cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Exploring diffuse radio emission in galaxy clusters and groups with the uGMRT and the SKA
Creators: name: Paul, Surajit
name: Kale, Ruta
name: Datta, Abhirup
name: Basu, Aritra
name: Sur, Sharanya
name: Parekh, Viral
name: Gupta, Prateek
name: Chatterjee, Swarna
name: Salunkhe, Sameer
name: Iqbal, Asif
name: Pandey-Pommier, Mamta
name: Raja, Ramij
name: Rahaman, Majidul
name: Raychaudhury, Somak
name: Nath, Biman B.
name: Majumdar, Subhabrata
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Diffuse radio emission has been detected in a considerable number of galaxy clusters and groups, revealing the presence of pervasive cosmic magnetic fields, and of relativistic particles in the large-scale structure (LSS) of the Universe. Since cluster radio emission is faint and steep spectrum, its observations are largely limited by the instrument sensitivity and frequency of observation, leading to a dearth of information, more so for lower-mass systems. The unprecedented sensitivity of recently commissioned low-frequency radio telescope arrays, aided by the development of advanced calibration and imaging techniques, have helped in achieving unparalleled image quality. At the same time, the development of sophisticated numerical simulations and the availability of supercomputing facilities have paved the way for high-resolution numerical modeling of radio emission, and the structure of the cosmic magnetic fields in LSS, leading to predictions matching the capabilities of observational facilities. In view of these rapidly-evolving scenerio in modeling and observations, in this review, we summarise the role of the new telescope arrays and the development of advanced imaging techniques and discuss the detections of various kinds of cluster radio sources. In particular, we discuss observations of the cosmic web in the form of supercluster filaments, studies of emission in poor clusters and groups of galaxies, and of ultra-steep spectrum sources. We also review the current theoretical understanding of various diffuse cluster radio sources and the associated magnetic field and polarization. As the statistics of detections improve along with our theoretical understanding, we update the source classification schemes based on their intrinsic properties. We conclude by summarising the role of the upgraded GMRT and our expectations from the upcoming Square Kilometre Array (SKA) observatories.
description: 32 pages, 10 figures, accepted for publication in the Journal of Astrophysics and Astronomy (JoAA) (to appear in the special issue on "Indian participation in the SKA")
Numerical accuracy and stability of semilinear Klein--Gordon equation in de Sitter spacetime
Creators: name: Tsuchiya, Takuya
name: Nakamura, Makoto
Publisher: name: arXiv
Year: 2022
Subjects: subject: Numerical Analysis (math.NA)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Numerical simulations of the semilinear Klein--Gordon equation in the de Sitter spacetime are performed. We use two structure-preserving discrete forms of the Klein--Gordon equation. The disparity between the two forms is the discretization of the differential term. We show that one of the forms has higher numerical stability and second-order numerical accuracy with respect to the grid, and we explain the reason for the instability of the other form.
description: 7 pages
Almost commuting self-adjoint matrices --- the real and self-dual cases
Creators: name: Loring, Terry A.
name: Sørensen, Adam P. W.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Operator Algebras (math.OA)
subject: FOS: Mathematics

description: We show that a pair of almost commuting self-adjoint, symmetric matrices is close to a pair of commuting self-adjoint, symmetric matrices (in a uniform way). Moreover we prove that the same holds with self-dual in place of symmetric. The notion of self-dual Hermitian matrices is important in physics when studying fermionic systems that have time reversal symmetry. Since a symmetric, self-adjoint matrix is real, we get a real version of Huaxin Lin's famous theorem on almost commuting matrices. Similarly the self-dual case gives a version for matrices over the quaternions. We prove analogous results for element of real C^*-algebras of "low rank." In particular, these stronger results apply to paths of almost commuting Hermitian matrices that are real or self-dual. Along the way we develop a theory of semiprojectivity for real C^*-algebras.
description: Expanded references. 33 pages
Coupling of gravity to matter, spectral action and cosmic topology
Creators: name: Cacic, Branimir
name: Marcolli, Matilde
name: Teh, Kevin
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We consider a model of modified gravity based on the spectral action functional, for a cosmic topology given by a spherical space form, and the associated slow-roll inflation scenario. We consider then the coupling of gravity to matter determined by an almost commutative geometry over the spherical space form. We show that this produces a multiplicative shift of the amplitude of the power spectra for the density fluctuations and the gravitational waves, by a multiplicative factor equal to the total number of fermions in the matter sector of the model. We obtain the result by an explicit nonperturbative computation, based on the Poisson summation formula and the spectra of twisted Dirac operators on spherical space forms, as well as by a heat-kernel computation.
description: 28 pages, LaTeX; v2: final version to appear in Journal of Noncommutative Geometry
Study of a 3D Ginzburg-Landau functional with a discontinuous pinning term
Creators: name: Santos, Mickaël Dos
Publisher: name: arXiv
Year: 2011
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: In a convex domain $Ø\subset\R^3$, we consider the minimization of a 3D-Ginzburg-Landau type energy $E_\v(u)=1/2\int_Ø|\n u|^2+\frac{1}{2\v^2}(a^2-|u|^2)^2$ with a discontinuous pinning term $a$ among $H^1(Ø,\C)$-maps subject to a Dirichlet boundary condition $g\in H^{1/2}(\pØ,§^1)$. The pinning term $a:\R^3\to\R^*_+$ takes a constant value $b\in(0,1)$ in $ø$, an inner strictly convex subdomain of $Ø$, and 1 outside $ø$. We prove energy estimates with various error terms depending on assumptions on $Ø,ø$ and $g$. In some special cases, we identify the vorticity defects via the concentration of the energy. Under hypotheses on the singularities of $g$ (the singularities are polarized and quantified by their degrees which are $\pm 1$), vorticity defects are geodesics (computed w.r.t. a geodesic metric $d_{a^2}$ depending only on $a$) joining two paired singularities of $g$ $p_i & n_{σ(i)}$ where $σ$ is a minimal connection (computed w.r.t. a metric $d_{a^2}$) of the singularities of $g$ and $p_1,...p_k$ are the positive (resp. $n_1,...,n_k$ the negative) singularities.
Explaining Image Classifiers with Multiscale Directional Image Representation
Creators: name: Kolek, Stefan
name: Windesheim, Robert
name: Loarca, Hector Andrade
name: Kutyniok, Gitta
name: Levie, Ron
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Image classifiers are known to be difficult to interpret and therefore require explanation methods to understand their decisions. We present ShearletX, a novel mask explanation method for image classifiers based on the shearlet transform -- a multiscale directional image representation. Current mask explanation methods are regularized by smoothness constraints that protect against undesirable fine-grained explanation artifacts. However, the smoothness of a mask limits its ability to separate fine-detail patterns, that are relevant for the classifier, from nearby nuisance patterns, that do not affect the classifier. ShearletX solves this problem by avoiding smoothness regularization all together, replacing it by shearlet sparsity constraints. The resulting explanations consist of a few edges, textures, and smooth parts of the original image, that are the most relevant for the decision of the classifier. To support our method, we propose a mathematical definition for explanation artifacts and an information theoretic score to evaluate the quality of mask explanations. We demonstrate the superiority of ShearletX over previous mask based explanation methods using these new metrics, and present exemplary situations where separating fine-detail patterns allows explaining phenomena that were not explainable before.
Entanglement thresholds for random induced states
Creators: name: Aubrun, Guillaume
name: Szarek, Stanislaw J.
name: Ye, Deping
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: Functional Analysis (math.FA)
subject: Probability (math.PR)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: For a random quantum state on $H=C^d \otimes C^d$ obtained by partial tracing a random pure state on $H \otimes C^s$, we consider the whether it is typically separable or typically entangled. For this problem, we show the existence of a sharp threshold $s_0=s_0(d)$ of order roughly $d^3$. More precisely, for any $a > 0$ and for d large enough, such a random state is entangled with very large probability when $s < (1-a)s_0$, and separable with very large probability when $s > (1+a)s_0$. One consequence of this result is as follows: for a system of N identical particles in a random pure state, there is a threshold $k_0 = k_0(N) \sim N/5$ such that two subsystems of k particles each typically share entanglement if $k > k_0$, and typically do not share entanglement if $k < k_0$. Our methods work also for multipartite systems and for "unbalanced" systems such as $C^{d} \otimes C^{d'}$, $d \neq d'$. The arguments rely on random matrices, classical convexity, high-dimensional probability and geometry of Banach spaces; some of the auxiliary results may be of reference value. A high-level non-technical overview of the results of this paper and of a related article arXiv:1011.0275 can be found in arXiv:1112.4582.
description: 34 pages; v.3: reorganized proof, new results only in section 7.1, references added; v.2: main result strengthened (much stronger threshold property) allowing the sharp "N-particle" interpretation of the results stated in the abstract, new appendix on majorization and \infty-Wasserstein distance, references added
The synthesis and photophysical properties of new phosphorus-containing macromolecules
Creators: name: Rawe, Benjamin Walter
Publisher: name: University of British Columbia
Year: 2019

description: The thesis outlines the synthesis and photophysical properties of novel macromolecules that contain phosphorus atoms. Significantly, the fluorescence properties of the polymers prepared in this thesis are dependent on the chemical environment at phosphorus. These materials have the potential to be useful sensors for analytes that react with the phosphine moieties in these polymers. Chapter 1 introduces conjugated polymers and details known examples of phosphorus-containing polymers of this class that have been previously reported. A particular focus is the synthesis of these materials, as well as their photophysical properties. The known examples of molecular phosphine sensors are also presented. Chapters 2 and 3 focus on the anionic polymerization of phosphaalkene monomers to make novel poly(methylenephosphine)s, (PMPs) that contain fluorescent polyaromatic substituents. The synthesized polymers exhibited “turn on” fluorescence upon oxidation of the phosphorus centres. Notably, the C-pyrenyl PMP synthesized in Chapter 3 was also fluorescent in the solid state when the phosphine centres were oxidized. Chapter 4 describes the synthesis and photophysical properties of poly(p-phenylenediethynylene phosphine)s, PPYPs, a new class of phosphorus-containing macromolecule. The polymers were prepared using a nickel-catalyzed coupling between phenyldichlorophosphine and dialkynes. The resulting materials displayed photophysical characteristics consistent with a degree of conjugation through the phosphorus centres within the polymer. Upon oxidation of the phosphorus atoms in PPYPs, “turn on” emission was observed. Remarkably oxidized PPYPs were also fluorescent in the solid state and therefore may have application as solid-state sensors or as OLEDs. Chapter 5 describes the study of a fluorene-containing PPYP as a fluorescent sensor for metal analytes. Remarkably the polymer exhibited a substantial fluorescence increase upon coordination to gold and mercury ions whereas exposure of the polymer to other ions resulted in no fluorescence increase. Chapter 6 provides a summary of the work contained within this thesis, and future directions for these projects are postulated.
Nonreciprocal Phonon Propagation in a Metallic Chiral Magnet
Creators: name: Nomura, T.
name: Zhang, X. -X.
name: Takagi, R.
name: Karube, K.
name: Kikkawa, A.
name: Taguchi, Y.
name: Tokura, Y.
name: Zherlitsyn, S.
name: Kohama, Y.
name: Seki, S.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The phonon magnetochiral effect (MChE) is the nonreciprocal acoustic and thermal transports of phonons caused by the simultaneous breaking of the mirror and time-reversal symmetries. So far, the phonon MChE has been observed only in a ferrimagnetic insulator Cu2OSeO3, where the nonreciprocal response disappears above the Curie temperature of 58 K. Here, we study the nonreciprocal acoustic properties of a room-temperature ferromagnet Co9Zn9Mn2 for unveiling the phonon MChE close to the room temperature. Surprisingly, the nonreciprocity in this metallic compound is enhanced at higher temperatures and observed up to 250 K. This clear contrast between insulating Cu2OSeO3 and metallic Co9Zn9Mn2 suggests that metallic magnets have a mechanism to enhance the nonreciprocity at higher temperatures. From the ultrasound and microwave-spectroscopy experiments, we conclude that the magnitude of the phonon MChE of Co9Zn9Mn2 mostly depends on the magnon bandwidth, which increases at low temperatures and hinders the magnon-phonon hybridization. Our results suggest that the phonon nonreciprocity could be further enhanced by engineering the magnon band of materials.
description: 6 pages, 4 figures, 1 table
An hourglass-free formulation for total Lagrangian smoothed particle hydrodynamics
Creators: name: Wu, Dong
name: Zhang, Chi
name: Tang, Xiaojing
name: Hu, Xiangyu
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The total Lagrangian smoothed particle hydrodynamics (TL-SPH) for elastic solid dynamics suffers from hourglass modes which can grow and lead to the failure of simulation for problems with large deformation. To address this long-standing issue, we present an hourglass-free formulation based on volumetric-devioatric stress decomposition. Inspired by the fact that the artifact of nonphysical zigzag particle distribution induced by the hourglass modes is mainly characterized by shear deformation and the standard SPH discretization for the viscous term in the Navier-Stokes (NS) equation, the present formulation computes the action of shear stress directly through the Laplacian of displacement other than from the divergence of shear stress. A comprehensive set of challenging benchmark cases are simulated to demonstrate that, while improving accuracy and computational efficiency, the present formulation is able to eliminate the hourglass modes and achieves very good numerical stability with a single general effective parameter. In addition, the deformation of a practically relevant stent structure is simulated to demonstrate the potential of the present method in the field of biomechanics.
description: 38 pages 21 figures
Shift current response in elemental two-dimensional ferroelectrics
Creators: name: Qian, Zhuang
name: Zhou, Jian
name: Wang, Hua
name: Liu, Shi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A bulk material without inversion symmetry can generate a direct current under illumination. This interface-free current generation mechanism, referred to as the bulk photovoltaic effect (BPVE), does not rely on $p$-$n$ junctions. Here, we explore the shift current generation, a major mechanism responsible for the BPVE, in single-element two-dimensional (2D) ferroelectrics represented by phosphorene-like monolayers of As, Sb, and Bi. The strong covalency, small band gap, and large joint density of states afforded by these elemental 2D materials give rise to large shift currents, outperforming many state-of-the-art materials. We find that the shift current, due to its topological nature, depends sensitively on the details of the Bloch wave functions. It is crucial to consider the electronic exchange-correlation potential beyond the generalized gradient approximation as well as the spin-orbit interaction in density functional theory calculations to obtain reliable frequency-dependent shift current responses.
description: 11 pages, 11 figures
Connectivité solidaire : Révéler l'essence de l'engagement communautaire à travers la communication virtuelle des associations
Creators: name: ALOUANE sara
name: BENGRICH Merieme
Publisher: name: Zenodo
Year: 2024

description: L'essor du secteur non lucratif, caractérisé par une prolifération d'organisations, soulève des questions cruciales quant à leur gestion et leur impact sur la société. Alors que les pôles universitaires se penchent sur l'économie sociale, la dimension managériale est souvent négligée. Parallèlement, l'émergence des réseaux sociaux numériques offre de nouvelles possibilités, en particulier au Maroc où ces plateformes sont largement utilisées, principalement par la jeunesse.

L'article explore comment les organisations non lucratives au Maroc, confrontées à des défis tels que la rareté des ressources financières et des obstacles internes en communication, pourraient tirer parti des réseaux sociaux. Les avantages potentiels de ces plateformes, à la fois économiques et pratiques, pourraient résoudre les problèmes liés à la communication et au marketing. La question centrale soulevée est de savoir dans quelle mesure la communication virtuelle des associations impacte l'intention de participation communautaire.

En résumé, cet article aborde la création d'un modèle conceptuel qui intègre les différents aspects de la communication virtuelle et l'intention de participation communautaire. Il met en lumière l'accroissement de l'importance des réseaux sociaux en tant qu'outil de communication pour les organisations à but non lucratif. Ces plateformes offrent une proximité accrue avec le public, en particulier les jeunes, et présentent une solution économique pour surmonter les défis liés à la communication et au marketing.
Evaluation of cyclotron produced radiometals for radiolabeling of immuno- and bio-conjugates for nuclear imaging.
Creators: name: Dias, Gemma Marie
Publisher: name: University of British Columbia
Year: 2018

description: The development of novel bioconjugates; antibodies, antibody mimetics and peptides is revolutionising the targeted molecular imaging approach to oncology. Many bioconjugates with high and specific uptake in tumours are transitioning into clinical oncology imaging. Monoclonal antibodies are returning to diagnostic imaging due to the clinical impact and commercial success of many disease-modifying monoclonal antibodies and antibody-drug conjugates. One hindrance to mAb based imaging is their long biological half-life; requiring days to visualise high tumour-to-non-target contrast. A variety of avenues to improve the contrast and clearance of circulating mAbs are in development. Radiometals that are well suited for imaging antibodies as well as antibody mimentics or peptides are becoming more in demand as clinical translation occurs. Current constraints and requirements for conventional radiometal production can limit the accessibility to certain cyclotron centers and may not be easily integrated into existing cyclotron centers. Efforts have been made to modify conventional radiometal production by introducing a liquid target approach. Limitations with yield and purification methods are hindering the feasibility of producing radiometals with a liquid target. Herein, we propose to produce radiometals with a liquid target and compare yields, optimize purification procedures to ensure high radiolabeling yields and assess their usefulness to radiolabel existing and novel bioconjugates. Additionally, we use a variety of strategies to improve tumour-to-non-target contrast ratios and pharmacokinetics of mAbs which can be applied to imaging of novel mAbs. We demonstrate the ability to produce and purify ⁸⁹Zr with both a solid and liquid target with sufficient yields for radiolabeling of antibodies. We demonstrate that liquid target produced ⁸⁹Zr is a suitable alternative approach to conventional solid target ⁸⁹Zr by demonstrating suitable antibody radiolabeling yields for in vivo imaging. We demonstrate that liquid target produced ⁶⁸Ga can be separated effectively from the staring zinc material and from other metal impurities. This successful purification enabled high radiolabeling of DOTATOC. The radiolabeled ⁶⁸GaDOTATOC from liquid target ⁶⁸Ga was compared with an in vivo study to that of conventional generator ⁶⁸Ga. We demonstrate the feasibility of producing, purifying and radiolabeling liquid target ⁶⁸Ga for in vivo imaging.
Comparison of Spontaneous Emission in Trapped Ion Multiqubit Gates at High Magnetic Fields
Creators: name: Carter, Allison L.
name: Muleady, Sean R.
name: Shankar, Athreya
name: Lilieholm, Jennifer F.
name: Bullock, Bryce B.
name: Affolter, Matthew
name: Rey, Ana Maria
name: Bollinger, John J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Penning traps have been used for performing quantum simulations and sensing with hundreds of ions and provide a promising route toward scaling up trapped ion quantum platforms because of the ability to trap and control up to thousands of ions in 2D and 3D crystals. A leading source of decoherence in laser-based multiqubit operations on trapped ions is off-resonant spontaneous emission. While many trapped ion quantum computers or simulators utilize clock qubits, other systems rely on Zeeman qubits, which require a more complex calculation of this decoherence. We examine theoretically the impacts of spontaneous emission on quantum gates performed with trapped ions in a high magnetic field. We consider two types of gates -- light-shift and Molmer-Sorensen gates -- and compare the decoherence errors in each. We also compare different detunings, polarizations, and required intensities of the laser beams used to drive the gates. We show that both gates can have similar performance at their optimal operating conditions and examine the experimental feasibility of various operating points. By examining the magnetic field dependence of each gate, we demonstrate that when the $P$ state fine structure splitting is large compared to the Zeeman splittings, the theoretical performance of the Molmer-Sorensen gate is significantly better than that of the light-shift gate. Additionally, for the light-shift gate, we make an approximate comparison between the fidelities that can be achieved at high fields with the fidelities of state-of-the-art two-qubit trapped ion quantum gates. We show that, with regard to spontaneous emission, the achievable infidelity of our current configuration is about an order of magnitude larger than that of the best low-field gates, but we also discuss alternative configurations with potential error rates that are comparable with state-of-the-art trapped ion gates.
description: Main text: 19 pages, 13 figures, Appendix: 7 pages, 1 figure, updated to improve presentation
Robust Coin Flipping
Creators: name: Kopp, Gene S.
name: Wiltshire-Gordon, John D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Computational Complexity (cs.CC)
subject: Cryptography and Security (cs.CR)
subject: Information Theory (cs.IT)
subject: Probability (math.PR)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Alice seeks an information-theoretically secure source of private random data. Unfortunately, she lacks a personal source and must use remote sources controlled by other parties. Alice wants to simulate a coin flip of specified bias $α$, as a function of data she receives from $p$ sources; she seeks privacy from any coalition of $r$ of them. We show: If $p/2 \leq r < p$, the bias can be any rational number and nothing else; if $0 < r < p/2$, the bias can be any algebraic number and nothing else. The proof uses projective varieties, convex geometry, and the probabilistic method. Our results improve on those laid out by Yao, who asserts one direction of the $r=1$ case in his seminal paper [Yao82]. We also provide an application to secure multiparty computation.
description: 22 pages, 1 figure
Quality assessment of Cadmium Telluride as a detector material for multispectral medical imaging
Creators: name: Kirschenmann, S.
name: Bezak, M.
name: Bharthuar, S.
name: Brücken, E.
name: Golovleva, M.
name: Gädda, A.
name: Kalliokoski, M.
name: Karadzhinova-Ferrer, A.
name: Koponen, P.
name: Kramarenko, N.
name: Luukka, P.
name: Ott, J.
name: Tikkanen, J.
name: Turpeinen, R.
name: Winkler, A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: Cadmium Telluride (CdTe) is a high-Z material with excellent photon radiation absorption properties, making it a promising material to include in radiation detection technologies. However, the brittleness of CdTe crystals as well as their varying concentration of defects necessitate a thorough quality assessment before the complex detector processing procedure. We present our quality assessment of CdTe as a detector material for multispectral medical imaging, a research which is conducted as part of the Consortium Project Multispectral Photon-counting for Medical Imaging and Beam characterization (MPMIB). The aim of the project is to develop novel CdTe detectors and obtain spectrum-per-pixel information that make the distinction between different radiation types and tissues possible. To evaluate the defect density inside the crystals -- which can deteriorate the detector performance -- we employ infrared microscopy (IRM). Posterior data analysis allows us to visualise the defect distributions as 3D defect maps. Additionally, we investigate front and backside differences of the material with current-voltage (IV) measurements to determine the preferred surface for the pixelisation of the crystal, and perform test measurements with the prototypes to provide feedback for further processing. We present the different parts of our quality assessment chain and will close with first experimental results obtained with one of our prototype PC detectors in a small tomographic setup.
description: This is the Accepted Manuscript version of an article accepted for publication in Journal of Instrumentation. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1748-0221/17/01/C01070
Rethinking the Interconnections between Family Socialization and Gender through the Lens of Multi-local, Post-separation Families
Creators: name: Merla, Laura
Publisher: name: Sociologica
Year: 2018
Subjects: gender; motility; ICT; children; shared custody

description: This paper presents new avenues for the study of gender socialisation within families, through a focus on children growing “in” and “between” two homes in the context of shared physical custody arrangements. Each of these two homes are indeed governed by specific gender regimes, that children must appropriate, negotiate and navigate to construct their own gender identity. The paper connects in particular gender socialization in shared custody arrangements with the acquisition of mobility capital and territorial appropriation; and highlights the role of ICTs in everyday lived experiences of shared physical custody and how these technologies intervene in gender socialization processes.
description: Sociologica, Vol 12, No 3 (2018)
Minimal spontaneous CP-violating GUT and predictions for leptonic CP phases
Creators: name: Patel, Ketan M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: A non-supersymmetric renormalizable $SO(10)$ model, with CP invariant Yukawa sector consisting of Lorentz scalars in $10$ and $\overline{126}$ dimensional representations, is proposed. The elemental Yukawa couplings are real due to CP symmetry. The latter is broken in the low energy effective theory through the standard model Higgs which is a complex linear combination of electroweak doublets residing in $10$ and $\overline{126}$ scalars. As a result, the mass matrices in the quark and lepton sectors, including those of heavy and light neutrinos, depend only on three phases which in turn determine CP violation in both sectors. The model is comprehensively analysed for its viability and predictions including the possibility to generate baryon asymmetry through thermal leptogenesis. It predicts relatively small values for CP phases in the lepton sector. Successful leptogenesis further restricts the ranges to $-0.4 \le \sinδ\le 0.4$ for the Dirac phase and $-0.3 \le \sin η_1 \le 0.2$, $-0.5 \le \sin η_2 \le 0.5$ for the Majorana phases.
description: 7 pages, 3 captioned figures. V2: an error in consideration of the light Higgs is corrected, revised numerical analysis and results, version to appear in PRD
The period-age relation of long-period variables
Creators: name: Trabucchi, Michele
name: Mowlavi, Nami
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Pieces of empirical evidence suggest the existence of a period-age relation for long-period variables (LPVs). Yet, this property has hardly been studied on theoretical grounds thus far. We aim to examine the period-age relation using the results from recent nonlinear pulsation calculations. We combined isochrone models with theoretical periods to simulate the distribution of fundamental mode LPV pulsators, which include Miras, in the period-age plane, and we compared it with observations of LPVs in Galactic and Magellanic Clouds' clusters. In agreement with observations, models predict that the fundamental mode period decreases with increasing age because of the dominant role of mass in shaping stellar structure and evolution. At a given age, the period distribution shows a non-negligible width and is skewed toward short periods, except for young C-rich stars. As a result, the period-age relations of O-rich and C-rich models are predicted to have different slopes. We derived best-fit relations describing age and initial mass as a function of the fundamental mode period for both O- and C-rich models. The study confirms the power of the period-age relations to study populations of LPVs of specific types, either O-rich or C-rich, on statistical grounds. In doing so, it is recommended not to limit a study to Miras, which would make it prone to selection biases, but rather to include semi-regular variables that pulsate predominantly in the fundamental mode. The use of the relations to study individual LPVs, on the other hand, requires more care given the scatter in the period distribution predicted at any given age.
description: Accepted for publication in A&A Letters; Main text: 5 pages, 6 figures, 2 tables. Three appendices. Replaced with language-revised version
Symmetry analysis of magnetoelectric effects in perovskite-based multiferroics
Creators: name: Gareeva, Zukhra
name: Zvezdin, Anatoly
name: Zvezdin, Konstantin
name: Chen, Xiang Ming
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences
subject: F.m
subject: 18B35

description: In this article, we perform the symmetry analysis of perovskite-based multiferroics: bismuth ferrite (BiFeO3)-like, orthochromites (RCrO3), and Ruddlesden-Popper perovskites (Ca3Mn2O7-like), being the typical representatives of multiferroics of the trigonal, rhombic, and tetragonal crystal families and explore the effect of crystallographic distortions on magnetoelectric properties. We determine the principal order parameters for each of the considered structures and obtain their invariant combinations consistent with the particular symmetry. This approach allowed us to analyze the features of the magnetoelectric effect observed during structural phase transitions in BixR1-xFeO3 compounds and show that the rare-earth sublattice gives an impact into the linear magnetoelectric effect allowed by the symmetry of the new structure. It is shown that the magnetoelectric properties of ortho-chromites are attributed to the couplings between the magnetic and electric dipole moments arising near Cr3+ ions due to distortions linked with rotations and deformations of the CrO6 octahedra. For the first time, such symmetry consideration was implemented in the analysis of the Ruddlesden-Popper structures, which demonstrates the possibility of realizing the magnetoelectric effect in the Ruddlesden-Popper phases containing magnetically active cations and allows to estimate conditions required for its optimization.
description: 15 pages, 2 figures, 6 Tables
Ultralow-noise terahertz detection by p-n junctions in gapped bilayer graphene
Creators: name: Titova, Elena
name: Mylnikov, Dmitry
name: Kashchenko, Mikhail
name: Zhukov, Sergey
name: Dzhikirba, Kirill
name: Novoselov, Kostya
name: Bandurin, Denis
name: Alymov, Georgy
name: Svintsov, Dmitry
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Graphene shows a strong promise for detection of terahertz (THz) radiation due to its high carrier mobility, compatibility with on-chip waveguides and transistors, and small heat capacitance. At the same time, weak reaction of graphene's physical properties on the detected radiation can be traced down to the absence of band gap. Here, we study the effect of electrically-induced band gap on THz detection in graphene bilayer with split-gate p-n junction. We show that gap induction leads to simultaneous increase in current and voltage responsivities. At operating temperatures of ~25 K, the responsivity at 20 meV band gap is from 3 to 20 times larger than that in the gapless state. The maximum voltage responsivity of our devices at 0.13 THz illumination exceeds 50 kV/W, while the noise equivalent power falls down to 36 fW/Hz^0.5. These values set new records for semiconductor-based cryogenic terahertz detectors, and pave the way for efficient and fast terahertz detection.
Quantum electrodynamic effects on counter-streaming instabilities in the whole \textbf{k} space
Creators: name: Bret, Antoine
Publisher: name: arXiv
Year: 2022
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In a recent work [Bret, EPL \textbf{135} (2021) 35001], quantum electrodynamic (QED) effects were evaluated for the two-stream instability. It pertains to the growth of perturbations with a wave vector oriented along the flow in a collisionless counter-streaming system. Here, the analysis is extended to every possible orientation of the wave vector. The previous result for the two-stream instability is recovered, and it is proved that even within the framework of a 3D analysis, this instability remains fundamentally 1D even when accounting for QED effects. The filamentation instability, found for wave vectors normal to the flow, is weakly affected by QED corrections. As in the classical case, its growth rate saturates at large $k_\perp$. The saturation value is found independent of QED corrections. Also, the smallest unstable $k_\perp$ is independent of QED corrections. Surprisingly, unstable modes found for oblique wave vectors do \emph{not} follow the same pattern. For some, QED corrections do reduce the growth rate. But for others, the same corrections increase the growth rate instead. The possibility for QED effects to play a role in un-magnetized systems is evaluated. Pair production resulting from gamma emission by particles oscillating in the exponentially growing fields, is not accounting for.
description: 19 pages, 7 figures, to appear in Physical Review E
Convolution-enhanced Evolving Attention Networks
Creators: name: Wang, Yujing
name: Yang, Yaming
name: Li, Zhuo
name: Bai, Jiangang
name: Zhang, Mingliang
name: Li, Xiangtai
name: Yu, Jing
name: Zhang, Ce
name: Huang, Gao
name: Tong, Yunhai
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Computation and Language (cs.CL)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: Attention-based neural networks, such as Transformers, have become ubiquitous in numerous applications, including computer vision, natural language processing, and time-series analysis. In all kinds of attention networks, the attention maps are crucial as they encode semantic dependencies between input tokens. However, most existing attention networks perform modeling or reasoning based on representations , wherein the attention maps of different layers are learned separately without explicit interactions. In this paper, we propose a novel and generic evolving attention mechanism, which directly models the evolution of inter-token relationships through a chain of residual convolutional modules. The major motivations are twofold. On the one hand, the attention maps in different layers share transferable knowledge, thus adding a residual connection can facilitate the information flow of inter-token relationships across layers. On the other hand, there is naturally an evolutionary trend among attention maps at different abstraction levels, so it is beneficial to exploit a dedicated convolution-based module to capture this process. Equipped with the proposed mechanism, the convolution-enhanced evolving attention networks achieve superior performance in various applications, including time-series representation, natural language understanding, machine translation, and image classification. Especially on time-series representation tasks, Evolving Attention-enhanced Dilated Convolutional (EA-DC-) Transformer outperforms state-of-the-art models significantly, achieving an average of 17% improvement compared to the best SOTA. To the best of our knowledge, this is the first work that explicitly models the layer-wise evolution of attention maps. Our implementation is available at https://github.com/pkuyym/EvolvingAttention.
description: Accepted by IEEE T-PAMI. Extension of the previous work (arXiv:2102.12895). arXiv admin note: text overlap with arXiv:2102.12895
Increasing Entanglement by Separable Operations and New Monotones for W-type Entanglement
Creators: name: Chitambar, Eric
name: Cui, Wei
name: Lo, Hoi-Kwong
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The class of local operations and classical communication (LOCC) pertains to an important measurement scenario in many quantum communication schemes. While LOCC belongs to the more general class of separable operations (SEP), the exact difference between the two remains a challenging open problem. In this article, we seek to better understand the structure of LOCC and its relationship to SEP by comparing their respective abilities for distilling EPR entanglement from one copy of an $N$-qubit W-class state (i.e. that of the form $\sqrt{x_0}\ket{00...0}+\sqrt{x_1}\ket{10...0}+...+\sqrt{x_n}\ket{00...1}$). In terms of transformation success probability, we are able to quantify a gap as large as 37% between the two classes. Our work involves constructing new analytic entanglement monotones for W-class states which can increase on average by separable operations. Additionally, we are able to show that the set of LOCC operations, considered as a subset of the most general quantum measurements, is not closed.
description: This is the published version Phys. Rev. A 85, 062316 (2012). It expands on the results of Phys. Rev. Lett. 108, 240504 (2012)
Comment: Parenting and Inequality in Insecure Times
Creators: name: Rao, Aliya Hamid
Publisher: name: Sociologica
Year: 2018
Subjects: social class; gender; parenting; inequality; uncertainty

description: This comment highlights how high income inequality and economic uncertainty produce new dimensions to intensive parenting amongst the middle-class. Parenting practices encourage children’s development of behaviors and values which are coveted in élite professions. Amongst the advantaged, these parenting practices encourage neo-traditional family structures as a means of coping with economic uncertainty.
description: Sociologica, Vol 12, No 3 (2018)
The Accretion flow in M87 is really MAD
Creators: name: Yuan, Feng
name: Wang, Haiyang
name: Yang, Hai
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The supermassive black holes in most galaxies in the universe are powered by hot accretion flows. Both theoretical analysis and numerical simulations have indicated that, depending on the degree of magnetization, black hole hot accretion flow is divided into two modes, namely SANE (standard and normal evolution) and MAD (magnetically arrested disk). It has been an important question which mode the hot accretion flows in individual sources should belong to in reality, SANE or MAD. This issue has been investigated in some previous works but they all suffer from various uncertainties. By using the measured rotation measure values in the prototype low-luminosity active galactic nuclei in {M87} at 2, 5, and 8 GHz along the jet at various distances from the black hole, combined with three dimensional general relativity magnetohydrodynamical numerical simulations of SANE and MAD, we show in this paper that the predicted rotation measure values by MAD are well consistent with observations, while the SANE model overestimates the rotation measure by over two orders of magnitude thus is ruled out.
description: 9 pages, 5 figures; accepted by ApJ
Cosmological future singularities in massive gravity and massive bigravity
Creators: name: Mousavi, M.
name: Atazadeh, K.
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the future cosmological singularities in the framework of massive gravity and minimal massive bigravity theory. In this regards, we consider the possible classes of finite-time future singularities such as sudden, big rip, big freeze and big brake singularities in the massive universe. In dRGT model with an open expanding universe we obtain the sudden singularity in the future at a finite-time which generally without taking account of any particular realistic equation of state, is not avoidable and except the fluid density, all dynamical physical quantities such as pressure approach to infinity. To complete our study, we search the future cosmological singularities in the context of minimal massive bigravity theory and we find that the cosmology of this theory suffers from the sudden and big brake singularities, in which we can see that the parameters of the model approaches to zero the sudden singularity can be removed.
description: 14 pages, 8(*6) figures, references added
Simultaneous description of wobbling and chiral properties in even-odd triaxial nuclei
Creators: name: Raduta, C. M.
name: Raduta, A. A.
name: Poenaru, R.
name: Raduta, Al. H.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: A particle-triaxial rigid core Hamiltonian is semi-classically treated. The coupling term corresponds to a particle rigidly coupled to the triaxial core, along a direction that does not belong to any principal plane of the inertia ellipsoid.The equations of motion for the angular momentum components provide a sixth-order algebraic equation for one component and subsequently equations for the other two. Linearizing the equations of motion, a dispersion equation for the wobbling frequency is obtained. The equations of motion are also considered in the reduced space of generalized phase space coordinates. Choosing successively the three axes as quantization axis will lead to analytical solutions for the wobbling frequency, respectively. The same analysis is performed for the chirally transformed Hamiltonian. With an illustrative example one identified wobbling states whose frequencies are mirror image to one another. Changing the total angular momentum I, a pair of twin bands emerged. Note that the present formalism conciliates between the two signatures of triaxial nuclei, i.e., they could coexist for a single nucleus.
description: 13 pages, 19figures
Astrometric excess noise in Gaia EDR3 and the search for X-ray binaries
Creators: name: Gandhi, P.
name: Buckley, D. A. H.
name: Charles, P. A.
name: Hodgkin, S.
name: Scaringi, S.
name: Knigge, C.
name: Rao, A.
name: Paice, J. A.
name: Zhao, Y.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Astrometric noise (AEN) in excess of parallax and proper motion is a potential signature of orbital wobble of individual components in binary star systems. The combination of X-ray selection with astrometric noise could then be a powerful tool for robustly isolating accreting binaries in large surveys. Here, we mine the Gaia EDR3 catalogue for Galactic sources with significant values of astrometric noise over the parameter space expected for known and candidate X-ray binaries (XRBs). Cross-matching our sample with the Chandra Source Catalogue returns a primary sample of ~6,500 X-ray sources with significant AEN. X-ray detection efficiency for objects with significant AEN is a factor of ~4.5 times higher than in a matched control sample exhibiting low AEN. The primary sample branches off the main sequence much more than control objects in colour-mag space, and includes a higher fraction of known binaries, variables and young stellar object class types. However, values of AEN reported in the Gaia pipeline releases so far can exceed expectations for individual XRBs with known semi-major axis size and other system parameters. It is likely that other factors (possibly attitude and modelling uncertainties, as well as source variability) currently dominate the observed excess noise in such systems. Confirmation of their nature must therefore await future Gaia releases. The full X-ray matched catalogue is released here to enable legacy follow-up.
description: MNRAS in press. Updates and supersedes arXiv:2009.07277 with Gaia EDR3; main inferences unchanged. Primary catalogue available http://www.southampton.ac.uk/~pg3e14/aen/, and also at CDS