cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Criticality in the configuration-mixed interacting boson model : (1) $U(5)-\hat{Q}(χ)\cdot\hat{Q}(χ)$ mixing
Creators: name: Hellemans, V.
name: Van Isacker, P.
name: De Baerdemacker, S.
name: Heyde, K.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The case of U(5)--$\hat{Q}(χ)\cdot\hat{Q}(χ)$ mixing in the configuration-mixed Interacting Boson Model is studied in its mean-field approximation. Phase diagrams with analytical and numerical solutions are constructed and discussed. Indications for first-order and second-order shape phase transitions can be obtained from binding energies and from critical exponents, respectively.
Embedding spacetime via a geodesically equivalent metric of Euclidean signature
Creators: name: Jonsson, Rickard
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Starting from the equations of motion in a 1 + 1 static, diagonal, Lorentzian spacetime, such as the Schwarzschild radial line element, I find another metric, but with Euclidean signature, which produces the same geodesics x(t). This geodesically equivalent, or dual, metric can be embedded in ordinary Euclidean space. On the embedded surface freely falling particles move on the shortest path. Thus one can visualize how acceleration in a gravitational field is explained by particles moving freely in a curved spacetime. Freedom in the dual metric allows us to display, with substantial curvature, even the weak gravity of our Earth. This may provide a nice pedagogical tool for elementary lectures on general relativity. I also study extensions of the dual metric scheme to higher dimensions. In an addendum I extend the analysis concerning the shape of an embedding of the dual spacetime of a line through a planet of constant proper density.
description: 28 pages, 17 figures. As compared to the published version there are corrections to Eqs. 46-49 (no impact on the discussion) and minor cosmetical updates in the figures. An addendum is also included, 5 pages, 2 figures
Giant Carrier Mobility in Single Crystals of FeSb2
Creators: name: Hu, Rongwei
name: Mitrovic, V. F.
name: Petrovic, C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We report the giant carrier mobility in single crystals of FeSb2. Nonlinear field dependence of Hall resistivity is well described with the two-carrier model. Maximum mobility values in high mobility band reach ~10^5 cm^2/Vs at 8 K, and are ~10^2 cm^2/Vs at the room temperature. Our results point to a class of materials with promising potential for applications in solid state electronics.
description: 5 pages, 3 figures. Applied Physics Letters (in press)
Pluto: A Monte Carlo Simulation Tool for Hadronic Physics
Creators: name: Froehlich, I.
name: Boado, L. Cazon
name: Galatyuk, T.
name: Hejny, V.
name: Holzmann, R.
name: Kagarlis, M.
name: Kuehn, W.
name: Messchendorp, J. G.
name: Metag, V.
name: Pleier, M. -A.
name: Przygoda, W.
name: Ramstein, B.
name: Ritman, J.
name: Salabura, P.
name: Stroth, J.
name: Sudol, M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Pluto is a Monte-Carlo event generator designed for hadronic interactions from Pion production threshold to intermediate energies of a few GeV per nucleon, as well as for studies of heavy ion reactions. This report gives an overview of the design of the package, the included models and the user interface.
description: XI International Workshop on Advanced Computing and Analysis Techniques in Physics Research, April 23-27 2007, Amsterdam, the Netherlands
XMM-Newton observations of the TeV BL Lac object PKS 2155--304 in 2006: signature of inverse Compton X-ray emission?
Creators: name: Zhang, Y. H.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: This paper reports the first discovery of possible inverse Compoton (IC) X-ray emission below 10 keV in the typical high-energy peaked BL Lac object (HBL) PKS 2155--304. Two XMM-Newton observations performed in 2006 reveal that the 0.6--10 keV X-ray spectra of the source harden ($ΔΓ\sim$ 0.1--0.3) at break energies of about 4 keV. The concave X-ray spectra of the source could be easily interpretated by a mixture of a steep component (i.e., the high energy tail of the synchrotron emission) and a flat one (i.e., the low energy side of the IC emission). However, the steep spectra ($Γ\sim$ 2.3) in the hard X-rays indicate that the synchrotron emission still domiantes over the IC one, while the latter is effectively present and perceived as flattening the synchrotron spectrum in this energy range. The quasi-simultaneous optical-UV-X-ray spectral energy distributions (SEDs) obtained with XMM-Newton suggest that the concave X-ray spectra of the source could be the result of down-ward shift of the synchrotron peak frequency to the optical band, incuring the IC emisssion to become more important in the hard ($\sim 4$--10 keV) X-ray band with respective to other cases in which the synchrotron emission peaks in the UV-soft-X-ray range. This discovery provides a new clue for a smooth transition between HBLs and the low-energy peaked BL Lac objects (LBLs).
description: accepted by ApJ (2008 August 1 issue)
Forecasting time series of inhomogeneous Poisson processes with application to call center workforce management
Creators: name: Shen, Haipeng
name: Huang, Jianhua Z.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: We consider forecasting the latent rate profiles of a time series of inhomogeneous Poisson processes. The work is motivated by operations management of queueing systems, in particular, telephone call centers, where accurate forecasting of call arrival rates is a crucial primitive for efficient staffing of such centers. Our forecasting approach utilizes dimension reduction through a factor analysis of Poisson variables, followed by time series modeling of factor score series. Time series forecasts of factor scores are combined with factor loadings to yield forecasts of future Poisson rate profiles. Penalized Poisson regressions on factor loadings guided by time series forecasts of factor scores are used to generate dynamic within-process rate updating. Methods are also developed to obtain distributional forecasts. Our methods are illustrated using simulation and real data. The empirical results demonstrate how forecasting and dynamic updating of call arrival rates can affect the accuracy of call center staffing.
description: Published in at http://dx.doi.org/10.1214/08-AOAS164 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org)
On asymptotic dimension of amalgamated products and right-angled Coxeter groups
Creators: name: Dranishnikov, Alexander
Publisher: name: arXiv
Year: 2007
Subjects: subject: Group Theory (math.GR)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics

description: We prove the inequality $$ \as A\ast_CB\le\max\{\as A,\as B,\as C+1\} $$ and we apply this inequality to show that the asymptotic dimension of any right-angled Coxeter group does not exceed the dimension of its Davis' complex.
description: 12 pages
A study of the reaction p+p-->p+p+[pi][superscript 0] from 320 MeV to 500 MeV
Creators: name: Stanislaus, Thanthirimudalige Don Shirvel
Publisher: name: University of British Columbia
Year: 2010

description: The reaction p+p → p+p+π⁰ has been studied from threshold up to 500 MeV, by detecting the decay 7-rays of the π⁰ in coincidence in two large NaI crystals (TINA and MIN A). It was possible to measure the energy spectra, the differential cross sections and the asymmetry of the π⁰. The total cross sections and the angular distribution parameter b (defined by [Formula Omitted] determined in this measurement are consistent with previous measurements, but are of a much higher precision. The value obtained for b is very small indicating that most of the π⁰ mesons are isotropically distributed in the centre of mass. Assuming the energy spectra predicted by Gell-Mann, we have deduced the intensities of the Ss, Ps and Pp transitions by a global fit to all the energy spectra and the resulting cross sections. For Ss we obtained [Formula Omitted] which is smaller and more accurate than the previous measurements. A model independent [Formula Omitted] would have an uncertainty of about 6 µb. We have compared our results with those of the reaction n+p → N + N + π± and found them to be fairly similar. Any difference would demand inelasticities in the 1=0 channels, but the total cross sections indicate that σ₀₁ is small. The centre of mass pion energy spectra for pp → ppπ⁰ and np → nnπ⁺ are also similar. However a large cosΦ term is observed in the π± differential cross sections from the np reaction which is an indication of a significant value for σ₀₁. The analysing powers are fairly large and negative. This is the first measurement of this observable, although evidence from the reaction ¹³C(p, π⁻) had suggested that the asymmetry in the free pn → ppπ⁻ reaction might be positive.
Sylvester's question and the Random Acceleration Process
Creators: name: Hilhorst, H. J.
name: Calka, P.
name: Schehr, G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Let n points be chosen randomly and independently in the unit disk. "Sylvester's question" concerns the probability p_n that they are the vertices of a convex n-sided polygon. Here we establish the link with another problem. We show that for large n this polygon, when suitably parametrized by a function r(phi) of the polar angle phi, satisfies the equation of the random acceleration process (RAP), d^2 r/d phi^2 = f(phi), where f is Gaussian noise. On the basis of this relation we derive the asymptotic expansion log p_n = -2n log n + n log(2 pi^2 e^2) - c_0 n^{1/5} + ..., of which the first two terms agree with a rigorous result due to Barany. The nonanalyticity in n of the third term is a new result. The value 1/5 of the exponent follows from recent work on the RAP due to Gyorgyi et al. [Phys. Rev. E 75, 021123 (2007)]. We show that the n-sided polygon is effectively contained in an annulus of width \sim n^{-4/5} along the edge of the disk. The distance delta_n of closest approach to the edge is exponentially distributed with average 1/(2n).
description: 29 pages, 4 figures; references added and minor changes
Some remarks on spherical harmonics
Creators: name: Gichev, V. M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 58J50; 51M16

description: The article contains several observations on spherical harmonics and their nodal sets: a construction for harmonics with prescribed zeroes; a kind of canonical representation of this type for harmonics on $\bbS^2$; upper and lower bounds for nodal length and inner radius (the upper bounds are sharp); precise upper bound for the number of common zeroes of two spherical harmonics on $\bbS^2$; the mean Hausdorff measure on the intersection of $k$ nodal sets for harmonics of different degrees on $\bbS^m$, where $k\leq m$ (in particular, the mean number of common zeroes of $m$ harmonics).
description: 20 pages. Translation of the version which is published in Russian. Minor modifications throughout the paper. An error in calculation is corrected (page 14)
The Physical Range of Majorana Neutrino Mixing Parameters
Creators: name: de Gouvêa, André
name: Jenkins, James
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: If neutrinos are Majorana fermions, the lepton mixing parameter space consists of six mixing parameters: three mixing angles and three CP-odd phases. A related issue concerns the physical range of the mixing parameters. What values should these take so that all physically distinguishable mixing scenarios are realized? We present a detailed discussion of the lepton mixing parameter space in the case of two and three active neutrinos, and in the case of three active and N sterile neutrinos. We emphasize that this question, which has been a source of confusion even among "neutrino" physicists, is connected to an unambiguous definition of the neutrino mass eigenstates. We find that all Majorana phases can always be constrained to lie between 0 and pi, and that all mixing angles can be chosen positive and at most less than or equal to pi/2 provided the Dirac phases are allowed to vary between -pi and pi. We illustrate our results with several examples. Finally, we point out that, in the case of new flavor-changing neutrino interactions, the lepton mixing parameter space may need to be enlarged. We properly qualify this statement, and offer concrete examples.
description: 16 pages, 2 .eps figures, references added, minor typos corrected
Le variazioni anatomiche: La vera immagine dell'anatomia dell'uomo
Anatomical variations: the true  face of human anatomy
Creators: name: Mariani, Giulia Adalgisa <1966>
Publisher: name: Alma Mater Studiorum - Università di Bologna
Year: 2015
Subjects: BIO/16 Anatomia umana

description: La studio dell’Anatomia umana presenta una varietà di sfaccettature, che sono alla base della reale comprensione del corpo umano; ovvero la vera anatomia non è quella rappresentata nei testi ma quella che appare durante la dissezione o nelle più sofisticate analisi di immagine.  Lo scopo di questa tesi è stato quello di rivisitare alcune situazioni vascolari che possono andare incontro a variazioni e cercare di comprendere, anche con l’aiuto della bibliografia, se tali variazioni possono essere causa o epifenomeni di patologie a carico delle arterie affette dalle variazioni stesse o di territori da esse dipendenti per l’afflusso sanguigno. E’ stata condotta una analisi su preparati cadaverici in particolare in tre distretti: a) addome e tripode celiaco/mesenterica superiore; b) circolo cerebrale; d) orco aortico.
description: The study Human Anatomy presents a variety of facets, which are the basis of the real understanding of the human body; i.e. the real anatomy that is not represented in the texts but one that appears during dissection or in the more sophisticated image analysis. The purpose of this thesis was to revisit some situations that are likely to experience vascular changes and try to understand, also with the help of the bibliography, if these changes can be cause or epiphenomena of pathologies of the arteries affected by the variations or of territories that they supply. It has been carried out an analysis on cadavers and namely in three districts: a) abdomen and celiac trunk/ superior mesenteric artery; b) cerebral circulation; d) aortic arch.
Semidefinite Programming Two-way TOA Localization for User Devices with Motion and Clock Drift
Creators: name: Zhao, Sihao
name: Zhang, Xiao-Ping
name: Cui, Xiaowei
name: Lu, Mingquan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: In two-way time-of-arrival (TOA) systems, a user device (UD) obtains its position by round-trip communications to a number of anchor nodes (ANs) at known locations. The objective function of the maximum likelihood (ML) method for two-way TOA localization is nonconvex. Thus, the widely-adopted Gauss-Newton iterative method to solve the ML estimator usually suffers from the local minima problem. In this paper, we convert the original estimator into a convex problem by relaxation, and develop a new semidefinite programming (SDP) based localization method for moving UDs, namely SDP-M. Numerical result demonstrates that compared with the iterative method, which often fall into local minima, the SDP-M always converge to the global optimal solution and significantly reduces the localization error by more than 40%. It also has stable localization accuracy regardless of the UD movement, and outperforms the conventional method for stationary UDs, which has larger error with growing UD velocity.
Surface charge algebra in gauge theories and thermodynamic integrability
Creators: name: Barnich, Glenn
name: Compere, Geoffrey
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Surface charges and their algebra in interacting Lagrangian gauge field theories are investigated by using techniques from the variational calculus. In the case of exact solutions and symmetries, the surface charges are interpreted as a Pfaff system. Integrability is governed by Frobenius' theorem and the charges associated with the derived symmetry algebra are shown to vanish. In the asymptotic context, we provide a generalized covariant derivation of the result that the representation of the asymptotic symmetry algebra through charges may be centrally extended. Finally, we make contact with Hamiltonian and with covariant phase space methods.
description: 40 pages Latex file, published version
Rational streams coalgebraically
Creators: name: Rutten, J. J. M. M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences
subject: F.1.1; G.1.0

description: We study rational streams (over a field) from a coalgebraic perspective. Exploiting the finality of the set of streams, we present an elementary and uniform proof of the equivalence of four notions of representability of rational streams: by finite dimensional linear systems; by finite stream circuits; by finite weighted stream automata; and by finite dimensional subsystems of the set of streams.
The polarization in the JVAS/CLASS flat-spectrum radio sources: II. A search for aligned radio polarizations
Creators: name: Joshi, S. A.
name: Battye, R. A.
name: Browne, I. W. A.
name: Jackson, N.
name: Muxlow, T. W. B.
name: Wilkinson, P. N.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have used the very large JVAS/CLASS 8.4-GHz surveys of flat-spectrum radio sources to test the hypothesis that there is a systematic alignment of polarization position angle vectors on cosmological scales of the type claimed by Hutsemekers et al (2005). The polarization position angles of 4290 sources with polarized flux density >=1 mJy have been examined. They do not reveal large-scale alignments either as a whole or when split in half into high-redshift (z >= 1.24) and low-redshift sub-samples. Nor do the radio sources which lie in the specific areas covered by Hutsemekers et al (2005). show any significant effect. We have also looked at the position angles of parsec-scale jets derived from VLBI observations and again find no evidence for systematic alignments. Finally, we have investigated the correlation between the polarization position angle and those of the parsec-scale jets. As expected, we find that there is a tendency for the polarization angles to be perpendicular to the jet angles. However, the difference in jet and polarization position angles does not show any systematic trend in different parts of the sky.
description: 13 pages, 11 figures, 1 table, accepted for publication by MNRAS
A Novel Context-Aware Multimodal Framework for Persian Sentiment Analysis
Creators: name: Dashtipour, Kia
name: Gogate, Mandar
name: Cambria, Erik
name: Hussain, Amir
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Most recent works on sentiment analysis have exploited the text modality. However, millions of hours of video recordings posted on social media platforms everyday hold vital unstructured information that can be exploited to more effectively gauge public perception. Multimodal sentiment analysis offers an innovative solution to computationally understand and harvest sentiments from videos by contextually exploiting audio, visual and textual cues. In this paper, we, firstly, present a first of its kind Persian multimodal dataset comprising more than 800 utterances, as a benchmark resource for researchers to evaluate multimodal sentiment analysis approaches in Persian language. Secondly, we present a novel context-aware multimodal sentiment analysis framework, that simultaneously exploits acoustic, visual and textual cues to more accurately determine the expressed sentiment. We employ both decision-level (late) and feature-level (early) fusion methods to integrate affective cross-modal information. Experimental results demonstrate that the contextual integration of multimodal features such as textual, acoustic and visual features deliver better performance (91.39%) compared to unimodal features (89.24%).
description: Accepted in Neurocomputing
Detection of large magnetoanisotropy of electron spin dephasing in a high-mobility two-dimensional electron system in a [001] GaAs/AlxGa1−xAs quantum well
Creators: name: Stich, Dominik
name: Jiang, J.
name: Korn, Tobias
name: Schulz, Robert
name: Schuh, Dieter
name: Wegscheider, Werner
name: Wu, M.
name: Schüller, Christian
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik

description: In time-resolved Faraday rotation experiments, we have detected an in-plane anisotropy of the electron spin-dephasing time SDT in an n-modulation-doped GaAs/Al0.3Ga0.7As single quantum well. The SDT was measured with magnetic fields of B1 T, applied in the 110 and 11¯0 in-plane crystal directions of the GaAs quantum well. For fields along 11¯0, we have found up to a factor of about 2 larger SDT than in the perpendicular direction. The observed SDTs also show strong anisotropic magnetic-field dependence. Fully microscopic calculations, by numerically solving the kinetic spin Bloch equations considering the Dyakonov- Perel and the Bir-Aronov-Pikus mechanisms, reproduce the experimental findings quantitatively. This quantitative analysis of the data allowed us to determine the relative strengths of Rashba and Dresselhaus terms in our sample. Moreover, we could predict the SDT for spins aligned in the 110 in-plane direction to be on the order of several nanoseconds, which is up to 2 orders of magnitude larger than that in the perpendicular in-plane direction.
Measuring the impact of spammers on e-mail and Twitter networks
Creators: name: Colladon, A. Fronzetti
name: Gloor, P. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Social and Information Networks (cs.SI)
subject: Computation and Language (cs.CL)
subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences
subject: I.2.7; J.4; H.4.0; H.3.0

description: This paper investigates the research question if senders of large amounts of irrelevant or unsolicited information - commonly called "spammers" - distort the network structure of social networks. Two large social networks are analyzed, the first extracted from the Twitter discourse about a big telecommunication company, and the second obtained from three years of email communication of 200 managers working for a large multinational company. This work compares network robustness and the stability of centrality and interaction metrics, as well as the use of language, after removing spammers and the most and least connected nodes. The results show that spammers do not significantly alter the structure of the information-carrying network, for most of the social indicators. The authors additionally investigate the correlation between e-mail subject line and content by tracking language sentiment, emotionality, and complexity, addressing the cases where collecting email bodies is not permitted for privacy reasons. The findings extend the research about robustness and stability of social networks metrics, after the application of graph simplification strategies. The results have practical implication for network analysts and for those company managers who rely on network analytics (applied to company emails and social media data) to support their decision-making processes.
Presentation: Evaluating Emerging Food Supply Chains from a Resilience and Cost Perspective: A Study on the Alternative Protein Industry
Creators: name: Alem Fonseca, Mariel
Publisher: name: Apollo - University of Cambridge Repository
Year: 2023

description: This study aims to examine the relationship between resilience and cost across the dimension of sustainability (i.e., economic, environmental, societal) in alternative protein supply chains (SCs). Our global food system is on the cusp of transformation, with new SCs emerging. Traditional food SCs are already inefficient, unsustainable and prone to disruptions. Thus, if these issues are not solved, emerging food SCs will face the same challenges. Hence this research focuses on emerging and evolving food SCs such as alternative proteins SCs. Developing resilience in food SCs is critical, but it may come at a cost. Emerging food SCs in particular, must balance cost-effectiveness and resilience to succeed in a competitive and disruptive environment. While reducing costs is critical to compete in the market, ensuring resilience is essential to withstand disruptions. However, it is widely reported that resilience is expensive, which has led companies to think that they cannot afford it. This perception may be rooted on the limited understanding of the relationship between cost and resilience, and the little guidance companies have on how to evaluate their SC resilience level. Therefore, this research addresses the following research question: “How do companies manage the trade-offs between resilience and cost in the context of emerging food SCs?”. In order to address this question, a research process is designed that involves three stages: (i) a critical literature review to develop a conceptual framework for evaluating the level of SC resilience and cost; (ii) qualitative case-based research and model development; and (iii) a quantitative approach involving system dynamics modelling to simulate different scenarios and test SC resilience under different types of stress. The outcome of this research will include a resilience stress-testing framework to evaluate the performance of SCs on multiple performance dimensions, and trade-offs analyses between resilience and cost which will assist companies in their SC management and decision-making processes. This research will also define the level of resilience for SCs based on the previous two expected outcomes. This study aims to contribute to SC resilience theories by bringing three concepts: cost of resilience, level of resilience, and stress-testing approach. There will be findings that have not been yet conceptualised in the context of alternative protein supply chain design.
Large N Optimization for multi-matrix systems
Creators: name: Koch, Robert de Mello
name: Jevicki, Antal
name: Liu, Xianlong
name: Mathaba, Kagiso
name: Rodrigues, João P.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we revisit the problem of solving multi-matrix systems through numerical large $N$ methods. The framework is a collective, loop space representation which provides a constrained optimization problem, addressed through master-field minimization. This scheme applies both to multi-matrix integrals ($c=0$ systems) and multi-matrix quantum mechanics ($c=1$). The complete fluctuation spectrum is also computable in the above scheme, and is of immediate physical relevance in the later case. The complexity (and the growth of degrees of freedom) at large $N$ have stymied earlier attempts and in the present work we present significant improvements in this regard. The (constrained) minimization and spectrum calculations are easily achieved with close to $10^4$ variables, giving solution to Migdal-Makeenko, and collective field equations. Considering the large number of dynamical (loop) variables and the extreme nonlinearity of the problem, high precision is obtained when confronted with solvable cases. Through numerical results presented, we prove that our scheme solves, by numerical loop space methods, the general two matrix model problem.
description: 38 pages. v2: minor typos corrected and refs added. v3: Published version
Optimal discrimination between quantum operations
Creators: name: Li, Lvzhou
name: Qiu, Daowen
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In this paper, we address the problem of discriminating two given quantum operations. Firstly, based on the Bloch representation of single qubit systems, we give the exact minimum error probability of discriminating two single qubit quantum operations by unentangled input states. In particular, for the Pauli channels discussed in [Phys. Rev. A {\bf 71}, 062340 (2005)], we use a more intuitional and visual method to deal with their discrimination problem. Secondly, we consider the condition for perfect discrimination of two quantum operations. Specially, we get that two generalized Pauli channels are perfectly distinguishable if and only if their characteristic vectors are orthogonal.
description: 6 pages (revtex4 version); comments are welcome
Observing the influence of the youngest super star clusters in NGC 1569: Keck Brackett $α$ spectroscopy
Creators: name: Cohen, Daniel P.
name: Turner, Jean L.
name: Beck, Sara C.
name: Consiglio, S. Michelle
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We report Keck-NIRSPEC observations of the Brackett $α$ 4.05 $μ$m recombination line across the two candidate embedded super star clusters (SSCs) in NGC 1569. These SSCs power a bright HII region and have been previously detected as radio and mid-infrared sources. Supplemented with high resolution VLA mapping of the radio continuum along with IRTF-TEXES spectroscopy of the [SIV] 10.5 $μ$m line, the Brackett $α$ spectra data provide new insight into the dynamical state of gas ionized by these forming massive clusters. NIR sources detected in 2 $μ$m images from the Slit-viewing Camera are matched with GAIA sources to obtain accurate celestial coordinates and slit positions to within $\sim 0.1''$. Br$α$ is detected as a strong emission peak powered by the less luminous infrared source, MIR1 ($L_{\rm IR}\sim 2\times10^7~L_\odot$). The second candidate SSC MIR2 is more luminous ($L_{\rm IR}\gtrsim 4\times10^8~L_\odot$) but exhibits weak radio continuum and Br$α$ emission, suggesting the ionized gas is extremely dense ($n_e\gtrsim 10^5$ cm$^{-3}$), corresponding to hypercompact HII regions around newborn massive stars. The Br$α$ and [SIV] lines across the region are both remarkably symmetric and extremely narrow, with observed line widths $Δv \simeq 40$ km s$^{-1}$, FWHM. This result is the first clear evidence that feedback from NGC 1569's youngest giant clusters is currently incapable of rapid gas dispersal, consistent with the emerging theoretical paradigm in the formation of giant star clusters.
description: Accepted for publication in MNRAS 2021 Feb 26; 9 pages, 7 figures
Designing a machine learning potential for molecular simulation of liquid alkanes
Creators: name: Veit, Max
Publisher: name: Apollo - University of Cambridge Repository
Year: 2018
Subjects: machine learning
many-body dispersion
alkanes
liquid simulation
viscosity
DFT
molecular dynamics

description: Molecular simulation is applied to understanding the behaviour of alkane liquids with the eventual goal of being able to predict the viscosity of an arbitrary alkane mixture from first principles. Such prediction would have numerous scientific and industrial applications, as alkanes are the largest component of fuels, lubricants, and waxes; furthermore, they form the backbones of a myriad of organic compounds. This dissertation details the creation of a potential, a model for how the atoms and molecules in the simulation interact, based on a systematic approximation of the quantum mechanical potential energy surface using machine learning. This approximation has the advantage of producing forces and energies of nearly quantum mechanical accuracy at a tiny fraction of the usual cost. It enables accurate simulation of the large systems and long timescales required for accurate prediction of properties such as the density and viscosity. The approach is developed and tested on methane, the simplest alkane, and investigations are made into potentials for longer, more complex alkanes. The results show that the approach is promising and should be pursued further to create an accurate machine learning potential for the alkanes. It could even be extended to more complex molecular liquids in the future.
description: First-year training funded by the EPSRC as part of the centre for doctoral training in computational methods for materials science (CDT CMM) under grant number EP/L015552/1. PhD studentship funding by Shell Global Solutions International B.V. Computer time provided by ARCHER (http://archer.ac.uk) under the UKCP Consortium, EPSRC grant number EP/P022596/1.
Gamma Ray Burst studies with THESEUS
Creators: name: Ghirlanda, G.
name: Salvaterra, R.
name: Toffano, M.
name: Ronchini, S.
name: Guidorzi, C.
name: Oganesyan, G.
name: Ascenzi, S.
name: Bernardini, M. G.
name: Camisasca, A. E.
name: Mereghetti, S.
name: Nava, L.
name: Ravasio, M. E.
name: Branchesi, M.
name: Castro-Tirado, A.
name: Amati, L.
name: Blain, A.
name: Bozzo, E.
name: O'Brien, P.
name: Götz, D.
name: Floch, E. Le
name: Osborne, J. P.
name: Rosati, P.
name: Stratta, G.
name: Tanvir, N.
name: Bogomazov, A. I.
name: D'Avanzo, P.
name: Hafizi, M.
name: Mandhai, S.
name: Melandri, A.
name: Peer, A.
name: Topinka, M.
name: Vergani, S. D.
name: Zane, S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Gamma-ray Bursts (GRBs) are the most powerful transients in the Universe, over-shining for a few seconds all other $γ$-ray sky sources. Their emission is produced within narrowly collimated relativistic jets launched after the core-collapse of massive stars or the merger of compact binaries. THESEUS will open a new window for the use of GRBs as cosmological tools by securing a statistically significant sample of high-$z$ GRBs, as well as by providing a large number of GRBs at low-intermediate redshifts extending the current samples to low luminosities. The wide energy band and unprecedented sensitivity of the Soft X-ray Imager (SXI) and X-Gamma rays Imaging Spectrometer (XGIS) instruments provide us a new route to unveil the nature of the prompt emission. For the first time, a full characterisation of the prompt emission spectrum from 0.3 keV to 10 MeV with unprecedented large count statistics will be possible revealing the signatures of synchrotron emission. SXI spectra, extending down to 0.3 keV, will constrain the local metal absorption and, for the brightest events, the progenitors' ejecta composition. Investigation of the nature of the internal energy dissipation mechanisms will be obtained through the systematic study with XGIS of the sub-second variability unexplored so far over such a wide energy range. THESEUS will follow the spectral evolution of the prompt emission down to the soft X-ray band during the early steep decay and through the plateau phase with the unique ability of extending above 10 keV the spectral study of these early afterglow emission phases.
description: Submitted to Experimental Astronomy
D4.2 Monitoring Indicators and Targets
Creators: name: Golightly, David
Publisher: name: Zenodo
Year: 2021
Subjects: RIDE2RAIL
Transport
Shift2Rail
KPI
Preparation

description: The deliverable specifies the Key performance indicators (KPI) and associated targets that will be used to evaluate the RIDE2RAIL project. The KPIs inform the calculation of impact as specified within WP5. The harmonisation of clear KPIs in a systematic manner means that KPIs can be tailored to the specific circumstances and aims of a given demonstrator site while providing a holistic picture of RIDE2RAIL impact.
Theory of quantum entanglement and the structure of two-mode squeezed antiferromagnetic magnon vacuum
Creators: name: Wuhrer, Dennis
name: Rohling, Niklas
name: Belzig, Wolfgang
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Recent investigations of the quantum properties of an antiferromagnet in the spin wave approximation have identified the eigenstates as two-mode squeezed sublattice states. The uniform squeezed vacuum and one-magnon states were shown to display a massive sublattice entanglement. Here we expand this investigation and study the squeezing properties of all sublattice Fock states throughout the magnetic Brillouin zone. We derive the full statistics of the sublattice magnon number with wave number $\vec k$ in the ground state and show that magnons are created in pairs with opposite wavevectors, hence, resulting in entanglement of both modes. To quantify the degree of entanglement we apply the Duan-Giedke-Cirac-Zoller inequality and show that it can be violated for all modes. The degree of entanglement decrease towards the corners of the Brillouin zone. We relate the entanglement to measurable correlations of components of the Néel and the magnetization vectors, thus, allowing to experimentally test the quantum nature of the squeezed vacuum. The distinct $\vec k$-space structure of the probabilites shows that the squeezed vacuum has a nonuniform shape that is revealed through the $\vec k$-dependent correlators for the magnetization and the Néel vectors.
Recensione a: Marina Congiu, Gela. Topografia e sviluppo urbano, Salvatore Sciascia Editore, Caltanissetta-Roma 2012, pp. 256, ISBN: 978-88-8241-449-8
Creators: name: Scirpo, Paolo Daniele
Publisher: name: Layers. Archeologia Territorio Contesti
Year: 2021

description: Recensione del volume: M. Congiu, Gela. Topografia e sviluppo urbano, Salvatore Sciascia Editore, Caltanisetta-Roma 2012.
description: Layers. Archeologia Territorio Contesti, No 6 (2021
Le ceramiche cosiddette "stampigliate in Sardegna": un aggiornamento alla ricerca
Creators: name: Pinelli, Laura
Publisher: name: Layers. Archeologia Territorio Contesti
Year: 2021

description: In questa sede vengono prese in esame le testimonianze edite in Sardegna riguardanti ceramiche da cucina, dispensa e conserva ad impasto grezzo accomunate da caratteristiche decorazioni realizzate con la tecnica della stampigliatura, alle quali spesso si associano motivi realizzati ad impressione ed incisione. In seguito a ricalibrature cronologiche vengono annoverate tra le produzioni dell’altomedievo bizantino e la loro cospicua presenza in numerosi insediamenti dell’entroterra rende tali manufatti possibili fossili-guida per ricostruire il paesaggio rurale nei secoli in questione.
description: Layers. Archeologia Territorio Contesti, No 6 (2021
M5 from M2
Creators: name: Ho, Pei-Ming
name: Matsuo, Yutaka
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Recently an action based on Lie 3-algebras was proposed to describe M2-branes. We study the case of infinite dimensional Lie 3-algebras based on the Nambu-Poisson structure of three dimensional manifolds. We show that the model contains self-dual 2-form gauge fields in 6 dimensions, and the result may be interpreted as the M5-brane world-volume action.
description: 15 pages, minor modification
Quantum metrology with one auxiliary particle in a correlated bath and its quantum simulation
Creators: name: He, Wan-Ting
name: Guang, Huan-Yu
name: Li, Zi-Yun
name: Deng, Ru-Qiong
name: Zhang, Na-Na
name: Zhao, Jie-Xing
name: Deng, Fu-Guo
name: Ai, Qing
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: In realistic metrology, entangled probes are more sensitive to noise, especially for a correlated environment. The precision of parameter estimation with entangled probes is even lower than that of the unentangled ones in a correlated environment. In this paper, we propose a measurement scheme with only one auxiliary qubit, which can selectively offset the impact of environmental noise under this situation. We analyse the estimation precision of our scheme and find out that it approaches the Heisenberg limit when prepared in a proper auxiliary state. We further discuss employing auxiliary states to improve the precision of measurement in other environment models such as a partially-correlated environment. In order to verify our scheme, we apply a recently-developed quantum algorithm to simulate the quantum dynamics of our proposal and show that it outperform the other proposals with less resources.
description: 10 pages, 5 figures
Text Summarization of Czech News Articles Using Named Entities
Creators: name: Marek, Petr
name: Müller, Štěpán
name: Konrád, Jakub
name: Lorenc, Petr
name: Pichl, Jan
name: Šedivý, Jan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: The foundation for the research of summarization in the Czech language was laid by the work of Straka et al. (2018). They published the SumeCzech, a large Czech news-based summarization dataset, and proposed several baseline approaches. However, it is clear from the achieved results that there is a large space for improvement. In our work, we focus on the impact of named entities on the summarization of Czech news articles. First, we annotate SumeCzech with named entities. We propose a new metric ROUGE_NE that measures the overlap of named entities between the true and generated summaries, and we show that it is still challenging for summarization systems to reach a high score in it. We propose an extractive summarization approach Named Entity Density that selects a sentence with the highest ratio between a number of entities and the length of the sentence as the summary of the article. The experiments show that the proposed approach reached results close to the solid baseline in the domain of news articles selecting the first sentence. Moreover, we demonstrate that the selected sentence reflects the style of reports concisely identifying to whom, when, where, and what happened. We propose that such a summary is beneficial in combination with the first sentence of an article in voice applications presenting news articles. We propose two abstractive summarization approaches based on Seq2Seq architecture. The first approach uses the tokens of the article. The second approach has access to the named entity annotations. The experiments show that both approaches exceed state-of-the-art results previously reported by Straka et al. (2018), with the latter achieving slightly better results on SumeCzech's out-of-domain testing set.
A centimetre-wave excess over free-free emission in planetary nebulae
Creators: name: Casassus, S.
name: Nyman, L. -A.
name: Dickinson, C.
name: Pearson, T. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report a centimetre-wave (cm-wave, 5-31GHz) excess over free-free emission in PNe. Accurate 31 and 250GHz measurements show that the 31GHz flux densities in our sample are systematically higher than the level of optically thin free-free continuum extrapolated from 250GHz. The 31GHz excess is observed, within one standard deviation, in all 18 PNe with reliable 31 and 250GHz data, and is significant in 9 PNe. The only exception is the peculiar object M2-9, whose radio spectrum is that of an optically thick stellar wind. On average the fraction of non-free-free emission represents 51% of the total flux density at 31GHz, with a scatter of 11%. The average 31-250GHz spectral index of our sample is = -0.43+-0.03 (in flux density, with a scatter of 0.14). The 31--250 GHz drop is reminiscent of the anomalous foreground observed in the diffuse ISM by CMB anisotropy experiments. The 5--31 GHz spectral indices are consistent with both flat spectra and spinning dust emissivities, given the 10% calibration uncertainty of the comparison 5GHz data. But a detailed study of the objects with the largest cm-excess, including the low frequency data available in the literature, shows that present spinning dust models cannot alone explain the cm-excess in PNe. Although we have no definitive interpretation of our data, the least implausible explanation involves a synchrotron component absorbed by a cold nebular screen. We give flux densities for 37 objects at 31GHz, and for 26 objects at 250GHz.
description: accepted for publication in MNRAS; corrected the title (the short running title was copied in the first posting)
Vanadium Dioxide Thin Films Synthesized Using Low Thermal Budget Atmospheric Oxidation
Creators: name: Ashok, P
name: Chauhan, Yogesh Singh
name: Verma, Amit
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Vanadium dioxide is a complex oxide material, which shows large resistivity and optical reflectance change while transitioning from the insulator to metal phase at ~68 °C. In this work, we use a modified atmospheric thermal oxidation method to oxidize RF-sputtered Vanadium films. Structural, surface-morphology and phase-transition properties of the oxidized films as a function of oxidation duration are presented. Phase-pure VO2 films are obtained by oxidizing ~130 nm Vanadium films in short oxidation duration of ~30 seconds. Compared to previous reports on VO2 synthesis using atmospheric oxidation of Vanadium films of similar thickness, we obtain a reduction in oxidation duration by more than one order. Synthesized VO2 thin film shows resistance switching of ~3 orders of magnitude. We demonstrate optical reflectance switching in long-wave infrared wavelengths in VO2 films synthesized using atmospheric oxidation of Vanadium. The extracted refractive index of VO2 in the insulating and in the metallic phase is in good agreement with VO2 synthesized using other methods. The considerable reduction in oxidation time of VO2 synthesis while retaining good resistance and optical switching properties will help in integration of VO2 in limited thermal budget processes, enabling further applications of this phase-transition material.
description: 15 pages, 5 figures