cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Semi-analytic forecasts for Roman -- the beginning of a new era of deep-wide galaxy surveys
Creators: name: Yung, L. Y. Aaron
name: Somerville, Rachel S.
name: Finkelstein, Steven L.
name: Behroozi, Peter
name: Davé, Romeel
name: Ferguson, Henry C.
name: Gardner, Jonathan P.
name: Popping, Gergö
name: Malhotra, Sangeeta
name: Papovich, Casey
name: Rhoads, James E.
name: Bagley, Micaela B.
name: Hirschmann, Michaela
name: Koekemoer, Anton M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The Nancy Grace Roman Space Telescope, NASA's next flagship observatory, will redefine deep-field galaxy survey with a field of view two orders of magnitude larger than Hubble and an angular resolution of matching quality. These future deep-wide galaxy surveys necessitate new simulations to forecast their scientific output and to optimise survey strategies. In this work, we present five realizations of 2-deg^2 lightcones, containing a total of >25 million simulated galaxies with -16 < MUV < -25 spanning z ~ 0 to 10. This dataset enables a new set of experiments with the impacts of survey size on the derived galaxy formation and cosmological constraints. The intrinsic and observable galaxy properties are predicted using a well-established, physics-based semi-analytic modelling approach. We provide forecasts for number density, cosmic SFR, field-to-field variance, and angular two-point correlation functions, and demonstrate how the future wide-field surveys will be able to improve these measurements relative to current generation surveys. We also present a comparison between these lightcones and others that have been constructed with empirical models. The mock lightcones are designed to facilitate the exploration of multi-instrument synergies and connecting with current generation instruments and legacy surveys. In addition to Roman, we also provide photometry for a number of other instruments on upcoming facilities, including Euclid and Rubin, as well as the instruments that are part of many legacy surveys. Full object catalogues and data tables for the results presented in this work are made available through a web-based, interactive portal https://www.simonsfoundation.org/semi-analytic-forecasts.
description: 25 pages, 16 figures. Accepted for publication in MNRAS
Robust Control Co-Design with Receding-Horizon MPC
Creators: name: Nash, Austin L.
name: Pangborn, Herschel C.
name: Jain, Neera
Publisher: name: arXiv
Year: 2021
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Control co-design (CCD) is a technique for improving the closed-loop performance of systems through the coordinated design of both plant parameters and an optimal control policy. While model predictive control (MPC) is an attractive control strategy for many systems, embedding it within a CCD algorithm presents challenges because obtaining a closed-form solution for this receding-horizon optimization strategy is often not feasible. This paper meets that challenge by including a robust MPC formulation within the inner loop of a CCD algorithm. As exemplified by application to an aircraft thermal management system, the proposed algorithm closely matches the plant design of an open-loop benchmark. However, unlike the open-loop approach, the proposed algorithm can leverage MPC control variables designed a priori to achieve robust online operation under disturbance profiles that differ from those used for design.
Strategy for designing broadband epsilon-near-zero metamaterial with loss compensation by gain media
Creators: name: Sun, Lei
name: Yu, Kin Wah
Publisher: name: arXiv
Year: 2012
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: A strategy is proposed to design the broadband gain-doped epsilon-near-zero (GENZ) metamaterial. Based on the Milton representation of effective permittivity, the strategy starts in a dimensionless spectral space, where the effective permittivity of GENZ metamaterial is simply determined by a pole-zero structure corresponding to the operating frequency range. The physical structure of GENZ metamaterial is retrieved from the pole-zero structure via a tractable inverse problem. The strategy is of great advantage in practical applications and also theoretically reveals the cancellation mechanism dominating the broadband near-zero permittivity phenomenon in the spectral space.
Matter traveling through a wormhole
Creators: name: Calhoun, Karina
name: Fay, Brendan
name: Kain, Ben
Publisher: name: arXiv
Year: 2022
Subjects: 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 revisit the numerical evolution of Ellis-Bronnikov-Morris-Thorne wormholes, which are constructed with a massless real ghost scalar field. For our simulations, we have developed a new code based on the standard 3+1 foliation of spacetime. We confirm that, for the massless symmetric wormhole, a pulse of regular scalar field causes the wormhole throat to collapse and form an apparent horizon, while a pulse of ghost scalar field can cause the wormhole throat to expand. As a new result, we show that it is possible for a pulse of regular matter to travel through the wormhole and then to send a light signal back before the wormhole collapses. We also evolve pulses of matter traveling through massive asymmetric wormholes, which has not previously been simulated.
description: 11 pages, 9 figures; v2: references added
On the pulse-width statistics in radio pulsars. II. Importance of the core profile components
Creators: name: Maciesiak, Krzysztof
name: Gil, Janusz
Publisher: name: arXiv
Year: 2011
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We performed a statistical analysis of half-power pulse-widths of the core components in average pulsar profiles. We confirmed an existence of the lower bound of the distribution of half-power pulse-width versus the pulsar period W50~2.45deg P^(-0.5) found by Rankin (1990). Using our much larger database we found W50= (2.51 +/- 0.08)deg P^(-0.50 +/-0.02) for 21 pulsars with double-pole interpulses for which measurement of the core component width was possible. On the other hand, all single-pole interpulse cases lie in the swarm of pulsars above the boundary line. Using the Monte Carlo simulations based on exact geometrical calculations we found that the Rankin's method of estimation of the inclination angle alpha ~ asin(2.45deg P^(-0.5)/W50) in pulsars with core components is quite good an approximation, except for very small angles alpha in almost aligned rotators.
description: 14 pages, 11 figures; Accepted for publication in MNRAS
On the benefit of overparameterization in state reconstruction
Creators: name: Haderlein, Jonas F.
name: Mareels, Iven M. Y.
name: Peterson, Andre
name: Eskikand, Parvin Zarei
name: Burkitt, Anthony N.
name: Grayden, David B.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: The identification of states and parameters from noisy measurements of a dynamical system is of great practical significance and has received a lot of attention. Classically, this problem is expressed as optimization over a class of models. This work presents such a method, where we augment the system in such a way that there is no distinction between parameter and state reconstruction. We pose the resulting problem as a batch problem: given the model, reconstruct the state from a finite sequence of output measurements. In the case the model is linear, we derive an analytical expression for the state reconstruction given the model and the output measurements. Importantly, we estimate the state trajectory in its entirety and do not aim to estimate just an initial condition: that is, we use more degrees of freedom than strictly necessary in the optimization step. This particular approach can be reinterpreted as training of a neural network that estimates the state trajectory from available measurements. The technology associated with neural network optimization/training allows an easy extension to nonlinear models. The proposed framework is relatively easy to implement, does not depend on an informed initial guess, and provides an estimate for the state trajectory (which incorporates an estimate for the unknown parameters) over a given finite time horizon.
Confidence disc and square for Cauchy distributions
Creators: name: Akaoka, Yuichi
name: Okamura, Kazuki
name: Otobe, Yoshiki
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62F25

description: We will construct a confidence region of parameters for a sample of size $N$ from Cauchy distributed random variables. Although Cauchy distribution has two parameters, a location parameter $μ\in \mathbb{R}$ and a scale parameter $σ> 0$, we will infer them at once by regarding them as a single complex parameter $γ:= μ+ iσ$. The region should be a domain in the complex plane, and we will give a simple and concrete formula to give the region as a disc and a square.
description: v4, 15 pages, 6 figures, typo in Eq. (3) corrected, some unnecessary columns in Figures 2,3,5 and 6 deleted, to appear in Ukrainian Mathematical Journal
The Galactic Chemical Evolution of phosphorus observed with IGRINS
Creators: name: Nandakumar, G.
name: Ryde, N.
name: Montelius, M.
name: Thorsbro, B.
name: Jönsson, H.
name: Mace, G.
name: Observatory, Lund
name: Astronomy, Department of
name: Physics, Theoretical
name: University, Lund
name: 43, Box
name: Lund, SE-221 00
name: Sweden
name: Institute, Kapteyn Astronomical
name: Groningen, University of
name: 12, Landleven
name: Groningen, NL-9747 AD
name: Netherlands, the
name: Astronomy, Department of
name: Science, School of
name: Tokyo, The University of
name: Hongo, 7-3-1
name: Bunkyo-Ku
name: 113-0033, Tokyo
name: Japan
name: Science, Materials
name: Mathematics, Applied
name: University, Malmö
name: Malmö, SE-205 06
name: Sweden
name: Astronomy, Department of
name: Observatory, McDonald
name: Texas, The University of
name: Austin
name: 78712, TX
name: USA
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Phosphorus (P) is considered to be one of the key elements for life, making it an important element to look for in the abundance analysis of spectra of stellar systems. Yet, there exists only a handful of spectroscopic studies to estimate the P abundances and investigate its trend across a range of metallicities. We have observed full HK band spectra at a spectral resolving power of R=45,000 with IGRINS instrument. Abundances are determined using SME in combination with 1D MARCS stellar atmosphere models. The investigated sample of stars have reliable stellar parameters estimated using optical FIES spectra (GILD; Jönsson et al. in prep.). In order to determine the P abundances from the 16482.92 Angstrom P line, we take special care of the CO($ν=7-4$) blend. We determine the C, N, O abundances from atomic carbon and a range of non-blended molecular lines (CO, CN, OH) which are aplenty in the H band region of K giant stars, assuring an appropriate modelling of the blending CO($ν=7-4$) line. We present [P/Fe] vs [Fe/H] trend for 38 K giant stars in the metallicity range of -1.2 dex $<$ [Fe/H] $<$ 0.4 dex. We find that our trend matches well with the compiled literature sample of prominently dwarf stars and limited number of giant stars. Our trend is found to be higher by $\sim$ 0.05 - 0.1 dex compared to the theoretical chemical evolution trend in Cescutti et al. 2012 resulting from core collapse supernova (type II) of massive stars with the P yields from Kobayashi et al. (2006) arbitrarily increased by a factor of 2.75. Thus the enhancement factor might need to be $\sim$ 0.05 - 0.1 dex higher to match our trend. We also find an empirically determined primary behaviour for phosphorus. Furthermore, the phosphorus abundance is found to be elevated by $\sim$ 0.6 - 0.9 dex in two metal poor s-enriched stars compared to the theoretical chemical evolution trend.
description: 13 pages, 9 figures, accepted for publication in Astronomy and Astrophysics
Entanglement between an auto-ionization system and a neighbor atom
Creators: name: Luks, Antonin
name: Perina, Jan
name: Leonski, Wieslaw
name: Perinova, Vlasta
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Entanglement between two electrons belonging to an auto-ionization system and a neighbor two-level atom produced by the dipole-dipole interaction is studied. The entanglement is quantified using the quadratic negativity of a bipartite system including the continuum of states. Suitable conditions for the generation of highly entangled states of two electrons are revealed. Internal structure of the entanglement is elucidated using the spectral density of quadratic negativity.
description: 11 pages, 14 figures
Specifics of the Elemental Excitations in "True One-Dimensional" MoI$_3$ van der Waals Nanowires
Creators: name: Kargar, Fariborz
name: Barani, Zahra
name: Sesing, Nicholas R.
name: Mai, Thuc T.
name: Debnath, Topojit
name: Zhang, Huairuo
name: Liu, Yuhang
name: Zhu, Yanbing
name: Ghosh, Subhajit
name: Biacchi, Adam J.
name: da Jornada, Felipe H.
name: Bartels, Ludwig
name: Adel, Tehseen
name: Walker, Angela R. Hight
name: Davydov, Albert V.
name: Salguero, Tina T.
name: Lake, Roger K.
name: Balandin, Alexander A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report on the temperature evolution of the polarization-dependent Raman spectrum of exfoliated MoI$_3$, a van der Waals material with a "true one-dimensional" crystal structure that can be exfoliated to individual atomic chains. The temperature evolution of several Raman features reveals anomalous behavior suggesting a phase transition of a magnetic origin. Theoretical considerations indicate that MoI$_3$ is an easy-plane antiferromagnet with alternating spins along the dimerized chains and with inter-chain helical spin ordering. The calculated frequencies of the phonons and magnons are consistent with the interpretation of the experimental Raman data. The obtained results shed light on the specifics of the phononic and magnonic states in MoI$_3$ and provide a strong motivation for future study of this unique material with potential for spintronic device applications.
description: 28 pages
Forward particle productions at RHIC and the LHC from CGC within local rcBK evolution
Creators: name: Fujii, H.
name: Itakura, K.
name: Kitadono, Y.
name: Nara, Y.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: In order to describe forward hadron productions in high-energy nuclear collisions, we propose a Monte-Carlo implementation of Dumitru-Hayashigaki-Jalilian-Marian formula with the unintegrated gluon distribution obtained numerically from the running-coupling BK equation. We discuss influence of initial conditions for the BK equation by comparing a model constrained by global fit of small-x HERA data and a newly proposed one from the running coupling MV model.
description: Talk given at conference Quark Matter 2011, 4 pages
Explicit Formula for the n-th Derivative of a Quotient
Creators: name: Haddad, Roudy El
Publisher: name: arXiv
Year: 2021
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 26A24 (Primary) 28A15, 11P99 (Secondary)

description: Leibniz's rule for the $n$-th derivative of a product is a very well known and extremely useful formula. In this article, we introduce an analogous explicit formula for the $n$-th derivative of a quotient of two functions. Later, we use this formula to derive new partition identities and to develop expressions for some special $n$-th derivatives.
description: 11 pages
An innovative and automated method for vortex identification. I. Description of the SWIRL algorithm
Creators: name: Cuissa, José Roberto Canivete
name: Steiner, Oskar
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Context. A universally accepted definition of what a vortex is has not yet been reached. Therefore, we lack an unambiguous and rigorous method for the identification of vortices in fluid flows. Such a method would be necessary to conduct robust statistical studies on vortices in highly dynamical and turbulent systems, such as the solar atmosphere. Aims. We aim to develop an innovative and robust automated methodology for the identification of vortices based on local and global characteristics of the flow. Moreover, the use of a threshold that could potentially prevent the detection of weak vortices in the identification process should be avoided. Methods. We present a new method that combines the rigor of mathematical criteria with the global perspective of morphological techniques. The core of the method consists in the estimation of the center of rotation for every point of the flow that presents some degree of curvature in its neighborhood. For that, we employ the Rortex criterion and combine it with morphological considerations of the velocity field. We then identify coherent vortical structures by clusters of estimated centers of rotation. Results. We demonstrate that the Rortex is a more reliable criterion than are the swirling strength and the vorticity for the extraction of physical information from vortical flows, because it measures the rigid-body rotational part of the flow alone and is not biased by the presence of pure or intrinsic shears. We show that the method performs well on a simplistic test case composed of two Lamb-Oseen vortices. We combine the proposed method with a state of the art clustering algorithm to build an automated vortex identification algorithm. (Abridged)
description: 14 pages, 12 figures, accepted for publication in A&A
Nonparametric Difference-in-Differences in Repeated Cross-Sections with Continuous Treatments
Creators: name: D'Haultfoeuille, Xavier
name: Hoderlein, Stefan
name: Sasaki, Yuya
Publisher: name: arXiv
Year: 2021
Subjects: subject: Econometrics (econ.EM)
subject: FOS: Economics and business

description: This paper studies the identification of causal effects of a continuous treatment using a new difference-in-difference strategy. Our approach allows for endogeneity of the treatment, and employs repeated cross-sections. It requires an exogenous change over time which affects the treatment in a heterogeneous way, stationarity of the distribution of unobservables and a rank invariance condition on the time trend. On the other hand, we do not impose any functional form restrictions or an additive time trend, and we are invariant to the scaling of the dependent variable. Under our conditions, the time trend can be identified using a control group, as in the binary difference-in-differences literature. In our scenario, however, this control group is defined by the data. We then identify average and quantile treatment effect parameters. We develop corresponding nonparametric estimators and study their asymptotic properties. Finally, we apply our results to the effect of disposable income on consumption.
description: 50 pages, 20 figures
Undemocratic Dirac seesaw
Creators: name: Chen, Su-Ping
name: Gu, Pei-Hong
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The standard model left-handed neutrinos and several right-handed neutrinos can obtain a tiny Dirac mass matrix through their mixings with relatively heavy Dirac fermions. In this Dirac seesaw scenario, the mixings involving the left-handed neutrinos can be allowed much larger than those involving the right-handed neutrinos. This undemocratic parameter choice is attractive to phenomenology. We show that the small mixings between the heavy Dirac fermions and the right-handed neutrinos can have a common origin with the observed baryon asymmetry in the universe. We also connect the introduction of right-handed neutrinos to the existence and stability of dark matter by a new $U(1)$ gauge symmetry for dark photon or baryon-minus-lepton number. We then specify how to embed our scenario into a left-right symmetric theory or a grand unification theory.
description: 6 pages, 2 figures
Spectroscopic properties of Young Stellar Objects in the Lupus Molecular Clouds
Creators: name: Mortier, Annelies
name: Oliveira, Isa
name: van Dishoeck, Ewine F.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The results of an optical spectroscopic survey of a sample of young stellar objects (YSOs) and pre-main sequence (PMS) stars in the Lupus Clouds are presented. 92 objects were observed with VLT/FLAMES. All of those objects show IR excess as discovered by the Spitzer Legacy Program "From Molecular Cores to Planet-Forming Disks" (c2d). After reduction, 54 spectra with good signal-to-noise ratio are spectrally classified. Effective temperatures and luminosities are derived for these objects, and used to construct H-R diagrams for the population. The sample consists mostly of M-type stars, with 10% K-type stars. Individual ages and masses are inferred for the objects according to theoretical evolutionary models. The mean population age is found to be between 3.6 and 4.4 Myr, depending on the model, while the mean mass is found to be ~0.3 M for either model. Together with literature data, the distribution of spectral types is found to be similar to that in Chamaeleon I and IC348. The Hα line in emission, found in 49% of the sample, is used to distinguish between classical and weak-line T Tauri stars. 56% of the objects show Hα in emission and are accreting T Tauri stars. Mass accretion rates between 10-8 and 10-11 M yr-1 are determined from the full width at 10% of the Hα peak intensity. These mass accretion rates are, within a large scatter, consistent with the Mac \propto M 2 relation found in the literature.
description: 13 figures, 4 tables, Accepted for publication in MNRAS
Computational methods to enable effective visualisations
Creators: name: Badni, Kevin
Publisher: name: Loughborough University
Year: 2020
Subjects: subject: 120399 Design Practice and Management not elsewhere classified
subject: FOS: Arts (arts, history of arts, performing arts, music)

description: At different times in history, visual communication has changed dependent upon the prevailing understanding and technology available for that period. The visualisations created by designer and artist are not just a simple response to their individual experience. They are ordered, coded and styled according to conventions which are developed through the tools and processes available at the time. This PhD submission reports investigations into the effective creation of visual communications using contemporary digital methods. The author’s overall aim was to develop a new methodology and toolset to assist designers in creating tangible outputs from 3D data.
A collection of 11 publications by the thesis author, and his co-authors, is presented along with 10 artistic productions that support the research enquiry. The research publications spanning from 2005 to 2017 add to the body of knowledge in the effective use of digital methods for visual communication. In addition, to the written works, the author has also produced a number of peer reviewed original creative works. These were based on the substantial development of a bespoke 3D eye-tracking software and scanning methodology. This methodology enabled the author to use eye-tracking technology and captured data to create unique, 3D artworks. From the literature review undertaken (confirmed by peer reviews of the publications) it appears that eye-tracking has never previously been used as a basis to create 3D sculptural work, so the scholarly work that informed the artworks is instrumental in adding to the body of knowledge.
VERTICO IV: Environmental Effects on the Gas Distribution and Star Formation Efficiency of Virgo Cluster Spirals
Creators: name: Villanueva, Vicente
name: Bolatto, Alberto D.
name: Vogel, Stuart
name: Brown, Tobias
name: Wilson, Christine D.
name: Zabel, Nikki
name: Ellison, Sara
name: Stevens, Adam R. H.
name: Donaire, Maria Jesus Jimenez
name: Spekkens, Kristine
name: Thorp, Mallory
name: Davis, Timothy A.
name: Parker, Laura C.
name: Roberts, Ian D.
name: Bisaria, Dhruv
name: Boselli, Alessandro
name: Catinella, Barbara
name: Chung, Aeree
name: Cortese, Luca
name: Lee, Bumhyun
name: Watts, Adam
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We measure the molecular-to-atomic gas ratio, $R_{\rm mol}$, and the star formation rate (SFR) per unit molecular gas mass, SFE$_{\rm mol}$, in 38 nearby galaxies selected from the Virgo Environment Traced in CO (VERTICO) survey. We determine their scale-lengths for the molecular and stellar components and find a roughly 3:5 ratio between them compared to $\sim$1:1 in field galaxies, indicating that the CO emission is more centrally concentrated than the stars. We compute $R_{\rm mol}$ as a function of different physical quantities. While the spatially-resolved $R_{\rm mol}$ on average decreases with increasing radius, we find that the mean molecular-to-atomic gas ratio within the stellar effective radius $R_{\rm e}$, $R_{\rm mol}(r
HYPERION: An open-source parallelized three-dimensional dust continuum radiative transfer code
Creators: name: Robitaille, Thomas P.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: HYPERION is a new three-dimensional dust continuum Monte-Carlo radiative transfer code that is designed to be as generic as possible, allowing radiative transfer to be computed through a variety of three-dimensional grids. The main part of the code is problem-independent, and only requires an arbitrary three-dimensional density structure, dust properties, the position and properties of the illuminating sources, and parameters controlling the running and output of the code. HYPERION is parallelized, and is shown to scale well to thousands of processes. Two common benchmark models for protoplanetary disks were computed, and the results are found to be in excellent agreement with those from other codes. Finally, to demonstrate the capabilities of the code, dust temperatures, SEDs, and synthetic multi-wavelength images were computed for a dynamical simulation of a low-mass star formation region. HYPERION is being actively developed to include new features, and is publicly available (http://www.hyperion-rt.org).
description: Accepted for publication in Astronomy & Astrophysics. HYPERION is being prepared for release at the start of 2012, but you can already sign up to the mailing list at http://www.hyperion-rt.org to be informed once it is available for download
Modeling photometric variations due to a global inhomogeneity on an obliquely rotating star: application to lightcurves of white dwarfs
Creators: name: Suto, Yasushi
name: Sasaki, Shin
name: Aizawa, Masataka
name: Fujisawa, Kotaro
name: Kashiyama, Kazumi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We develop a general framework to compute photometric variations induced by the oblique rotation of a star with an axisymmetric inhomogeneous surface. We apply the framework to compute lightcurves of white dwarfs adopting two simple models of their surface inhomogeneity. Depending on the surface model and the location of the observer, the resulting lightcurve exhibits a departure from a purely sinusoidal curve that are observed for a fraction of white dwarfs. As a specific example, we fit our model to the observed phase-folded lightcurve of a fast-spinning white dwarf ZTF J190132.9+145808.7 (with the rotation period of 419s). We find that the size and obliquity angle of the spot responsible for the photometric variation are $\dts \approx 60^\circ$ and $\thetaS \approx 60^\circ$ or $90^\circ$, respectively, implying an interesting constraint on the surface distribution of the magnetic field on white dwarfs.
description: 25 pages, 9 figures, accepted for publication in PASJ
Ensemble Quantile Networks: Uncertainty-Aware Reinforcement Learning with Applications in Autonomous Driving
Creators: name: Hoel, Carl-Johan
name: Wolff, Krister
name: Laine, Leo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Robotics (cs.RO)
subject: Artificial Intelligence (cs.AI)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Reinforcement learning (RL) can be used to create a decision-making agent for autonomous driving. However, previous approaches provide only black-box solutions, which do not offer information on how confident the agent is about its decisions. An estimate of both the aleatoric and epistemic uncertainty of the agent's decisions is fundamental for real-world applications of autonomous driving. Therefore, this paper introduces the Ensemble Quantile Networks (EQN) method, which combines distributional RL with an ensemble approach, to obtain a complete uncertainty estimate. The distribution over returns is estimated by learning its quantile function implicitly, which gives the aleatoric uncertainty, whereas an ensemble of agents is trained on bootstrapped data to provide a Bayesian estimation of the epistemic uncertainty. A criterion for classifying which decisions that have an unacceptable uncertainty is also introduced. The results show that the EQN method can balance risk and time efficiency in different occluded intersection scenarios, by considering the estimated aleatoric uncertainty. Furthermore, it is shown that the trained agent can use the epistemic uncertainty information to identify situations that the agent has not been trained for and thereby avoid making unfounded, potentially dangerous, decisions outside of the training distribution.
Electric field formulation for thin film magnetization problems
Creators: name: Barrett, John W
name: Prigozhin, Leonid
Publisher: name: arXiv
Year: 2012
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We derive a variational formulation for thin film magnetization problems in type-II superconductors written in terms of two variables, the electric field and the magnetization function. A numerical method, based on this formulation, makes it possible to accurately compute all variables of interest, including the electric field, for any value of the power in the power law current-voltage relation characterizing the superconducting material. For high power values we obtain a good approximation to the critical state model solution. Numerical simulation results are presented for simply and multiply connected films, and also for an inhomogeneous film.
description: 15 p., submitted
A moving-boundary model of reactive settling in wastewater treatment. Part 1: Governing equations
Creators: name: Bürger, Raimund
name: Careaga, Julio
name: Diehl, Stefan
name: Pineda, Romel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 35K65, 35Q35, 65M06, 76V05

description: Reactive settling is the process of sedimentation of small solid particles in a fluid with simultaneous reactions between the components of the solid and liquid phases. This process is important in sequencing batch reactors (SBRs) in wastewater treatment plants. In that application the particles are biomass (bacteria; activated sludge) and the liquid contains substrates (nitrogen, phosphorus) to be removed through reactions with the biomass. The operation of an SBR in cycles of consecutive fill, react, settle, draw, and idle stages is modelled by a system of spatially one-dimensional, nonlinear, strongly degenerate parabolic convection-diffusion-reaction equations. This system is coupled via conditions of mass conservation to transport equations on a half line, whose origin is located at a moving boundary and that model the effluent pipe. An invariant-region-preserving finite difference scheme is used to simulate operating cycles and the denitrification process within an SBR.
Quasar and galaxy classification using Gaia EDR3 and CatWise2020
Creators: name: Hughes, Arvind C. N.
name: Bailer-Jones, Coryn A. L.
name: Jamal, Sara
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: In this work, we assess the combined use of Gaia photometry and astrometry with infrared data from CatWISE in improving the identification of extragalactic sources compared to the classification obtained using Gaia data. We evaluate different input feature configurations and prior functions, with the aim of presenting a classification methodology integrating prior knowledge stemming from realistic class distributions in the universe. In our work, we compare different classifiers, namely Gaussian Mixture Models (GMMs), XGBoost and CatBoost, and classify sources into three classes - star, quasar, and galaxy, with the target quasar and galaxy class labels obtained from SDSS16 and the star label from Gaia EDR3. In our approach, we adjust the posterior probabilities to reflect the intrinsic distribution of extragalactic sources in the universe via a prior function. We introduce two priors, a global prior reflecting the overall rarity of quasars and galaxies, and a mixed prior that incorporates in addition the distribution of the these sources as a function of Galactic latitude and magnitude. Our best classification performances, in terms of completeness and purity of the galaxy and quasar classes, are achieved using the mixed prior for sources at high latitudes and in the magnitude range G = 18.5 to 19.5. We apply our identified best-performing classifier to three application datasets from Gaia DR3, and find that the global prior is more conservative in what it considers to be a quasar or a galaxy compared to the mixed prior. In particular, when applied to the pure quasar and galaxy candidates samples, we attain a purity of 97% for quasars and 99.9% for galaxies using the global prior, and purities of 96% and 99% respectively using the mixed prior. We conclude our work by discussing the importance of applying adjusted priors portraying realistic class distributions in the universe.
description: 21 pages, 23 figures, Accepted for publication in A&A
Electroweak Asymmetric Early Universe via a Scalar Condensate
Creators: name: Chang, Jae Hyeok
name: Olea-Romacho, María Olalla
name: Tanin, Erwin H.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Finite temperature effects in the Standard Model tend to restore the electroweak symmetry in the early universe, but new fields coupled to the higgs field may as well reverse this tendency, leading to the so-called electroweak symmetry non-restoration (EW SNR) scenario. Previous works on EW SNR often assume that the reversal is due to the thermal fluctuations of new fields with negative quartic couplings to the higgs, and they tend to find that a large number of new fields are required. We observe that EW SNR can be minimally realized if the field(s) coupled to the higgs field develop(s) a stable condensate. We show that one complex scalar field with a sufficiently large global-charge asymmetry can develop a condensate as an outcome of thermalization and keep the electroweak symmetry broken up to temperatures well above the electroweak scale. In addition to providing a minimal benchmark model, our work hints on a class of models involving scalar condensates that yield electroweak symmetry non-restoration in the early universe.
description: 12 pages, 2 figures, journal version
Directional detection of Dark Matter
Creators: name: Mayet, F.
name: Billard, J.
name: Santos, D.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Directional detection is a promising Dark Matter search strategy. Taking advantage on the rotation of the Solar system around the galactic center through the Dark Matter halo, it allows to show a direction dependence of WIMP events. It requires the simultaneous measurement of the energy and the 3D track of low energy recoils, which is a common challenge for all current projects of directional detectors. The third CYGNUS workshop on directional dark matter detection has brought together the scientific community working on both theoretical and experimental aspects of the subject. In this paper, we give an introductory revue of directional detection of Dark Matter, focusing on the main recent progresses.
description: Proceedings of the 3rd International conference on Directional Detection of Dark Matter (CYGNUS 2011), Aussois, France, 8-10 June 2011
Cramer-Rao Lower Bound Optimization for Hidden Moving Target Sensing via Multi-IRS-Aided Radar
Creators: name: Esmaeilbeig, Zahra
name: Mishra, Kumar Vijay
name: Eamaz, Arian
name: Soltanalian, Mojtaba
Publisher: name: arXiv
Year: 2022
Subjects: subject: Signal Processing (eess.SP)
subject: Optimization and Control (math.OC)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Mathematics

description: Intelligent reflecting surface (IRS) is a rapidly emerging paradigm to enable non-line-of-sight (NLoS) wireless transmission. In this paper, we focus on IRS-aided radar estimation performance of a moving hidden or NLoS target. Unlike prior works that employ a single IRS, we investigate this problem using multiple IRS platforms and assess the estimation performance by deriving the associated Cramer-Rao lower bound (CRLB). We then design Doppler-aware IRS phase shifts by minimizing the scalar A-optimality measure of the joint parameter CRLB matrix. The resulting optimization problem is non-convex, and is thus tackled via an alternating optimization framework. Numerical results demonstrate that the deployment of multiple IRS platforms with our proposed optimized phase shifts leads to a higher estimation accuracy compared to non-IRS and single-IRS alternatives.
Local antiferromagnetic exchange and collaborative Fermi surface as key ingredients of high temperature superconductors
Creators: name: Hu, Jiangping
name: Ding, Hong
Publisher: name: arXiv
Year: 2011
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Cuprates, ferropnictides and ferrochalcogenides are three classes of unconventional high-temperature superconductors, who share similar phase diagrams in which superconductivity develops after a magnetic order is suppressed, suggesting a strong interplay between superconductivity and magnetism, although the exact picture of this interplay remains elusive. Here we show that there is a direct bridge connecting antiferromagnetic exchange interactions determined in the parent compounds of these materials to the superconducting gap functions observed in the corresponding superconducting materials. High superconducting transition temperature is achieved when the Fermi surface topology matches the form factor of the pairing symmetry favored by local magnetic exchange interactions. Our result offers a principle guide to search for new high temperature superconductors.
description: 12 pages, 5 figures, 1 table, 1 supplementary material
Active Learning in Bayesian Neural Networks with Balanced Entropy Learning Principle
Creators: name: Woo, Jae Oh
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Acquiring labeled data is challenging in many machine learning applications with limited budgets. Active learning gives a procedure to select the most informative data points and improve data efficiency by reducing the cost of labeling. The info-max learning principle maximizing mutual information such as BALD has been successful and widely adapted in various active learning applications. However, this pool-based specific objective inherently introduces a redundant selection and further requires a high computational cost for batch selection. In this paper, we design and propose a new uncertainty measure, Balanced Entropy Acquisition (BalEntAcq), which captures the information balance between the uncertainty of underlying softmax probability and the label variable. To do this, we approximate each marginal distribution by Beta distribution. Beta approximation enables us to formulate BalEntAcq as a ratio between an augmented entropy and the marginalized joint entropy. The closed-form expression of BalEntAcq facilitates parallelization by estimating two parameters in each marginal Beta distribution. BalEntAcq is a purely standalone measure without requiring any relational computations with other data points. Nevertheless, BalEntAcq captures a well-diversified selection near the decision boundary with a margin, unlike other existing uncertainty measures such as BALD, Entropy, or Mean Standard Deviation (MeanSD). Finally, we demonstrate that our balanced entropy learning principle with BalEntAcq consistently outperforms well-known linearly scalable active learning methods, including a recently proposed PowerBALD, a simple but diversified version of BALD, by showing experimental results obtained from MNIST, CIFAR-100, SVHN, and TinyImageNet datasets.
Block-Diagonalization of Operators with Gaps, with Applications to Dirac Operators
Creators: name: Cuenin, Jean-Claude
Publisher: name: arXiv
Year: 2011
Subjects: subject: Spectral Theory (math.SP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We present new results on the block-diagonalization of Dirac operators on three-dimensional Euclidean space with unbounded potentials. Classes of admissible potentials include electromagnetic potentials with strong Coulomb singularities and more general matrix-valued potentials, even non-self-adjoint ones. For the Coulomb potential, we achieve an exact diagonalization up to nuclear charge Z=124 and prove the convergence of the Douglas-Kroll-Heß approximation up to Z=62, thus improving the upper bounds Z=93 and Z=51, respectively, by H.\ Siedentop and E.\ Stockmeyer considerably. These results follow from abstract theorems on perturbations of spectral subspaces of operators with gaps, which are based on a method of H.\ Langer and C.\ Tretter and are also of independent interest.
Untersuchungen an Tension-Leg-Plattformen für die Nordsee
Creators: name: Ochocinski, Blazej
Publisher: name: TUHH Universitätsbibliothek
Year: 1990
Subjects: subject: tension-leg-Plattform
classificationCode: 52.00
subject: Maschinenbau, Energietechnik, Fertigungstechnik: Allgemeines
subject: Halbtaucher

description: Untersuchungen an Tension-Leg-Plattformen für die Nordsee Die Tension-Leg-Plattformen werden seit Beginn der 70er Jahre als das wichtigste Konzept für Offshore-Felder mit größeren Wassertiefen angesehen. Die in mehreren Ländern, wie in den USA, Großbritannien, Norwegen, Japan und Frankreich in den Jahren 1975 bis 1985 intensiv betriebene Grundlagen- und angewandte Forschung auf dem Gebiet der TLP- Technologie hat eindeutig bewiesen, daß bei der Auslegung dieser technisch komplizierten Systeme hochwertige ingenieurwissenschaftliche Methoden eingesetzt werden müssen, um die Forderungen nach Sicherheit und Wirtschaftlichkeit des Gesamtsystems erfüllen zu können. Ziel der in dieser Arbeit dargestellten Untersuchungen an Tension-Leg-Plattformen für die Nordsee war es, für einige der wichtigsten Bereiche des Entwurfs einer Tension-Leg-Plattform die ingenieurwissenschaftlichen Methoden zu entwickeln und eine Reihe von theoretischen Untersuchungen in Bezug auf TLP's für die Nordsee durchzuführen. Letztere umfaßten insbesondere die hydromechanische Analyse des Schwimmkörpers, Untersuchungen des Seeverhaltens der Plattform im intakten Zustand und nach Teilversagen des Verspannungssystems sowie die Auslegung der Riser und der Verspannung.
Asymptotics of robust utility maximization
Creators: name: Knispel, Thomas
Publisher: name: arXiv
Year: 2012
Subjects: subject: Probability (math.PR)
subject: Pricing of Securities (q-fin.PR)
subject: FOS: Mathematics
subject: FOS: Economics and business

description: For a stochastic factor model we maximize the long-term growth rate of robust expected power utility with parameter $λ\in(0,1)$. Using duality methods the problem is reformulated as an infinite time horizon, risk-sensitive control problem. Our results characterize the optimal growth rate, an optimal long-term trading strategy and an asymptotic worst-case model in terms of an ergodic Bellman equation. With these results we propose a duality approach to a "robust large deviations" criterion for optimal long-term investment.
description: Published in at http://dx.doi.org/10.1214/11-AAP764 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Observation of Weyl point pair annihilation in a gyromagnetic photonic crystal
Creators: name: Liu, Gui-Geng
name: Gao, Zhen
name: Zhou, Peiheng
name: Wang, Qiang
name: Hu, Yuan-Hang
name: Wang, Maoren
name: Liu, Chengqi
name: Lin, Xiao
name: Yang, Shengyuan A.
name: Yang, Yihao
name: Chong, Yidong
name: Zhang, Baile
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Weyl semimetals are gapless three-dimensional (3D) phases whose bandstructures contain Weyl point (WP) degeneracies. WPs carry topological charge and can only be eliminated by mutual annihilation, a process that generates the various topologically distinct 3D insulators. Time reversal (T) symmetric Weyl phases, containing a minimum of four WPs, have been extensively studied in real materials, photonic metamaterials, and other systems. Weyl phases with a single WP pair - the simplest configuration of WPs - are more elusive as they require T-breaking. Here, we implement a microwave-scale gyromagnetic 3D photonic crystal, and use field-mapping experiments to track a single pair of ideal WPs whose momentum space locations depend strongly on the biasing magnetic field. By continuously varying the field strength, we observe the annihilation of the WPs, and the formation of a 3D Chern insulator, a previously unrealised member of the family of 3D topological insulators (TIs). Surface measurements show, in unprecedented detail, how the Fermi arc states connecting the WPs evolve into TI surface states.