cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Determination of Biologically Relevant Dosimetric Quantities for HadronTherapy
Creators: name: Magini, Jacopo
Publisher: name: Zenodo
Year: 2020
Subjects: hadrontherapy, protontherapy, mkm, lem

description: Each year, more and more cancer patients are being treated with charged hadrons instead of conventional photon therapy.
 To properly plan treatments with protons it’s important to study their energy deposition at a micrometric scale.
Shear-stress fluctuations in self-assembled transient elastic networks
Creators: name: Wittmer, J. P.
name: Kriuchevskyi, I.
name: Cavallo, A.
name: Xu, H.
name: Baschnagel, J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Focusing on shear-stress fluctuations we investigate numerically a simple generic model for self-assembled transient networks formed by repulsive beads reversibly bridged by ideal springs. With $Δdt$ being the sampling time and $t_*(f) \sim 1/f$ the Maxwell relaxation time (set by the spring recombination frequency $f$) the dimensionless parameter $Δx = dt/t_*(f)$ is systematically scanned from the liquid limit ($Δdx \gg 1)$ to the solid limit ($Δx \ll 1$) where the network topology is quenched and an ensemble average over $m$ independent configurations is required. Generalizing previous work on permanent networks it is shown that the shear-stress relaxation modulus $G(t)$ may be efficiently determined for all $Δx$ using the simple-average expression $G(t) = μ_A - h(t)$ with $μ_A = G(0)$ characterizing the canonical-affine shear transformation of the system at $t=0$ and $h(t)$ the (rescaled) mean-square displacement of the instantaneous shear stress as a function of time $t$. This relation is compared to the standard expression $G(t) = C(t)$ using the (rescaled) shear-stress autocorrelation function $C(t)$. Lower bounds for the $m$ configurations required by both relations are given.
description: 12 pages, 11 figures
Frequency-Selective Geometry Upsampling of Point Clouds
Creators: name: Heimann, Viktoria
name: Spruck, Andreas
name: Kaup, André
Publisher: name: arXiv
Year: 2022
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: The demand for high-resolution point clouds has increased throughout the last years. However, capturing high-resolution point clouds is expensive and thus, frequently replaced by upsampling of low-resolution data. Most state-of-the-art methods are either restricted to a rastered grid, incorporate normal vectors, or are trained for a single use case. We propose to use the frequency selectivity principle, where a frequency model is estimated locally that approximates the surface of the point cloud. Then, additional points are inserted into the approximated surface. Our novel frequency-selective geometry upsampling shows superior results in terms of subjective as well as objective quality compared to state-of-the-art methods for scaling factors of 2 and 4. On average, our proposed method shows a 4.4 times smaller point-to-point error than the second best state-of-the-art PU-Net for a scale factor of 4.
description: 5 pages, 3 figures, International Conference on Image Processing (ICIP) 2022
Radial Velocity Fitting Challenge. I. Simulating the data set including realistic stellar radial-velocity signals
Creators: name: Dumusque, X.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Stellar signals are the main limitation for precise radial-velocity (RV) measurements. These signals arise from the photosphere of the stars. The m/s perturbation created by these signals prevents the detection and mass characterization of small-mass planetary candidates such as Earth-twins. Several methods have been proposed to mitigate stellar signals in RV measurements. However, without precisely knowing the stellar and planetary signals in real observations, it is extremely difficult to test the efficiency of these methods. The goal of the RV fitting challenge is to generate simulated RV data including stellar and planetary signals and to perform a blind test within the community to test the efficiency of the different methods proposed to recover planetary signals despite stellar signals. In this first paper, we describe the simulation used to model the measurements of the RV fitting challenge. Each simulated planetary system includes the signals from instrumental noise, stellar oscillations, granulation, supergranulation, stellar activity, and observed and simulated planetary systems. In addition to RV variations, this simulation also models the effects of instrumental noise and stellar signals on activity observables obtained by HARPS-type high-resolution spectrographs, that is, the calcium activity index log(R'hk) and the bisector span and full width at half maximum of the cross-correlation function. We publish the 15 systems used for the RV fitting challenge including the details about the planetary systems that were injected into each of them (data available at CDS and here: https://rv-challenge.wikispaces.com.
description: 23 pages, 16 figures, accepted for publication in Astronomy and Astrophysics
Revisiting Modality Imbalance In Multimodal Pedestrian Detection
Creators: name: Das, Arindam
name: Das, Sudip
name: Sistu, Ganesh
name: Horgan, Jonathan
name: Bhattacharya, Ujjwal
name: Jones, Edward
name: Glavin, Martin
name: Eising, Ciarán
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Multimodal learning, particularly for pedestrian detection, has recently received emphasis due to its capability to function equally well in several critical autonomous driving scenarios such as low-light, night-time, and adverse weather conditions. However, in most cases, the training distribution largely emphasizes the contribution of one specific input that makes the network biased towards one modality. Hence, the generalization of such models becomes a significant problem where the non-dominant input modality during training could be contributing more to the course of inference. Here, we introduce a novel training setup with regularizer in the multimodal architecture to resolve the problem of this disparity between the modalities. Specifically, our regularizer term helps to make the feature fusion method more robust by considering both the feature extractors equivalently important during the training to extract the multimodal distribution which is referred to as removing the imbalance problem. Furthermore, our decoupling concept of output stream helps the detection task by sharing the spatial sensitive information mutually. Extensive experiments of the proposed method on KAIST and UTokyo datasets shows improvement of the respective state-of-the-art performance.
description: 5 pages, 3 figure, 4 tables
Darboux tranformation and solutions of some integrable systems
Creators: name: Rolania, Dolores Barrios
Publisher: name: arXiv
Year: 2016
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Mathematical Physics (math-ph)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: The relation between the Darboux transformation and the solutions of the full Kostant Toda lattice is analyzed. The discrete Korteweg de Vries equation is used to obtain such solutions and the main result of [1] is extended to the case of general (p + 2)-banded Hessenberg matrices.
Dicke-state preparation through global transverse control of Ising-coupled qubits
Creators: name: Stojanovic, Vladimir M.
name: Nauth, Julian K.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider the problem of engineering the two-excitation Dicke state $|D^{3}_{2}\rangle$ in a three-qubit system with all-to-all Ising-type qubit-qubit interaction, which is also subject to global transverse (Zeeman-type) control fields. The theoretical underpinning for our envisioned state-preparation scheme, in which $|000\rangle$ is adopted as the initial state of the system, is provided by a Lie-algebraic result that guarantees state-to-state controllability of this system for an arbitrary choice of initial- and final states that are invariant with respect to permutations of qubits. This scheme is envisaged in the form of a pulse sequence that involves three instantaneous control pulses, which are equivalent to global qubit rotations, and two Ising-interaction pulses of finite durations between consecutive control pulses. The design of this pulse sequence (whose total duration is $T\approx 0.95\:\hbar/J$, where $J$ is the Ising-coupling strength) leans heavily on the concept of the symmetric sector, a four-dimensional, permutationally-invariant subspace of the three-qubit Hilbert space. We demonstrate the feasibility of the proposed state-preparation scheme by carrying out a detailed numerical analysis of its robustness to systematic errors, i.e. deviations from the optimal values of the eight parameters that characterize the underlying pulse sequence. Finally, we discuss how our proposed scheme can be generalized for engineering Dicke states in systems with $N \ge 4$ qubits. For the sake of illustration, we describe the preparation of the two-excitation Dicke state $|D^{4}_{2}\rangle$ in a four-qubit system.
description: final, published version
Performance analysis of high-resolution ice sheet simulations
Creators: name: Bueler, Ed
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences
subject: 76A05, 86A40, 65M50, 65N55

description: Numerical ice sheet models compute evolving ice geometry and velocity fields using various stress-balance approximations and boundary conditions. At high spatial resolution, with horizontal mesh/grid resolutions of a few kilometers or smaller, these models usually require time steps shorter than climate-coupling time scales because they update ice thickness after each velocity solution. High-resolution performance is degraded by the stability restrictions of such explicit time-stepping. This short note, which considers the shallow ice approximation and Stokes models as stress-balance end members, attempts to clarify numerical model performance by quantifying simulation cost per model year in terms of mesh resolution and the number of degrees of freedom. The performance of current-generation explicit time-stepping models is assessed, and then compared to the prospective performance of implicit schemes. The main result, Table 2, highlights the key roles played by the algorithmic scaling of stress-balance and implicit-step solvers.
description: 6 pages, no figures
Moving Magnetic Features around a Pore
Creators: name: Kaithakkal, A. J.
name: Riethmüller, T. L.
name: Solanki, S. K.
name: Lagg, A.
name: Barthol, P.
name: Gandorfer, A.
name: Gizon, L.
name: Hirzberger, J.
name: vanNoort, M.
name: Rodríguez, J. Blanco
name: Iniesta, J. C. Del Toro
name: Suárez, D. Orozco
name: Schmidt, W.
name: Pillet, V. Martínez
name: Knölker, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Spectropolarimetric observations from Sunrise II/IMaX obtained in June 2013 are used for a statistical analysis to determine the physical properties of moving magnetic features (MMFs) observed near a pore. MMFs of the same and opposite polarity with respect to the pore are found to stream from its border at an average speed of 1.3 km s$^{-1}$ and 1.2 km s$^{-1}$ respectively, with mainly same-polarity MMFs found further away from the pore. MMFs of both polarities are found to harbor rather weak, inclined magnetic fields. Opposite-polarity MMFs are blue-shifted, while same-polarity MMFs do not show any preference for up- or downflows. Most of the MMFs are found to be of sub-arcsecond size and carry a mean flux of $\sim$ 1.2$\times 10^{17}$ Mx.
description: 8 pages, 4 figures, accepted for publication in ApJS
Investigating the Relation between CO (3-2) and Far Infrared Luminosities for Nearby Merging Galaxies Using ASTE
Creators: name: Michiyama, Tomonari
name: Iono, Daisuke
name: Nakanishi, Kouichiro
name: Ueda, Junko
name: Saito, Toshiki
name: Ando, Misaki
name: Kaneko, Hiroyuki
name: Yamashita, Takuji
name: Matsuda, Yuichi
name: Hatsukade, Bunyo
name: Kikuchi, Kenichi
name: Komugi, Shinya
name: Muto, Takayuki
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the new single dish CO (3-2) emission data obtained toward 19 early stage and 7 late stage nearby merging galaxies using the Atacama Submillimeter Telescope Experiment (ASTE). Combining with the single dish and interferometric data of galaxies observed in previous studies, we investigate the relation between the CO (3-2) luminosity (L'CO(3-2)) and the far Infrared luminosity (LFIR) in a sample of 29 early stage and 31 late stage merging galaxies, and 28 nearby isolated spiral galaxies. We find that normal isolated spiral galaxies and merging galaxies have different slopes (alpha) in the log L'CO(3-2) - log LFIR plane (alpha ~ 0.79 for spirals and ~ 1.12 for mergers). The large slope (alpha > 1) for merging galaxies can be interpreted as an evidence for increasing Star Formation Efficiency (SFE=LFIR/L'CO(3-2)) as a function of LFIR. Comparing our results with sub-kpc scale local star formation and global star-burst activity in the high-z Universe, we find deviations from the linear relationship in the log L'CO(3-2) - log LFIR plane for the late stage mergers and high-z star forming galaxies. Finally, we find that the average SFE gradually increases from isolated galaxies, merging galaxies, and to high-z submillimeter galaxies / quasi-stellar objects (SMGs/QSOs). By comparing our findings with the results from numerical simulations, we suggest; (1) inefficient star-bursts triggered by disk-wide dense clumps occur in the early stage of interaction and (2) efficient star-bursts triggered by central concentration of gas occur in the final stage. A systematic high spatial resolution survey of diffuse and dense gas tracers is a key to confirm this scenario.
description: 21 pages, 11 figures, accepted for publication in PASJ
The effects of capital and labour distortion on innovation
Creators: name: Liang, Yidan
Publisher: name: Macquarie University
Year: 2022
Subjects: Other education not elsewhere classified

description: Factor misallocation has significant effects on productivity and innovation (Bento and Restuccia, 2017). In addition, aggregate total factor productivity could be lowered by factor misallocation across heterogeneous production units (Restuccia and Rogerson, 2013). Factor misallocation not only has important effects on productivity, but also plays a significant role in innovation (Bai and Bian, 2016). Innovation is widely regarded as the most important element for economic growth (Feldman and Link, 2001; Guellec and Potterie, 2004; Chen et al., 2015). The purpose of this thesis is to study how capital distortions and labour distortions influence innovation activities in China. Province-level data is manually collected from the China Statistical Yearbook and the China Statistical Yearbook on Science and Technology. This research applies the generalized least square (GLS) method with province and year fixed effects, the Generalized Method of Moments (GMM) model with introduced instrumental variables, and a natural experiment with an exogenous shock. The results indicate that the measurements for factor misallocation – capital distortion and labour distortion - are significantly negatively correlated to innovation. The findings have important implications for emerging countries to improve their innovation productivity.
Probing the Stellar Wind of the Wolf-Rayet Star in IC 10 X-1
Creators: name: Bhattacharya, Sayantan
name: Laycock, Silas G. T.
name: Chene, Andre-Nicolas
name: Binder, Breanna A.
name: Christodoulou, Dimitris M.
name: Roy, Ankur
name: Sorabella, Nicholas M.
name: Cappallo, Rigel C.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: IC 10 X-1 is an eclipsing high mass X-ray binary (HMXB) containing a stellar-mass black hole (BH) and a Wolf-Rayet (WR) donor star with an orbital period of P = 34.9 hr. This binary belongs to a group of systems that can be the progenitors of gravitational wave sources, hence understanding the dynamics of systems such as IC 10 X-1 is of paramount importance. The prominent He II 4686 emission line (previously used in mass estimates of the BH) is out of phase with the X-ray eclipse, suggesting that this line originates somewhere in the ionized wind of the WR star or in the accretion disk. We obtained 52 spectra from the GEMINI/GMOS archive, observed between 2001 and 2019. We analyzed the spectra both individually, and after binning them by orbital phase to improve the signal-to-noise ratio. The RV curve from the stacked data is similar to historical results, indicating the overall parameters of the binary have remained constant. However, the He II line profile shows a correlation with the X-ray hardness-ratio values, also, we report a pronounced skewness of the line-profile, and the skewness varies with the orbital phase. These results support a paradigm wherein the He II line tracks structures in the stellar wind that are produced by interactions with the BH's ionizing radiation and the accretion flow. We compare the observable signatures of two alternative hypotheses proposed in the literature: wind irradiation plus shadowing, and accretion disk hotspot; and we explore how the line-profile variations fit into each of these models.
description: 10 pages, 5 figures, 2 tables, ApJ Accepted
Efficient computation of rankings from pairwise comparisons
Creators: name: Newman, M. E. J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (stat.ML)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: We study the ranking of individuals, teams, or objects, based on pairwise comparisons between them, using the Bradley-Terry model. Estimates of rankings within this model are commonly made using a simple iterative algorithm first introduced by Zermelo almost a century ago. Here we describe an alternative and similarly simple iteration that provably returns identical results but does so much faster -- over a hundred times faster in some cases. We demonstrate this algorithm with applications to a range of example data sets and derive a number of results regarding its convergence.
description: 25 pages, 1 figure, 1 table; additional material on MAP estimation and rates of convergence
A study of the effect of rotational mixing on massive stars evolution: surface abundances of Galactic O7-8 giant stars
Creators: name: Martins, F.
name: Simon-Diaz, S.
name: Barba, R. H.
name: Gamen, R. C.
name: Ekstroem, S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Massive star evolution remains only partly constrained. In particular, the exact role of rotation has been questioned by puzzling properties of OB stars in the Magellanic Clouds. Our goal is to study the relation between surface chemical composition and rotational velocity, and to test predictions of evolutionary models including rotation. We have performed a spectroscopic analysis of a sample of fifteen Galactic O7-8 giant stars. This sample is homogeneous in terms of mass, metallicity and evolutionary state. It is made of stars with a wide range of projected rotational velocities. We show that the sample stars are located on the second half of the main sequence, in a relatively narrow mass range (25-40 Msun). Almost all stars with projected rotational velocities above 100 km/s have N/C ratios about ten times the initial value. Below 100 km/s a wide range of N/C values is observed. The relation between N/C and surface gravity is well reproduced by various sets of models. Some evolutionary models including rotation are also able to consistently explain slowly rotating, highly enriched stars. This is due to differential rotation which efficiently transports nucleosynthesis products and allows the surface to rotate slower than the core. In addition, angular momentum removal by winds amplifies surface braking on the main sequence. Comparison of the surface composition of O7-8 giant stars with a sample of B stars with initial masses about four times smaller reveal that chemical enrichment scales with initial mass, as expected from theory. Although evolutionary models that include rotation face difficulties in explaining the chemical properties of O- and B-type stars at low metallicity, some of them can consistently account for the properties of main-sequence Galactic O stars in the mass range 25-40 Msun
description: 14 pages, 10 figures + appendix , A&A accepted
Accurate first-principle bandgap predictions in strain-engineered ternary III-V semiconductors
Creators: name: Mondal, Badal
name: Kröner, Marcel
name: Hepp, Thilo
name: Volz, Kerstin
name: Tonner-Zech, Ralf
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Tuning the bandgap in ternary III-V semiconductors via modification of the composition or the strain in the material is a major approach for the design of optoelectronic materials. Experimental approaches screening a large range of possible target structures are hampered by the tremendous effort to optimize the material synthesis for every target structure. We present an approach based on density functional theory efficiently capable of providing the bandgap as a function of composition and strain. Using a specific density functional designed for accurate bandgap computation (TB09) together with a band unfolding procedure and special quasirandom structures, we develop a computational protocol efficiently able to predict bandgaps. The approach's accuracy is validated by comparison to selected experimental data. We thus map the phase space of composition and strain (we call this the ``bandgap phase diagram'') for several important III-V compound semiconductors: GaAsP, GaAsN, GaPSb, GaAsSb, GaPBi, and GaAsBi. We show the application of these diagrams for identifying the most promising materials for device design. Furthermore, our computational protocol can easily be generalized to explore the vast chemical space of III-V materials with all other possible combinations of III- and V-elements.
description: 13 pages, 7 figures, GitHub (https://bmondal94.github.io/Bandgap-Phase-Diagram/)
Radiation and Polarization Signatures of 3D Multi-zone Time-dependent Hadronic Blazar Model
Creators: name: Zhang, Haocheng
name: Diltz, Chris
name: Böttcher, Markus
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present a newly developed time-dependent three-dimensional multi-zone hadronic blazar emission model. By coupling a Fokker-Planck based lepto-hadronic particle evolution code 3DHad with a polarization-dependent radiation transfer code, 3DPol, we are able to study the time-dependent radiation and polarization signatures of a hadronic blazar model for the first time. Our current code is limited to parameter regimes in which the hadronic $γ$-ray output is dominated by proton synchrotron emission, neglecting pion production. Our results demonstrate that the time-dependent flux and polarization signatures are generally dominated by the relation between the synchrotron cooling and the light crossing time scale, which is largely independent of the exact model parameters. We find that unlike the low-energy polarization signatures, which can vary rapidly in time, the high-energy polarization signatures appear stable. As a result, future high-energy polarimeters may be able to distinguish such signatures from the lower and more rapidly variable polarization signatures expected in leptonic models.
description: Accepted for Publication in The Astrophysical Journal
The Use of the “Useless Aesthetics:” a quest for non-utilitarian spiritual healing
Creators: name: Tong, Yumeng
Publisher: name: University of Chicago
Year: 2022
Subjects: subject: Aesthetics
subject: Culture
subject: Critical Theory
subject: Photography
subject: China

description: When the internet and social networking sites became a part of modern urban life, extensive research across social sciences has studied the motivation for participating in them; on the other hand, the mass aesthetic practice was a valid topic for philosophers even in ancient times. However, few studies combine those two topics to understand online artistic practices. The theoretical debate on mass art practices has often fallen into the dichotomy between the elite/capitalism industry and the repressed masses without digging into its subtlety. What should online mass artistic practice be like if decoupled from capitalism, and why would people join an online group where information exchange, sociality, and solidarity are not primary motivations? As a response, this study uses semi-structured qualitative interviews with active participants in a Douban (a Chinese Social Networking Site) group named “useless aesthetics,” whose members share the pictures that they regard as having pure aesthetic value without “utility” to fill the gaps in the previous two trends of discussions. The study demonstrates that the central motivation for participating in the online aesthetic group is to affirm a lifestyle of being perceptive and enamored with everyday experiences and rejecting mainstream thinking governed by the mere utility or material achievement. The participants need to demonstrate their affirmation through various techniques in their posts. However, as Adorno argued in his Aesthetic Theory, this potential power of art (in this study, the lifestyle) might not be achieved in reality and only manifests itself in an ideal. When the artistic lifestyle temporarily calls the participants, they might regard themselves as being healed from the utilitarian pressure; when the participants are continually on the stage free from the utilitarian pressure, they might, as a healer, radiate their spiritual brightness to others through posting.
Variational deep learning of equilibrium transition path ensembles
Creators: name: Singh, Aditya N.
name: Limmer, David T.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We present a time dependent variational method to learn the mechanisms of equilibrium reactive processes and efficiently evaluate their rates within a transition path ensemble. This approach builds off variational path sampling methodology by approximating the time dependent commitment probability within a neural network ansatz. The reaction mechanisms inferred through this approach are elucidated by a novel decomposition of the rate in terms of the components of a stochastic path action conditioned on a transition. This decomposition affords an ability to resolve the typical contribution of each reactive mode and their couplings to the rare event. The associated rate evaluation is variational and systematically improvable through the development of a cumulant expansion. We demonstrate this method in both over- and under-damped stochastic equations of motion, in low-dimensional model systems and the isomerization of solvated alanine dipeptide. In all examples, we find that we can obtain quantitatively accurate estimates of the rates of the reactive events with minimal trajectory statistics, and gain unique insight into the transitions through the analysis of their commitment probability.
X-Ray Emitting Active Galactic Nuclei from z = 0.6-1.3 in the Intermediate and High-Density Environments of the ORELSE Survey
Creators: name: Rumbaugh, N.
name: Lemaux, B.
name: Tomczak, A.
name: Kocevski, D.
name: Lubin, L.
name: Wu, P. -F.
name: Gal, R.
name: Shen, L.
name: Mansheim, A.
name: Fassnacht, C.
name: Squires, G.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We studied AGN activity in twelve LSSs in the ORELSE survey, at 0.65
description: 26 pages, 8 figures, submitted to MNRAS
Composite Optimization Algorithms for Sigmoid Networks
Creators: name: Chen, Huixiong
name: Ye, Qi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optimization and Control (math.OC)
subject: Machine Learning (cs.LG)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: In this paper, we use composite optimization algorithms to solve sigmoid networks. We equivalently transfer the sigmoid networks to a convex composite optimization and propose the composite optimization algorithms based on the linearized proximal algorithms and the alternating direction method of multipliers. Under the assumptions of the weak sharp minima and the regularity condition, the algorithm is guaranteed to converge to a globally optimal solution of the objective function even in the case of non-convex and non-smooth problems. Furthermore, the convergence results can be directly related to the amount of training data and provide a general guide for setting the size of sigmoid networks. Numerical experiments on Franke's function fitting and handwritten digit recognition show that the proposed algorithms perform satisfactorily and robustly.
A note on asymptotic profiles for the thermoelastic plate system
Creators: name: Chen, Wenhui
name: Liu, Yan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We investigate the Cauchy problem for the thermoelastic plate system associated with Newton's law of cooling, where optimal growth ($n\leqslant 4$) or decay ($n\geqslant 5$) estimates and asymptotic profiles of solutions for large-time are studied. Especially, the additional lower-order term in the temperature equation weakens decay rates of the vertical displacement, and leads to a new leading term comparing with the classical thermoelastic plates.
In-beam measurement of the hydrogen hyperfine splitting - towards antihydrogen spectroscopy
Creators: name: Diermaier, M.
name: Jepsen, C. B.
name: Kolbinger, B.
name: Malbrunot, C.
name: Massiczek, O.
name: Sauerzopf, C.
name: Simon, M. C.
name: Zmeskal, J.
name: Widmann, E.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison to hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of $ν_\mathrm{HF}$=$1~420~405~748.4(3.4)(1.6)~\textrm{Hz}$ with a relative precision of $Δ$$ν_\mathrm{HF}$/$ν_\mathrm{HF}$=$2.7\times10^{-9}$ constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the ppb level. Together with the recently presented observation of antihydrogen atoms $2.7~\textrm{m}$ downstream of the production region, the prerequisites for a measurement with antihydrogen are now available within the ASACUSA collaboration.
The CR umbilical locus of a real ellipsoid in $\mathbb{C}^2$
Creators: name: Son, Duong Ngoc
Publisher: name: arXiv
Year: 2022
Subjects: subject: Complex Variables (math.CV)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: This paper concerns the CR umbilical locus of a real ellipsoid in $\mathbb{C}^2$, the set of points at which the ellipsoid can be osculated by a biholomorphic image of the sphere up to 6th order. Huang and Ji proved that this locus is non-empty. Ebenfelt and Zaitsev proved that, for ellipsoids that are sufficiently "closed" to the sphere, the locus actually contains a "stable" curve of umbilical points. Foo, Merker and Ta later provided an explicit curve that is contained in it. The main result in this paper exhibits that the umbilical locus is the union of the curves mentioned above and a non-trivial real variety which is defined by two homogeneous real sextic equations of four real variables. When there are suitable pairs of equal semi-axes, one of them factors allowing us to determine the locus explicitly.
description: minor improvements, 17 pages
Review on carrier multiplication in graphene
Creators: name: Malic, Ermin
name: Winzer, Torben
name: Wendler, Florian
name: Knorr, Andreas
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The remarkable gapless and linear band structure of graphene opens up new carrier relaxation channels bridging the valence and the conduction band. These Auger scattering processes change the number of charge carriers and can give rise to a significant multiplication of optically excited carriers in graphene. This is an ultrafast many-particle phenomenon that is of great interest both for fundamental many-particle physics as well as technological applications. Here, we review the research on carrier multiplication in graphene and Landau-quantized graphene including theoretical modelling and experimental demonstration.
Spin-valley magnetism on the triangular moiré lattice with SU(4) breaking interactions
Creators: name: Gresista, Lasse
name: Kiese, Dominik
name: Trebst, Simon
name: Scherer, Michael M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The discovery of correlated insulating states in moiré heterostructures has renewed the interest in strongly-coupled electron systems where spin and valley (or layer) degrees of freedom are intertwined. In the strong-coupling limit, such systems can be effectively described by SU(4) spin-valley models akin to Kugel-Khomskii models long studied in the context of spin-orbit coupled materials. However, typical moiré heterostructures also exhibit interactions that break the SU(4) symmetry down to SU(2)${}_{\mathrm{spin}}\otimes$U(1)${}_{\mathrm{valley}}$. Here we investigate the impact of such symmetry-breaking couplings on the magnetic phase diagram for triangular superlattices considering a filling of two electrons (or holes) per moiré unit cell. We explore a broad regime of couplings -- including XXZ anisotropies, Dzyaloshinskii-Moriya exchange and on-site Hund's couplings -- using semi-classical Monte Carlo simulations. We find a multitude of classically ordered phases, including (anti-)ferromagnetic, incommensurate, and stripe order, manifesting in different sectors of the spin-valley model's parameter space. Zooming in on the regimes where quantum fluctuations are likely to have an effect, we employ pseudo-fermion functional renormalization group (pf-FRG) calculations to resolve quantum disordered ground states such as spin-valley liquids, which we indeed find for certain parameter regimes. As a concrete example, we discuss the case of trilayer graphene aligned with hexagonal boron nitride using material-specific parameters.
description: 20 pages, 16 figures
Relativistic distortions in galaxy density-ellipticity correlations: gravitational redshift and peculiar velocity effects
Creators: name: Saga, Shohei
name: Okumura, Teppei
name: Taruya, Atsushi
name: Inoue, Takuya
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study relativistic effects, arising from the light propagation in an inhomogeneous universe. We particularly investigate the effects imprinted in a cross-correlation function between galaxy positions and intrinsic galaxy shapes (GI correlation). Considering the Doppler and gravitational redshift effects as major relativistic effects, we present an analytical model of the GI correlation function, from which we find that the relativistic effects induce non-vanishing odd multipole anisotropies. Focusing particularly on the dipole anisotropy, we show that the Doppler effect dominates at large scales, while the gravitational redshift effect originated from the halo potential dominates at the scales below $10$-$30\, {\rm Mpc}/h$, with the amplitude of the dipole GI correlation being positive over all the scales. Also, we newly derive the covariance matrix for the modelled GI dipole. Taking into account the full covariance, we estimate the signal-to-noise ratio and show that the GI dipole induced by the relativistic effects is detectable in future large-volume galaxy surveys. We discuss how the measurement of dipole GI correlation could be helpful to detect relativistic effects in combination with the conventional galaxy-galaxy cross correlation.
description: 16 pages, 7 figures
Low frequency observations of transient quasi-periodic radio emission from the solar atmosphere
Creators: name: Raja, K. Sasikumar
name: Ramesh, R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We report low frequency observations of the quasi-periodic, circularly polarized, harmonic type III radio bursts whose associated sunspot active regions were located close to the solar limb. The measured periodicity of the bursts at 80 MHz was $\approx$ 5.2 s and their average degree of circular polarization ($dcp$) was $\approx 0.12$. We calculated the associated magnetic field $B$ : (1) using the empirical relationship between the $dcp$ and $B$ for the harmonic type III emission, and (2) from the observed quasi-periodicity of the bursts. Both the methods result in $B \approx$ 4.2 G at the location of the 80 MHz plasma level (radial distance $r \approx 1.3~\rm R_{\odot}$) in the active region corona.
description: Published in Astrophysical Journal
Supernova fast flavor conversions in 1+1D : Influence of mu-tau neutrinos
Creators: name: Capozzi, Francesco
name: Chakraborty, Madhurima
name: Chakraborty, Sovan
name: Sen, Manibrata
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In the dense supernova environment, neutrinos can undergo fast flavor conversions which depend on the large neutrino-neutrino interaction strength. It has been recently shown that both their presence and outcome can be affected when passing from the commonly used three neutrino species approach to the more general one with six species. Here, we build up on a previous work performed on this topic and perform a numerical simulation of flavor evolution in both space and time, assuming six neutrino species. We find that the results presented in our previous work remain qualitatively the same even for flavor evolution in space and time. This emphasizes the need for going beyond the simplistic approximation with three species when studying fast flavor conversions.
description: 9 pages, 3 figures
Causal Conceptions of Fairness and their Consequences
Creators: name: Nilforoshan, Hamed
name: Gaebler, Johann
name: Shroff, Ravi
name: Goel, Sharad
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: Recent work highlights the role of causality in designing equitable decision-making algorithms. It is not immediately clear, however, how existing causal conceptions of fairness relate to one another, or what the consequences are of using these definitions as design principles. Here, we first assemble and categorize popular causal definitions of algorithmic fairness into two broad families: (1) those that constrain the effects of decisions on counterfactual disparities; and (2) those that constrain the effects of legally protected characteristics, like race and gender, on decisions. We then show, analytically and empirically, that both families of definitions \emph{almost always} -- in a measure theoretic sense -- result in strongly Pareto dominated decision policies, meaning there is an alternative, unconstrained policy favored by every stakeholder with preferences drawn from a large, natural class. For example, in the case of college admissions decisions, policies constrained to satisfy causal fairness definitions would be disfavored by every stakeholder with neutral or positive preferences for both academic preparedness and diversity. Indeed, under a prominent definition of causal fairness, we prove the resulting policies require admitting all students with the same probability, regardless of academic qualifications or group membership. Our results highlight formal limitations and potential adverse consequences of common mathematical notions of causal fairness.
description: ICML 2022. arXiv admin note: substantial text overlap with arXiv:1808.00023
Long-range charge density wave proximity effect at cuprate-manganate interfaces
Creators: name: Frano, A.
name: Blanco-Canosa, S.
name: Schierle, E.
name: Lu, Y.
name: Wu, M.
name: Bluschke, M.
name: Minola, M.
name: Christiani, G.
name: Habermeier, H. U.
name: Logvenov, G.
name: Wang, Y.
name: van Aken, P. A.
name: Benckiser, E.
name: Weschke, E.
name: Tacon, M. Le
name: Keimer, B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The interplay between charge density waves (CDWs) and high-temperature superconductivity is currently under intense investigation. Experimental research on this issue is difficult because CDW formation in bulk copper-oxides is strongly influenced by random disorder, and a long-range-ordered CDW state in high magnetic fields is difficult to access with spectroscopic and diffraction probes. Here we use resonant x-ray scattering in zero magnetic field to show that interfaces with the metallic ferromagnet La$_{2/3}$Ca$_{1/3}$MnO$_3$ greatly enhance CDW formation in the optimally doped high-temperature superconductor YBa$_2$Cu$_3$O$_{6+δ}$ ($\bf δ\sim 1$), and that this effect persists over several tens of nm. The wavevector of the incommensurate CDW serves as an internal calibration standard of the charge carrier concentration, which allows us to rule out any significant influence of oxygen non-stoichiometry, and to attribute the observed phenomenon to a genuine electronic proximity effect. Long-range proximity effects induced by heterointerfaces thus offer a powerful method to stabilize the charge density wave state in the cuprates, and more generally, to manipulate the interplay between different collective phenomena in metal oxides.
description: modified version published in Nature Materials
Dark Matter Annihilation inside Large Volume Neutrino Detectors
Creators: name: McKeen, David
name: Morrissey, David E.
name: Pospelov, Maxim
name: Ramani, Harikrishnan
name: Ray, Anupam
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: New particles in theories beyond the standard model can manifest as stable relics that interact strongly with visible matter and make up a small fraction of the total dark matter abundance. Such particles represent an interesting physics target since they can evade existing bounds from direct detection due to their rapid thermalization in high-density environments. In this work we point out that their annihilation to visible matter inside large-volume neutrino telescopes can provide a new way to constrain or discover such particles. The signal is the most pronounced for relic masses in the GeV range, and can be efficiently constrained by existing Super-Kamiokande searches for di-nucleon annihilation. We also provide an explicit realization of this scenario in the form of secluded dark matter coupled to a dark photon, and we show that the present method implies novel and stringent bounds on the model that are complementary to direct constraints from beam dumps, colliders, and direct detection experiments.
description: v2: 7 pages, 2 figures. Conclusions Unchanged. Matches version Published in Physical Review Letters
Partition function on spheres: how (not) to use zeta function regularization
Creators: name: Monin, A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: It is known that not all summation methods are linear and stable. Zeta function regularization is in general non-linear. However, in some cases formal manipulations with "zeta function" regularization (assuming linearity of sums) lead to correct results. We consider several examples and show why this happens.
description: 20 pages
An algebraic characterization of self-generating chemical reaction networks using semigroup models
Creators: name: Loutchko, Dimitri
Publisher: name: arXiv
Year: 2022
Subjects: subject: Molecular Networks (q-bio.MN)
subject: Combinatorics (math.CO)
subject: Rings and Algebras (math.RA)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Biological sciences
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: The ability of a chemical reaction network to generate itself by catalyzed reactions from constantly present environmental food sources is considered a fundamental property in origin-of-life research. Based on Kaufmann's autocatalytic sets, Hordijk and Steel have constructed the versatile formalism of catalytic reaction systems (CRS) to model and to analyze such self-generating networks, which they named reflexively autocatalytic and food generated (RAF). Previously, it was established that the subsequent and simultaenous catalytic functions of the chemicals of a CRS give rise to an algebraic structure, termed a semigroup model. The semigroup model allows to naturally consider the function of any subset of chemicals on the whole CRS. This gives rise to a generative dynamics by iteratively applying the function of a subset to the externally supplied food set. The fixed point of this dynamics yields the maximal self-generating set of chemicals. Moreover, the lattice of all functionally closed self-generating sets of chemicals is discussed and a structure theorem for this lattice is proven. It is also shown that a CRS which contains self-generating sets of chemicals cannot be nilpotent and thus a useful link to the combinatorial theory of finite semigroups is established. The main technical tool introduced and utilized in this work is the representation of the semigroup elements as decorated rooted trees, allowing to translate the generation of chemicals from a given set of resources into the semigroup language.
description: 33 pages, 6 figures