cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Strain Coupled Domains in BaTiO3(111)-CoFeB Heterostructures
Creators: name: Hunt, Robbie G.
name: Franke, Kévin J. A.
name: Shepley, Philippa M.
name: Moore, Thomas A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Domain pattern transfer from ferroelectric to ferromagnetic materials is a critical step for the electric field control of magnetism and has the potential to provide new schemes for low-power data storage and computing devices. Here we investigate domain coupling in BaTiO$_3$(111)/CoFeB heterostructures by direct imaging in a wide-field Kerr microscope. The magnetic easy axis is found to locally change direction as a result of the underlying ferroelectric domains and their polarisation. By plotting the remanent magnetisation as a function of angle in the plane of the CoFeB layer, we find that the magnetic easy axes in adjacent domains are angled at 60$^\circ$ or 120$^\circ$, corresponding to the angle of rotation of the polarisation from one ferroelectric domain to the next, and that the magnetic domain walls may be charged or uncharged depending on the magnetic field history. Micromagnetic simulations show that the properties of the domain walls vary depending on the magnetoelastic easy axis configuration and the charged or uncharged nature of the wall. The configuration where the easy axis alternates by 60$^\circ$ and a charged wall is initialised exhibits the largest change in domain wall width from 192 nm to 119 nm as a function of in-plane magnetic field. Domain wall width tuning provides an additional degree of freedom for devices that seek to manipulate magnetic domain walls using strain coupling to ferroelectrics.
description: 7 pages, 8 figures
Design of a wavelength-tunable optical tweezer using a graded-index multimode optical fiber
Creators: name: Mobini, Esmaeil
name: Mafi, Arash
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: A wavelength-tunable Optical Fiber Tweezer (OFT) based on a Graded Index Multimode Fiber (GIMF) with a flat endface is proposed. It is shown that the design can support a trapping position which is far from the tip of the GIMF compared with other common optical tweezing methods, hence reducing the possibility of a contact between the trapped particle and the fiber tip. Moreover, because of the wavelength dependence of the GIMF design parameters such the Numerical Aperture (NA), the trapping position can become wavelength-dependent. Therefore, the trapping position can be tuned over a long range using a common wave-length tunable laser. The proposed OFT differs from previous fiber-based demonstrations by using a flat-endface fiber making the fabrication and experiment quite easier than previously proposed tapered-endface OFTs.
Quantum metrology with quantum Wheatstone bridge composed of Bose systems
Creators: name: Xie, Dong
name: Xu, Chunling
name: Yao, Xiwei
name: Wang, An Min
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The quantum version of a special classical Wheatstone bridge built with a boundary-driven spin system has recently been proposed. We propose a quantum Wheatstone bridge consisting of Bose systems, which can simulate the general classical Wheatstone bridge. Unknown coupling can be obtained when the quantum Wheatstone bridge is balanced, which can be determined simply by the homodyne detection. When the expectation value of the homodyne detection is 0, the quantum Wheatstone bridge is unbalanced. Regulate a known coupling strength to make the expectation value of the homodyne detection be proportional to the square root of the initial number of bosons, which means that the quantum Wheatstone bridge is balanced. By calculating the quantum Fisher information, we show that the measurement precision is optimal when the quantum Wheatstone bridge is balanced. And the homodyne detection is close to the optimal measurement in the case of low-temperature baths.
description: 8pages, 3figures
On a diffusion model with absorption and production
Creators: name: Franca, Matteo
name: Sfecci, Andrea
Publisher: name: arXiv
Year: 2016
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics

description: We discuss the structure of radial solutions of some superlinear elliptic equations which model diffusion phenomena when both absorption and production are present. We focus our attention on solutions defined in R (regular) or in R \ {0} (singular) which are infinitesimal at infinity, discussing also their asymptotic behavior. The phenomena we find are present only if absorption and production coexist, i.e., if the reaction term changes sign. Our results are then generalized to include the case where Hardy potentials are considered.
Geometry and Topological photonics
Creators: name: Silveirinha, Mario G.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Topological photonics provides a powerful framework to describe and understand many nontrivial wave phenomena in complex electromagnetic platforms. The topological index of a physical system is an abstract global property that depends on the family of operators that describes the propagation of Bloch waves. Here, we highlight that there is a profound geometrical connection between topological physics and the topological theory of mathematical surfaces. We show that topological band theory can be understood as a generalization of the topological theory of surfaces and that the genus of a surface can be regarded as a Chern number of a suitable operator defined over the surface. We point out some nontrivial implications of topology in the context of radiation problems and discuss why for physical problems the topological index is often associated with a bulk-edge correspondence.
description: 24 pages
Measuring directed interactions using cellular neural networks with complex connection topologies
Creators: name: Dickten, Henning
name: Elger, Christian E.
name: Lehnertz, Klaus
Publisher: name: arXiv
Year: 2016
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: Chaotic Dynamics (nlin.CD)
subject: Cellular Automata and Lattice Gases (nlin.CG)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: We advance our approach of analyzing the dynamics of interacting complex systems with the nonlinear dynamics of interacting nonlinear elements. We replace the widely used lattice-like connection topology of cellular neural networks (CNN) by complex topologies that include both short- and long-ranged connections. With an exemplary time-resolved analysis of asymmetric nonlinear interdependences between the seizure generating area and its immediate surrounding we provide first evidence for complex CNN connection topologies to allow for a faster network optimization together with an improved approximation accuracy of directed interactions.
From Collective Adaptive Systems to Human Centric Computation and Back: Spatial Model Checking for Medical Imaging
Creators: name: Belmonte, Gina
name: Ciancia, Vincenzo
name: Latella, Diego
name: Massink, Mieke
Publisher: name: arXiv
Year: 2016
Subjects: subject: Logic in Computer Science (cs.LO)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences
subject: D.2.4 model checking; F.4.1 modal logic; J.3 medical information systems

description: Recent research on formal verification for Collective Adaptive Systems (CAS) pushed advancements in spatial and spatio-temporal model checking, and as a side result provided novel image analysis methodologies, rooted in logical methods for topological spaces. Medical Imaging (MI) is a field where such technologies show potential for ground-breaking innovation. In this position paper, we present a preliminary investigation centred on applications of spatial model checking to MI. The focus is shifted from pure logics to a mixture of logical, statistical and algorithmic approaches, driven by the logical nature intrinsic to the specification of the properties of interest in the field. As a result, novel operators are introduced, that could as well be brought back to the setting of CAS.
description: In Proceedings FORECAST 2016, arXiv:1607.02001
A Probabilistic Proof of the Multinomial Theorem
Creators: name: Kataria, K. K.
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Mathematics (math.GM)
subject: FOS: Mathematics
subject: 60C05

description: In this note, we give an alternate proof of the multinomial theorem using a probabilistic approach. Although the multinomial theorem is basically a combinatorial result, our proof may be simpler for a student familiar with only basic probability concepts.
description: This is a preprint version. A revised version is available at AMM website
On the Use of the Tsallis Distribution at LHC Energies
Creators: name: Cleymans, J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Numerous papers have appeared recently showing fits to transverse momentum ($p_T$) spectra measured at the Large Hadron Collider (LHC) in proton - proton collisions.This talk focuses on the fits extending to very large values of the transverse momentum with $p_T$ values up to 200 GeV/c as measured by the ATLAS and CMS collaborations at $\sqrt{s}$ = 0.9 and 7 TeV. A thermodynamically consistent form of the Tsallis distribution is used for fitting the transverse momentum spectra at mid-rapidity. The fits based on the proposed distribution provide an excellent description over 14 orders of magnitude. Despite this success, an ambiguity is noted concerning the determination of the parameters in the Tsallis distribution. This prevents drawing firm conclusions as to the universality of the parameters appearing in the Tsallis distribution.
description: 4 pages, 3 figures, contribution to conference Strangeness in Quark Matter sqm2016
Band structure reconstruction across nematic order in high quality FeSe single crystal as revealed by optical spectroscopy study
Creators: name: Wang, Haipeng
name: Ye, Zirong
name: Zhang, Yan
name: Wang, Nan-Lin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We perform an in-plane optical spectroscopy measurement on high quality FeSe single crystals grown by a vapor transport technique. Below the structural transition at $T_{\rm s}\sim$90 K, the reflectivity spectrum clearly shows a gradual suppression around 400 cm$^{-1}$ and the conductivity spectrum shows a peak at higher frequency. The energy scale of this gap-like feature is comparable to the width of the band splitting observed by ARPES. The low-frequency conductivity consists of two Drude components and the overall plasma frequency is smaller than that of the FeAs based compounds, suggesting a lower carrier density or stronger correlation effect. The plasma frequency becomes even smaller below $T_{\rm s}$ which agrees with the very small Fermi energy estimated by other experiments. Similar to iron pnictides, a clear temperature-induced spectral weight transfer is observed for FeSe, being indicative of strong correlation effect.
description: 6 pages
Mergers as a Probe of Particle Dark Matter
Creators: name: Ray, Anupam
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Black holes below Chandrasekhar mass limit (1.4 $M_{\odot}$) can not be produced via any standard stellar evolution. Recently, gravitational wave experiments have also discovered unusually low mass black holes whose origin is yet to be known. We propose a simple yet novel formation mechanism of such low mass black holes. Non-annihilating particle dark matter, owing to their interaction with stellar nuclei, can gradually accumulate inside compact stars, and eventually swallows them to low mass black holes, ordinarily impermissible by the Chandrasekhar limit. We point out several avenues to test this proposal, concentrating on the cosmic evolution of the binary merger rates.
description: v2: 8 pages, 2 figures. Published in SciPost Physics Proceedings: 14th International Conference on Identification of Dark Matter (IDM) 2022
D4.2 First PATTERN Policy Brief
Creators: name: Salnikova, Asya
name: Brandstetter-Kunc, Adam
name: Ipolyi, Ildiko
Publisher: name: Zenodo
Year: 2024

description: The First PATTERN Policy Brief draws on the state-of-the-art analysis of the policy landscape for training opportunities for researchers on Open RRI at European, national and institutional levels (2023) as well as on co-creation in Open Studio Cycle 1 (2024) in which the insights were operationalised into recommendations.

This Policy Brief focuses on the identified gaps in the policy landscape and how they could be addressed from the European and/or national perspective.
An empirical model of noise sources in subsonic jets
Creators: name: Karban, Ugur
name: Bugeat, Benjamin
name: Towne, Aaron
name: Lesshafft, Lutz
name: Agarwal, Anurag
name: Jordan, Peter
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Modelling the noise emitted by turbulent jets is made difficult by their acoustic inefficiency: only a tiny fraction of the near-field turbulent kinetic energy is propagated to the far field as acoustic waves. As a result, jet-noise models must accurately capture this small, acoustically efficient component hidden among comparatively inefficient fluctuations. In this paper, we identify this acoustically efficient near-field source from large-eddy-simulation data and use it to inform a predictive model. Our approach uses the resolvent framework, in which the source takes the form of nonlinear fluctuation terms that act as a forcing on the linearized Navier-Stokes equations. First, we identify the forcing that, when acted on by the resolvent operator, produces the leading spectral proper orthogonal decomposition modes in the acoustic field for a Mach 0.4 jet. Second, the radiating components of this forcing are isolated by retaining only portions with a supersonic phase speed. This component makes up less than 0.05% of the total forcing energy but generates most of the acoustic response, especially at peak (downstream) radiation angles. Finally, we propose an empirical model for the identified acoustically efficient forcing components. The model is tested at other Mach numbers and flight-stream conditions and predicts noise within 2 dB accuracy for a range of frequencies, downstream angles, and flight conditions.
description: 33 pages, 22 figures
Fast probe of local electronic states in nanostructures utilizing a single-lead quantum dot
Creators: name: Otsuka, Tomohiro
name: Amaha, Shinichi
name: Nakajima, Takashi
name: Delbecq, Matthieu R.
name: Yoneda, Jun
name: Takeda, Kenta
name: Sugawara, Retsu
name: Allison, Giles
name: Ludwig, Arne
name: Wieck, Andreas D.
name: Tarucha, Seigo
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Transport measurements are powerful tools to probe electronic properties of solid-state materials. To access properties of local electronic states in nanostructures, such as local density of states, electronic distribution and so on, micro-probes utilizing artificial nanostructures have been invented to perform measurements in addition to those with conventional macroscopic electronic reservoirs. Here we demonstrate a new kind of micro-probe: a fast single-lead quantum dot probe, which utilizes a quantum dot coupled only to the target structure through a tunneling barrier and fast charge readout by RF reflectometry. The probe can directly access the local electronic states with wide bandwidth. The probe can also access more electronic states, not just those around the Fermi level, and the operations are robust against bias voltages and temperatures.
description: 6 pages, 6 figures
A non-local quasi-equilibrium state in the Bhatnagar-Gross-Krook Boltzmann equation for thermo-hydrodynamics: Conservation laws, the Boltzmann H-theorem, and the fluctuation-dissipation theorem
Creators: name: Otomo, Hiroshi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The Bhatnagar-Gross-Krook (BGK) Boltzmann equation with the Maxwellian-Boltzmann-type equilibrium state leads to the set of thermo-hydrodynamic equations such as the continuity, the Navier-Stokes, and the heat-transfer equations in the scaling limit. With its efficient and promising framework handling multi-scale physics, the collision model has been studied with both of theoretical and numerical approaches to apply it for extensive flow conditions such as the flexible choices of the Prandtl number. In this study, using an analytic technique of the kinetic generator, we employ a non-local formulation for the equilibrium state leading to the thermo-hydrodynamic equations with flexible choices of transport coefficients and the equation of state (EOS). The equilibrium state includes the quasi-equilibrium state intrinsically, being formulated with the non-local macroscopic quantities so that the longer-range interaction is explicitly involved. According to the new formulation, the consistency with conservation laws, the Boltzmann H-theorem, and the fluctuation-dissipation theorem are examined.
Asymptotic boundary behavior of the Bergman curvatures of a pseudoconvex domain
Creators: name: Yoo, Sungmin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 32T27

description: We present a method of obtaining a lower bound estimate of the curvatures of the Bergman metric without using the regularity of the kernel function on the boundary. As an application, we prove the existence of an uniform lower bound of the bisectional curvatures of the Bergman metric of a smooth bounded pseudoconvex domain near the boundary with constant Levi rank.
Surface induced electronic Berry curvature in Berry curvature free bulk materials
Creators: name: Wawrzik, Dennis
name: Facio, Jorge I.
name: Brink, Jeroen van den
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In recent years it has become clear that electronic Berry curvature (BC) is a key concept to understand and predict physical properties of crystalline materials. A wealth of interesting Hall-type responses in charge, spin and heat transport are caused by the BC associated to electronic bands inside a solid: anomalous Hall effects in magnetic materials, and various nonlinear Hall and Nernst effects in non-magnetic systems that lack inversion symmetry. However, for the largest class of known materials -- non-magnetic ones with inversion symmetry -- electronic BC is strictly zero. Here we show that precisely for these bulk BC-free materials, a finite BC can emerge at their surfaces and interfaces. This immediately activates certain surfaces in producing Hall-type transport responses. We demonstrate this by first principles calculations of the BC at bismuth, mercury-telluride (HgTe) and rhodium surfaces of various symmetries, revealing the presence of a surface Berry curvature dipole and associated quantum nonlinear Hall effects at a number of these. This opens up a plethora of materials to explore and harness the physical effects emerging from the electronic Berry curvature associated exclusively to their boundaries.
description: 3 figures
Strong-Field S-Matrix Theory With Coulomb-Volkov Final State in All Orders
Creators: name: Faisal, F. H. M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Despite its long standing usefulness for the analysis of various processes in intense laser fields, it is well-known that the so-called strong-field KFR or SFA ansatz does not account for the final-state Coulomb interaction. Due to its importance for the ubiquitous ionisation process, numerous heuristic attempts have been made during the last several decades to account for the final state Coulomb interaction with in the SFA. Also to this end an ad hoc model with the so-called Coulomb-Volkov final state was introduced a long time ago. However, till now, no systematic strong-field S-matrix expansion using the Coulomb-Volkov final state could be found. Here we solve this long standing problem by determining the Coulomb-Volkov Hamiltonian, identifying the rest-interaction in the final state, and explicitly constructng the Coulomb-Volkov propagator (or Green's function). We employ them to derive the complete S-matrix series for the ionisation amplitude governed by the Coulomb-Volkov final state in all orders. The results are given in both "velocity" and "length" gauges. We also present a gauge independent version of the Coulomb-Volkov S-matrix series.
The Infrared Imaging Spectrograph (IRIS) for TMT: Instrument Overview
Creators: name: Larkin, James E.
name: Moore, Anna M.
name: Wright, Shelley A.
name: Wincentsen, James E.
name: Anderson, David
name: Chisholm, Eric M.
name: Dekany, Richard G.
name: Dunn, Jennifer S.
name: Ellerbroek, Brent L.
name: Hayano, Yutaka
name: Phillips, Andrew C.
name: Simard, Luc
name: Smith, Roger
name: Suzuki, Ryuji
name: Weber, Robert W.
name: Weiss, Jason L.
name: Zhang, Kai
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: IRIS is a near-infrared (0.84 to 2.4 microns) integral field spectrograph and wide-field imager being developed for first light with the Thirty Meter (TMT). It mounts to the advanced optics (AO) system NFIRAOS and has integrated on-instrument wavefront sensors (OIWFS) to achieve diffraction-limited spatial resolution at wavelengths longer than 1 micron. With moderate spectral resolution (R ~4,000 - 8,000) and large bandpass over a continuous field of view, IRIS will open new opportunities in virtually every area of astrophysical science. It will be able to resolve surface features tens of kilometers across Titan, while also mapping the distant galaxies at the scale of an individual star forming region. This paper summarizes the entire design and capabilities, and includes the results from the nearly completed preliminary design phase.
description: 13 pages, SPIE proceeedings
Magnonic black holes
Creators: name: Roldán-Molina, A.
name: Nunez, A. S.
name: Duine, R. A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We show that the interaction between spin-polarized current and magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons - the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.
description: 6 pages, 1 figure
Implications for primordial black holes from cosmological constraints on scalar-induced gravitational wave
Creators: name: Cang, Junsong
name: Ma, Yin-Zhe
name: Gao, Yu
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: Sufficiently large scalar perturbations in the early Universe can create over-dense regions that collapse into primordial black holes (PBH). This process is accompanied by the emission of scalar-induced gravitational waves (SIGW) that behave like an extra radiation component, thus contributing to the relativistic degrees of freedom ($N_{\rm{eff}}$). We show that the cosmological constraints on $N_{\rm{eff}}$ can be used to pose stringent limits on PBHs created from this particular scenario as well as the relevant small-scale curvature perturbation ($\mathcal{P}_{\mathcal{R}}(k)$). We show that the combination of cosmic microwave background (CMB), baryon acoustic oscillation (BAO) and Big-Bang nucleosynthesis (BBN) datasets can exclude supermassive PBHs with peak mass $M_{\bullet} \in [5 \times 10^{5}, 5 \times 10^{10}]\,{\rm M}_{\odot}$ as the major component of dark matter, while the detailed constraints depend on the shape of the PBHs mass distribution. The future CMB mission like CMB-S4 can broaden this constraint window to a much larger range $M_{\bullet} \in [8 \times 10^{-5}, 5 \times 10^{10}]\,{\rm M}_{\odot}$, covering sub-stellar masses. These limits on PBH correspond to a tightened constraint on $\mathcal{P}_{\mathcal{R}}$ on scales of $k \in [10, 10^{22}]\ {\rm{Mpc^{-1}}}$, much smaller than those probed by direct CMB and large-scale structure power spectra.
description: The abstract of previous version was not displayed properly on arXiv website due to the use of commands defined only in tex source codes, this update fix this issue so that the abstract is shown properly on arXiv. Content of the paper pdf itself remains unchanged
Developing and testing Safety Beach - a game for Surf Life Saving WA
Creators: name: Evans, Lisa
name: Dyet, Matthew
Publisher: name: Zenodo
Year: 2017

description: View a video of this presentation on YouTube here.

Stirfire created "Safety Beach" for Surf Live Saving WA to help children learn important rules to keep them safe at the beach. 

In this talk, Matthew Dyet and Lisa Evans discuss how they wanted to demonstrate to the customer that a game of this kind would be effective as well as fun. In developing the game, they focused on the design principle of "procedural rhetoric" to make sure the rules of the game reflected the safety rules of the beach, so it was teaching not just what the rules are, but why they're important.

Before releasing the game they did some qualitative testing with children to see whether it really did work as designed. The results were very useful for them as developers as well as for the customer.

Stirfire would like to share what they learned to help other studios develop serious games on a tight budget for customers that are perhaps hesitant to go in this direction.

Game Connect Asia Pacific 2017: The Ripple Effect

Game Connect Asia Pacific is Australia's premiere game development conference, a part of Melbourne International Games Week. Situated in Melbourne, Australia in the October-November period, GCAP is world-renowned for its talks, networking and inclusive environment.

Video courtesy of GCAP and the Game Developers' Association of Australia.

www.gcap.com.au

www.gdaa.com.au
D2.4 – Report on pre-release of an integrated platform with inter-operable Open Source flagship codes, including the I/O and, gradually, the QMCkl libraries
Creators: name: Sorella, Sandro
Publisher: name: Zenodo
Year: 2022
Subjects: QMC
HPC
TREX codes

description: The TREX project is in the field of high-accuracy quantum chemical and materials simulations with a special focus on Quantum Monte Carlo (QMC) approaches to the solution of the quantum many-body problem at the heart of atomistic physics, chemistry, and materials science. Importantly, due to their inherent parallelizability and high computational cost, QMC approaches, and thus TREX is uniquely positioned to fully exploit the massive parallelism of the upcoming exascale supercomputer architectures. The software developed in this project for improving code inter-operability and interfacing will be referenced in the following as TREXIO. The library was released in the previous D2.2 deliverable and is being continuously updated to facilitate its use and maximize its portability. This document will be the basis for the next D2.5 and the final D2.6 deliverable. Let us remind the main idea of TREXIO that can be useful within and outside TREX CoEs. In a brute force approach, each developer, in order to interface its own code (e.g. TurboRVB) with any other code (see Fig.1, outer and inner shells), is forced to write a different interface for each of them, and this is a clearly inefficient waste of human resources. Instead with the TREXIO library, by means of highly developed and standardized input and output paradigms, only one interface is necessary: the one with the TREXIO library. This clearly represents an enormous simplification of the effort. Moreover, once all planned interfaces (green balls in Fig.1) will be available the visibility and the scientific appeal of the TREX codes, will be clearly enhanced. In this report, we will mainly focus on the pre-release of an integrated platform with inter-operable Open Source flagship codes, including the I/O. This library is important for the gradual integration of the QMCkl library (its status has been recently reported in the D3.2 deliverable) in the TREX flagship codes. All the technical aspects related to this important development will be dealt with in the next D3 reports.
The Discovery of Transitive Phenomenon in the Radio Emission of the mode-switcher PSR B0943+10
Creators: name: Suleymanova, Svetlana
name: Bilous, Anna
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: B0943+10 is known to switch between two distinct, hours-long modes of radio emission, Bright (B) and Quiet (Q). Up to now the switches in both directions were believed to occur instantly (on the scale of a spin period). We have found a transitive process around the Q-to-B-mode switch, which consists of two additional short-lived modes, each with distinct average profiles and subpulse drift rates. Based on observations at low radio frequencies, we examine the properties of these transitive modes and discuss their implications in the framework of the traditional carousel model of drifting subpulses.
description: submitted to A&A
Temperature Evolution of Molecular Clouds in the Central Molecular Zone
Creators: name: Krieger, Nico
name: Ott, Jürgen
name: Walter, Fabian
name: Kruijssen, J. M. Diederik
name: Beuther, Henrik
name: team, the SWAG
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We infer the absolute time dependence of kinematic gas temperature along a proposed orbit of molecular clouds in the Central Molecular Zone (CMZ) of the Galactic Center (GC). Ammonia gas temperature maps are one of the results of the "Survey of Water and Ammonia in the Galactic Center" (SWAG, PI: J. Ott); the dynamical model of molecular clouds in the CMZ was taken from Kruijssen et al. (2015). We find that gas temperatures increase as a function of time in both regimes before and after the cloud passes pericenter on its orbit in the GC potential. This is consistent with the recent proposal that pericenter passage triggers gravitational collapse. Other investigated quantities (line width, column density, opacity) show no strong sign of time dependence but are likely dominated by cloud-to-cloud variations.
description: 2 pages, 2 figures, to appear in Proceedings of IAU Symposium 322, The Multi-Messenger Astrophysics of the Galactic Centre, Steve Longmore, Geoff Bicknell and Roland Crocker, eds
Can large inhomogeneities generate target patterns?
Creators: name: Jaramillo, Gabriela
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We study the existence of target patterns in oscillatory media with weak local coupling and in the presence of an impurity, or defect. We model these systems using a viscous eikonal equation posed on the plane, and represent the defect as a perturbation. In contrast to previous results we consider large defects, which we describe using a function with slow algebraic decay, i.e., $g \sim {\mathcal O}(1/|x|^m)$ for $m \in (1,2]$. We prove that these defects are able to generate target patterns and that, just as in the case of strongly localized impurities, their frequency is small beyond all orders of the small parameter describing their strength. Our analysis consists of finding two approximations to target pattern solutions, one which is valid at intermediate scales and a second one which is valid in the far field. This is done using weighted Sobolev spaces, which allow us to recover Fredholm properties of the relevant linear operators, as well as the implicit function theorem, which is then used to prove existence. By matching the intermediate and far field approximations we then determine the frequency of the pattern that is selected by the system.
description: 26 pages, 3 Figures
Converting heat into directed transport on a tilted lattice
Creators: name: Teo, Colin
name: Bissbort, Ulf
name: Poletti, Dario
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We present a self-contained engine, which is made of one or more two-level systems, each of which is coupled to a single bath, as well as to a common load composed of a particle on a tilted lattice. We show that the energy and the entropy absorbed by the spins are transferred to the particle thus setting it into upward motion at an average constant speed, even when driven by a single spin connected to a single bath. When considering an ensemble of different spins, the velocity of the particle is larger when the tilt is on resonance with any of the spins' energy splitting. Interestingly, we find regimes where the spins' polarization enters periodic cycles with the oscillation period being determined by the tilt of the lattice.
description: 7 pages, 4 figures
Upholding the Unified Model for Active Galactic Nuclei: VLT/FORS2 Spectropolarimetry of Seyfert 2 galaxies
Creators: name: Almeida, Cristina Ramos
name: Gonzalez, M. J. Martínez
name: Ramos, A. Asensio
name: Acosta-Pulido, J. A.
name: Hönig, S. F.
name: Alonso-Herrero, A.
name: Tadhunter, C. N.
name: González-Martín, O.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The origin of the unification model for Active Galactic Nuclei (AGN) was the detection of broad hydrogen recombination lines in the optical polarized spectrum of the Seyfert 2 galaxy (Sy2) NGC 1068. Since then, a search for the hidden broad-line region (HBLR) of nearby Sy2s started, but polarized broad lines have only been detected in 30-40% of the nearby Sy2s observed to date. Here we present new VLT/FORS2 optical spectropolarimetry of a sample of 15 Sy2s, including Compton-thin and Compton-thick sources. The sample includes six galaxies without previously published spectropolarimetry, some of them normally treated as non-hidden BLR (NHBLR) objects in the literature, four classified as NHBLR, and five as HBLR based on previous data. We report >=4σ detections of a HBLR in 11 of these galaxies (73% of the sample) and a tentative detection in NGC 5793, which is Compton-thick according to the analysis of X-ray data performed here. Our results confirm that at least some NHBLRs are misclassified, bringing previous publications reporting differences between HBLR and NHBLR objects into question. We detect broad Hα and Hβ components in polarized light for 10 targets, and just broad Hα for NGC 5793 and NGC 6300, with line widths ranging between 2100 and 9600 km/s. High bolometric luminosities and low column densities are associated with higher polarization degrees, but not necessarily with the detection of the scattered broad components.
description: 18 pages, 19 figures (including appendices). Accepted in MNRAS
PIERRE SACREE AU TOGO
Creators: name: TCHETA, Bidabi
Publisher: name: Inspection de l'Education Nationale, Togo
Year: 2024

description: Épe-Ékpé est un  rassemblement du peuple Guin de Glidji, au Togo. C’est un voyage spirituel profond, permettant aux participants de communier avec leurs ancêtres et de rendre hommage aux 41 divinités centrales de la cosmologie Guin.
Convergence analysis of critical point regularization with non-convex regularizers
Creators: name: Obmann, Daniel
name: Haltmeier, Markus
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optimization and Control (math.OC)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics

description: One of the key assumptions in the stability and convergence analysis of variational regularization is the ability of finding global minimizers. However, such an assumption is often not feasible when the regularizer is a black box or non-convex making the search for global minimizers of the involved Tikhonov functional a challenging task. This is in particular the case for the emerging class of learned regularizers defined by neural networks. Instead, standard minimization schemes are applied which typically only guarantee that a critical point is found. To address this issue, in this paper we study stability and convergence properties of critical points of Tikhonov functionals with a possible non-convex regularizer. To this end, we introduce the concept of relative sub-differentiability and study its basic properties. Based on this concept, we develop a convergence analysis assuming relative sub-differentiability of the regularizer. The rationale behind the proposed concept is that critical points of the Tikhonov functional are also relative critical points and that for the latter a convergence theory can be developed. For the case where the noise level tends to zero, we derive a limiting problem representing first-order optimality conditions of a related restricted optimization problem. Besides this, we also give a comparison with classical methods and show that the class of ReLU-networks are appropriate choices for the regularization functional. Finally, we provide numerical simulations that support our theoretical findings and the need for the sort of analysis that we provide in this paper.
title: Improving Rust Mutation Testing using Static and Dynamic Program Analysis
Creators: name: Pilz, Samuel
Publisher: name: TU Wien
Year: 2023
Subjects: subject: software correctness
subject: software testing
subject: mutation testing
subject: weak and strong mutation analysis
subject: static and dynamic program analysis
subject: Rust

description: Mutationstesten ist eine mächtiger Prozess um Software zu testen. Dabei wird das Zielprogramm mit künstlichen Fehlern versehen, die als mögliche Programmierfehler angenommen werden und die durch qualitativ hochwertige Testfälle entdeckt werden sollten. Die Kosten des Mutationstestens sind einer der kritischsten Eigenschaften, welche die praktische Anwendung erschwert. In dieser Arbeit stellen wir das Tool `muttest` für Mutationsanalyse von Rust Programmen vor, das die Qualität und Performanz von Mutationsanalyse von vergleichbaren Systemen übertrifft. Diese Arbeit stellt einige Techniken vor wie Sprachfeatures von Rust sowie die Ergebnisse von statischer Programmanalyse dazu verwendet werden Mutationsoperatoren zu implementieren, die keine ungültigen Mutationen generieren. Außerdem wird dynamische Programmanalyse dafür verwendet schwache Mutationsanalyse durchzuführen. Diese Ergebnisse werden wiederum dafür eingesetzt die Laufzeit von starker Mutationsanalyse zu verbessern. Durch die Einschränkung auf stabile Sprachfeatures von Rust, stellen wir optimale Kompatibilität von `muttest` mit zukünftigen Versionen von Rust sicher. Die experimentelle Evaluation dieser Arbeit zeigt, dass `muttest` konkurrenzfähige Laufzeit aufweist und einen qualitativ hochwertigen Mutationsanalysebericht liefert.
description: Mutation testing is a powerful software testing method in which the program under test is seeded with artificial faults that are considered to be possible programming errors and should be discovered by a high-quality test suite. The cost of mutation testing is one of the most critical issues for its practical applications. In this thesis, we present the tool `muttest` for mutation analysis of Rust programs that improves quality and performance of mutation analysis compared to related systems. This thesis proposes several methods for leveraging Rust language features and results of static analysis to implement mutation operators while preventing the generation of invalid mutations. Moreover, dynamic program analysis is used to perform weak mutation analysis and its results are utilized to improve the performance of strong mutation analysis. By relying only on stable features of Rust, we ensure best-possible compatibility of `muttest` with future versions of Rust. The experimental evaluation in this thesis shows that `muttest` has competitive performance and produces a high-quality mutation analysis report.
On the heat capacity of liquids at high temperatures
Creators: name: Stishov, S. M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Making use of a simple approximation for the evolution of the radial distribution function, we calculate the temperature dependence of the heat capacity $C_v$ of Ar at constant density. $C_v$ decreases with temperature roughly according to the law $\sim T^{-1/4}$, slowly approaching the hard sphere asymptotic value $C_v=\frac{3}{2}R$. However, the asymptotic value of $C_v$ is not reachable at reasonable temperatures , but stays close to 1.7--1.8 $R$ over a wide range of temperatures after passing a " magic " $2R$ value at about 2000 K. Nevertheless these values has nothing to do with loss of vibrational degrees of freedom, but arises as a result of a temperature variation of the collision diameter $σ$. \end{abstract}
A JWST/NIRCam Study of Key Contributors to Reionization: The Star-forming and Ionizing Properties of UV-faint $z\sim7-8$ Galaxies
Creators: name: Endsley, Ryan
name: Stark, Daniel P.
name: Whitler, Lily
name: Topping, Michael W.
name: Chen, Zuyi
name: Plat, Adele
name: Chisholm, John
name: Charlot, Stéphane
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Spitzer/IRAC imaging has revealed that the brightest $z\sim7-8$ galaxies often exhibit young ages and strong nebular line emission, hinting at high ionizing efficiency among early galaxies. However, IRAC's limited sensitivity has long hindered efforts to study the fainter, more numerous population often thought largely responsible for reionization. Here we use CEERS JWST/NIRCam data to characterize 116 UV-faint (median M$_{UV}=-19.5$) $z\sim6.5-8$ galaxies. The SEDs are typically dominated by young ($\sim$10-50 Myr), low-mass ($M_\ast\sim10^8\ M_\odot$) stellar populations, and we find no need for extremely high stellar masses ($\sim10^{11} M_\odot$). Considering previous studies of UV-bright (M$_{UV}\sim-22$) $z\sim7-8$ galaxies, we find evidence for a strong (5-10$\times$) increase in specific star formation rate toward lower luminosities (median sSFR=103 Gyr$^{-1}$ in CEERS). The larger sSFRs imply a more dominant contribution from OB stars in the relatively numerous UV-faint population, perhaps suggesting that these galaxies are very efficient ionizing agents (median $ξ_{ion}=10^{25.7}$ erg$^{-1}$ Hz). In spite of their much larger sSFRs, we find no significant increase in [OIII]$+$H$β$ EWs towards fainter M$_{UV}$ (median $\approx$780 $\mathring{A}$). If confirmed, this may indicate that a substantial fraction of our CEERS galaxies possess extremely low metallicities ($\lesssim$3% $Z_\odot$) where [OIII] emission is suppressed. Alternatively, high ionizing photon escape fractions or bursty star formation histories can also weaken the nebular lines in a subset of our CEERS galaxies. While the majority of our objects are very blue (median $β=-2.0$), we identify a significant tail of very dusty galaxies ($β\sim-1$) at $\approx$0.5$L_{UV}^\ast$ which may contribute significantly to the $z\sim7-8$ star formation rate density.
description: Accepted in MNRAS. Updated to use the most recent NIRCam zeropoints. There are no significant changes to the conclusions relative to v1
Applying Gaussian distributed constraints to Gaussian distributed variables
Creators: name: Palmer, Andrew W.
name: Hill, Andrew J.
name: Scheding, Steven J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Systems and Control (eess.SY)
subject: Robotics (cs.RO)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: This paper develops an analytical method of truncating inequality constrained Gaussian distributed variables where the constraints are themselves described by Gaussian distributions. Existing truncation methods either assume hard constraints, or use numerical methods to handle uncertain constraints. The proposed approach introduces moment-based Gaussian approximations of the truncated distribution. This method can be applied to numerous problems, with the motivating problem being Kalman filtering with uncertain constraints. In a simulation example, the developed method is shown to outperform unconstrained Kalman filtering by over 40% and hard-constrained Kalman filtering by over 17%.
description: 34 pages, 12 figures, accepted to Information Fusion. Updated to fix minor errors in equations (33), (34), and (B.12)
Variant Parallelism: Lightweight Deep Convolutional Models for Distributed Inference on IoT Devices
Creators: name: Asadi, Navidreza
name: Goudarzi, Maziar
Publisher: name: arXiv
Year: 2022
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Two major techniques are commonly used to meet real-time inference limitations when distributing models across resource-constrained IoT devices: (1) model parallelism (MP) and (2) class parallelism (CP). In MP, transmitting bulky intermediate data (orders of magnitude larger than input) between devices imposes huge communication overhead. Although CP solves this problem, it has limitations on the number of sub-models. In addition, both solutions are fault intolerant, an issue when deployed on edge devices. We propose variant parallelism (VP), an ensemble-based deep learning distribution method where different variants of a main model are generated and can be deployed on separate machines. We design a family of lighter models around the original model, and train them simultaneously to improve accuracy over single models. Our experimental results on six common mid-sized object recognition datasets demonstrate that our models can have 5.8-7.1x fewer parameters, 4.3-31x fewer multiply-accumulations (MACs), and 2.5-13.2x less response time on atomic inputs compared to MobileNetV2 while achieving comparable or higher accuracy. Our technique easily generates several variants of the base architecture. Each variant returns only 2k outputs 1 <= k <= (#classes/2), representing Top-k classes, instead of tons of floating point values required in MP. Since each variant provides a full-class prediction, our approach maintains higher availability compared with MP and CP in presence of failure.
description: 8 pages, 6 figures, 7 tables