ times the central, supermassive black hole, gravitational radius ($\sim 0.3-1.5$\,lt-yrs) from the point of origin.
description: To appear in ApJ
The Mass Budget Necessary to Explain `Oumuamua as a Nitrogen Iceberg
Creators: name: Siraj, Amir
name: Loeb, Abraham
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Recently, a nitrogen iceberg was proposed as a possible origin for the first interstellar object, 1I/2017 U1, also known as `Oumuamua. Here, we show that the mass budget in exo-Pluto planets necessary to explain the detection of `Oumuamua as a nitrogen iceberg chipped off from a planetary surface requires a mass of heavy elements exceeding the total quantity locked in stars with 95\% confidence, making the scenario untenable because only a small fraction of the mass in stars ends in exo-Plutos.
description: 3 pages, 2 figures; accepted for publication in New Astronomy
Creation of a geographic information system database of Pacific Spirit Park
Creators: name: Helewa, Norman Thomas
Publisher: name: University of British Columbia
Year: 2008

description: Pacific Spirit Park is a 776.0 hectare urban park located on the Point Grey Peninsula in Vancouver, British Columbia. The park is managed by the Greater Vancouver Regional District (GVRD) for recreation opportunities and the preservation of the area's natural resources. Appropriate geographic data were collected and entered into a geographic information system (GIS) in order to create a spatial database of the park. Guidelines from published documents on database creation were followed in the development of the park database. Data collection and design of the database were based on the information requirements of the GVRD park staff (e.g., database users). Information requirements were derived from the activities carried out by the database users. The database could be used to examine the efficiency of activities carried out by park staff on a daily, weekly and yearly basis or assist University of British Columbia faculty and students with research and educational activities in the park. An extended example of how to use the Pacific Spirit Park database for park management was carried out. It exemplified how data on forest vegetation damage can be correlated with other environmental variables (e.g., soils, topography, forest cover, hydrology). Correlations were identified between forest vegetation damage and topography, areas with a high water table and along University Boulevard. The suggested course of action for GVRD park staff is to carry out additional research. Future research could compare the level of forest cover damage in Pacific Spirit Park with similar sites in Southwestern British Columbia, examine how the urban environment impacts the forest vegetation (e.g., damage, composition and growth) and how forest vegetation damage changes over time.
Manipulating superconductivity through the domain structure of a ferromagnet: experimental aspects and theoretical implications
Creators: name: Stamopoulos, D.
name: Pissas, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In the present work we study experimentally the influence that the domain structure of a fer- romagnet (FM) has on the properties of a superconductor (SC) in bilayers and multilayers of La0.60Ca0.40MnO3/Nb and FePt/Nb proximity hybrids. Specific experimental protocols that were employed in the performed magnetization measurements enabled us to directly uncover a generic property of FM/SC hybrids: in the absence of an external magnetic field, the multidomain struc- ture of the FM promotes the nucleation of superconductivity, while its monodomain state strongly suppresses it. Our experimental findings support recent theoretical studies proposing that when an inhomogeneous exchange field is offered by the FM to the SC the superconducting pairs are not susceptible to pair-breaking.
description: 4 pages, 4 figures
Soft X-ray Absorption and Photoemission Studies of Ferromagnetic Mn-Implanted 3$C$-SiC
Creators: name: Song, Gyong Sok
name: Kataoka, Takashi
name: Kobayashi, Masaki
name: Hwang, Jong Il
name: Takizawa, Masaru
name: Fujimori, Atsushi
name: Ohkochi, Takuo
name: Takeda, Yukiharu
name: Okane, Tetsuo
name: Saitoh, Yuji
name: Yamagami, Hiroshi
name: Takano, Fumiyoshi
name: Akinaga, Hiro
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We have performed x-ray photoemission spectroscopy (XPS), x-ray absorption spectroscopy (XAS), and resonant photoemission spectroscopy (RPES) measurements of Mn-implanted 3$C$-SiC (3$C$-SiC:Mn) and carbon-incorporated Mn$_{5}$Si$_{2}$ (Mn$_{5}$Si$_{2}$:C). The Mn 2$p$ core-level XPS and XAS spectra of 3$C$-SiC:Mn and Mn$_{5}$Si$_{2}$:C were similar to each other and showed "intermediate" behaviors between the localized and itinerant Mn 3$d$ states. The intensity at the Fermi level was found to be suppressed in 3$C$-SiC:Mn compared with Mn$_{5}$Si$_{2}$:C. These observations are consistent with the formation of Mn$_{5}$Si$_{2}$:C clusters in the 3$C$-SiC host, as observed in a recent transmission electron microscopy study.
description: 4 pages, 3 figures
Half-lives of $α$-emitters approaching the N=Z line
Creators: name: Xu, Chang
name: Ren, Zhongzhou
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The half-lives of newly observed $α$-emitters $^{105}$Te and $^{109}$Xe [Seweryniak \textit{et al.}, Phys. Rev. C \textbf{73}, 061301(R) (2006); Liddick \textit{et al.}, Phys. Rev. Lett. \textbf{97}, 082501 (2006)] are investigated by the density-dependent cluster model. The half-lives of $α$-emitters close to the N=Z line are also studied in a unified framework where the influence of the nuclear deformation is properly taken into account. Good agreement between model and data is obtained and some possible $α$-emitters are suggested for future experiments.
description: 9 pages, 3 figures, To appear in Phys. Rev. C
Evolution of stellar-gaseous disks in cosmological haloes
Creators: name: Curir, A.
name: Mazzei, P.
name: Murante, G.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We explore the growth and the evolution of the bar instability in stellar-gaseous disks embedded in a suitable dark matter halo evolving in a fully consistent cosmological framework. The aim of this paper is to point out the impact of different gas fractions on the bar formation, inside disks of different disk-to-halo mass ratio, and the role of the cosmological framework. We perform cosmological simulations with the same disk-to-halo mass ratios as in a previous work where the gas was not taken into account. We compare results of the new simulations with the previous ones to investigate the effect of the gas by analysing the morphology of the stellar and gaseous components, the stellar bar strength and the behaviour of its pattern speed. In our cosmological simulations, inside dark-matter dominated disks, a stellar bar, lasting 10 Gyr, is still living at z=0 even if the gaseous fraction exceeds half of the disk mass. However, in the most massive disks we find a threshold value (0.2) of the gas fraction able to destroy the bar. The stellar bar strength is enhanced by the gas and in the more massive disks higher gas fractions increase the bar pattern speed.
description: 13 pages, 14 figures (2 in low-res), A&A in press
Dynamical Formation of Scalarized Black Holes and Neutron Stars through Stellar Core Collapse
Creators: name: Kuan, Hao-Jui
name: Doneva, Daniela D.
name: Yazadjiev, Stoytcho S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In a certain class of scalar-Gauss-Bonnet gravity, the black holes and the neutron stars can undergo spontaneous scalarization -- a strong gravity phase transition triggered by a tachyonic instability due to the nonminimal coupling between the scalar field and the spacetime curvature. Studies of this phenomenon have, so far, been restricted mainly to the study of the tachyonic instability and stationary scalarized black holes and neutron stars. To date, no realistic physical mechanism for the formation of isolated scalarized black holes and neutron stars has been proposed. We study, for the first time, the spherically symmetric fully nonlinear stellar core collapse to a black hole and a neutron star in scalar-Gauss-Bonnet theories allowing for a spontaneous scalarization. We show that the core collapse can produce scalarized black holes and scalarized neutron stars starting with a nonscalarized progenitor star. The possible paths to reach the end (non)scalarized state are quite rich leading to interesting possibilities for observational manifestations.
description: 9 pages, 10 figures; accepted in PRL. This version is based on fully nonlinear simulations beyond the decoupling limit
First-principles study on the electron-phonon coupling and magnetoresistance of LaBi under pressure
Creators: name: Zhang, Jian-Feng
name: Guo, Peng-Jie
name: Gao, Miao
name: Liu, Kai
name: Lu, Zhong-Yi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The extremely large magnetoresistance (XMR) material LaBi was reported to become superconducting under pressure accompanying with suppressed magnetoresistance. However, the underlying mechanism is unclear. By using first-principles electronic structure calculations in combination with a semiclassical model, we have studied the electron-phonon coupling and magnetoresistance of LaBi in the pressure range from 0 to 18 GPa. Our calculations show that LaBi undergoes a structural phase transition from a face-centered cubic lattice to a primitive tetragonal lattice at $\sim$7 GPa, verifying previous experimental results. Meanwhile, LaBi remains topologically nontrivial across the structural transition. Under all pressures that we have studied, the phonon-mediated mechanism based on the weak electron-phonon coupling cannot account for the observed superconductivity in LaBi, and the calculated magnetoresistance for LaBi does not show a suppression. The distinct difference between our calculations and experimental observations suggests either the existence of extra Bi impurities in the real LaBi compound or the possibility of other unknown mechanism.
description: 7 pages, 5 figures, 1 table
First principles study of the electronic and magnetic structures of the tetragonal and orthorhombic phases of Ca3Mn2O7
Creators: name: Matar, S. F.
name: Eyert, V.
name: Villesuzanne, A.
name: Whangbo, M. -H.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: On the basis of density functional theory electronic band structure calculations using the augmented spherical wave method, the electronic and magnetic properties of the orthorhombic and tetragonal phases of Ca3Mn2O7 were investigated and the spin exchange interactions of the orthorhombic phase were analyzed. Our calculations show that the magnetic insulating states are more stable than the non-magnetic metallic state for both polymorphs of Ca3Mn2O7, the orthorhombic phase is more stable than the tetragonal phase, and the ground state of the orthorhombic phase is antiferromagnetic. The total energies calculated for the three spin states of the orthorhombic phase of Ca3Mn2O7 led to estimates of the spin exchange interactions Jnn = -3.36 meV and Jnnn = -0.06 meV. The accuracy of these estimates were tested by calculating the Curie-Weiss temperature within the mean-field approximation.
description: 11 pages, 7 figures
Η συρροή καταδικαστικών αποφάσεων κατ’ άρθρο 551 ΚΠΔ
Creators: name: Ζάμπρας, Παναγιώτης-Ηλίας Λάζαρου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Εκτέλεση αποφάσεων
Συνολική ποινή
Συγχώνευση αποφάσεων
Decisions execution
Overall penalty
Decisions merger

description: Η παρούσα διπλωματική εργασία πραγματεύεται την ερμηνευτική προσέγγιση του άρθρου 551 ΚΠΔ, το οποίο αφορά τη συρροή καταδικαστικών αποφάσεων εναντίον ενός προσώπου για διαφορετικά εγκλήματα. Ειδικότερα, θίγονται νομικά ζητήματα τα οποία απορρέουν από νομολογιακές αποφάσεις και επιστημονικές μελέτες και συγκεκριμένα αφορούν: τα είδη συρροής, τις προϋποθέσεις εφαρμογής του άρθρου 551 ΚΠΔ, το αρμόδιο Δικαστήριο, τη διαδικασία σχηματισμού συνολικής ποινής, τη διάκριση της επιγενόμενης συρροής κατά άρθρο 97 ΠΚ με το άρθρο 551 ΚΠΔ, τη κλήτευση του καταδικασθέντος και την ακρόασή του, τους κανόνες και περιορισμούς ως προς την εφαρμογή του άρθρου 551 ΚΠΔ, την έκταση δικαιοδοσίας του Δικαστηρίου, τον αναιρετικό έλεγχο και την αναστολή εκτέλεσης της απόφασης
description: The present study discusses the interpretative approach of Article 551 C.Cr.Pr., which concerns the concourse of convictions against one person for different crimes. In particular, legal issues arising from judicial decisions and scientific studies, namely the kinds of concourse, the terms and conditions for applying Article 551 C.Cr.Pr, the Competent Court of Justice, the procedure for forming an overall penalty, the discrimination of the supervening concurrence under the Article 97 of the Greek penal code (CP) with 551 C.Cr.Pr., the presentation ad hearing of the convicted person, the rules and restrictions on the application of Article 551 C.Cr.Pr, the extend of jurisdiction of the Court, review and suspension of enforcement of the judgment by the Supreme Court
Culture-specific, hands-on, interactive dignity dining workshops cultivating medical students’ awareness of elderly care
Creators: name: Lo, Amy W.S.
name: K.W.  Lee
name: C.L. Lee
name: Man, Queenie
name: Yeung, Po H.M.
name: Hwang, Isabel S.S
Publisher: name: F1000 Research Limited
Year: 2024

description: Background

The ageing population and extended life expectancy in Hong Kong highlight the pressing issue of elderly care. Our preliminary survey (n = 101) revealed that 59% of preclinical medical students had no experience in elderly care. They perceived older adults as ‘fragile’, ‘lonely’ and ‘weak’, with a lack of care, privacy and dignity in elderly care facilities.



Chinese dim sum restaurants are culturally and socially important places for the older adults. The increasing prevalence of dysphagia among them removes their ability to enjoy dim sum, diminishes their social life and the chance to recount cherished memories.



Summary of work

Regarding these challenges, we collaborated with a social enterprise, The Project Futurus, to launch an innovative series of ‘Dim Sum Dignity Dining Workshops’ tailored for medical students. These hands-on workshops involved creating soft meals resembling traditional Chinese dim sum, along with interactive discussions among medical students, teachers and staff from the social enterprise on the multifaceted challenges faced by the older adults and their potential solutions.



Moreover, the ‘Sensory Restaurant on Wheels’ initiative aimed to recreate an authentic Chinese restaurant experience for nursing home residents. Students acted as Chinese restaurant staff to serve the older adults soft dim sum meals. This innovative approach helped to relive cherished nostalgic memories of enjoying dim sum with their loved ones in the past, while cultivating empathy and communication skills among students.



Summary of Results

Quantitative evaluations using pre-surveys (n = 33, response rate = 94.3%) and post-surveys (n = 29, response rate = 82.9%), demonstrated a positive shift in participants' awareness of elderly care and quality of life. A preliminary data analysis indicated a statistically significant reduction in the acceptance of bland soft meals (P < 0.05). All of the respondents strongly agreed/agreed that their understanding of dignity dining and the older adults’ needs had increased.



Discussion and Conclusions

The workshops fostered compassion, inspired future doctors to contribute to elderly care and advocated for a lasting positive impact on its provision by medical professionals.



Take-home message

We encourage medical schools worldwide to adopt similar initiatives, emphasising cultural specificity to address local challenges and promote comprehensive elderly care.
Dopant-defect interactions and their impact on local crystal stoichiometry studies in Mg-doped GaN via atom probe tomography
Creators: name: Licata, Olivia Grace
name: Broderick, Scott
name: Rocco, Emma
name: Shahedipour-Sandvik, Fatemeh
name: Mazumder, Baishakhi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In this work, doping-defect interactions relevant to self-compensation in p-type GaN were investigated using atom probe tomography. The 3D visualization of ion distribution revealed the formation of spherical Mg-rich clusters and the segregation of Mg dopant towards dislocations in MOCVD-grown GaN:Mg. Impurities related to self-compensation, such as oxygen and hydrogen, were identified and detected adjacent to Mg-rich dislocations. Crystal stoichiometry around the defect regions was investigated to understand how the defects can serve as traps and influence dopant diffusion. Non-stoichiometric regions of N:Ga were found adjacent to Mg-rich dislocations and overlapping with some Mg-rich clusters, indicating potential traps. Variations in N:Ga were not proportional to the Mg content, suggesting that the microfeatures (clusters and dislocations) interact differently with local chemistry. Techniques for defining the quality of an APT experiment through invalidation of artifacts are also demonstrated. Mg-rich defects and variations in N:Ga were found to be independent of artifacts related to the evaporation field in APT.
description: 16 pages, 4 figures (+2 in supplementary), and 1 table. Revision includes additional references for discussion and clarification of PCA methods
Examples of M5-Brane Elliptic Genera
Creators: name: Gaiotto, Davide
name: Yin, Xi
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We determine the modified elliptic genus of an M5-brane wrapped on various one modulus Calabi-Yau spaces, using modular invariance together with some known Gopakumar-Vafa invariants of small degrees. As a bonus, we find nontrivial relations among Gopakumar-Vafa invariants of different degrees and genera from modular invariance.
description: 13 pages
Electronic properties and quasi-particle model of monolayer MoSi$_2$N$_4$
Creators: name: Wang, Zhenwei
name: Kuang, Xueheng
name: Yu, Guodong
name: Zhao, Peiliang
name: Zhong, Hongxia
name: Yuan, Shengjun
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: By a combined study with first-principles calculations and symmetry analysis, we theoretically investigate the electronic properties of monolayer MoSi$_2$N$_4$. While the spin-orbital coupling results in bands splitting, the horizontal mirror symmetry locks the spin polarization along z-direction. In addition, a three-band tight-binding model is constructed to describe the low-energy quasi-particle states of monolayer MoSi$_2$N$_4$, which can be generalized to strained MoSi$_2$N$_4$ and its derivatives. The calculations using the tight-binding model show an undamped $\sqrt{q}$-dependent plasmon mode that agrees well with the results of first-principles calculations. Our model can be extended to be suitable for future theoretical and numerical studies of low-energy properties in MoSi$_2$N$_4$ family materials. Furthermore, the study of electronic properties of monolayer MoSi$_2$N$_4$ paves a way for its applications in spintronics and plasmonics.
description: 8 pages, 8 figures
Lorentz-covariant deformed algebra with minimal length and application to the 1+1-dimensional Dirac oscillator
Creators: name: Quesne, C.
name: Tkachuk, V. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Quantum Algebra (math.QA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The $D$-dimensional $(β, β')$-two-parameter deformed algebra introduced by Kempf is generalized to a Lorentz-covariant algebra describing a ($D+1$)-dimensional quantized space-time. In the D=3 and $β=0$ case, the latter reproduces Snyder algebra. The deformed Poincaré transformations leaving the algebra invariant are identified. It is shown that there exists a nonzero minimal uncertainty in position (minimal length). The Dirac oscillator in a 1+1-dimensional space-time described by such an algebra is studied in the case where $β'=0$. Extending supersymmetric quantum mechanical and shape-invariance methods to energy-dependent Hamiltonians provides exact bound-state energies and wavefunctions. Physically acceptable states exist for $β< 1/(m^2 c^2)$. A new interesting outcome is that, in contrast with the conventional Dirac oscillator, the energy spectrum is bounded.
description: 20 pages, no figure, some very small changes, published version
Effect of yarding operations on log recovery value
Creators: name: Copithorne, Robert Dalgleish
Publisher: name: University of British Columbia
Year: 2009

description: This thesis deals with the problem of controlling losses in log recovery value in yarding operations. It is believed that losses under current operating methods can be substantial over time. The objective is to find ways of applying statistical quality control methods to controlling and reducing these losses. A literature review was done to determine the statistical techniques available. A pilot study was done concurrently to determine the current levels of value loss and test methods of measuring value loss. The final step was to recommend a procedure for monitoring and controlling log value losses based on the findings of the literature review and the pilot study. Value loss estimates in the pilot study were consistent with losses discussed in the literature (1-2%). The problems encountered with the methods used in the pilot study, however, were believed to be severe enough to limit the usefulness of the methods and the results. The methods were found to be cumbersome and time consuming as well as needing considerable refinement in the area of scaling and grading for true value recognition. The recommended statistical quality control method can be used operationally without the necessity of immediate improvement of scaling and grading techniques. The method involves observing occurrences of log damage and recording detailed information related to those occurrences so that the causes of the damage can determined. Procedures can then be developed to correct these causes. The method relies on the use of statistical control charts for attributes for monitoring log damage and highlighting periods of abnormal results for further investigation.
A new class ${\hat o}_N$ of statistical models: Transfer matrix eigenstates, chain Hamiltonians, factorizable $S$-matrix
Creators: name: Abdesselam, B.
name: Chakrabarti, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Algebra (math.QA)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Statistical models corresponding to a new class of braid matrices ($\hat{o}_N; N\geq 3$) presented in a previous paper are studied. Indices labeling states spanning the $N^r$ dimensional base space of $T^{(r)}(θ)$, the $r$-th order transfer matrix are so chosen that the operators $W$ (the sum of the state labels) and (CP) (the circular permutation of state labels) commute with $T^{(r)}(θ)$. This drastically simplifies the construction of eigenstates, reducing it to solutions of relatively small number of simultaneous linear equations. Roots of unity play a crucial role. Thus for diagonalizing the 81 dimensional space for N=3, $r=4$, one has to solve a maximal set of 5 linear equations. A supplementary symmetry relates invariant subspaces pairwise ($W=(r,Nr)$ and so on) so that only one of each pair needs study. The case N=3 is studied fully for $r=(1,2,3,4)$. Basic aspects for all $(N,r)$ are discussed. Full exploitation of such symmetries lead to a formalism quite different from, possibly generalized, algebraic Bethe ansatz. Chain Hamiltonians are studied. The specific types of spin flips they induce and propagate are pointed out. The inverse Cayley transform of the YB matrix giving the potential leading to factorizable $S$-matrix is constructed explicitly for N=3 as also the full set of $\hat{R}tt$ relations. Perspectives are discussed in a final section.
description: 27 pages
Searching for axion-like particles at future electron-positron colliders
Creators: name: Zhang, Hua-Ying
name: Yue, Chong-Xing
name: Guo, Yu-Chen
name: Yang, Shuo
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We investigate the prospects for discovering axion-like particles (ALPs) via a light-by-light (LBL) scattering at two colliders, the future circular collider (FCC-ee) and circular electron-positron collider (CEPC). The promising sensitivities to the effective ALP-photon coupling $g_{aγγ}$ are obtained. Our numerical results show that the FCC-ee and CEPC might be more sensitive to the ALPs with mass 2 GeV $\sim$ 10 GeV than the LHC and CLIC.
description: 16 pages, 9 figures, 3 tables. Submitted to Physical Review D
Systematic Analysis of Scaling Properties in Deep Inelastic Scattering
Creators: name: Beuf, Guillaume
name: Peschanski, Robi
name: Royon, Christophe
name: Salek, David
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Using the ``Quality Factor'' (QF) method, we analyse the scaling properties of deep-inelastic processes at HERA and fixed target experiments for x<0.01. We look for scaling formulae of the form sigma(tau), where tau(log Q^2, Y) is a scaling variable suggested by the asymptotic properties of QCD evolution equations with rapidity Y. We consider four cases: ``Fixed Coupling'', corresponding to the original geometric scaling proposal and motivated by the asymptotic properties of the Balitsky-Kovchegov (BK) equation with fixed QCD coupling constant, two versions ``Running Coupling I,II'' of the scaling suggested by the BK equation with running coupling, and ``Diffusive Scaling'' suggested by the QCD evolution equation with Pomeron loops. The Quality Factors, quantifying the phenomenological validity of the candidate scaling variables, are fitted on the total and DVCS cross-section data from HERA and predictions are made for the elastic vector-meson and for the diffractive cross-sections at fixed small x_pom or beta. The first three scaling formulae have comparably good QF while the fourth one is disfavored. Adjusting initial conditions gives a significant improvement of the ``Running Coupling II'' scaling.
description: 25 pages,15 figures, 6 tables. New version with misprints corrected, and reference to the published version added
Evolution of the Stokes parameters, polarization singularities, and optical skyrmion
Creators: name: Kuratsuji, Hiroshi
name: Tsuchida, Satoshi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Pattern Formation and Solitons (nlin.PS)
subject: FOS: Physical sciences

description: A physical theory is presented for polarized light from an aspect of polarization singularity.This is carried out by analyzing the evolution equation of the Stokes parameters that is derived from the nonlinear Schrodinger type equation. The problem is explored from two aspects:The first is concerning the single mode Stokes parameter that is described by the propagation distance $ z $. The trajectory of the polarization singularities is simply given by the points satisfying a rule: $ S_3 (z) = +(-)S_0 $ and $ 0 $ ($ S_3 $ represents the third component of the Stokes parameters), which form a tube like surface centered with the C-line surrounded by L-surfaces in the presence of the linear as well as the nonlinear birefringence. It is pointed out that the optical activity (or chirality) plays an "obstacle" to reveal the polarization singularity. As the other aspect, we consider the field theoretic aspect of the Stokes parameters, for which a special solution, called an optical skyrmion, is constructed to explicate the polarization singularity.The skyrmion forms a {tube}, and the dynamical content of which is briefly discussed. On the basis of the work presented here further analysis would be expected to reveal hidden aspects of polarization optics.
description: 12 pages, 4 figures: published in Physical Review A