cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Interstellar Scintillation of an Extreme Scintillator: PKS B1144-379
Creators: name: Said, N. M. M.
name: Ellingsen, S. P.
name: Bignall, H. E.
name: Shabala, S.
name: McCallum, J. N.
name: Reynolds, C.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The University of Tasmania Ceduna radio telescope has been used to investigate rapid variability in the radio flux density of the BL Lac object PKS B1144-379 at 6.7 GHz. High-cadence monitoring of this extreme scintillator was carried out over a period of approximately nine years, between 2003 and 2011. We have used structure functions created from the intensity time series to determine the characteristic timescale of the variability. The characteristic timescale is consistently observed to increase during certain periods of each year, demonstrating the annual cycle expected for scintillation through an interstellar scattering screen. The best-fitting annual cycle model for each year suggests that the scintillation pattern has an anisotropic structure and that the upper limit of its scattering screen is at a distance of ~0.84 kpc. Higher anisotropy in some of the annual cycle fits suggests that changes in the intrinsic source structure might be influencing the variability timescale. We found a prominent annual cycle is only present in the variability timescale for certain years where other evidence suggests that the core is compact. From our measurements, we calculated that the core angular size varied between 5.65-15.90 $μ$as (0.05-0.13 pc). The core component was found to be at its most compact during two flares in the total flux density, which were observed in 2005 and 2008. We conclude that the long-term variability in the radio flux density of PKS B1144-379 is due to intrinsic changes in the source and that these affect our ability to measure an annual cycle in its variability time scale.
description: 24 pages, 22 figures
Spin-modulated quasi-1D antiferromagnet LiCuVO_4
Creators: name: Buettgen, N.
name: von Nidda, H. -A. Krug
name: Svistov, L. E.
name: Prozorova, L. A.
name: Prokofiev, A.
name: Assmus, W.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report on magnetic resonance studies within the magnetically ordered phase of the quasi-1D antiferromagnet LiCuVO_4. Our studies reveal a spin reorientational transition at a magnetic field H_c1 ~ 25 kOe applied within the crystallographical (ab)-plane in addition to the recently observed one at H_c2 \~75 kOe [ M.G. Banks et al., cond-mat/0608554 (2006)]. Spectra of the antiferromagnetic resonance (AFMR) along low-frequency branches can be described in the frame of a macroscopic theory of exchange-rigid planar magnetic structures. These data allow to obtain the anisotropy of the exchange interaction together with a constant of the uniaxial anisotropy. Spectra of 7Li nuclear magnetic resonance (NMR) show that, within the magnetically ordered phase of LiCuVO_4 in the low-field range H < H_c1, a planar spiral spin structure is realized with the spins lying in the (ab)-plane in agreement with neutron scattering studies of B.J. Gibson et al. [Physica B Vol. 350, 253 (2004)]. Based on NMR spectra simulations, the transition at H_c1 can well be described as a spin-flop transition, where the spin plane of the magnetically ordered structure rotates to be perpendicular to the direction of the applied magnetic field. For H > H_c2 ~ 75 kOe, our NMR spectra simulations show that the magnetically ordered structure exhibits a modulation of the spin projections along the direction of the applied magnetic field H.
Μορφές τυπικής λογικής σκέψης ανάμεσα σε μαθητές τρίτης λυκείου
Creators: name: Βαλανίδης, Νίκος
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1995

description: The subjects of the study were twelfth-grade students from 21 intact classes (227 boys and 242 girls). These classes were randomly selected among the 33 twelfth-grade classes of four schools in a city of Cyprus. The sample of students represented the science section, the economic section and the unified section consisting of sections following common curricula in science and mathematics, Students' performance on a standardized Test of Logical Thinking (TOLT) was used as a measure of their cognitive abilities related to control of variables, proportional, probabilistic, correlational and combinatorial reasoning. The students of the unified section had lower performance than the students of both the science and economic section on all cognitive measures and female students had lower performance than male students on cognitive measures related to control of variables and probabilistic reasoning. Multiple regression analysis between performance on TOLT and gender, section of study, and measures of school achievement showed that, beyond gender and section of study, both achievement in mathematics and gpa, but not achievement in science and Greek language, contributed significantly to predicting performance on TOLT. Observed differences related to measures of school achievement either among the subjects of the three sections or between male and female students did not correspond to differences related to cognitive measures. Factor analysis of performance of the ten TOLT items (two items from each reasoning mode) produced a two - factor solution. There were also significant differences of students' performance between items related to the same or different reasoning mode. The results of the study, in general, cast doubt to the appropriateness of the existing curricula or their implementation and indicate that different theoretical perspectives should be considered when evaluating cognitive development.
description: Παιδαγωγική Επιθεώρηση, Vol. 22 (1995)
Thermal transport properties of disordered spin-1/2 systems
Creators: name: Heidrich-Meisner, Fabian
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: This work studies heat transport of bond-disordered spin-1/2 chains. As an example, the XX case is analyzed, which corresponds to a model of noninteracting spinless fermions. Within the fermion representation, the single-particle eigenenergies are determined numerically, which allow one to compute transport coefficients. Since the ballistic transport properties of a clean chain are destroyed by disorder, the focus is on the frequency dependence of the thermal conductivity and on a qualitative comparison with the spin conductivity, both at finite temperatures.
description: 2 pages, 1 figure. To be published in the Proceedings of SCES '05, Vienna, in Physica B
On the Achievable Rate Region of the $ K $-Receiver Broadcast Channels via Exhaustive Message Splitting
Creators: name: Tang, Rui
name: Xie, Songjie
name: Wu, Youlong
Publisher: name: arXiv
Year: 2020
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: This paper focuses on $ K $-receiver discrete-time memoryless broadcast channels (DM-BCs) with private messages, where the transmitter wishes to convey $K$ private messages to $K$ receivers respectively. A general inner bound on the capacity region is proposed based on an exhaustive message splitting and a $K$-level modified Marton's coding. The key idea is to split every message into $ \sum_{j=1}^K {K\choose j} $ submessages each corresponding to a set of users who are assigned to recover them, and then send these submessages through codewords that are jointly typical with each other. To guarantee the joint typicality among all transmitted codewords, a sufficient condition on the subcodebooks sizes is derived through a newly establishing hierarchical covering lemma, which extends the 2-level multivariate covering lemma to the $K$-level case including $(2^{K}-1)$ random variables with more intricate dependence. As the number of auxiliary random variables and rate constraints both increase linearly with $(2^{K}-1)$, the standard Fourier-Motzkin elimination procedure becomes infeasible when $K$ is large. To tackle this problem, we obtain the final form of achievable rate region with a special observation of disjoint unions of sets that constitute the power set of $ \{1,\dots,K\}$. The proposed achievable rate region allows arbitrary input probability mass functions (pmfs) and improves over all previously known ones for $ K$-receiver ($K\geq 3$) BCs whose input pmfs should satisfy certain Markov chain(s).
Angular Correlations in STAR
Creators: name: Daugherity, Michael
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The related studies of two-particle correlations and event-by-event fluctuations have played important roles in the search for new physics through the experimental study of relativistic heavy ion collisions. We present a general method of determining minimum-bias two-particle correlations and show the relationship between these correlations and event-by-event fluctuations. Data from the STAR experiment at RHIC for Au-Au collisions at $\sqrt{s_{NN}}$ = 62 and 200 GeV will be presented that show the energy and centrality dependences of angular correlations. This analysis provides a unique method for studying the interaction of semi-hard scattered partons with the dense medium produced at RHIC as well as properties of the bulk medium itself, and will shed new light on the sources of non-statistical fluctuations.
description: Proceedings for Correlations and Fluctuations in Relativistic Nuclear Collisions workshop, July 7-9 2006, Florence, Italy; 10 pages, 4 figures
Συγκεντρωτισμός και αποκεντρωτισμός στην εκπαίδευση: μια απόπειρα συγκριτικής προσέγγισης
Creators: name: Μπόμπας, Λεωνίδας Χ.
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1995

description: Based on the existing literature on centralization and decentralization in education systems across the European Union (EU), this cursive presentation explores possible correlates and characteristics of centralized/decentralized education systems. Throughout this analysis particular emphasis is placed upon the "Greek case", which traditionally has been characterized among other things by its extreme centralization features in the Greek education system. Embarking upon a comparative education perspective, Greece's performance in several "non-educational" variables (e.g. inflation rate, GNP, monthly salary and pension, money spent in research and technology, traveling abroad, etc.) is compared to the EU average. Furthermore, a similar comparison is carried out between the six EU country members (including Greece) categorized as "centralized" in terms of their education systems and the other six (a little before the latest enlargement of the EU), the "decentralized". The overal outcome of the analysis points to: a) Greece, with its highly centralized education system, lags considerably behind in all measures of the dependent variables adopted here; and b) The six "centralized" EU countries fall well below the corresponding scores of the other six "decentralized" EU members. Although this apparent correlation in no way implies (necessarily) causality, it points -nevertheless- to a number of possible trends that need further exploration.
description: Παιδαγωγική Επιθεώρηση, Vol. 22 (1995)
The end of the galactic cosmic ray spectrum
Creators: name: Stanev, Todor
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We discuss the region of transition between galactic and extragalactic cosmic rays. The exact shapes and compositions of these two components contains information about important parameters of powerful astrophysical sources and the conditions in extragalactic space as well as for the cosmological evolution of the sources of high energy cosmic rays. Several types of experimental data, including the exact shape of the ultrahigh energy cosmic rays, their chemical composition and their anisotropy, and the fluxes of cosmogenic neutrinos have to be included in the solution of this problem.
description: 8 pages, 5 figures, to appear in the Proceedings of CRIS 2006
Context to a conversation : the contribution of science to sustainable forestry
Creators: name: Cushon, Geoffrey Harold
Publisher: name: University of British Columbia
Year: 2009

description: The currently topical problems of forest management are issues of trans-science. They can be framed in the language of science but they cannot be resolved in the language of science. They involve historically contingent phenomena for which predictive certainty is not possible and they involve issues of moral, aesthetic and economic value. What is the role of science in contributing to the public debate on what are fundamentally social issues such as clear-cut logging or the preservation of old-growth forests? A history and philosophy of science, in general, and ecological science, in particular, is presented that traces the transition, over the last half century, from a positivist science of universal, timeless, predictable order to a science that attempts to interpret local, particular aspects of nature. The former relies on identifying restricted spatio-temporal scales that facilitate prediction while the latter focuses on an understanding of the causal relations within interrelated systems that facilitate explanation of system properties. A kind of contextual or dialectical holism is advocated wherein system components are considered in the context of the whole and the whole is considered as an epiphenomenon resulting from causal interaction of the parts. A history of forest science is presented that identifies sustained yield forestry as a construct of positivist science. Recent insights by ecological science, into the complexity and contingency of forest ecosystems, reveal the limitations of this simplified view. Moreover, the application of a single large-scale strategy such as sustained yield forestry to managing forests in British Columbia contained value assumptions that no longer reflect the full range of values that the public express. The currently topical debates on clear-cutting, logging in municipal watersheds and over-cutting are offered as examples of how questions of fact and questions of value become linked. Although these debates have been carried on in the language of science they are essentially social issues and cannot be resolved by science. The role of science in contributing to the resolution of social issues, such as the development of a sustainable forestry, is not to develop specific solutions but to contribute to the social dialogue in a subservient fashion. Science can characterize the context in which disagreements about matters of value take place. Science can use its experimental protocols to help society construct living experiments that allow us to learn our way into the future. Science can take part in an equitable conversation on sustainable forestry that will facilitate a better understanding of the beliefs and values of the human component of forested ecosystems.
NbIr$_2$B$_2$ and TaIr$_2$B$_2$ -- new low symmetry noncentrosymmetric superconductors with strong spin orbit coupling
Creators: name: Górnicka, Karolina
name: Gui, Xin
name: Wiendlocha, Bartlomiej
name: Nguyen, Loi T.
name: Xie, Weiwei
name: Cava, Robert J.
name: Klimczuk, Tomasz
Publisher: name: arXiv
Year: 2021
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Superconductivity was first observed more than a century ago, but the search for new superconducting materials remains a challenge. The Cooper pairs in superconductors are ideal embodiments of quantum entanglement. Thus, novel superconductors can be critical for both learning about electronic systems in condensed matter and for possible application in future quantum technologies. Here two previously unreported materials, NbIr$_2$B$_2$ and TaIr$_2$B$_2$, are presented with superconducting transitions at 7.2 and 5.2 K, respectively. They display a unique noncentrosymmetric crystal structure, and for both compounds the magnetic field that destroys the superconductivity at 0 K exceeds one of the fundamental characteristics of conventional superconductors (the Pauli limit), suggesting that the superconductivity may be unconventional. Supporting this experimentally based deduction, first-principle calculations show a spin split Fermi surface due to the presence of strong spin-orbit coupling. These materials may thus provide an excellent platform for the study of non-BCS superconductivity in intermetallic compounds.
description: 36 pages, 11 figures
Over 30,000-fold field enhancement of terahertz nanoresonators enabled by rapid inverse design
Creators: name: Lee, Hyoung-Taek
name: Kim, Jeonghoon
name: Lee, Joon Sue
name: Yoon, Mina
name: Park, Hyeong-Ryeol
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optics (physics.optics)
subject: Applied Physics (physics.app-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: The rapid development of 6G communications using terahertz (THz) electromagnetic waves has created a demand for highly sensitive THz nanoresonators capable of detecting these waves. Among the potential candidates, THz nanogap loop arrays show promising characteristics but require significant computational resources for accurate simulation. This requirement arises because their unit cells are 10 times smaller than millimeter wavelengths, with nanogap regions that are 1,000,000 times smaller. To address this challenge, we propose a rapid inverse design method using physics-informed machine learning, employing double deep Q-learning with an analytical model of the THz nanogap loop array. In about 39 hours on a middle-level personal computer, our approach identifies the optimal structure through 200,000 iterations, achieving experimental electric field enhancement of 32,000 at 0.2 THz, 300 % stronger than prior results. Our analytical model-based approach significantly reduces computational resources, offering a practical alternative to numerical simulation-based inverse design
Designing Voice-Controllable APIs
Creators: name: Sulír, Matúš
name: Porubän, Jaroslav
Publisher: name: arXiv
Year: 2020
Subjects: subject: Software Engineering (cs.SE)
subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences

description: The main purpose of a voice command system is to process a sentence in natural language and perform the corresponding action. Although there exist many approaches to map sentences to API (application programming interface) calls, this mapping is usually performed after the API is already implemented, possibly by other programmers. In this paper, we describe how the API developer can use patterns to map sentences to API calls by utilizing the similarities between names and types in the sentences and the API. In the cases when the mapping is not straightforward, we suggest the usage of suitable annotations (attribute-oriented programming).
Unconventional Superconductivity Induced by Quantum Critical Fluctuations in Hydrate Cobaltate Na$_{x}$(H$_3$O)$_{z}$CoO$_{x}\cdot$ $y$H$_{2}$O -- Relationship between Magnetic Fluctuations and the Superconductivity Revealed by a Co Nuclear Quadrupole Resonance --
Creators: name: Ihara, Y.
name: Takeya, H.
name: Ishida, K.
name: Ikeda, H.
name: Michioka, C.
name: Yoshimura, K.
name: Takada, K.
name: Sasaki, T.
name: Sakurai, H.
name: Takaayama-Muromachi, E.
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: Co nuclear-quadrupole-resonance (NQR) measurements were performed on various bilayered hydrate cobaltate Na_x(H_3O)_zCoO_2\cdot yH_2O with different values of the superconducting and magnetic-ordering temperatures, T_c and T_M, respectively. From measurements of the temperature and sample dependence of the NQR frequency, it was revealed that the NQR frequency is changed by the change of the electric field gradient (EFG) along the c axis ν_{zz} rather than the asymmetry of EFG within the ab-plane. In addition, it is considered that the change of ν_{zz} is gaverned mainly by the trigonal distortion of the CoO_2 block layers along the c axis, from the relationships between ν_{zz} and the various physical parameters. We found the tendency that samples with ν_{zz} larger than 4.2 MHz show magnetic ordering, whereas samples with lower ν_{zz} show superconductivity. We measured the nuclear spin-lattice relaxation rate 1/T_1 in these samples, and found that magnetic fluctuations depend on samples. The higher-ν_{zz} sample has stronger magnetic fluctuations at T_c. From the relationship between ν_{zz} and T_c or T_M, we suggest that the NQR frequency can be regarded as a tuning parameter to determine the ground state of the system, and develop the phase diagram using ν_{zz}. This phase diagram shows that the highest-T_c sample is located at the point where T_M is considered to be zero, which suggests that the superconductivity is induced by quantum critical fluctuations. We strongly advocate that the hydrate cobaltate superconductor presents an example of the magnetic-fluctuation-mediated superconductivity argued in the heavy-fermion compounds. The coexistence of superconductivity and magnetism observed in the sample with the highest ν_{zz} is also discussed on the basis of the results of our experiments.
description: 11 pages, 14 figures
Liquid 4He: contributions to first principles theory of quantized vortices, thermohydrodynamic properties, and the lambda transition
Creators: name: Jackson, H. W.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Liquid 4He has been studied extensively for almost a century, but there are still a number of outstanding weak or missing links in our comprehension of it. This paper reviews some of the principal paths taken in previous research and then proceeds to fill gaps and create an integrated picture with more complete understanding through first principles treatment of a realistic model that starts with a microscopic, atomistic description of the liquid. Newly derived results for vortex cores and thermohydrodynamic properties for a two-fluid model are used to show that interacting quantized vortices may produce a lambda anomaly in specific heat near the superfluid transition where flow properties change. The nature of the order in the superfluid state is explained. Experimental support for new calculations is exhibited, and a unique specific heat experiment is proposed to test predictions of the theory. Relevance of the theory to modern research in cosmology, astrophysics, and Bose-Einstein condensates is discussed.
description: 155 pages, 28 figures
Improved test-retest reliability of $\textit{R}_2^*$ and susceptibility quantification using multi-shot multi echo 3D EPI
Creators: name: Huang, Yujia
name: Chen, Lin
name: Li, Xu
name: Liu, Jiaen
Publisher: name: arXiv
Year: 2023
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: This study aimed to evaluate the potential of 3D echo-planar imaging (EPI) for improving the reliability of $T_2^*$-weighted ($T_2^*w$) data and quantification of $\textit{R}_2^*$ decay rate and susceptibility ($χ$) compared to conventional gradient echo (GRE)-based acquisition. Eight healthy subjects in a wide age range were recruited. Each subject received repeated scans for both GRE and EPI acquisitions with an isotropic 1 mm resolution at 3 T. Maps of $\textit{R}_2^*$ and $χ$ were quantified and compared using their inter-scan difference to evaluate the test-retest reliability. Inter-protocol differences of $\textit{R}_2^*$ and $χ$ between GRE and EPI were also measured voxel by voxel and in selected ROIs to test the consistency between the two acquisition methods. The quantifications of $\textit{R}_2^*$ and $χ$ using EPI protocols showed increased test-retest reliability with higher EPI factors up to 5 as performed in the experiment and were consistent with those based on GRE. This result suggested multi-shot multi-echo 3D EPI can be a useful alternative acquisition method for $T_2^*w$ MRI and quantification of $\textit{R}_2^*$ and $χ$ with reduced scan time, improved test-retest reliability and similar accuracy compared to commonly used 3D GRE.
description: 18 pages, 8 figures and 1 table
Explaining the Electroweak Scale and Stabilizing Moduli in M Theory
Creators: name: Acharya, Bobby S.
name: Bobkov, Konstantin
name: Kane, Gordon L.
name: Kumar, Piyush
name: Shao, Jing
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In a recent paper \cite{Acharya:2006ia} it was shown that in $M$ theory vacua without fluxes, all moduli are stabilized by the effective potential and a stable hierarchy is generated, consistent with standard gauge unification. This paper explains the results of \cite{Acharya:2006ia} in more detail and generalizes them, finding an essentially unique de Sitter (dS) vacuum under reasonable conditions. One of the main phenomenological consequences is a prediction which emerges from this entire class of vacua: namely gaugino masses are significantly suppressed relative to the gravitino mass. We also present evidence that, for those vacua in which the vacuum energy is small, the gravitino mass, which sets all the superpartner masses, is automatically in the TeV - 100 TeV range.
description: 73 pages, 39 figures, Minor typos corrected, Figures and References added
Search for Hadronic Decays of W and Z Bosons in Photon Events in ppbar Collisions at s**(1/2)=1.96 GeV
Creators: name: CDF Collaboration
name: Aaltonen, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We report on a search for the process $p\bar{p}\to γ+W/Z$ with $W/Z\to q\bar{q}$ in events containing two jets and a photon at the center-of-mass energy $\sqrt{s}=1.96$ TeV, using 184 pb$^{-1}$ of data collected by the CDF II detector. A neural network event selection has been developed to optimize the rejection of the large QCD production background; it is shown that this method gives a significant improvement in both signal-to-noise ratio and signal sensitivity, as compared with an event selection based on conventional cuts. An upper limit is presented for the $γ+W/Z$ production cross section with the $W$ and $Z$ decaying hadronically.
description: Submitted to Phys.Rev.D
Anthropic predictions for vacuum energy and neutrino masses in the light of WMAP-3
Creators: name: Pogosian, Levon
name: Vilenkin, Alexander
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Anthropic probability distributions for the cosmological constant and for the sum of neutrino masses are updated using the WMAP-3 data release. The new distribution for Lambda is in a better agreement with observation than the earlier one. The typicality of the observed value, defined as the combined probability of all values less likely than the observed, is no less than 22%. We discuss the dependence of our results on the simplifying assumptions used in deriving the distribution for Lambda and show that the agreement of the anthropic prediction with the data is rather robust. The distribution for the sum of the neutrino masses is peaked at 1 eV, suggesting degenerate masses, but a hierarchical mass pattern is still marginally allowed at a 2 sigma level.
description: References added; 11 pages, 6 figures
Electromagnetic radiation at extreme angular velocity
Creators: name: Buzzegoli, Matteo
name: Tuchin, Kirill
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We consider a system rotating at extremely high angular velocity, so that its matter is found mostly at the light-cylinder. We posit that it can be described by quantum fields confined to the two-dimensional cylindrical surface rotating about its symmetry axis. We apply this model to study the electromagnetic radiation. In particular, we compute the photon spectrum emitted by the quark-gluon plasma.
description: 15 pages, 6 figures. v2: typos and minor errors fixed
A network-ready random-access qubits memory
Creators: name: Langenfeld, S.
name: Morin, O.
name: Körber, M.
name: Rempe, G.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Photonic qubits memories are essential ingredients of numerous quantum networking protocols. The ideal situation features quantum computing nodes that are efficiently connected to quantum communication channels via quantum interfaces. The nodes contain a set of long-lived matter qubits, the channels support the propagation of light qubits, and the interface couples light and matter qubits. Towards this vision, we here demonstrate a random-access multi-qubit write-read memory for photons using two rubidium atoms coupled to the same mode of an optical cavity, a setup which is known to feature quantum computing capabilities. We test the memory with more than ten independent photonic qubits, observe no noticeable cross talk, and find no need for re-initialization even after ten write-read attempts. The combined write-read efficiency is 26% and the coherence time approaches 1ms. With these features, the node constitutes a promising building block for a quantum repeater and ultimately a quantum internet.
Rotation-Invariant Completion Network
Creators: name: Chen, Yu
name: Shi, Pengcheng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Real-world point clouds usually suffer from incompleteness and display different poses. While current point cloud completion methods excel in reproducing complete point clouds with consistent poses as seen in the training set, their performance tends to be unsatisfactory when handling point clouds with diverse poses. We propose a network named Rotation-Invariant Completion Network (RICNet), which consists of two parts: a Dual Pipeline Completion Network (DPCNet) and an enhancing module. Firstly, DPCNet generates a coarse complete point cloud. The feature extraction module of DPCNet can extract consistent features, no matter if the input point cloud has undergone rotation or translation. Subsequently, the enhancing module refines the fine-grained details of the final generated point cloud. RICNet achieves better rotation invariance in feature extraction and incorporates structural relationships in man-made objects. To assess the performance of RICNet and existing methods on point clouds with various poses, we applied random transformations to the point clouds in the MVP dataset and conducted experiments on them. Our experiments demonstrate that RICNet exhibits superior completion performance compared to existing methods.
description: 12 pages, accepted to PRCV 2023 (The 6th Chinese Conference on Pattern Recognition and Computer Vision)
Identifying and Mitigating the Security Risks of Generative AI
Creators: name: Barrett, Clark
name: Boyd, Brad
name: Burzstein, Elie
name: Carlini, Nicholas
name: Chen, Brad
name: Choi, Jihye
name: Chowdhury, Amrita Roy
name: Christodorescu, Mihai
name: Datta, Anupam
name: Feizi, Soheil
name: Fisher, Kathleen
name: Hashimoto, Tatsunori
name: Hendrycks, Dan
name: Jha, Somesh
name: Kang, Daniel
name: Kerschbaum, Florian
name: Mitchell, Eric
name: Mitchell, John
name: Ramzan, Zulfikar
name: Shams, Khawaja
name: Song, Dawn
name: Taly, Ankur
name: Yang, Diyi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Every major technical invention resurfaces the dual-use dilemma -- the new technology has the potential to be used for good as well as for harm. Generative AI (GenAI) techniques, such as large language models (LLMs) and diffusion models, have shown remarkable capabilities (e.g., in-context learning, code-completion, and text-to-image generation and editing). However, GenAI can be used just as well by attackers to generate new attacks and increase the velocity and efficacy of existing attacks.
 This paper reports the findings of a workshop held at Google (co-organized by Stanford University and the University of Wisconsin-Madison) on the dual-use dilemma posed by GenAI. This paper is not meant to be comprehensive, but is rather an attempt to synthesize some of the interesting findings from the workshop. We discuss short-term and long-term goals for the community on this topic. We hope this paper provides both a launching point for a discussion on this important topic as well as interesting problems that the research community can work to address.
Carbonate-Silicate Cycle Predictions of Earth-like Planetary Climates and Testing the Habitable Zone Concept
Creators: name: Lehmer, Owen R.
name: Catling, David C.
name: Krissansen-Totton, Joshua
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: In the conventional habitable zone (HZ) concept, a CO$_{2}$-H$_2$O greenhouse maintains surface liquid water. Through the water-mediated carbonate-silicate weathering cycle, atmospheric CO$_{2}$ partial pressure (pCO$_{2}$) responds to changes in surface temperature, stabilizing the climate over geologic timescales. We show that this weathering feedback ought to produce a log-linear relationship between pCO$_{2}$ and incident flux on Earth-like planets in the HZ. However, this trend has scatter because geophysical and physicochemical parameters can vary, such as land area for weathering and CO$_2$ outgassing fluxes. Using a coupled climate and carbonate-silicate weathering model, we quantify the likely scatter in pCO$_2$ with orbital distance throughout the HZ. From this dispersion, we predict a two-dimensional relationship between incident flux and pCO$_2$ in the HZ and show that it could be detected from at least 83 ($2σ$) Earth-like exoplanet observations. If fewer Earth-like exoplanets are observed, testing the HZ hypothesis from this relationship could be difficult.
description: Published 12/1/2020 in Nature Communications. The supplemental data and code referenced in this work are available from the Nature Communications website (see DOI below) or by email from the authors
Diagrammatic Multiplet-Sum Method (MSM) Density-Functional Theory (DFT): Investigation of the Transferability of Integrals in "Simple" DFT-Based Approaches to Multi-Determinantal Problems
Creators: name: Ponra, Abraham
name: Bakasa, Carolyne
name: Etindele, Anne Justine
name: Casida, Mark E.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Static correlation is a difficult problem for density-functional theory (DFT) as it arises in cases of degenerate or quasi-degenerate states where a multideterminantal wave function provides the simplest reasonable first approximation to the true interacting wave function. This is also where Kohn-Sham DFT may also fail to be noninteracting v-representible (NVR). In contrast, Kohn-Sham DFT typically works well for describing the missing dynamic correlation when a single-determinantal reference wave function provides a good first approximation to the true interacting wave function. Multiplet sum method (MSM) DFT [Theor. Chim. Acta 4, 877 (1977)] provides one of the earliest and simplest ways to include static correlation in DFT. MSM-DFT assumes that DFT provides a good description of single-determant energies and uses symmetry and simple ansatzes to include the effects of static correlation. This is equivalent to determining the off-diagonal matrix elements in a small configuration interaction (CI) eigenvalue problem. We have developed a diagrammatic approach to MS-DFT facilitates comparison with wave function CI and so allows educated guesses of off-diagonal CI matrix elements even in the absence of symmetry. In every case, an additional exchange-only ansatz (EXAN) allows the MSM-DFT formulae to be transformed into wave function formulae. This EXAN also works for transforming time-dependent DFT into time-dependent Hartree-Fock. Although not enough to uniquely guess DFT formulae from wave function formulae, the diagrammatic approach and the EXAN provide important constraints on any guesses that might be used. Some alternative guesses are tried out for problems concerning the ground and excited states of H2 , LiH, and O2 in order to assess how much difference might be involved for different DFT guesses for off-diagonal matrix elements.
Comment on "Negative Refractive Index in Artificial Metamaterials" [A. N. Grigorenko, Opt. Lett., 31, 2483 (2006)]
Creators: name: Kildishev, Alexander V.
name: Drachev, Vladimir P.
name: Chettiar, Uday K.
name: Werner, Douglas
name: Kwon, Do-Hoon
name: Shalaev, Vladimir M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: A key optical parameter characterizing the existence of negative refraction in a thin layer of a composite material is the effective refractive index of an equivalent, homogenized layer with the same physical thickness as the initial inhomogeneous composite. Measuring the complex transmission and reflection coefficients is one of the most rigorous ways to obtain this parameter. We dispute Grigorenko's statement (Optics Letters 31, 2483 (2006)) that measuring only the reflection intensity spectrum is sufficient for determining the effective refractive index. We discuss fundamental drawbacks of Grigorenko's technique of using a best-fit approximation with an a priori prescribed dispersive behavior for a given metamaterial and an 'effective optical thickness' that is smaller than the actual thickness of the sample. Our simulations do not confirm the Grigorenko paper conclusions regarding the negative refractive index and the negative permeability of the nanopillar sample in the visible spectral range.
description: 18 pages, 7 figures
Fabrication, optical characterization and modeling of strained core-shell nanowires
Creators: name: Zanolli, Z.
name: Froeberg, L. E.
name: Bjoerk, M. T.
name: Pistol, M. -E.
name: Samuelson, L.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Strained nanowires with varying InAs/InP core-shell thicknesses were grown using Chemical Beam Epitaxy. Microphotoluminescence spectroscopy, performed at low temperature, was then used to study the optical properties of single wires. Emission from the InAs core was observed and its dependence on the shell thickness/core diameter ratio was investigated. We found that it is possible to tune the emission energy towards 0.8 eV by controlling this ratio. We have compared the measured energies with calculated energies. Our findings are consistent with the wires having a hexagonal crystal structure.
description: 9 pages, 5 figures, Proceedings of the Eighth International Conference on Atomically Controlled Surfaces, Interfaces and Nanostructures and the Thirteenth International Congress on Thin Films - ACSIN-8/ICTF-13
Simulations of real-time system identification for superconducting cavities with a recursive least-squares algorithm
Creators: name: Ziemann, Volker
Publisher: name: arXiv
Year: 2023
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: We explore the performance of a recursive least-squares algorithm to determine the bandwidth $ω_{12}$ and the detuning $Δω$ of a superconducting cavity. We base the simulations on parameters of the ESS double-spoke cavities. Expressions for the signal-to-noise ratio of derived parameters are given to explore the applicability of the algorithm to other configurations.
description: 16 pages, 5 figures, substantial text overlap with arXiv:2307.07386
Sending-or-not-sending twin-filed quantum key distribution with discrete phase modulation
Creators: name: Jiang, Cong
name: Yu, Zong-Wen
name: Hu, Xiao-Long
name: Wang, Xiang-Bin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the sending-or-not-sending (SNS) protocol with discrete phase modulation of coherent states. We first make the security of the SNS protocol with discrete phase modulation. We then present analytic formulas for key rate calculation. We take numerical simulations for the key rate through discrete phase modulation of both the original SNS protocol and the SNS protocol with two way classical communications of active-odd-parity pairing (AOPP). Our numerical simulation results show that only with $6$ phase values, the key rates of the SNS protocol can exceed the linear bound, and with $12$ phase values, the key rates are very close to the results of the SNS protocol with continuously modulated phase-randomization.
On a Class of Permutation Rational Functions Involving Trace Maps
Creators: name: Chen, Ruikai
name: Mesnager, Sihem
Publisher: name: arXiv
Year: 2023
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11T06, 14H05

description: Permutation rational functions over finite fields have attracted high interest in recent years. However, only a few of them have been exhibited. This article studies a class of permutation rational functions constructed using trace maps on extensions of finite fields, especially for the cases of quadratic and cubic extensions. Our achievements are obtained by investigating absolute irreducibility of some polynomials in two indeterminates.
Εκπαίδευση των Μαθηματικών μέσω του Wikimedia Education Program. Το παράδειγμα του Τμήματος Μαθηματικών και η χρησιμότητά του.
Creators: name: Αγγέλου, Αγάπη Θεολόγου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: subject: Βικιπαιδεία
subject: Συνεργατική μάθηση
subject: Μαθηματικά
subject: Wikipedia
subject: Collaborating Learning
subject: Mathematics
subject: FOS: Mathematics

description: Η παρούσα μελέτη αφορά το εκπαιδευτικό Πρόγραμμα της Wikipedia (Wikimedia Education Program) το οποίο εφαρμόστηκε στο Τμήμα Μαθηματικών για δύο συνεχόμενα έτη (2013 και 2014). Πραγματοποιείται μία έρευνα στους φοιτητές που παρακολούθησαν το πρόγραμμα. Τα αποτελέσματα της έρευνας αυτής σχετίζονται τόσο με τη χρήση της ίδιας της Wikipedia όσο και με τις δεξιότητες που αναπτύσσουν χρησιμοποιώντας την. Επιπλέον εξάγονται συμπεράσματα που αφορούν την εκπαιδευτική διεργασία καθώς και τα μέσα που χρησιμοποιούνται σε αυτή, στη τριτοβάθμια εκπαίδευση.
description: The study presents the Wikimedia Education Program which was applied for two consecutive years (2013 and 2014) to the Department of Mathematics of Aristotle University of Thessaloniki. A survey was curried out to students who attended the program. The survey’s results are related both to the use of Wikipedia itself and the skills students develop using it. Moreover important conclusions extracted regarding the educational process and the means that are used in higher education.
Μεταμοσχεύσεις: ποιμαντικοψυχολογικοί προβληματισμοί
Creators: name: Κοτσάνη, Φανή Βασιλείου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Μεταμοσχεύσεις
Εγκεφαλικός θάνατος
Ποιμαντική προσέγγιση
Transplants
Brain death
Pastoral approach

description: Σκοπός της διατριβής ήταν η ψυχολογική και η ποιμαντική προσέγγιση των μεταμοσχεύσεων. Αρχικά εξετάσαμε τη γενική θεώρηση του ζητήματος. Αφετηρία ήταν η εννοιολογική περιγραφή του όρου, σε μία προσπάθεια να δοθούν οι απαραίτητοι ορισμοί και στη συνέχεια περιγράψαμε τις διάφορες κατηγορίες μεταμοσχεύσεων. Ιδιαίτερη αναφορά έγινε στους φορείς που σχετίζονται με το χώρο αυτό, όπως είναι ο Εθνικός Οργανισμός Μεταμοσχεύσεων. Στη συνέχεια παρουσιάσαμε το νομικό πλαίσιο που διέπει τον τομέα των μεταμοσχεύσεων, κυρίως στην Ελλάδα αλλά και σε διεθνές επίπεδο. Ακόμη αναφερθήκαμε αναλυτικά στους παράγοντες που μπορεί να επηρεάσουν αρνητικά την ομαλή διαδικασία των μεταμοσχεύσεων. Εξετάσαμε το εξέχον ζήτημα του εγκεφαλικού θανάτου, ο οποίος πρέπει να επέλθει έτσι ώστε να προχωρήσει η διαδικασία της αφαίρεσης οργάνων από θανόντα δότη. Αναλύσαμε τις θέσεις που έχουν διατυπωθεί τόσο υπέρ όσο και κατά του εγκεφαλικού θανάτου, καθώς και τα κριτήρια διάγνωσής του. Ακολούθησε η διαθρησκειακή θεώρηση των μεταμοσχεύσεων, ώστε να διαφανούν οι ομοιότητες και οι διαφορές στις απόψεις των διαφόρων θρησκειών σχετικά με το ζήτημα και τέλος παρουσιάσαμε τη θεολογική προσέγγιση του ζητήματος, τη θέση της Εκκλησίας της Ελλάδος και της Ειδικής Συνοδικής Επιτροπής Βιοηθικής.
description: The aim of the thesis was the psychological and pastoral approach of transplants. Initially we looked at the overview of the issue. Starting point was the conceptual description of the term in an attempt to give the necessary definitions and then described the various categories of transplants. Particular reference was made to institutions relating to this area, as is the National Transplant Organization. Then we presented the legal framework regarding the field of transplantation, especially in Greece but also internationally. Also we mentioned the factors that may negatively affect the normal process of transplantation. We examined the prominent issue of brain death, which must occur in order to proceed to the removing of organs from a deceased donor. We analyzed the positions expressed both for and against brain death and the diagnosis criteria. Furthermore we examine the interfaith approach of transplants to clarify the similarities and differences in opinions of different religions on the issue and finally we presented the theological approach to the issue, by the position of Greek Church and by the Special Synodical Committee of Bioethics.