cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A Monte-Carlo Method for Making SDSS $u$-Band Magnitude more accurate
Creators: name: Gu, Jiayin
name: Du, Cuihua
name: Zuo, Wenbo
name: Jing, Yingjie
name: Wu, Zhenyu
name: Ma, Jun
name: Zhou, Xu
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We develop a new Monte-Carlo-based method to convert the SDSS (Sloan Digital Sky Survey) $u$-band magnitude to the SCUSS (South Galactic Cap of $u$-band Sky Survey) $u$-band magnitude. Due to more accuracy of SCUSS $u$-band measurements, the converted $u$-band magnitude becomes more accurate comparing with the original SDSS $u$-band magnitude, in particular at the faint end. The average $u$ (both SDSS and SCUSS) magnitude error of numerous main-sequence stars with $0.2
description: 6 pages, 5 figures, accepted for publication in AJ
An overview of the spin dynamics of antiferromagnetic Mn$_5$Si$_3$
Creators: name: Biniskos, N.
name: Santos, F. J. dos
name: Dias, M. dos Santos
name: Raymond, S.
name: Schmalzl, K.
name: Steffens, P.
name: Persson, J.
name: Marzari, N.
name: Blügel, S.
name: Lounis, S.
name: Brückel, T.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The metallic compound Mn$_5$Si$_3$ hosts a series of antiferromagnetic phases which can be controlled by external stimuli such as temperature and magnetic field. In this work, we investigate the spin-excitation spectrum of bulk Mn$_5$Si$_3$ by combining inelastic neutron scattering measurements and density functional theory calculations. We study the evolution of the dynamical response under external parameters and demonstrate that the spin dynamics of each phase is robust against any combination of temperature and magnetic field. In particular, the high-energy spin dynamics is very characteristic of the different phases consisting of either spin waves or broad fluctuations patterns.
description: 5 figures
Astronomy Education: Planetarium and Museum Features
Creators: name: Tikhomirova, Ekaterina
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Astronomy Education: Planetarium and Museum Features

Presenter: Ekaterina Tikhomirova (Yaroslavl, The Russian Federation)

 

This was a poster presented at the 5th Shaw-IAU Workshop on Astronomy for Education, organised by the IAU Office of Astronomy for Education (OAE, http//astro4edu.org).

The Cultural and educational center n.a. V.V.Tereshkova has the planetarium, the space museum, the Exposition Hall,the observatory and educational interactive classroom. The astronomy education and enlightenment in the example of the Center is considered.

About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

Keep up to date with future Shaw-IAU Workshops and other opportunities at the IAU Office of Astronomy for Education by joining our mailing list https://astro4edu.org/mailing-list/

Follow the IAU OAE on X and Facebook under @astro4edu
Impact of level densities and $γ$-strength functions on $r$-process simulations
Creators: name: Pogliano, Francesco
name: Larsen, Ann-Cecilie
Publisher: name: arXiv
Year: 2023
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Studies attempting to quantify the sensitivity of the $r$-process abundances to nuclear input have to cope with the fact that the theoretical models they rely on, rarely come with confidence intervals. This problem has been dealt with by either estimating these intervals and propagating them statistically to the final abundances using reaction networks within simplified astrophysical models, or by running more realistic astrophysical simulations using different nuclear-physics models consistently for all the involved nuclei. Both of these approaches have their strengths and weaknesses. In this work, we run $r$-process calculations for five trajectories using 49 different neutron-capture rate models. Our results shed light on the importance of taking into account shell effects and pairing correlations in the network calculations.
description: 11 pages, 7 figures
Boosting Distributed Machine Learning Training Through Loss-tolerant Transmission Protocol
Creators: name: Chen, Zixuan
name: Shi, Lei
name: Liu, Xuandong
name: Ai, Xin
name: Liu, Sen
name: Xu, Yang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Machine Learning (cs.LG)
subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: Distributed Machine Learning (DML) systems are utilized to enhance the speed of model training in data centers (DCs) and edge nodes. The Parameter Server (PS) communication architecture is commonly employed, but it faces severe long-tail latency caused by many-to-one "incast" traffic patterns, negatively impacting training throughput. To address this challenge, we design the \textbf{L}oss-tolerant \textbf{T}ransmission \textbf{P}rotocol (LTP), which permits partial loss of gradients during synchronization to avoid unneeded retransmission and contributes to faster synchronization per iteration. LTP implements loss-tolerant transmission through \textit{out-of-order transmission} and \textit{out-of-order Acknowledges (ACKs)}. LTP employs \textit{Early Close} to adjust the loss-tolerant threshold based on network conditions and \textit{Bubble Filling} for data correction to maintain training accuracy. LTP is implemented by C++ and integrated into PyTorch. Evaluations on a testbed of 8 worker nodes and one PS node demonstrate that LTP can significantly improve DML training task throughput by up to 30x compared to traditional TCP congestion controls, with no sacrifice to final accuracy.
description: This paper will be published on IWQoS 2023. Preview version only
Oscillating Chiral Tensor Spectrum from Axionic Inflation
Creators: name: Obata, Ippei
name: Soda, Jiro
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the axionic inflation with a modulated potential and examine if the primordial tensor power spectrum exhibits oscillatory feature, which is testable with future space-based gravitational wave experiments such as DECIGO and BBO. In the case of the single-field axion monodromy inflation, it turns out that it is difficult to detect the oscillation in the spectrum due to suppression of the sub-Planckian decay constant of axion. On the other hand, in the case of aligned chromo-natural inflation where the axion is coupled to a SU(2) gauge field, it turns out that the sizable oscillation in the tensor spectrum can occur due to the enhancement of chiral gravitational waves sourced by the gauge field. We expect that this feature will be a new probe to axion phenomenologies in early universe through the chiral gravitational waves.
Astronomy on TikTok
Creators: name: Prodanovic, Tijana
Publisher: name: Zenodo
Year: 2023

description: Title: Astronomy on TikTok

Presenter: Tijana Prodanovic (Department of Astronomy, Faculty of Mathematics, University of Belgrade, Serbia)

This was a poster presented at the 5th Shaw-IAU Workshop on Astronomy for Education, organised by the IAU Office of Astronomy for Education (OAE, http//astro4edu.org).

Besides being a researcher in the field of astrophysics for 20 years, I have also been a science communicator for 15 years. It s my feeling that in that time none of my efforts, and those include organizing science festivals and researchers night attended by 25k visitors, have resulted in such an impact as my TikTok educational astronomy profile (Dr Cosmic Ray) has. In this talk I will present some main benefits and potential that TikTok and similar platforms have for astronomy education in digital space.

About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

Keep up to date with future Shaw-IAU Workshops and other opportunities at the IAU Office of Astronomy for Education by joining our mailing list https://astro4edu.org/mailing-list/

Follow the IAU OAE on X and Facebook under @astro4edu
Response of a dusty plasma system to external charge perturbations
Creators: name: Sarkar, Hitendra
name: Bora, Madhurjya P.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The excitation of nonlinear wave structures in a dusty plasma caused by a moving external charge perturbation is examined in this work, which uses a 1-D flux corrected transport simulation. The plasma responds uniquely to different nature of the moving charge, depending on which, for small amplitude perturbations, pinned envelope solitons are generated and electrostatic dispersive ion-acoustic shock waves are formed for a large amplitude perturbation. The presence of dust particles is found to suppress the formation of dispersive shocks at low velocity of the external charge debris. The results are also investigated theoretically as a solution to the generalized Gross-Piteavskii equation, which broadly supports the simulation results.
description: 19 pages, 11 figures
Trial of Various Astronomical Educational Applications in Japan, a Planetarim Nation
Creators: name: Agata, Hidehiko
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Trial of Various Astronomical Educational Applications in Japan, a Planetarim Nation

Presenter: Hidehiko Agata (NAOJ, Japan)

 

This was a poster presented at the 5th Shaw-IAU Workshop on Astronomy for Education, organised by the IAU Office of Astronomy for Education (OAE, http//astro4edu.org).

There are more than 350 planetarium facilities nationwide in Japan, with an estimated 9 million visitors per year. Planetariums have been important regional centers for astronomy education and promotion for the past 100 years. Of these, school education use accounts for about 20%. However, in addition, mobile planetariums for school visits are now widespread. Furthermore, the educational content taught using planetariums is also diversifying, and we would like to include some examples.

About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

Keep up to date with future Shaw-IAU Workshops and other opportunities at the IAU Office of Astronomy for Education by joining our mailing list https://astro4edu.org/mailing-list/

Follow the IAU OAE on X and Facebook under @astro4edu
title: Analyses of geophysical borehole data of Prees-2 (England) as part of the ICDP JET project
Creators: name:  Leu , Katharina
name:  Wonik , Thomas
name:  Zeeden , Christian
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2021

description: In the end of 2020, an approx. 650 m deep core was drilled at Prees in Shropshire, England, as part of the ICDP project JET (Integrated Understanding of the Early Jurassic Earth System and Timescale). The main objective of this project is to obtain and characterize a complete and continuous sedimentary archive of the 25 million years of the Early Jurassic. The Early Jurassic period (200-175 million years) was a period of extreme environmental changes: Rapid transitions from cold or ice ages to super-greenhouse events have been documented, including global changes in sea level and organic carbon distribution, as well as mass extinctions. Knowledge of this part of the Earth's history is supposed to serve as an analogue for present and future environmental changes. The project will provide a "master record" for an integrated stratigraphy (bio-, cyclo-, chemo- and magnetostratigraphy) of this period. In addition, the project will allow the reconstruction of the local and global palaeoenvironment and the driving mechanisms and feedbacks responsible for environmental changes in the Early Jurassic. The analysis of geophysical borehole measurements contributes to interpretations with respect to the lithological characterization of sediments and their boundaries, but also allows the description of sedimentary cycles related to orbital parameters, insolation and therefore to paleoclimatic history. First results of these borehole measurements include a lithological classification which is based on cluster analysis of solely physical data. Furthermore, core-log integration has been carried out and a first attempt towards astrochronology and cyclostratigraphy has been made.
Double dimensional reduction of M5-brane action in Sen formalism
Creators: name: Phonchantuek, Anajak
name: Vanichchapongjaroen, Pichet
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper, we present double dimensional reduction of the complete M5-brane action in the Sen formalism of self-dual form. Although in this formalism the gravity couples to the independent pseudo-$2$-form and pseudo-$3$-form fields in a non-standard and very complicated way, the double dimensional reduction on the complete action can be carried out. This is by dualising some components of the pseudo-$2$-form field and integrating out the pseudo-$3$-form field. We show explicitly that the double dimensional reduction on a circle gives rise to the complete D4-brane or the complete dual D4-brane action depending on what components of the pseudo-$2$-form field are dualised. The duality between the D4-brane and dual D4-brane actions are realised in the viewpoint of the Sen formalism as the swapping of the roles of the components of the pseudo-$2$-form field between those which are dualised and those which remain. We also make a brief outline on how to generalise this to the cases of dimensional reduction on some other spaces as well as how to understand the duality of reduced action from the viewpoint of the Sen formalism. An explicit example for dimensional reduction of the quadratic six-dimensional action on a torus is given and the realisation of its S-duality is also discussed.
description: 20 pages, no figure; slight edit of texts; Version submitted and accepted by EPJ C
The panchromatic spectroscopic evolution of the classical CO nova V339 Del (Nova Del 2013) until X-ray turnoff
Creators: name: Shore, S. N.
name: Mason, E.
name: Schwarz, G. J.
name: Teyssier, F. M.
name: Buil, C.
name: Aquino, I. De Gennaro
name: Page, K. L.
name: Osborne, J. P.
name: Scaringi, S.
name: Starrfield, S.
name: van Winckel, H.
name: Williams, R. E.
name: Woodward, C. E.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Classical novae are the product of thermonuclear runaway-initiated explosions occurring on accreting white dwarfs. V339 Del (Nova Delphinus 2013) was one of the brightest classical novae of the last hundred years. Spectroscopy and photometry are available from $γ$-rays through infrared at stages that have frequently not been well observed. The complete data set is intended to provide a benchmark for comparison with modeling and for understanding more sparsely monitored historical classical and recurrent novae. This paper is the first in the series of reports on the development of the nova. We report here on the early stages of the outburst, through the X-ray active stage. A time sequence of optical, flux calibrated high resolution spectra was obtained with the Nordic Optical Telescope (NOT) using FIES simultaneously, or contemporaneously, with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope during the early stages of the outburst. These were supplemented with MERCATOR/HERMES optical spectra. High resolution IUE ultraviolet spectra of OS And 1986, taken during the Fe curtain phase, served as a template for the distance determination. We used standard plasma diagnostics (e.g., [O III] and [N II] line ratios, and the H$β$ line flux) to constrain electron densities and temperatures of the ejecta. Using Monte Carlo modeling of the ejecta, we derived the structure, filling factor, and mass from comparisons of the optical and ultraviolet line profiles.
description: 14 pages, 18 figures
Exploring the Secrets of the Cosmos on Foot: Astronomy Clubs and Peripatetism
Creators: name: D'Santiago García, José Antonio
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Exploring the Secrets of the Cosmos on Foot: Astronomy Clubs and Peripatetism

Presenter: José Antonio D'Santiago García (Universidad Nacional Experimental Rafael María Baralt, Venezuela)

 

This was a poster presented at the 5th Shaw-IAU Workshop on Astronomy for Education, organised by the IAU Office of Astronomy for Education (OAE, http//astro4edu.org).

Today in the traditional educational environment, the teaching of astronomy is often limited to the confines of the classroom, based on textbooks and theoretical explanations. This methodology can seem abstract and distant for students, who cannot directly experience celestial phenomena and their connection to the universe.But the world of astronomy is changing. The astronomy and peripatetic clubs, the latter an educational philosophy that proposes learning outside the classroom and in open spaces, using everything that surrounds us as we walk as the main resource for teaching, they have emerged as vehicles for teaching of astronomy beyond the classroom and bring it closer to tangible reality.About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

Keep up to date with future Shaw-IAU Workshops and other opportunities at the IAU Office of Astronomy for Education by joining our mailing list https://astro4edu.org/mailing-list/

Follow the IAU OAE on X and Facebook under @astro4edu
FastDiagP: An Algorithm for Parallelized Direct Diagnosis
Creators: name: Le, Viet-Man
name: Silva, Cristian Vidal
name: Felfernig, Alexander
name: Benavides, David
name: Galindo, José
name: Tran, Thi Ngoc Trang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Constraint-based applications attempt to identify a solution that meets all defined user requirements. If the requirements are inconsistent with the underlying constraint set, algorithms that compute diagnoses for inconsistent constraints should be implemented to help users resolve the "no solution could be found" dilemma. FastDiag is a typical direct diagnosis algorithm that supports diagnosis calculation without predetermining conflicts. However, this approach faces runtime performance issues, especially when analyzing complex and large-scale knowledge bases. In this paper, we propose a novel algorithm, so-called FastDiagP, which is based on the idea of speculative programming. This algorithm extends FastDiag by integrating a parallelization mechanism that anticipates and pre-calculates consistency checks requested by FastDiag. This mechanism helps to provide consistency checks with fast answers and boosts the algorithm's runtime performance. The performance improvements of our proposed algorithm have been shown through empirical results using the Linux-2.6.3.33 configuration knowledge base.
description: presented at The 37th AAAI Conference on Artificial Intelligence, AAAI'23, Washington DC, USA
Little Earth Experiment: an instrument to model planetary cores
Creators: name: Aujogue, Kelig
name: Potherat, Alban
name: Bates, Ian
name: Debray, François
name: Sreenivasan, Binod
Publisher: name: arXiv
Year: 2016
Subjects: subject: Geophysics (physics.geo-ph)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: In this paper, we present a new experimental facility, Little Earth Experiment, designed to study the hydrodynamics of liquid planetary cores. The main novelty of this apparatus is that a transparent electrically conducting electrolyte is subject to extremely high magnetic fields (up to 10T) to produce electromagnetic effects comparable to those produced by moderate magnetic fields in planetary cores. This technique makes it possible to visualise for the first time the coupling between the principal forces in a convection-driven dynamo by means of Particle Image Velocimetry (PIV) in a geometry relevant to planets. We first present the technology that enables us to generate these forces and implement PIV in a high magnetic field environment. We then show that the magnetic field drastically changes the structure of convective plumes in a configuration relevant to the tangent cylinder region of the Earth's core.
description: 9 pages, 9 figures, under review
Frequency Comb Generation in 300 nm Thick SiN Concentric-Racetrack-Resonators: Overcoming the Material Dispersion Limit
Creators: name: Kim, Sangsik
name: Han, Kyunghun
name: Wang, Cong
name: Jaramillo-Villegas, Jose A.
name: Xue, Xiaoxiao
name: Bao, Chengying
name: Xuan, Yi
name: Leaird, Daniel E.
name: Weiner, Andrew M.
name: Qi, Minghao
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Kerr nonlinearity based frequency combs and solitons have been generated from on-chip optical microresonators with high quality factors and global or local anomalous dispersion. However, fabrication of such resonators usually requires materials and/or processes that are not standard in semiconductor manufacturing facilities. Moreover, in certain frequency regimes such as visible and ultra-violet, the large normal material dispersion makes it extremely difficult to achieve anomalous dispersion. Here we present a concentric racetrack-shaped resonator that achieves anomalous dispersion in a 300 nm thick silicon nitride film, suitable for semiconductor manufacturing but previously thought to result only in waveguides with high normal dispersion, a high intrinsic Q of 1.5 million, and a novel mode-selective coupling scheme that allows coherent combs to be generated. We also provide evidence suggestive of soliton-like pulse formation in the generated comb. Our method can achieve anomalous dispersion over moderately broad bandwidth for resonators at almost any wavelength while still maintaining material and process compatibility with high-volume semiconductor manufacturing.
A Survey on Intersectional Fairness in Machine Learning: Notions, Mitigation, and Challenges
Creators: name: Gohar, Usman
name: Cheng, Lu
Publisher: name: arXiv
Year: 2023
Subjects: subject: Machine Learning (cs.LG)
subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: The widespread adoption of Machine Learning systems, especially in more decision-critical applications such as criminal sentencing and bank loans, has led to increased concerns about fairness implications. Algorithms and metrics have been developed to mitigate and measure these discriminations. More recently, works have identified a more challenging form of bias called intersectional bias, which encompasses multiple sensitive attributes, such as race and gender, together. In this survey, we review the state-of-the-art in intersectional fairness. We present a taxonomy for intersectional notions of fairness and mitigation. Finally, we identify the key challenges and provide researchers with guidelines for future directions.
description: IJCAI 2023
Investigation of Transport Properties for FeSe$_{1-x}$Te$_x$ Thin Films under Magnetic Fields
Creators: name: Sawada, Yuichi
name: Nabeshima, Fuyuki
name: Imai, Yoshinori
name: Maeda, Atsutaka
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We investigated the transport properties under magnetic fields of up to 9 T for FeSe$_{1-x}$Te$_x$ thin films on CaF$_2$. Measurements of the temperature dependence of the electrical resistivity revealed that for $x = 0.2 - 0.4$, where $T_{\rm c}$ is the highest, the width of the superconducting transition increased with increasing magnetic field, while the width was almost the same with increasing magnetic field for $x = 0 - 0.1$. In addition, the temperature dependence of the Hall coefficient drastically changed between $x = 0.1$ and $0.2$ at low temperatures. These results indicate that clear differences in the nature of the superconductivity and electronic structure exist between $x=0-0.1$ and $x \ge 0.2$.
description: 10 pages, 5 figures
Dimer-induced heavy-fermion superconductivity in the Shastry-Sutherland Kondo lattice model
Creators: name: Su, Lei
name: Sengupta, Pinaki
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the Kondo lattice model on the geometrically frustrated Shastry-Sutherland lattice focusing on the quantum phase transition between the valence bond solid and the heavy fermion liquid phase. By explicitly including spinon pairing of local moments at the mean-field level, we establish the emergence of a unique heavy fermion superconducting phase induced by dimer ordering of the local moments coexisting with Kondo hybridization. Furthermore, we demonstrate that for suitable choices of parameters, a partial Kondo-screening phase, where some of the valence bonds are broken, precedes the aforementioned dimer-induced superconducting phase. Our results have important implications in understanding the experimental observations in the heavy fermion Shasstry-Sutherland compounds.
description: 8 pages, 7 figures
Local structure, thermodynamics, and melting curve of boron phosphide at high pressures by deep learning-driven ab initio simulations
Creators: name: Chtchelkatchev, N. M.
name: Ryltsev, R. E.
name: Magnitskaya, M. V.
name: Gorbunov, S. M.
name: Cherednichenko, K. A.
name: Solozhenko, V. L.
name: Brazhkin, V. V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: Boron phosphide (BP) is a (super)hard semiconductor constituted of light elements, which is promising for high demand applications at extreme conditions. The behavior of BP at high temperatures and pressures is of special interest but is also poorly understood because both experimental and conventional ab initio methods are restricted to studying refractory covalent materials. The use of machine learning interatomic potentials is a revolutionary trend that gives a unique opportunity for high-temperature study of materials with ab initio accuracy. We develop a deep machine learning potential (DP) for accurate atomistic simulations of solid and liquid phases of BP as well as their transformations near the melting line. Our DP provides quantitative agreement with experimental and ab initio molecular dynamics data for structural and dynamic properties. DP-based simulations reveal that at ambient pressure tetrahedrally bonded cubic BP crystal melts into an open structure consisting of two interpenetrating sub-networks of boron and phosphorous with different structures. Structure transformations of BP melts under compressing are reflected by the evolution of low-pressure tetrahedral coordination to high-pressure octahedral coordination. The main contributions to structural changes at low pressures are made by the evolution of medium-range order in B-subnetwork and at high pressures by the change of short-range order in P-sub-network. Such transformations exhibit an anomalous behavior of structural characteristics in the range of 12--15 GPa. Analysis of the results obtained raise open issues in developing machine learning potentials for covalent materials and stimulate further experimental and theoretical studies of melting behavior in BP.
description: 12 pages, 9 figures
Fast driving between arbitrary states of a quantum particle by trap deformation
Creators: name: Martínez-Garaot, S.
name: Palmero, M.
name: Muga, J. G.
name: Guéry-Odelin, D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: By performing a slow adiabatic change between two traps of a quantum particle, it is possible to transform an eigenstate of the original trap into the corresponding eigenstate of the final trap. If no level crossings are involved, the process can be made faster than adiabatic by setting first the interpolated evolution of the wave function from its initial to its final form and inferring from this evolution the trap deformation. We find a simple and compact formula which gives the trap shape at any time for any interpolation scheme. It is applicable even in complicated scenarios where there is no adiabatic process for the desired state-transformation, e.g., if the state changes its topological properties. We illustrate its use for the expansion of a harmonic trap, for the transformation of a harmonic trap into a linear trap and into an arbitrary number of traps of a periodic structure. Finally, we study the creation of a node exemplified by the passage from the ground state to the first excited state of a harmonic oscillator.
description: 6 pages, 5 figures
FU Orionis outbursts, preferential recondensation of water ice, and the formation of giant planets
Creators: name: Hubbard, Alexander
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Ices, including water ice, prefer to recondense onto pre-existing nuclei rather than spontaneously forming grains from a cloud of vapor. Interestingly, different potential recondensation nuclei have very different propensities to actually nucleate water ice at the temperatures associated with freeze-out in protoplanetary discs. Therefore, if a region in a disc is warmed and then recooled, water vapor should not be expected to refreeze evenly onto all available grains. Instead it will preferentially recondense onto the most favorable grains. When the recooling is slow enough, only the most favorable grains will nucleate ice, allowing them to recondense thick ice mantles. We quantify the conditions for preferential recondensation to rapidly create pebble-sized grains in protoplanetary discs and show that FU Orionis type outbursts have the appropriate cooling rates to drive pebble creation in a band about 5 astronomical units wide outside of the quiescent frost line from approximately Jupiter's orbit to Saturn's (about 4 to 10 au). Those pebbles could be of the appropriate size to proceed to planetesimal formation via the Streaming Instability, or to contribute to the growth of planetesimals through pebble accretion. We suggest that this phenomenon contributed to the formation of the gas giants in our own Solar System.
description: 5 pages, Accepted for publication, MNRAS
Shielding collisions of ultracold CaF molecules with static electric fields
Creators: name: Mukherjee, Bijit
name: Frye, Matthew D.
name: Sueur, C. Ruth Le
name: Tarbutt, Michael R.
name: Hutson, Jeremy M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study collisions of ultracold CaF molecules in strong static electric fields. These fields allow the creation of long-range barriers in the interaction potential, effectively preventing the molecules from reaching the short-range region where inelastic and other loss processes are likely to occur. We carry out coupled-channel calculations of rate coefficients for elastic scattering and loss. We develop an efficient procedure for including energetically well-separated rotor functions in the basis set via a Van Vleck transformation. We show that shielding is particularly efficient for CaF and allows the rate of two-body loss processes to be reduced by a factor of $10^7$ or more at a field of 23 kV/cm. The loss rates remain low over a substantial range of fields. Electron and nuclear spins cause strong additional loss in some small ranges of field, but have little effect elsewhere. These results pave the way for evaporative cooling of CaF towards quantum degeneracy.
description: 18 pages, 21 figures
Discovering Phase Transitions with Unsupervised Learning
Creators: name: Wang, Lei
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Machine Learning (stat.ML)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Unsupervised learning is a discipline of machine learning which aims at discovering patterns in big data sets or classifying the data into several categories without being trained explicitly. We show that unsupervised learning techniques can be readily used to identify phases and phases transitions of many body systems. Starting with raw spin configurations of a prototypical Ising model, we use principal component analysis to extract relevant low dimensional representations the original data and use clustering analysis to identify distinct phases in the feature space. This approach successfully finds out physical concepts such as order parameter and structure factor to be indicators of the phase transition. We discuss future prospects of discovering more complex phases and phase transitions using unsupervised learning techniques.
description: corrected typos, fixed links in references
Bridges Between Cultures: Activities and Meetings About Cultural Astronomy (NASE)
Creators: name: Garcia, Beatriz
Publisher: name: Zenodo
Year: 2023
Subjects: Astronomy Education

description: Title: Bridges Between Cultures: Activities and Meetings About Cultural Astronomy (NASE)

Presenter: Beatriz Garcia (NASE, Spain)

Colaborator:Ricardo Moreno (NASE)Rosa M. Ros (NASE)Ederlinda Viñuales (NASE)

 

This was a poster presented at the 5th Shaw-IAU Workshop on Astronomy for Education, organised by the IAU Office of Astronomy for Education (OAE, http//astro4edu.org).

To commemorate the UNESCO International Day of Light, NASE proposes to all its participants, instructors and referents to carry out simple experiences but of great educational interest. Although the day of light is May 16, the activities can be done from the March to the September equinoxes. The idea started in 2018, inviting people to measure the invisible, performing the Herschel experiment to detect the infrared, and continuing each year until now with different topics. connecting Astronomy and everyday life. This new approach to concepts of Cultural Astronomy has permitted 2 meetings each year, the “Bridges Between Cultures” and “NASE+”. We present here some results of these activities and will show how simple experiences can transform the life of a lot of people on the Globe.About the 5th Shaw-IAU Workshop on Astronomy for Education:This year’s Shaw-IAU Workshop on Astronomy for Education focuses on two themes: one special practical astronomy education topic and one scientific topic. The special topic is astronomy education outside the classroom, looking at how astronomy can be taught in a diverse range of environments such as science centers, planetaria and youth clubs. The scientific topic is planetary atmospheres, both in the solar system and exoplanets as well as our own Earth. The workshop was organised by the IAU Office of Astronomy for Education (http://astro4edu.org). More details can be found on: https://astro4edu.org/shaw-iau/5th-shaw-iau-workshop/schedule/

Keep up to date with future Shaw-IAU Workshops and other opportunities at the IAU Office of Astronomy for Education by joining our mailing list https://astro4edu.org/mailing-list/

Follow the IAU OAE on X and Facebook under @astro4edu
Interacting in-plane molecular dipoles in a zig-zag chain
Creators: name: Wang, Qingyang
name: Otterbach, Johannes
name: Yelin, Susanne F.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The system with externally polarized dipole molecules at half-filling moving along a one-dimensional zig-zag chain is studied theoretically, including the ground-state phase diagram. The dipoles are oriented in-plane. Together with the geometry of the chain this gives rise to a bond-alternating nearest neighbor interaction due to simultaneous attractive and repulsive interactions. Because of the quantum Zeno effect due to the reactive nature of molecules the system can be treated as hard-core. By tuning the ratio between the nearest-neighbor interaction and hopping, various phases can be accessed by controlling the polarization angle. In the ultra-strong coupling limit, the system simplifies to a frustrated extended axial Ising model. For the small coupling limit, qualitative discussion of the ordering behavior using effective field theory arguments is provided. We show that when chain angle is small, the system mostly exhibits BKT-type phase transitions, whereas large chain angle would drive the system into a gapped (Ising) dimerized phase, where the hopping strength is closely related to the orientation of dimerized pairs.
description: 11 pages, 6 figures
Quantum Scar States in Coupled Random Graph Models
Creators: name: Jeevanesan, Bhilahari
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: We analyze the Hilbert space connectivity of the $L$ site PXP-model by constructing the Hamiltonian matrices via a Gray code numbering of basis states. The matrices are all formed out of a single Hamiltonian-path backbone and entries on skew-diagonals. Starting from this observation, we construct an ensemble of related Hamiltonians based on random graphs with tunable constraint degree and variable network topology. We study the entanglement structure of their energy eigenstates and find two classes of weakly-entangled mid-spectrum states. The first class contains scars that are approximate products of eigenstates of the subsystems. Their origin can be traced to the near-orthogonality of random vectors in high-dimensional spaces. The second class of scars has $\log 2$ entanglement entropy and is tied to the occurrence of special types of subgraphs. The latter states have some resemblance to the Lin-Motrunich $\sqrt{2}$-scars.
description: discussion of experiments added; heuristic argument for boxed scars given; references added
Blowout Jets and Impulsive Eruptive Flare in a Bald-Patch Topology
Creators: name: Chandra, R.
name: Mandrini, C. H.
name: Schmieder, B.
name: Joshi, B.
name: Cristiani, G. D.
name: Cremades, H.
name: Pariat, E.
name: Nuevo, F. A.
name: Srivastava, A. K.
name: Uddin, W.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Context: A subclass of broad EUV and X-ray jets, called blowout jets, have become a topic of research since they could be the link between standard collimated jets and CMEs.} Aim: Our aim is to understand the origin of a series of broad jets, some accompanied by flares and associated with narrow and jet-like CMEs. Methods: We analyze observations of a series of recurrent broad jets observed in AR 10484 on 21-24 October 2003. In particular, one of them occurred simultaneously with an M2.4 flare on 23 October at 02:41 UT (SOLA2003-10-23). Both events were observed by ARIES H-alpha Solar Tower-Telescope, TRACE, SOHO, and RHESSI instruments. The flare was very impulsive and followed by a narrow CME. A local force-free model of AR 10484 is the basis to compute its topology. We find bald patches (BPs) at the flare site. This BP topology is present for at least two days before. Large-scale field lines, associated with the BPs, represent open loops. This is confirmed by a global PFSS model. Following the brightest leading edge of the H-alpha and EUV jet emission, we can temporarily associate it with a narrow CME. Results: Considering their characteristics, the observed broad jets appear to be of the blowout class. As the most plausible scenario, we propose that magnetic reconnection could occur at the BP separatrices forced by the destabilization of a continuously reformed flux rope underlying them. The reconnection process could bring the cool flux-rope material into the reconnected open field lines driving the series of recurrent blowout jets and accompanying CMEs. Conclusions: Based on a model of the coronal field, we compute the AR 10484 topology at the location where flaring and blowout jets occurred from 21 to 24 October 2003. This topology can consistently explain the origin of these events.
Determination of intrinsic ferroelectric polarization in lossy improper ferroelectric systems
Creators: name: Chowdhury, Ujjal
name: Goswami, Sudipta
name: Bhattacharya, Dipten
name: Midya, Arindam
name: Mandal, P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We measured the intrinsic hysteretic polarization in lossy improper and nanoferroelectric systems where the nonhysteretic polarization and leakage are large and the relaxation takes place over a broader time scale. We used different measurement protocols such as standard single triangular voltage pulse, a pulse train of PUND (Positive Up Negative Down), and an even more complicated pulse train of fourteen voltage pulses and compared the results obtained. We show that a protocol which sends a train of fourteen pulses is more appropriate for extracting relaxed (i.e., time scale independent) and intrinsic remanent polarization for these samples. We also point out that it is possible to select and design an appropriate measurement protocol depending on the magnitude of polarization and leakage of the system.
description: 5 pages, 6 figures, published in Appl. Phys. Lett
Predictions for Dusty Mass Loss from Asteroids during Close Encounters with Solar Probe Plus
Creators: name: Cranmer, Steven R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The Solar Probe Plus (SPP) mission will explore the Sun's corona and innermost solar wind starting in 2018. The spacecraft will also come close to a number of Mercury-crossing asteroids with perihelia less than 0.3 AU. At small heliocentric distances, these objects may begin to lose mass, thus becoming "active asteroids" with comet-like comae or tails. This paper assembles a database of 97 known Mercury-crossing asteroids that may be encountered by SPP, and it presents estimates of their time-dependent visible-light fluxes and mass loss rates. Assuming a similar efficiency of sky background subtraction as was achieved by STEREO, we find that approximately 80% of these asteroids are bright enough to be observed by the Wide-field Imager for SPP (WISPR). A model of gas/dust mass loss from these asteroids is developed and calibrated against existing observations. This model is used to estimate the visible-light fluxes and spatial extents of spherical comae. Observable dust clouds occur only when the asteroids approach the Sun closer than 0.2 AU. The model predicts that during the primary SPP mission between 2018 and 2025, there should be 113 discrete events (for 24 unique asteroids) during which the modeled comae have angular sizes resolvable by WISPR. The largest of these correspond to asteroids 3200 Phaethon, 137924, 155140, and 289227, all with angular sizes of roughly 15 to 30 arcminutes. We note that the SPP trajectory may still change, but no matter the details there should still be multiple opportunities for fruitful asteroid observations.
description: Accepted for publication in Earth, Moon, and Planets. 28 pages, 12 figures