cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Neutron and muon-induced background studies for the AMoRE double-beta decay experiment
Creators: name: Bae, H. W.
name: Jeon, E. J.
name: Kim, Y. D.
name: Lee, S. W.
Publisher: name: arXiv
Year: 2018
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: AMoRE (Advanced Mo-based Rare process Experiment) is an experiment to search a neutrinoless double-beta decay of $^{100}$Mo in molybdate crystals. The neutron and muon-induced backgrounds are crucial to obtain the zero-background level (<$10^{-5}$ counts/(keV$\cdot$kg$\cdot$yr)) for the AMoRE-II experiment, which is the second phase of the AMoRE project, planned to run at YEMI underground laboratory. To evaluate the effects of neutron and muon-induced backgrounds, we performed Geant4 Monte Carlo simulations and studied a shielding strategy for the AMORE-II experiment. Neutron-induced backgrounds were also included in the study. In this paper, we estimated the background level in the presence of possible shielding structures, which meet the background requirement for the AMoRE-II experiment.
Experimental radiative lifetimes for highly excited states and calculated oscillator strengths for lines of astrophysical interest in singly ionized cobalt (Co II)
Creators: name: Quinet, P.
name: Fivet, V.
name: Palmeri, P.
name: Engstrom, L.
name: Hartman, H.
name: Lundberg, H.
name: Nilsson, H.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions of astrophysical interest in singly ionized cobalt. More precisely, nineteen radiative lifetimes in Co+ have been measured with the time-resolved laser-induced fluorescence technique using one- and two-step excitations. Out of these, seven belonging to the high lying 3d$^7$($^4$F)4d configuration in the energy range 90697 - 93738 cm$^{-1}$ are new, and the other twelve from th3d$^7$($^4$F)F)4p configuration with energies between 45972 and 49328 cm$^{-1}$1 are compared with previous measurements. In addition, a relativistic Hartree-Fock model including core-polarization effects has been employed to compute transition rates. Supported by the good agreement between theory and experiment for the lifetimes, new reliable transition probabilities and oscillator strengths have been deduced for 5080 Co II transitions in the spectral range 114 - 8744 nm.
Strategy for implementing novel societal applications of accelerators
Creators: name: IFAST WP12 Members
Publisher: name: Zenodo
Year: 2023

description: Particle accelerators are already extensively used in health and industry for a wide range of applications, including cancer treatment, polymer modification, sterilisation of medical products, radioisotope production, imaging, phyto-sanitation, food treatment, etc. These exploit the unique features of the accelerated beams and the control the use of accelerators provides. Nevertheless, accelerators have a much greater potential which is currently not being fully exploited. This is due to many reasons, including a lack of knowledge in industry of what benefits they could bring, the perceived and real cost of the technology, the absence of the skills required to assess the potential for a specific industry and to implement the technology and concerns over safety and regulation.
description: {"references": ["I.FAST Del12.1"]}
Supplementary document for Multi-Solution Inverse Design in Photonics using Generative Modelling - 6822136.pdf
Creators: name: Kumar, Preetam
name: Patra, Aniket
name: Shivaleela, E.S.
name: Caligiuri, Vincenzo
name: Krahne, Roman
name: De Luca, Antonio
name: Talabattula, Srinivas
Publisher: name: Optica Publishing Group
Year: 2024
Subjects: Uncategorized

description: This is a supporting document for our work.
Stroke-based sketched symbol reconstruction and segmentation
Creators: name: Kaiyrbekov, Kurmanbek
name: Sezgin, Metin
Publisher: name: arXiv
Year: 2019
Subjects: subject: Graphics (cs.GR)
subject: FOS: Computer and information sciences

description: Hand-drawn objects usually consist of multiple semantically meaningful parts. For example, a stick figure consists of a head, a torso, and pairs of legs and arms. Efficient and accurate identification of these subparts promises to significantly improve algorithms for stylization, deformation, morphing and animation of 2D drawings. In this paper, we propose a neural network model that segments symbols into stroke-level components. Our segmentation framework has two main elements: a fixed feature extractor and a Multilayer Perceptron (MLP) network that identifies a component based on the feature. As the feature extractor we utilize an encoder of a stroke-rnn, which is our newly proposed generative Variational Auto-Encoder (VAE) model that reconstructs symbols on a stroke by stroke basis. Experiments show that a single encoder could be reused for segmenting multiple categories of sketched symbols with negligible effects on segmentation accuracies. Our segmentation scores surpass existing methodologies on an available small state of the art dataset. Moreover, extensive evaluations on our newly annotated big dataset demonstrate that our framework obtains significantly better accuracies as compared to baseline models. We release the dataset to the community.
Bar-driven evolution and quenching of spiral galaxies in cosmological simulations
Creators: name: Spinoso, Daniele
name: Bonoli, Silvia
name: Dotti, Massimo
name: Mayer, Lucio
name: Madau, Piero
name: Bellovary, Jillian
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We analyse the output of the hi-res cosmological zoom-in simulation ErisBH to study self-consistently the formation of a strong stellar bar in a Milky Way-type galaxy and its effect on the galactic structure, on the central gas distribution and on star formation. The simulation includes radiative cooling, star formation, SN feedback and a central massive black hole which is undergoing gas accretion and is heating the surroundings via thermal AGN feedback. A large central region in the ErisBH disk becomes bar-unstable after z~1.4, but a clear bar-like structure starts to grow significantly only after z~0.4, possibly triggered by the interaction with a massive satellite. At z~0.1 the bar reaches its maximum radial extent of l~2.2 kpc. As the bar grows, it becomes prone to buckling instability, which we quantify based on the anisotropy of the stellar velocity dispersion. The actual buckling event is observable at z~0.1, resulting in the formation of a boxy-peanut bulge clearly discernible in the edge-on view of the galaxy at z=0. The bar in ErisBH does not dissolve during the formation of the bulge but remains strongly non-axisymmetric down to the resolution limit of ~100 pc at z=0. During its early growth, the bar exerts a strong torque on the gas within its extent and drives gas inflows that enhance the nuclear star formation on sub-kpc scales. Later on the infalling gas is nearly all consumed into stars and, to a lesser extent, accreted onto the central black hole, leaving behind a gas-depleted region within the central ~2 kpc. Observations would more likely identify a prominent, large-scale bar at the stage when the galactic central region has already been quenched. Bar-driven quenching may play an important role in disk-dominated galaxies at all redshift. [Abridged]
description: 13 pages, 12 figures, MNRAS submitted
Real-root property of the spectral polynomial of the Treibich-Verdier potential and related problems
Creators: name: Chen, Zhijie
name: Kuo, Ting-Jung
name: Lin, Chang-Shou
name: Takemura, Kouichi
Publisher: name: arXiv
Year: 2016
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We study the spectral polynomial of the Treibich-Verdier potential. Such spectral polynomial, which is a generalization of the classical Lame polynomial, plays fundamental roles in both the finite-gap theory and the ODE theory of Heun's equation. In this paper, we prove that all the roots of such spectral polynomial are real and distinct under some assumptions. The proof uses the classical concept of Sturm sequence and isomonodromic theories. We also prove an analogous result for a polynomial associated with a generalized Lame equation. Differently, our new approach is based on the viewpoint of the monodromy data.
description: 22 pages
Optimized Lie-Trotter-Suzuki decompositions for two and three non-commuting terms
Creators: name: Barthel, Thomas
name: Zhang, Yikang
Publisher: name: arXiv
Year: 2019
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Lie-Trotter-Suzuki decompositions are an efficient way to approximate operator exponentials $\exp(t H)$ when $H$ is a sum of $n$ (non-commuting) terms which, individually, can be exponentiated easily. They are employed in time-evolution algorithms for tensor network states, digital quantum simulation protocols, path integral methods like quantum Monte Carlo, and splitting methods for symplectic integrators in classical Hamiltonian systems. We provide optimized decompositions up to order $t^6$. The leading error term is expanded in nested commutators (Hall bases) and we minimize the 1-norm of the coefficients. For $n=2$ terms, several of the optima we find are close to those in McLachlan, SlAM J. Sci. Comput. 16, 151 (1995). Generally, our results substantially improve over unoptimized decompositions by Forest, Ruth, Yoshida, and Suzuki. We explain why these decompositions are sufficient to efficiently simulate any one- or two-dimensional lattice model with finite-range interactions. This follows by solving a partitioning problem for the interaction graph.
description: 30 pages, 8 figures, 8 tables; added results, figures, and references, extended discussion
Maintaining the Union of Unit Discs under Insertions with Near-Optimal Overhead
Creators: name: Agarwal, Pankaj K.
name: Cohen, Ravid
name: Halperin, Dan
name: Mulzer, Wolfgang
Publisher: name: arXiv
Year: 2019
Subjects: subject: Computational Geometry (cs.CG)
subject: FOS: Computer and information sciences

description: We present efficient dynamic data structures for maintaining the union of unit discs and the lower envelope of pseudo-lines in the plane. More precisely, we present three main results in this paper: (i) We present a linear-size data structure to maintain the union of a set of unit discs under insertions. It can insert a disc and update the union in $O((k+1) \log^2 n)$ time, where $n$ is the current number of unit discs and $k$ is the combinatorial complexity of the structural change in the union due to the insertion of the new disc. It can also compute, within the same time bound, the area of the union after the insertion of each disc. (ii) We propose a linear-size data structure for maintaining the lower envelope of a set of $x$-monotone pseudo-lines. It can handle insertion/deletion of a pseudo-line in $O(\log^2 n)$ time; for a query point $x_0\in\mathbb{R}$, it can report, in $O(\log n)$ time, the point on the lower envelope with $x$-coordinate $x_0$; and for a query point $q\in\mathbb{R}^2$, it can return all $k$ pseudo-lines lying below $q$ in time $O(\log n+k\log^2 n)$. (iii) We present a linear-size data structure for storing a set of circular arcs of unit radius (not necessarily on the boundary of the union of the corresponding discs), so that for a query unit disc $D$, all input arcs intersecting $D$ can be reported in $O(n^{1/2+\varepsilon} + k)$ time, where $k$ is the output size and $\varepsilon > 0$ is an arbitrarily small constant. A unit-circle arc can be inserted or deleted in $O(\log^2 n)$ time.
description: 29 pages, 19 figures; this article is an extension of our previous work arXiv:1902.09565; a preliminary version appeared at SoCG 2019
Integrating out heavy particles with functional methods: a simplified framework
Creators: name: Fuentes-Martin, Javier
name: Portoles, Jorge
name: Ruiz-Femenia, Pedro
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present a systematic procedure to obtain the one-loop low-energy effective Lagrangian resulting from integrating out the heavy fields of a given ultraviolet theory. We show that the matching coefficients are determined entirely by the hard region of the functional determinant involving the heavy fields. This represents an important simplification with respect the conventional matching approach, where the full and effective theory contributions have to be computed separately and a cancellation of the infrared divergent parts has to take place. We illustrate the method with a descriptive toy model and with an extension of the Standard Model with a heavy real scalar triplet. A comparison with other schemes that have been put forward recently is also provided.
description: 24 pages. Uses feynMF package
No-dimensional Tverberg Theorems and Algorithms
Creators: name: Choudhary, Aruni
name: Mulzer, Wolfgang
Publisher: name: arXiv
Year: 2019
Subjects: subject: Computational Geometry (cs.CG)
subject: FOS: Computer and information sciences

description: Tverberg's theorem states that for any $k \ge 2$ and any set $P \subset \mathbb{R}^d$ of at least $(d + 1)(k - 1) + 1$ points in $d$ dimensions, we can partition $P$ into $k$ subsets whose convex hulls have a non-empty intersection. The associated search problem of finding the partition lies in the complexity class $\text{CLS} = \text{PPAD} \cap \text{PLS}$, but no hardness results are known. In the colorful Tverberg theorem, the points in $P$ have colors, and under certain conditions, $P$ can be partitioned into colorful sets, in which each color appears exactly once and whose convex hulls intersect. To date, the complexity of the associated search problem is unresolved. Recently, Adiprasito, Barany, and Mustafa gave a no-dimensional Tverberg theorem, in which the convex hulls may intersect in an approximate fashion. This relaxes the requirement on the cardinality of $P$. The argument is constructive, but does not result in a polynomial-time algorithm. We present a deterministic algorithm that finds for any $n$-point set $P \subset \mathbb{R}^d$ and any $k \in \{2, \dots, n\}$ in $O(nd \lceil{\log k}\rceil)$ time a $k$-partition of $P$ such that there is a ball of radius $O\left((k/\sqrt{n})\mathrm{diam(P)}\right)$ that intersects the convex hull of each set. Given that this problem is not known to be solvable exactly in polynomial time, our result provides a remarkably efficient and simple new notion of approximation. Our main contribution is to generalize Sarkaria's method to reduce the Tverberg problem to the Colorful Caratheodory problem (in the simplified tensor product interpretation of Barany and Onn) and to apply it algorithmically. It turns out that this not only leads to an alternative algorithmic proof of a no-dimensional Tverberg theorem, but it also generalizes to other settings such as the colorful variant of the problem.
description: 29 pages, 3 figures; a preliminary version appeared as SoCG 2020
Stability analysis of the homogeneous hydrodynamics of a model for a confined granular gas
Creators: name: Brey, J. Javier
name: Buzón, V.
name: de Soria, M. I. García
name: Maynar, P.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The linear hydrodynamic stability of a model for confined quasi-two-dimensional granular gases is analyzed. The system exhibits homogeneous hydrodynamics, i.e. there are macroscopic evolution equations for homogeneous states. The stability analysis is carried out around all these states and not only the homogeneous steady state reached eventually by the system. It is shown that in some cases the linear analysis is not enough to reach a definite conclusion on the stability, and molecular dynamics simulation results are presented to elucidate these cases. The analysis shows the relevance of nonlinear hydrodynamic contributions to describe the behavior of spontaneous fluctuations occurring in the system, that lead even to the transitory formation of clusters of particles. The conclusion is that the system is always stable. The relevance of the results for describing the instabilities of confined granular gases observed experimentally is discussed.
Isotope hydrology and water sources in a heavily urbanized stream
Creators: name: Marx, Christian
name: Tetzlaff, Dörthe
name: Hinkelmann, Reinhard
name: Soulsby, Chris
Publisher: name: Technische Universität Berlin
Year: 2021
Subjects: subject: 550 Geowissenschaften
subject: ecohydrology
subject: end member mixing analysis
subject: isotopes
subject: urban hydrology
subject: wastewater

description: Complex networks of both natural and engineered flow paths control the hydrology of streams in major cities through spatio‐temporal variations in connection and disconnection of diverse water sources. We used spatially extensive and temporally intensive sampling of water stable isotopes to disentangle the hydrological sources of the heavily urbanized Panke catchment (~220 km2) in the north of Berlin, Germany. The isotopic data enabled us to partition stream water sources across the catchment using a Bayesian mixing analysis. The upper part of the catchment streamflow is dominated by groundwater (~75%) from gravel aquifers. In dry summer periods, streamflow becomes intermittent in the upper catchment, possibly as a result of local groundwater abstractions. Storm drainage dominates the responses to precipitation events. Although such events can dramatically change the isotopic composition of the upper stream network, storm drainage only accounts for 10%–15% of annual streamflow. Moving downstream, subtle changes in sources and isotope signatures occur as catchment characteristics vary and the stream is affected by different tributaries. However, effluents from a wastewater treatment plant (WWTP), serving 700,000 people, dominate stream flow in the lower catchment (~90% of annual runoff) where urbanization effects are more dramatic. The associated increase in sealed surfaces downstream also reduces the relative contribution of groundwater to streamflow. The volume and isotopic composition of storm runoff is again dominated by urban drainage, though in the lower catchment, still only about 10% of annual runoff comes from storm drains. The study shows the potential of stable water isotopes as inexpensive tracers in urban catchments that can provide a more integrated understanding of the complex hydrology of major cities. This offers an important evidence base for guiding the plans to develop and re‐develop urban catchments to protect, restore, and enhance their ecological and amenity value.
Phonon-assisted diffusion in bcc phase of titanium and zirconium from first-principles
Creators: name: Kadkhodaei, Sara
name: Davariashtiyani, Ali
Publisher: name: arXiv
Year: 2019
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Diffusion is the underlying mechanism for many complicated materials phenomena, and understanding it is basic to the discovery of novel materials with desired physical and mechanical properties. Certain groups of solid phases, such as the bcc phase of IIIB and IVB metals and their alloys, which are only stable when they reach high enough temperatures and experience anharmonic vibration entropic effects, exhibit "anomalously fast diffusion". However, the underlying reason for the observed extraordinary fast diffusion is poorly understood and due to the existence of harmonic vibration instabilities in these phases the standard models fail to predict their diffusivity. Here, we indicate that the anharmonic phonon-phonon coupling effects can accurately describe the anomalously large macroscopic diffusion coefficients in the bcc phase of IVB metals, and therefore yield a new understanding of the underlying mechanism for diffusion in these phases. We utilize temperature-dependent phonon analysis by combining ab initio molecular dynamics with lattice dynamics calculations to provide a new approach to use the transition state theory beyond the harmonic approximation. We validate the diffusivity predictions for the bcc phase of titanium and zirconium with available experimental measurements, while we show that predictions based on harmonic transition state theory severely underestimates diffusivity in these phases.
description: 11 pages, 5 figures, supplemental material of 18 pages with 11 figures
Rigorous engineering of collective adaptive systems: special section
Creators: name: De Nicola, Rocco
name: Jähnichen, Stefan
name: Wirsing, Martin
Publisher: name: Technische Universität Berlin
Year: 2020
Subjects: subject: 000 Informatik, Informationswissenschaft, allgemeine Werke::000 Informatik, Wissen, Systeme::004 Datenverarbeitung; Informatik
subject: adaptive systems
subject: collective adaptive systems
subject: software engineering
subject: formal methods
subject: rigorous methods

description: An adaptive system is able to adapt at runtime to dynamically changing environments and to new requirements. Adaptive systems can be single adaptive entities or collective ones that consist of several collaborating entities. Rigorous engineering requires appropriate methods and tools that help guaranteeing that an adaptive system lives up to its intended purpose. This paper introduces the special section on “Rigorous Engineering of Collective Adaptive Systems.” It presents the seven contributions of the section and gives a short overview of the field of rigorously engineering collective adaptive systems by structuring it according to three topics: systematic development, methods and theories for modelling and analysis, and techniques for programming and operating collective adaptive systems.
An exactly mass conserving space-time embedded-hybridized discontinuous Galerkin method for the Navier-Stokes equations on moving domains
Creators: name: Horvath, Tamas L.
name: Rhebergen, Sander
Publisher: name: arXiv
Year: 2019
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: This paper presents a space-time embedded-hybridized discontinuous Galerkin (EHDG) method for the Navier--Stokes equations on moving domains. This method uses a different hybridization compared to the space-time hybridized discontinuous Galerkin (HDG) method we presented previously in (Int. J. Numer. Meth. Fluids 89: 519--532, 2019). In the space-time EHDG method the velocity trace unknown is continuous while the pressure trace unknown is discontinuous across facets. In the space-time HDG method, all trace unknowns are discontinuous across facets. Alternatively, we present also a space-time embedded discontinuous Galerkin (EDG) method in which all trace unknowns are continuous across facets. The advantage of continuous trace unknowns is that the formulation has fewer global degrees-of-freedom for a given mesh than when using discontinuous trace unknowns. Nevertheless, the discrete velocity field obtained by the space-time EHDG and EDG methods, like the space-time HDG method, is exactly divergence-free, even on moving domains. However, only the space-time EHDG and HDG methods result in divergence-conforming velocity fields. An immediate consequence of this is that the space-time EHDG and HDG discretizations of the conservative form of the Navier--Stokes equations are energy stable. The space-time EDG method, on the other hand, requires a skew-symmetric formulation of the momentum advection term to be energy-stable. Numerical examples will demonstrate the differences in solution obtained by the space-time EHDG, EDG, and HDG methods.
Mechanism of chain collapse of strongly charged polyelectrolytes
Creators: name: Tom, Anvy Moly
name: Vemparala, Satyavani
name: Rajesh, R.
name: Brilliantov, Nikolai V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We perform extensive molecular dynamics simulations of a charged polymer in a good solvent in the regime where the chain is collapsed. We analyze the dependence of the gyration radius $R_g $ on the reduced Bjerrum length $\ell_B$ and find two different regimes. In the first one, called as a weak electrostatic regime, $R_g \sim \ell_B^{-1/2}$, which is consistent only with the predictions of the counterion-fluctuation theory. In the second one, called a strong electrostatic regime, we find $R_g \sim \ell_B^{-1/5}$. To explain the novel regime we modify the counterion-fluctuation theory.
On occupation times of one-dimensional diffusions
Creators: name: Salminen, Paavo
name: Stenlund, David
Publisher: name: arXiv
Year: 2019
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60J60, 60J55 (Primary), 05A10, 60J65 (Secondary)

description: In this paper we study the moment generating function and the moments of occupation time functionals of one-dimensional diffusions. Assuming, specifically, that the process lives on $\mathbb{R}$ and starts at~0, we apply Kac's moment formula and the strong Markov property to derive an expression for the moment generating function in terms of the Green kernel of the underlying diffusion. Moreover, the approach allows us to derive a recursive equation for the Laplace transforms of the moments of the occupation time on $\mathbb{R}_+$. If the diffusion has a scaling property, the recursive equation simplifies to an equation for the moments of the occupation time up to time 1. As examples of diffusions with scaling property we study in detail skew two-sided Bessel processes and, as a special case, skew Brownian motion. It is seen that for these processes our approach leads to simple explicit formulas. The recursive equation for a sticky Brownian motion is also discussed.
description: 32 pages
title: Local Outlier Detection for Compositional Data
Creators: name: Braus, Lorena
Publisher: name: TU Wien
Year: 2023
Subjects: subject: Robust statistics
subject: Outliers

description: This master thesis explores the application of outlier detection techniques on compositional data, focusing on local outlier detection methods. Compositional data, where relevant information is contained in ratios between the components, require specialized analysis approaches. The thesis begins with an introduction to compositional data and local outlier detection, providing a foundation for the subsequent chapters. The analysis of compositional data involves understanding their geometrical properties and employing the so-called Aitchison geometry on the simplex. Coordinate representations and preprocessing issues are also discussed, highlighting the challenges unique to compositional data analysis.The thesis delves into outlier detection, covering classical and robust statistical analysis techniques and emphasizing their significance in the context of compositional data. The main focus is on local outlier detection methods, specifically exploring two robust methods and the Local Outlier Factor (LOF) technique. The practical application of these methods is demonstrated using spatially dependent geochemical data obtained from the Geological Survey of Finland. The thesis provides a detailed description of the data and explains the necessary data preparation and cleaning steps. The four relevant methods are applied to identify outliers in the data. Furthermore, the identified outliers are analyzed and explained. The thesis concludes with a comprehensive evaluation and comparison of the applied methods, considering their overall effectiveness and performance. Parameters used in the analysis, including the parameter k for the k-nearest neighbors (kNN) method, are discussed to provide insights into their impact on the results.
Single-Shot Decoding of Linear Rate LDPC Quantum Codes with High Performance
Creators: name: Breuckmann, Nikolas P.
name: Londe, Vivien
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We construct and analyze a family of low-density parity check (LDPC) quantum codes with a linear encoding rate, polynomial scaling distance and efficient decoding schemes. The code family is based on tessellations of closed, four-dimensional, hyperbolic manifolds, as first suggested by Guth and Lubotzky. The main contribution of this work is the construction of suitable manifolds via finite presentations of Coxeter groups, their linear representations over Galois fields and topological coverings. We establish a lower bound on the encoding rate~k/n of~13/72 = 0.180... and we show that the bound is tight for the examples that we construct. Numerical simulations give evidence that parallelizable decoding schemes of low computational complexity suffice to obtain high performance. These decoding schemes can deal with syndrome noise, so that parity check measurements do not have to be repeated to decode. Our data is consistent with a threshold of around 4% in the phenomenological noise model with syndrome noise in the single-shot regime.
description: 15 pages, 6 figures
Black holes in stellar-mass binary systems: expiating original spin?
Creators: name: King, Andrew
name: Nixon, Chris
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We investigate systematically whether accreting black hole systems are likely to reach global alignment of the black hole spin and its accretion disc with the binary plane. In low-mass X-ray binaries (LMXBs) there is only a modest tendency to reach such global alignment, and it is difficult to achieve fully: except for special initial conditions we expect misalignment of the spin and orbital planes by ~1 radian for most of the LMXB lifetime. The same is expected in high-mass X-ray binaries (HMXBs). A fairly close approach to global alignment is likely in most stellar-mass ultraluminous X-ray binary systems (ULXs) where the companion star fills its Roche lobe and transfers on a thermal timescale to a black hole of lower mass. These systems are unlikely to show orbital eclipses, as their emission cones are close to the hole's spin axis. This offers a potential observational test, as models for ULXs invoking intermediate-mass black holes do predict eclipses for ensembles of > ~10 systems. Recent observational work shows that eclipses are either absent or extremely rare in ULXs, supporting the picture that most ULXs are stellar-mass binaries with companion stars more massive than the accretor.
description: Accepted for publication in MNRAS in original form. 4 pages, 1 figure
Inverse Participation Ratios in the XX spin chain
Creators: name: Tsukerman, Emmanuel
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We continue the study of the Inverse Participation Ratios (IPRs) of the XXZ Heisenberg spin chain initiated by Misguich, Pasquier and Luck (2016) by focusing on the case of the XX Heisenberg Spin Chain. For the ground state, Misguich et al. note that calculating the IPR is equivalent to Dyson's constant term ex-conjecture. We express the IPRs of excited states as an apparently new "discrete" Hall inner product. We analyze this inner product using the theory of symmetric functions (Jack polynomials, Schur polynomials, the standard Hall inner product and $ω_{q,t}$) to determine some exact expressions and asymptotics for IPRs. We show that IPRs can be indexed by partitions, and asymptotically the IPR of a partition is equal to that of the conjugate partition. We relate the IPRs to two other models from physics, namely, the circular symplectic ensemble of Dyson and the Dyson-Gaudin two-dimensional Coulomb lattice gas. Finally, we provide a description of the IPRs in terms of a signed count of diagonals of permutohedra.
description: 16 pages, 1 figure
Vortex Structure and Anisotropic Superconducting Gaps in Ba[Fe(Ni)]$_2$As$_2$
Creators: name: Kuzmicheva, T. E.
name: Vlasenko, V. A.
name: Gavrilkin, S. Yu.
name: Kuzmichev, S. A.
name: Pervakov, K. S.
name: Roshchina, I. V.
name: Pudalov, V. M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We studied nearly optimally Ni-substituted BaFe$_{2-x}$Ni$_x$As$_2$ (BFNA) single crystals with $T_C \approx 18.5$\,K. In irreversible magnetization measurements, we determined the field dependence of the critical-current density and discuss the nature of observed strong bulk pinning. Using intrinsic multiple Andreev reflections effect (IMARE) spectroscopy, we directly determine two distinct superconducting gaps and resolve their moderate anisotropy in the momentum space. The BCS-ratio for the large gap $2Δ_L/k_BT_C > 4.1$ evidences for a strong coupling in the $Δ_L$-bands.
description: 6 pages, 4 figures. To be published in Proceedings of Superstripes 2016 Conference
Surface single-molecule dynamics controlled by entropy at low temperatures
Creators: name: Gehrig, Jeffrey C.
name: Penedo, Marcos
name: Parschau, Manfred
name: Schwenk, Johannes
name: Marioni, Miguel A.
name: Hudson, Eric W.
name: Hug, Hans J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Configuration transitions of individual molecules and atoms on surfaces are traditionally described with energy barriers and attempt rates using an Arrhenius law. This approach yields consistent energy barrier values, but also attempt rates orders of magnitude below expected oscillation frequencies of particles in the meta-stable state. Moreover, even for identical systems, the measurements can yield values differing from each other by orders of magnitude. Using low temperature scanning tunnelling microscopy (STM) to measure an individual dibutyl-sulfide molecule (DBS) on Au(111), we show that we can avoid these apparent inconsistencies if we account for the relative position of tip apex and molecule with accuracy of a fraction of the molecule size. Altering the tip position on that scale modifies the transition's barrier and attempt rate in a highly correlated fashion, which on account of the relation between the latter and entropy results in a single-molecular enthalpy-entropy compensation. By appropriately positioning the tip apex the STM tip can be used to select the operating point on the compensation line and modify the transition rates. The results highlight the need to consider entropy in transition rates of a single molecule, even at temperatures where entropy effects are usually neglected.
description: 15 pages, 4 figures
Strong Asymptotics of Planar Orthogonal Polynomials: Gaussian Weight Perturbed by Finite Number of Point Charges
Creators: name: Lee, Seung-Yeop
name: Yang, Meng
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We consider the planar orthogonal polynomial $p_{n}(z)$ with respect to the measure supported on the whole complex plane $${\rm e}^{-N|z|^2} \prod_{j=1}^ν|z-a_j|^{2c_j}\,{\rm d} A(z)$$ where ${\rm d} A$ is the Lebesgue measure of the plane, $N$ is a positive constant, $\{c_1,\cdots,c_ν\}$ are nonzero real numbers greater than $-1$ and $\{a_1,\cdots,a_ν\}\subset{\mathbb D}\setminus\{0\}$ are distinct points inside the unit disk. In the scaling limit when $n/N = 1$ and $n\to \infty$ we obtain the strong asymptotics of the polynomial $p_n(z)$. We show that the support of the roots converges to what we call the "multiple Szego curve," a certain connected curve having $ν+1$ components in its complement. We apply the nonlinear steepest descent method on the matrix Riemann-Hilbert problem of size $(ν+1)\times(ν+1)$.
description: 61 pages, 12 figures. In the revised version, we correct one phase factor see Definition 1.4
The Relation between Stellar and Dynamical Surface Densities in the Central Regions of Disk Galaxies
Creators: name: Lelli, Federico
name: McGaugh, Stacy S.
name: Schombert, James M.
name: Pawlowski, Marcel S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We use the SPARC (Spitzer Photometry & Accurate Rotation Curves) database to study the relation between the central surface density of stars Sstar and dynamical mass Sdyn in 135 disk galaxies (S0 to dIrr). We find that Sdyn correlates tightly with Sstar over 4 dex. This central density relation can be described by a double power law. High surface brightness galaxies are consistent with a 1:1 relation, suggesting that they are self-gravitating and baryon dominated in the inner parts. Low surface brightness galaxies systematically deviate from the 1:1 line, indicating that the dark matter contribution progressively increases but remains tightly coupled to the stellar one. The observed scatter is small (~0.2 dex) and largely driven by observational uncertainties. The residuals show no correlations with other galaxy properties like stellar mass, size, or gas fraction.
description: Accepted for publication in ApJL (6 pages, 3 figures)
Primitive permutation groups with a suborbit of length 5 and vertex-primitive graphs of valency 5
Creators: name: Fawcett, Joanna B.
name: Giudici, Michael
name: Li, Cai Heng
name: Praeger, Cheryl E.
name: Royle, Gordon
name: Verret, Gabriel
Publisher: name: arXiv
Year: 2016
Subjects: subject: Group Theory (math.GR)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: We classify finite primitive permutation groups having a suborbit of length 5. As a corollary, we obtain a classification of finite vertex-primitive graphs of valency 5. In the process, we also classify finite almost simple groups that have a maximal subgroup isomorphic to $\mathrm{Alt}(5)$ or $\mathrm{Sym}(5)$.
Information-Theoretic Foundations of Mismatched Decoding
Creators: name: Scarlett, Jonathan
name: Fàbregas, Albert Guillén i
name: Somekh-Baruch, Anelia
name: Martinez, Alfonso
Publisher: name: arXiv
Year: 2020
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: Shannon's channel coding theorem characterizes the maximal rate of information that can be reliably transmitted over a communication channel when optimal encoding and decoding strategies are used. In many scenarios, however, practical considerations such as channel uncertainty and implementation constraints rule out the use of an optimal decoder. The mismatched decoding problem addresses such scenarios by considering the case that the decoder cannot be optimized, but is instead fixed as part of the problem statement. This problem is not only of direct interest in its own right, but also has close connections with other long-standing theoretical problems in information theory. In this monograph, we survey both classical literature and recent developments on the mismatched decoding problem, with an emphasis on achievable random-coding rates for memoryless channels. We present two widely-considered achievable rates known as the generalized mutual information (GMI) and the LM rate, and overview their derivations and properties. In addition, we survey several improved rates via multi-user coding techniques, as well as recent developments and challenges in establishing upper bounds on the mismatch capacity, and an analogous mismatched encoding problem in rate-distortion theory. Throughout the monograph, we highlight a variety of applications and connections with other prominent information theory problems.
description: Published in Foundations and Trends in Communications and Information Theory (Volume 17, Issue 2-3)
Kinetic Equation and Non-equilibrium Entropy for a Quasi-two-dimensional Gas
Creators: name: Brey, J. Javier
name: Maynar, P.
name: de Soria, M. I. García
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: A kinetic equation for a dilute gas of hard spheres confined between two parallel plates separated a distance smaller than two particle dimeters is derived. It is a Boltzmann-like equation, which incorporates the effect of the confinement on the particle collisions. A function $S(t)$ is constructed by adding to the Boltzmann expression a confinement contribution. Then it is shown that for the solutions of the kinetic equation, $S(t)$ increases monotonically in time, until the system reaches a stationary inhomogeneous state, when $S$ becomes the equilibrium entropy of the confined system as derived from equilibrium statistical mechanics. From the entropy, other equilibrium properties are obtained, and Molecular Dynamics simulations are used to verify some of the theoretical predictions.
Muon-Electron Conversion in a Family Gauge Boson Model
Creators: name: Koide, Yoshio
name: Yamanaka, Masato
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the $μ$-$e$ conversion in muonic atoms via an exchange of family gauge boson (FGB) $A_{2}^{\ 1}$ in a $U(3)$ FGB model. Within the class of FGB model, we consider three types of family-number assignments for quarks. We evaluate the $μ$-$e$ conversion rate for various target nuclei, and find that next generation $μ$-$e$ conversion search experiments can cover entire energy scale of the model for all of types of the quark family-number assignments. We show that the conversion rate in the model is so sensitive to up- and down-quark mixing matrices, $U^{u}$ and $U^{d}$, where the CKM matrix is given by $V_\text{CKM} = U^{u\dagger} U^d$. Precise measurements of conversion rates for various target nuclei can identify not only the types of quark family-number assignments, but also each quark mixing matrix individually.
description: 14 pages, 3 figures
Unification of quantum Zeno-anti Zeno effects and parity-time symmetry breaking transitions
Creators: name: Li, Jiaming
name: Wang, Tishuo
name: Luo, Le
name: Vemuri, Sreya
name: Joglekar, Yogesh N
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The decay of any unstable quantum state can be inhibited or enhanced by carefully tailored measurements, known as the quantum Zeno effect (QZE) or anti-Zeno effect (QAZE). To date, studies of QZE (QAZE) transitions have since expanded to various system-environment coupling, in which the time evolution can be suppressed (enhanced) not only by projective measurement but also through dissipation processes. However, a general criterion, which could extend to arbitrary dissipation strength and periodicity, is still lacking. In this letter, we show a general framework to unify QZE-QAZE effects and parity-time (PT) symmetry breaking transitions, in which the dissipative Hamiltonian associated to the measurement effect is mapped onto a PT-symmetric non- Hermitian Hamiltonian, thus applying the PT symmetry transitions to distinguish QZE (QAZE) and their crossover behavior. As a concrete example, we show that, in a two-level system periodically coupled to a dissipative environment, QZE starts at an exceptional point (EP), which separates the PT-symmetric (PTS) phase and PT-symmetry broken (PTB) phase, and ends at the resonance point (RP) of the maximum PT-symmetry breaking; while QAZE extends the rest of PTB phase and remains the whole PTS phase. Such findings reveal a hidden relation between QZE-QAZE and PTS-PTB phases in non-Hermitian quantum dynamics.
The XXL Survey: IX. Optical overdensity and radio continuum analysis of a supercluster at $z=0.43$
Creators: name: Baran, N.
name: Smolčić, V.
name: Milaković, D.
name: Novak, M.
name: Delhaize, J.
name: Gastaldello, F.
name: Ramos-Ceja, M. E.
name: Pacaud, F.
name: Bourke, S.
name: Carilli, C. L.
name: Ettori, S.
name: Hallinan, G.
name: Horellou, C.
name: Koulouridis, E.
name: Chiappetti, L.
name: Miettinen, O.
name: Melnyk, O.
name: Mooley, K.
name: Pierre, M.
name: Pompei, E.
name: Schinnerer, E.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present observations with the Karl G. Jansky Very Large Array (VLA) at 3 GHz toward a sub-field of the XXL-North 25 deg$^{2}$ field targeting the first supercluster discovered in the XXL Survey. The structure has been found at a spectroscopic redshift of 0.43 and extending over $0.35\times0.1$ deg$^{2}$ on the sky. We present the 3 GHz VLA radio continuum observations, the radio mosaic and radio source catalogue, and, perform an analysis of the supercluster in the optical and radio regimes using photometric redshifts from the CFHTLS survey and our new VLA data. Our 3 GHz radio mosaic has a resolution of $3.2\times1.9$ arcsec$^2$, and covers an area of $41\times41$ arcmin$^2$ with rms noise level below $\sim20 μ$Jy beam$^{-1}$ ($\sim11μ$Jy beam$^{-1}$ in central $15\times15$ arcmin$^2$). We extract a catalogue of 155 radio sources $\geq6σ$, 8 of which are multicomponent sources, and 123 ($79\%$) can be associated with optical sources in the CFHTLS W1 catalogue. Applying Voronoi tessellation analysis (VTA) in the area around the X-ray identified supercluster we identify a total of 17 overdensities at $z=0.35-0.50$, 7 of which are associated with clusters detected in the $XMM-Newton$ XXL data. We find a mean photometric redshift of 0.43 for our overdensities, consistent with the spectroscopic redshifts of 7 X-ray detected clusters. The full VTA-identified structure extends over $\sim0.6\times0.2$ deg$^2$ on the sky, ($\sim12\times4$ Mpc$^{2}$ at $z=0.43$). We associate 8 radio sources with potential group/cluster member galaxies none of which are large radio galaxies. The spatial distribution of the red and blue potential group member galaxies suggests that the clusters are dynamically young and not virialised yet, as expected for hierarchical structure growth in a $Λ$CDM universe. Further spectroscopic data are required to analyze the dynamical state of the groups.
Spectral Data Augmentation Techniques to quantify Lung Pathology from CT-images
Creators: name: Kayal, Subhradeep
name: Dubost, Florian
name: Tiddens, Harm A. W. M.
name: de Bruijne, Marleen
Publisher: name: arXiv
Year: 2020
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Data augmentation is of paramount importance in biomedical image processing tasks, characterized by inadequate amounts of labelled data, to best use all of the data that is present. In-use techniques range from intensity transformations and elastic deformations, to linearly combining existing data points to make new ones. In this work, we propose the use of spectral techniques for data augmentation, using the discrete cosine and wavelet transforms. We empirically evaluate our approaches on a CT texture analysis task to detect abnormal lung-tissue in patients with cystic fibrosis. Empirical experiments show that the proposed spectral methods perform favourably as compared to the existing methods. When used in combination with existing methods, our proposed approach can increase the relative minor class segmentation performance by 44.1% over a simple replication baseline.
description: 5 pages including references, accepted as Oral presentation at IEEE ISBI 2020