cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Theoretical investigation of vacancy related defects at 4H-SiC(000$\bar{1}$)/SiO$_2$ interface after wet oxidation
Creators: name: Tsunasaki, Mukai
name: Ono, Tomoya
name: Uemoto, Mitsuharu
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The stability and formation mechanism of the defects relevant to silicon and carbon vacancies at the 4H-SiC(000$\bar{1}$)/SiO$_2$ interface after wet oxidation are investigated by first-principles calculation based on the density functional theory. The difference in the total energy of the defects agrees with the experimental results concerning the dencity of defects. We found that the characteristic behaviors of the generation of defects are explained by the positions of vacancies and antisites in the SiC(000$\bar{1}$) substrate and that the formation of silicon and carbon vacancies is relevant to the generation mechanism of defects. The generation of silicon and carbon vacancies is attributed to the termination of dangling bonds by H atoms introduced by wet oxidation, resulting in generation of carbon-antisite--carbon-vacancy and divacancies defects in wet oxidation.
description: 12 pages
Spin orbital reorientation transitions induced by magnetic field
Creators: name: Sztenkiel, Dariusz
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Here we report on a new effect similar to the spin reorientation transition (SRT) that takes place at two magnetic fields of $B_{SORT1}$ and $B_{SORT2}$. The effect is observed in the magnetization curves of small Mn$^{3+}$ magnetic clusters in the wurtzite GaN (being in a paramagnetic state) calculated using crystal field model approach. The obtained results suggest that the computed magnetic anisotropy (MA) reverses its sign on increasing $B$ across $B_{SORT}$. Detailed analysis show however that MA is unchanged for high magnetic fields. We show that the observed effect arises from the interplay of the crystalline environment and the spin-orbit coupling $λ\hat{\textbf{S}} \hat{\textbf{L}}$, therefore we name it spin orbital reorientation transition (SORT). The value of $B_{SORT1}$ depends on the crystal field model parameters and the number of ions $N$ in a given cluster, whereas $B_{SORT2}$ is controlled mostly by the magnitude of the spin-orbit coupling $λ$. The explanation of SORT is given in terms of the spin $M_S$ and orbital momentum $M_L$ contributions to the total magnetization $M = M_S + M_L$. The similar effect should also be present in other materials with not completely quenched (non zero) orbital angular momentum $L$, a uniaxial magnetic anisotropy and the positive value of $λ$.
description: 8 pages, 6 figures
A counterexample to dispersive estimates for Schrödinger operators in higher dimensions
Creators: name: Goldberg, M.
name: Visan, M.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Analysis of PDEs (math.AP)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: In dimension $n>3$ we show the existence of a compactly supported potential in the differentiability class $C^α$, $α< \frac{n-3}2$, for which the solutions to the linear Schrödinger equation in $\R^n$, $$ -i\partial_t u = - Δu + Vu, \quad u(0)=f, $$ do not obey the usual $L^1\to L^{\infty}$ dispersive estimate. This contrasts with known results in dimensions $n \leq 3$, where a pointwise decay condition on $V$ is generally sufficient to imply dispersive bounds.
A counterexample to the monotone increasing behavior of an Alt-Caffarelli-Friedman formula in the Heisenberg group
Creators: name: Ferrari, Fausto
name: Forcillo, Nicolò
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35R03, 35R35

description: In this paper we provide a counterexample about the existence of an increasing monotonicity behavior of a function introduced in \cite{FeFo}, companion of the celebrated Alt-Caffarelli-Friedman monotonicity formula, in the noncommutative framework.
Optical/near-infrared observations of the black hole candidate XTE J1720-318: from high-soft to low-hard state
Creators: name: Chaty, Sylvain
name: Bessolaz, Nicolas
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Aims: To gain a better understanding of high-energy Galactic sources, we observed the Galactic X-ray binary and black hole candidate XTE J1720-318 in the optical and near-infrared, just after the onset of its X-ray outburst in January, 2003. These observations were obtained with the ESO/NTT as the Target of Opportunity, in February and April 2003. Methods: We performed an accurate astrometry and analysed photometrical and spectroscopic observations. We then produced a colour-magnitude diagram, looked at the overall evolution of the multi-wavelength light curve, and analysed the spectral energy distribution. Results: We discovered the optical counterpart in the R-band (R ~ 21.5) and confirmed the near-infrared counterpart. We show that, for an absorption between 6 and 8 magnitudes, XTE J1720-318 is likely to be an intermediate mass X-ray binary located at a distance between 3 and 10 kpc, hosting a main sequence star of spectral type between late B and early G. Our second set of observations took place simultaneously with the third secondary outburst present in X-ray and near-infrared light curves. The evolution of its spectral energy distribution shows that XTE J1720-318 entered a transition from a high-soft to a low-hard state in-between the two observations.
description: Astronomy and Astrophysics (in press). 7 pages, 7 figures
Spectrality of random convolutions generated by finitely many Hadamard triples
Creators: name: Li, Wenxia
name: Miao, Jun Jie
name: Wang, Zhiqiang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 28A80, 42C30

description: Let $\{(N_j, B_j, L_j): 1 \le j \le m\}$ be finitely many Hadamard triples in $\mathbb{R}$. Given a sequence of positive integers $\{n_k\}_{k=1}^\infty$ and $ω=(ω_k)_{k=1}^\infty \in \{1,2,\cdots, m\}^\mathbb{N}$, let $μ_{ω,\{n_k\}}$ be the infinite convolution given by $$μ_{ω,\{n_k\}} = δ_{N_{ω_1}^{-n_1} B_{ω_1}} * δ_{N_{ω_1}^{-n_1} N_{ω_2}^{-n_2} B_{ω_2}} * \cdots * δ_{N_{ω_1}^{-n_1} N_{ω_2}^{-n_2} \cdots N_{ω_k}^{-n_k} B_{ω_k} }* \cdots. $$ In order to study the spectrality of $μ_{ω,\{ n_k\}}$, we first show the spectrality of general infinite convolutions generated by Hadamard triples under the equi-positivity condition. Then by using the integral periodic zero set of Fourier transform we show that if $\mathrm{gcd}(B_j - B_j)=1$ for $1 \le j \le m$, then all infinite convolutions $μ_{ω,\{n_k\}}$ are spectral measures. This implies that we may find a subset $Λ_{ω,\{n_k\}}\subseteq \mathbb{R}$ such that $\big\{ e_λ(x) = e^{2πi λx}: λ\in Λ_{ω,\{n_k\}} \big\}$ forms an orthonormal basis for $L^2(μ_{ω,\{ n_k\}})$.
description: 21 pages; final version
Ion source operation at GSI
Creators: name: Hollinger, R.
name: Tinschert, K.
name: Adonin, A.
name: Agahi, D.
name: Berezov, R.
name: Brühl, M.
name: Gutermuth, B.
name: Heymach, F.
name: Ivanova, V.
name: Lang, R.
name: Mäder, J.
name: Maimone, F.
name: Ochs, K.
name: Patchakui, P. T.
name: Roßbach, J.
name: Schäffer, P.
name: Schäffer, S.
name: Vierheller, C.
name: Wesp, A.
name: Zulauf, S.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
An allowed window for heavy neutral leptons below the kaon mass
Creators: name: Bondarenko, Kyrylo
name: Boyarsky, Alexey
name: Klaric, Juraj
name: Mikulenko, Oleksii
name: Ruchayskiy, Oleg
name: Syvolap, Vsevolod
name: Timiryasov, Inar
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The extension of the Standard Model with two gauge-singlet Majorana fermions can simultaneously explain two beyond-the-Standard-model phenomena: neutrino masses and oscillations, as well as the origin of the matter-antimatter asymmetry in the Universe. The parameters of such a model are constrained by the neutrino oscillation data, direct accelerator searches, big bang nucleosynthesis, and requirement of successful baryogenesis. We show that the combination of all these constraints still leaves an allowed region in the parameter space below the kaon mass. This region can be probed by the further searches of NA62, DUNE, or SHiP experiments.
description: 30 pages, 10 figures
Photon pair production at flavour factories with per mille accuracy
Creators: name: Balossini, G.
name: Bignamini, C.
name: Calame, C. M. Carloni
name: Montagna, G.
name: Nicrosini, O.
name: Piccinini, F.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We present a high-precision QED calculation, with 0.1% theoretical accuracy, of two photon production in $e^+ e^-$ annihilation, as required by more and more accurate luminosity monitoring at flavour factories. The accuracy of the approach, which is based on the matching of exact next-to-leading order corrections with a QED Parton Shower algorithm, is demonstrated through a detailed analysis of the impact of the various sources of radiative corrections to the experimentally relevant observables. The calculation is implemented in the latest version of the event generator BabaYaga, available for precision simulations of photon pair production at $e^+ e^-$ colliders of moderately high energies.
description: 11 pages, 5 figures, 1 table
Bistable optical transmission through arrays of atoms in free space
Creators: name: Parmee, C. D.
name: Ruostekoski, J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We determine the transmission of light through a planar atomic array beyond the limit of low light intensity that displays optical bistability in the mean-field regime. We develop a theory describing the intrinsic optical bistability, which is supported purely by resonant dipole-dipole interactions in free space, showing how bistable light amplitudes exhibit both strong cooperative and weak single-atom responses and how they depend on the underlying low light intensity collective excitation eigenmodes. Similarities of the theory with optical bistability in cavities are highlighted, while recurrent light scattering between atoms takes on the role of cavity mirrors. Our numerics and analytic estimates show a sharp variation in the extinction, reflectivity, and group delays of the array, with the incident light completely extinguished up to a critical intensity well beyond the low light intensity limit. Our analysis paves a way for collective nonlinear optics with cooperatively responding dense atomic ensembles.
description: 16 pages, 7 figures; discussion added to conclusions
UNILAC status report
Creators: name: Gerhard, P.
name: Barth, W.
name: Groening, L.
name: Maier, M.
name: Mickat, S.
name: Scheeler, U.
name: Vormann, H.
name: Xiao, C.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Amenable actions, free products and a fixed point property
Creators: name: Glasner, Yair
name: Monod, Nicolas
Publisher: name: arXiv
Year: 2005
Subjects: subject: Group Theory (math.GR)
subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 43A07 (Primary) 20E06, 20F65 (Secondary)

description: We investigate the class of groups admitting an action on a set with an invariant mean. It turns out that many free products admit such an action. We give a complete characterisation of such free products in terms of a strong fixed point property.
description: 12 pages
MGDCF: Distance Learning via Markov Graph Diffusion for Neural Collaborative Filtering
Creators: name: Hu, Jun
name: Hooi, Bryan
name: Qian, Shengsheng
name: Fang, Quan
name: Xu, Changsheng
Publisher: name: arXiv
Year: 2022
Subjects: subject: Social and Information Networks (cs.SI)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Graph Neural Networks (GNNs) have recently been utilized to build Collaborative Filtering (CF) models to predict user preferences based on historical user-item interactions. However, there is relatively little understanding of how GNN-based CF models relate to some traditional Network Representation Learning (NRL) approaches. In this paper, we show the equivalence between some state-of-the-art GNN-based CF models and a traditional 1-layer NRL model based on context encoding. Based on a Markov process that trades off two types of distances, we present Markov Graph Diffusion Collaborative Filtering (MGDCF) to generalize some state-of-the-art GNN-based CF models. Instead of considering the GNN as a trainable black box that propagates learnable user/item vertex embeddings, we treat GNNs as an untrainable Markov process that can construct constant context features of vertices for a traditional NRL model that encodes context features with a fully-connected layer. Such simplification can help us to better understand how GNNs benefit CF models. Especially, it helps us realize that ranking losses play crucial roles in GNN-based CF tasks. With our proposed simple yet powerful ranking loss InfoBPR, the NRL model can still perform well without the context features constructed by GNNs. We conduct experiments to perform detailed analysis on MGDCF.
description: Accepted by IEEE Transactions on Knowledge and Data Engineering (TKDE)
The Axion Mass in Modular Invariant Supergravity
Creators: name: Butter, Daniel
name: Gaillard, Mary K.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: When supersymmetry is broken by condensates with a single condensing gauge group, there is a nonanomalous R-symmetry that prevents the universal axion from acquiring a mass. It has been argued that, in the context of supergravity, higher dimension operators will break this symmetry and may generate an axion mass too large to allow the identification of the universal axion with the QCD axion. We show that such contributions to the axion mass are highly suppressed in a class of models where the effective Lagrangian for gaugino and matter condensation respects modular invariance (T-duality).
description: 10 pages
Flows Between Parallel Plates: Analytical Solutions of Regularized 13-Moment Equations for Inverse-Power-Law Models
Creators: name: Hu, Zhicheng
name: Yang, Siyao
name: Cai, Zhenning
Publisher: name: arXiv
Year: 2020
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We study the structure of stationary channel flows predicted by the regularized 13-moment equations. Compared with the previous work [P. Taheri et al., Phys. Fluids, 21 (2009), 017102], we focus on gases whose molecules satisfy the general inverse power law. The analytical solutions are obtained for the semi-linear equations, and the structures of Couette, Fourier, and Poiseuille flows are solved by coupling the general solutions with newly derived boundary conditions. The results show excellent agreement with the reference solution in the slip-flow regime. Our results also show that the R13 equations derived from inverse power law models can have better accuracy than the R13 equations of Maxwell molecules with altered viscosity.
Measurement of the Helicity of W Bosons in Top-Quark Decays
Creators: name: Abulencia, A.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We measure the branching fraction of the top quark to longitudinally and right-handed polarized $W$ bosons, $F_0$ and $F_+$, using approximately 200 pb$^{-1}$ of $\bar{p}p$ collisions collected by the CDF II detector. We analyze two quantities sensitive to the $W$ helicity: the invariant mass of the charged lepton and the bottom-quark jet in the decay $t\to Wb \to \ellνb$ (where $\ell=e$ or $μ$), and the transverse momentum of the charged lepton. We find $F_0=0.74^{+0.22}_{-0.34}$, and $F_+<0.27$ at the 95% confidence level. These measurements are in agreement with the standard model predictions.
description: 7 pages, 4 figures, submitted to Physical Review Letters
Z_2 x Z_2 Heterotic Orbifold Models of Non Factorisable Six Dimensional Toroidal Manifolds
Creators: name: Faraggi, Alon E.
name: Forste, Stefan
name: Timirgaziu, Cristina
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We discuss heterotic strings on Z_2 x Z_2 orbifolds of non factorisable six-tori. Although the number of fixed tori is reduced as compared to the factorisable case, Wilson lines are still needed for the construction of three generation models. An essential new feature is the straightforward appearance of three generation models with one generation per twisted sector. We illustrate our general arguments for the occurrence of that property by an explicit example. Our findings give further support for the conjecture that four dimensional heterotic strings formulated at the free fermionic point are related to Z_2 x Z_2 orbifolds.
description: 33 pages, LaTeX; discussion of modular invariance added in section four; added references; to be published in JHEP
Detecting Tropical Cyclone from the basic overview of life cycle of Extremely Severe Cyclonic Storm, Tauktae
Creators: name: Yadav, Monu
name: Das, Laxminarayan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: The Extremely Severe Cyclonic Storm (ESCS) Tauktae, which made landfall on the Gujarat coast on May 17, 2021, is discussed in the current study. The analysis is based on INSAT-3D and passive microwave (PMW) images, focusing on the cyclone's eye characteristics and intensity. The satellite images and products are utilized to determine the cyclone's intensity and the specific characteristics of its eye.
 The study showcases the variations in intensity and eye features of the cyclone throughout its life span, providing insights into the process of tropical cyclone intensification. The paper is structured to cover the methods for analysis, an overview of ESCS Tauktae's life cycle, the regulation of intensity based on Dvorak's technique, intensity estimation using ADT9.0 and comparison with SATCON method and Indian Meteorological Department (IMD) provided best track data. Furthermore, the formation of Tauktae's eye, timeframes for eye scenes, comparison with sea surface temperature data, and concluding thoughts are also discussed.
AC electric trapping of neutral atoms
Creators: name: Schlunk, Sophie
name: Marian, Adela
name: Schoellkopf, Wieland
name: Meijer, Gerard
Publisher: name: arXiv
Year: 2008
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We study the dynamic behavior of ultracold neutral atoms in a macroscopic ac electric trap. Confinement in such a trap is achieved by switching between two saddle-point configurations of the electric field. The gradual formation of a stably trapped cloud is observed and the trap performance is studied versus the switching frequency and the symmetry of the switching cycle. Additionally, the electric field in the trap is mapped out by imaging the atom cloud while the fields are still on. Finally, the phase-space acceptance of the trap is probed by introducing a modified switching cycle. The experimental results are reproduced using full three-dimensional trajectory calculations.
description: 10 pages, 13 figures, updated version, added journal reference
Thermal stress analysis of defect formation in fused-cast alumina refractories
Creators: name: Au, Dominic Ka Man
Publisher: name: University of British Columbia
Year: 2009

description: Mathematical models have been developed to predict the temperature, stress and strain evolution during the manufacture of fused-cast αβ-alumina refractories approximately consistent with the process used at Monofrax Inc.. An uncoupled thermal stress model, which consists of a heat transfer model to predict the temperature evolution and a mechanical model to predict the stress and strain evolution, has been formulated. The commercial finite element code ABAQUS was employed in the thermal stress analysis. The thermal model was validated against industrial thermocouple and pyrometer measurements obtained at Monofrax Inc., located in Falconer, NY. The model predictions were in good agreement with the thermocouple data obtained at several locations from within the graphite mold, during Stage I cooling, and in the alumina annealing ore, during Stage II cooling. In Stage I cooling, it has been necessary to augment the conductivity of the liquid alumina to account for convective heat transport. In Stage II cooling, it proved necessary to account for asymmetric placement of the block in the annealing bin. The temperatures obtained from the thermal model were utilized as input to the mechanical model. Elastic and elastic-plastic stress analyses were conducted to assess the evolution of stress and strain during the casting process. The strain rate independent inelastic behavior of the casting based on the flexural tests performed at Oak Ridge National Laboratory was incorporated into the elastic-plastic stress model. The results obtained from the elastic-plastic stress model were more realistic than those predicted by the elastic analyses. However, the plastic strain may be under-predicted during Stage II cooling owing to the strain rate independent plasticity employed in the analysis. The preliminary stress/strain predictions indicate that the β-alumina core plays an important role in the generation of tensile stresses and likely gives rise to the generation of cracks. Since high tensile stress/strain was found to develop within the refractory, it is likely that crack initiates subsurface and propagates outwards. Overall, the results of the present research show the importance and usefulness of developing the ability to predict temperature, stress and strain evolution in the fused-cast αβ-alumina refractories during the manufacturing process.
ANDREA, a compact neutron dosimeter
Creators: name: Sokolov, A.
name: Fehrenbacher, G.
name: Kozlova, E.
name: Radon, T.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Radiation damage to materials for FAIR
Creators: name: Belousov, A.
name: Fehrenbacher, G.
name: Lang, R.
name: Radon, T.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Shielding upgrade for the section S05 - S06 of the SIS18 beam tunnel
Creators: name: Stuman, F.
name: Kozlova, E.
name: Lang, R.
name: Radon, T.
name: Fehrenbacher, G.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Interplay between friction and spin-orbit coupling as a source of spin polarization
Creators: name: Volosniev, Artem G.
name: Alpern, Hen
name: Paltiel, Yossi
name: Millo, Oded
name: Lemeshko, Mikhail
name: Ghazaryan, Areg
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study an effective one-dimensional quantum model that includes friction and spin-orbit coupling (SOC), and show that the model exhibits spin polarization when both terms are finite. Most important, strong spin polarization can be observed even for moderate SOC, provided that friction is strong. Our findings might help to explain the pronounced effect of chirality on spin distribution and transport in chiral molecules. In particular, our model implies static magnetic properties of a chiral molecule, which lead to Shiba-like states when a molecule is placed on a superconductor, in accordance with recent experimental data.
description: Version accepted for publication in Physical Review B
A review of path following control strategies for autonomous robotic vehicles: theory, simulations, and experiments
Creators: name: Hung, Nguyen
name: Rego, Francisco
name: Quintas, Joao
name: Cruz, Joao
name: Jacinto, Marcelo
name: Souto, David
name: Potes, Andre
name: Sebastiao, Luis
name: Pascoal, Antonio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: Systems and Control (eess.SY)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This article presents an in-depth review of the topic of path following for autonomous robotic vehicles, with a specific focus on vehicle motion in two dimensional space (2D). From a control system standpoint, path following can be formulated as the problem of stabilizing a path following error system that describes the dynamics of position and possibly orientation errors of a vehicle with respect to a path, with the errors defined in an appropriate reference frame. In spite of the large variety of path following methods described in the literature we show that, in principle, most of them can be categorized in two groups: stabilization of the path following error system expressed either in the vehicle's body frame or in a frame attached to a "reference point" moving along the path, such as a Frenet-Serret (F-S) frame or a Parallel Transport (P-T) frame. With this observation, we provide a unified formulation that is simple but general enough to cover many methods available in the literature. We then discuss the advantages and disadvantages of each method, comparing them from the design and implementation standpoint. We further show experimental results of the path following methods obtained from field trials testing with under-actuated and fully-actuated autonomous marine vehicles. In addition, we introduce open-source Matlab and Gazebo/ROS simulation toolboxes that are helpful in testing path following methods prior to their integration in the combined guidance, navigation, and control systems of autonomous vehicles.
Radiation protection update for the FAIR APPA building
Creators: name: Lang, R.
name: Belousov, A.
name: Fehrenbacher, G.
name: Radon, T.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Conjectures on reductive homogeneous spaces
Creators: name: Kobayashi, Toshiyuki
Publisher: name: arXiv
Year: 2022
Subjects: subject: Representation Theory (math.RT)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: Primary 22E40, 22E46, 58J50, Secondary 11F72, 43C35

description: We address some conjectures and open problems in "analysis of symmetries" which include the study of non-commutative harmonic analysis and discontinuous groups for reductive homogeneous spaces beyond the classical framework:
(1) discrete series for non-symmetric homogeneous spaces $G/H$;
(2) discontinuous group $Γ$ for $G/H$ beyond the Riemannian setting;
(3) analysis on pseudo-Riemannian locally homogeneous spaces.
description: To appear in "Mathematics Going Forward", Lecture Notes in Mathematics, vol.2313
Particle decay in false vacuum
Creators: name: Gorsky, A.
name: Voloshin, M. B.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We revisit the problem of decay of a metastable vacuum induced by the presence of a particle. For the bosons of the `master field' the problem is solved in any number of dimensions in terms of the spontaneous decay rate of the false vacuum, while for a fermion we find a closed expression for the decay rate in (1+1) dimensions. It is shown that in the (1+1) dimensional case an infrared problem of one-loop correction to the decay rate of a boson is resolved due to a cancellation between soft modes of the field. We also find the boson decay rate in the `sine-Gordon staircase' model in the limits of strong and weak coupling.
description: 19 pages, 2 figures
Approximate Sampling of Graphs with Near-$P$-stable Degree Intervals
Creators: name: Erdős, Péter L.
name: Mezei, Tamás Róbert
name: Miklós, István
Publisher: name: arXiv
Year: 2022
Subjects: subject: Combinatorics (math.CO)
subject: Discrete Mathematics (cs.DM)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 05C30 60J10 68R10

description: The approximate uniform sampling of graph realizations with a given degree sequence is an everyday task in several social science, computer science, engineering etc. projects. One approach is using Markov chains. The best available current result about the well-studied switch Markov chain is that it is rapidly mixing on P-stable degree sequences (see DOI:10.1016/j.ejc.2021.103421). The switch Markov chain does not change any degree sequence. However, there are cases where degree intervals are specified rather than a single degree sequence. (A natural scenario where this problem arises is in hypothesis testing on social networks that are only partially observed.) Rechner, Strowick, and Müller-Hannemann introduced in 2018 the notion of degree interval Markov chain which uses three (separately well-studied) local operations (switch, hinge-flip and toggle), and employing on degree sequence realizations where any two sequences under scrutiny have very small coordinate-wise distance. Recently Amanatidis and Kleer published a beautiful paper (arXiv:2110.09068), showing that the degree interval Markov chain is rapidly mixing if the sequences are coming from a system of very thin intervals which are centered not far from a regular degree sequence. In this paper we extend substantially their result, showing that the degree interval Markov chain is rapidly mixing if the intervals are centred at P-stable degree sequences.
description: Fixed the title
The Swift Bulge Survey: Motivation, Strategy, and First X-ray Results
Creators: name: Bahramian, A.
name: Heinke, C. O.
name: Kennea, J. A.
name: Maccarone, T. J.
name: Evans, P. A.
name: Wijnands, R.
name: Degenaar, N.
name: Zand, J. J. M. in't
name: Shaw, A. W.
name: Sandoval, L. E. Rivera
name: McClure, S.
name: Tetarenko, A. J.
name: Strader, J.
name: Kuulkers, E.
name: Sivakoff, G. R.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Very faint X-ray transients (VFXTs) are X-ray transients with peak X-ray luminosities ($L_X$) of $L_X\lesssim10^{36}$ erg/s, which are not well-understood. We carried out a survey of 16 square degrees of the Galactic Bulge with the Swift Observatory, using short (60 s) exposures, and returning every 2 weeks for 19 epochs in 2017-18 (with a gap from November 2017 to February 2018, when the Bulge was in sun-constraint). Our main goal was to detect and study VFXT behaviour in the Galactic Bulge across various classes of X-ray sources. In this work, we explain the observing strategy of the survey, compare our results with the expected number of source detections per class, and discuss the constraints from our survey on the Galactic VFXT population. We detected 91 X-ray sources, 25 of which have clearly varied by a factor of at least 10. 45 of these X-ray sources have known counterparts: 17 chromospherically active stars, 12 X-ray binaries, 5 cataclysmic variables (and 4 candidates), 3 symbiotic systems, 2 radio pulsars, 1 AGN, and a young star cluster. The other 46 are of previously undetermined nature. We utilize X-ray hardness ratios, searches for optical/infrared counterparts in published catalogs, and flux ratios from quiescence to outburst to constrain the nature of the unknown sources. Of these 46, 7 are newly discovered hard transients, which are likely VFXT X-ray binaries. Furthermore, we find strong new evidence for a symbiotic nature of 4 sources in our full sample, and new evidence for accretion power in 6 X-ray sources with optical counterparts. Our findings indicate that a large subset of VXFTs is likely made up of symbiotic systems.
description: 23 pages, 9 figures, 7 tables, MNRAS in press. The machine-readable catalog and the complete figure-set of light curves included in the arxiv source (accessible via "other formats")
Single Spin Asymmetries in the BRAHMS Experiment
Creators: name: Videbaek, F.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The BRAHMS experiment at RHIC has the capability to measure the transverse spin asymmetries in polarized pp induced pion production at RHIC. The first results from the short run-4 show a signaificant asymmetry for pi-plus and pi-minus at moderate xF. The trend of the data is in agreement with lower energy data while the absolute value are surprisingly large.
description: 4 pages, 3 figures. To appear in the proceedings of the XIII International Workshop on Deep Inelastic Scattering (DIS 2005, Madison)
Radiation protection for SIS 100 - Shielding in extraction area
Creators: name: Conrad, I.
name: Fehrenbacher, G.
name: Lang, Rupert
name: Sokolov, A.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Density functional theory calculations for investigation of atomic structures of 4H-SiC/SiO$_2$ interface after NO annealing
Creators: name: Komatsu, Naoki
name: Ohmoto, Mizuho
name: Uemoto, Mitsuharu
name: Ono, Tomoya
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We propose the atomic structures of the 4H-SiC/SiO$_2$ interface for the $a$, $m$, C, and Si faces after NO annealing. Our proposed structures preferentially form at the topmost layers of the SiC side of the interface, which agrees with the experimental finding of secondary-ion mass spectrometry, that is, the N atoms accumulate at the interface. In addition, the areal N-atom density is on the order of 10$^{14}$ atom/cm$^2$ for each plane, which is also consistent with the experimental result. Moreover, the electronic structure of the interface after NO annealing, in which the CO bonds are removed and the nitride layer only at the interface is inserted, is free from gap states, although some interface models before NO annealing include the gap states arising from the CO bonds near the valence band edge of the bandgap. Our results imply that NO annealing can contribute to the reduction in the density of interface defects by forming the nitride layer.
description: 10 pages and 7 figures
Dose Measurements at SIS18 and in the experimental halls TR, EX, TH
Creators: name: Radon, T.
name: Beverung, K.
name: Fleissner, R.
name: Freml, P.
name: Kewes, P.
name: Pöppe, C.
name: Sauer, J.
Publisher: name: GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
Year: 2015
Subjects: Physics

description: GSI Scientific Report 2014 - GSI Report 2015-1
Enhancement of Proximity Induced Superconductivity in a Planar Ge Hole Gas
Creators: name: Aggarwal, Kushagra
name: Hofmann, Andrea
name: Jirovec, Daniel
name: Prieto, Ivan
name: Sammak, Amir
name: Botifoll, Marc
name: Marti-Sanchez, Sara
name: Veldhorst, Menno
name: Arbiol, Jordi
name: Scappucci, Giordano
name: Danon, Jeroen
name: Katsaros, Georgios
Publisher: name: arXiv
Year: 2020
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Hole gases in planar germanium can have high mobilities in combination with strong spin-orbit interaction and electrically tunable g-factors, and are therefore emerging as a promising platform for creating hybrid superconductor-semiconductor devices. A key challenge towards hybrid Ge-based quantum technologies is the design of high-quality interfaces and superconducting contacts that are robust against magnetic fields. In this work, by combining the assets of aluminum, which provides good contact to the Ge, and niobium, which has a significant superconducting gap, we demonstrate highly transparent low-disordered JoFETs with relatively large \IcRn \ products that are capable of withstanding high magnetic fields. We furthermore demonstrate the ability of phase-biasing individual JoFETs, opening up an avenue to explore topological superconductivity in planar Ge. The persistence of superconductivity in the reported hybrid devices beyond 1.8 Tesla paves the way towards integrating spin qubits and proximity-induced superconductivity on the same chip.
GANs as Gradient Flows that Converge
Creators: name: Huang, Yu-Jui
name: Zhang, Yuchong
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Optimization and Control (math.OC)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: This paper approaches the unsupervised learning problem by gradient descent in the space of probability density functions. A main result shows that along the gradient flow induced by a distribution-dependent ordinary differential equation (ODE), the unknown data distribution emerges as the long-time limit. That is, one can uncover the data distribution by simulating the distribution-dependent ODE. Intriguingly, the simulation of the ODE is shown equivalent to the training of generative adversarial networks (GANs). This equivalence provides a new "cooperative" view of GANs and, more importantly, sheds new light on the divergence of GANs. In particular, it reveals that the GAN algorithm implicitly minimizes the mean squared error (MSE) between two sets of samples, and this MSE fitting alone can cause GANs to diverge. To construct a solution to the distribution-dependent ODE, we first show that the associated nonlinear Fokker-Planck equation has a unique weak solution, by the Crandall-Liggett theorem for differential equations in Banach spaces. Based on this solution to the Fokker-Planck equation, we construct a unique solution to the ODE, using Trevisan's superposition principle. The convergence of the induced gradient flow to the data distribution is obtained by analyzing the Fokker-Planck equation.
Linearly discounted economic MPC without terminal conditions for periodic optimal operation
Creators: name: Schwenkel, Lukas
name: Hadorn, Alexander
name: Müller, Matthias A.
name: Allgöwer, Frank
Publisher: name: arXiv
Year: 2022
Subjects: subject: Systems and Control (eess.SY)
subject: Optimization and Control (math.OC)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Mathematics

description: In this work, we study economic model predictive control (MPC) in situations where the optimal operating behavior is periodic. In such a setting, the performance of a standard economic MPC scheme without terminal conditions can generally be far from optimal even with arbitrarily long prediction horizons. Whereas there are modified economic MPC schemes that guarantee optimal performance, all of them are based on prior knowledge of the optimal period length or of the optimal periodic orbit itself. In contrast to these approaches, we propose to achieve optimality by multiplying the stage cost by a linear discount factor. This modification is not only easy to implement but also independent of any system- or cost-specific properties, making the scheme robust against online changes therein. Under standard dissipativity and controllability assumptions, we can prove that the resulting linearly discounted economic MPC without terminal conditions achieves optimal asymptotic average performance up to an error that vanishes with growing prediction horizons. Moreover, we can guarantee practical asymptotic stability of the optimal periodic orbit under the additional technical assumption that dissipativity holds with a continuous storage function. We complement these qualitative guarantees with a quantitative analysis of the transient and asymptotic average performance of the linearly discounted MPC scheme in a numerical simulation study.
A FIRST-APM-SDSS survey for high-redshift radio QSOs
Creators: name: Carballo, R.
name: Gonzalez-Serrano, J. I.
name: Montenegro-Montes, F. M.
name: Benn, C. R.
name: Mack, K. -H.
name: Pedani, M.
name: Vigotti, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We selected from VLA-FIRST a sample of 94 objects starlike in SDSSS, and with APM colour O-E>2, i.e. consistent with their being high-z QSOs. 78 candidates were classified spectroscopically from published data (mainly SDSS) or observations reported here. The fractions of QSOs (51/78) and z > 3 QSOs (23/78) are comparable to those found in other photometric searches for high-z QSOs. We confirm that O-E>2 ensures inclusion of all QSOs with 3.7 < z < 4.4. The fraction of broad absorption line (BAL) QSOs for 2 < z < 4.4 is 27+-10 per cent (7/26), and the estimated BAL fraction for radio loud (RL) QSOs is at least as high as for optically selected QSOs (about 13 per cent). The high BAL fraction and the high fraction of LoBALs in our sample are likely due to the red colour selection. The space density of RL QSOs for 3.7 < z < 4.4, MAB (1450 A) < -26.6 and P(1.4 GHz) > 10^25.7 W Hz^(-1) is 1.7+-0.6 Gpc^(-3). Adopting a RL fraction 13.4+-3 per cent, this corresponds to rho = 12.5+-5.6 Gpc^(-3), in good agreement with the SDSS QSO luminosity function in Fan et al. (2001). We note the unusual QSO FIRST 1413+4505 (z=3.11), which shows strong associated Lyalpha absorption and an extreme observed luminosity, L about 2 x 10^(15) solar luminosities.
description: Accepted for publication in MNRAS; 9 figures and 6 tables; Table 2 is in landscape format
Emergent gauge symmetries: Yang-Mills theory
Creators: name: Barceló, Carlos
name: Carballo-Rubio, Raúl
name: Garay, Luis J.
name: García-Moreno, Gerardo
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Gauge symmetries remove unphysical states and guarantee that field theories are free from the pathologies associated with these states. In this work we find a set of general conditions that guarantee the removal of unphysical states in field theories describing interacting vector fields. These conditions are obtained through the extension of a mechanism for the emergence of gauge symmetries proposed in a previous article [C. Barceló et al. JHEP 10 (2016) 084] in order to account for non-Abelian gauge symmetries, and are the following: low-energy Lorentz invariance, emergence of massless vector fields describable by an action quadratic in those fields and their derivatives, and self-coupling to a conserved current associated with specific rigid symmetries. Using a bootstrapping procedure, we prove that these conditions are equivalent to the emergence of gauge symmetries and, therefore, guarantee that any theory satisfying them must be equivalent to a Yang-Mills theory at low energies.
description: 15 pages, no figures; v2: Added minor changes in text to match published version
Center of mass motion in bag model
Creators: name: Liu, Chia-Wei
name: Geng, Chao-Qiang
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Despite the great success on the mass spectra, the reputation of the bag model has been closely followed by the embarrassment from the center of mass motion. It leads to severe theoretical inconsistencies. For instance, the masses and the decay constants would no longer be independent of the momentum. In this work, we provide a systematical approach to resolve this problem. The meson decay constants as well as the baryon transition form factors can be computed consistently in our framework. Notably, the form factors in the neutron $β$ decays do not depend on any free parameters, and are determined to be $F^V_1 =1 $ and $F^A_1 = 1.31$ or $F_1^A/F_1^V= 1.31$, which is close the experimental value of $F^A_1/F^V_1 = 1.27$. In addition, we find that ${\cal B} (Λ_b \to Λγ) = (6.8 \pm 3.3 ) \times 10^{-6} $, which agrees to the experimental value of $(7.1\pm 1.7)\times 10^{-6}$.
description: 21 pages, 2 figures
Phase coherent transport in (Ga,Mn)As
Creators: name: Neumaier, D.
name: Wagner, K.
name: Wurstbauer, U.
name: Reinwald, M.
name: Wegscheider, W.
name: Weiss, D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Quantum interference effects and resulting quantum corrections of the conductivity have been intensively studied in disordered conductors over the last decades. The knowledge of phase coherence lengths and underlying dephasing mechanisms are crucial to understand quantum corrections to the resistivity in the different material systems. Due to the internal magnetic field and the associated breaking of time-reversal symmetry quantum interference effects in ferromagnetic materials have been scarcely explored. Below we describe the investigation of phase coherent transport phenomena in the newly discovered ferromagnetic semiconductor (Ga,Mn)As. We explore universal conductance fluctuations in mesoscopic (Ga,Mn)As wires and rings, the Aharonov-Bohm effect in nanoscale rings and weak localization in arrays of wires, made of the ferromagnetic semiconductor material. The experiments allow to probe the phase coherence length L_phi and the spin flip length L_SO as well as the temperature dependence of dephasing.
description: 22 pages, 10 figures
Global optimization of tensor renormalization group using the corner transfer matrix
Creators: name: Morita, Satoshi
name: Kawashima, Naoki
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: A tensor network renormalization algorithm with global optimization based on the corner transfer matrix is proposed. Since the environment is updated by the corner transfer matrix renormalization group method, the forward-backward iteration is unnecessary, which is a time-consuming part of other methods with global optimization. In addition, a further approximation reducing the order of the computational cost of contraction for the calculation of the coarse-grained tensor is proposed. The computational time of our algorithm in two dimensions scales as the sixth power of the bond dimension while the higher-order tensor renormalization group and the higher-order second renormalization group methods have the seventh power. We perform benchmark calculations in the Ising model on the square lattice and show that the time-to-solution of the proposed algorithm is faster than that of other methods.
description: 6 pages, 9 figures