cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Influence of nuclear de-excitation on observables relevant for space exploration
Creators: name: Mancusi, Davide
name: Boudard, Alain
name: Cugnon, Joseph
name: David, Jean-Christophe
name: Leray, Sylvie
Publisher: name: arXiv
Year: 2010
Subjects: subject: Nuclear Theory (nucl-th)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The composition of the space radiation environment inside spacecrafts is modified by the interaction with shielding material, with equipment and even with the astronauts' bodies. Accurate quantitative estimates of the effects of nuclear reactions are necessary, for example, for dose estimation and prediction of single-event-upset rates. To this end, it is necessary to construct predictive models for nuclear reactions, which usually consist of an intranuclear-cascade or quantum-molecular-dynamics stage, followed by a nuclear-de-excitation stage. While it is generally acknowledged that it is necessary to accurately simulate the first reaction stage, transport-code users often neglect or underestimate the importance of the choice of the de-excitation code. The purpose of this work is to prove that the de-excitation model is in fact a non-negligible source of uncertainty for the prediction of several observables of crucial importance for space applications. For some particular observables, the systematic uncertainty due to the de-excitation model actually dominates the total uncertainty. Our point will be illustrated by making use of nucleon-nucleus calculations performed with several intranuclear-cascade/de-excitation models, such as the Liège Intranuclear Cascade model (INCL) and Isabel (for the cascade part) and ABLA07, Dresner, GEM, GEMINI++ and SMM (on the de-excitation side).
description: 12 pages, 6 figures. Presented at the 38th COSPAR Scientific Assembly (Bremen, Germany, 18-25 July 2010). Submitted to Advances in Space Research
Constraints on Primordial Non-Gaussianity from Large Scale Structure Probes
Creators: name: Xia, Jun-Qing
name: Baccigalupi, Carlo
name: Matarrese, Sabino
name: Verde, Licia
name: Viel, Matteo
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In this paper we measure the angular power spectra $C_\ell$ of three high-redshift large-scale structure probes: the radio sources from the NRAO VLA Sky Survey (NVSS), the quasar catalogue of Sloan Digital Sky Survey Release Six (SDSS DR6 QSOs) and the MegaZ-LRG (DR7), the final SDSS II Luminous Red Galaxy (LRG) photometric redshift survey. We perform a global analysis of the constraints on the amplitude of primordial non-Gaussianity from these angular power spectra, as well as from their cross-correlation power spectra with the cosmic microwave background (CMB) temperature map. In particular, we include non-Gaussianity of the type arising from single-field slow roll, multifields, curvaton (local type), and those which effects on the halo clustering can be described by the equilateral template (related to higher-order derivative type non-Gaussianity) and by the enfolded template (related to modified initial state or higher-derivative interactions). When combining all data sets, we obtain limits of $f_{\rm NL}=48\pm20$, $f_{\rm NL}=50\pm265$ and $f_{\rm NL}=183\pm95$ at 68% confidence level for local, equilateral and enfolded templates, respectively. Furthermore, we explore the constraint on the cubic correction $g_{\rm NL}ϕ^3$ on the bias of dark matter haloes and obtain a limit of $-1.2\times10^5
description: 15 pages, 4 figures, 1 table
Partial collapsing and the spectrum of the Hodge Laplacian
Creators: name: Anné, Colette
name: Takahashi, Junya
Publisher: name: arXiv
Year: 2010
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: The goal of the present paper is to calculate the limit spectrum of the Hodge-de Rham operator under the perturbation of collapsing one part of a manifold obtained by gluing together two manifolds with the same boundary. It appears to take place in the general problem of blowing up conical singularities as introduced in \cite{Maz} and \cite{Row1,Row2}.
description: 23 pages
The destiny of obstructed atomic insulator under correlation
Creators: name: Jiang, Kun
name: Weng, Hongming
name: Hu, Jiangping
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The obstructed atomic insulators are insulators with both atomic limits and boundary states. In this work, we study the obstructed atomic insulators under correlation. We use the symmetry indicators by constructing many-body wavefunctions in momentum space to prove the obstruction properties in different models including the SSH chain, anisotropic square lattice model, the quadrupole insulator model and etc. We demonstrate that the obstruction properties with boundary modes persist at large $U$ where the charge freedom is well-gapped, namely, this insulator phase can smoothly connect to its Mott phase without Mott transition.
description: 5 pages, 5 figures and supplemental material
Review article: MHD wave propagation near coronal null points of magnetic fields
Creators: name: McLaughlin, J. A.
name: Hood, A. W.
name: De Moortel, I.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We present a comprehensive review of MHD wave behaviour in the neighbourhood of coronal null points: locations where the magnetic field, and hence the local Alfven speed, is zero. The behaviour of all three MHD wave modes, i.e. the Alfven wave and the fast and slow magnetoacoustic waves, has been investigated in the neighbourhood of 2D, 2.5D and (to a certain extent) 3D magnetic null points, for a variety of assumptions, configurations and geometries. In general, it is found that the fast magnetoacoustic wave behaviour is dictated by the Alfven-speed profile. In a $β=0$ plasma, the fast wave is focused towards the null point by a refraction effect and all the wave energy, and thus current density, accumulates close to the null point. Thus, null points will be locations for preferential heating by fast waves. Independently, the Alfven wave is found to propagate along magnetic fieldlines and is confined to the fieldlines it is generated on. As the wave approaches the null point, it spreads out due to the diverging fieldlines. Eventually, the Alfven wave accumulates along the separatrices (in 2D) or along the spine or fan-plane (in 3D). Hence, Alfven wave energy will be preferentially dissipated at these locations. It is clear that the magnetic field plays a fundamental role in the propagation and properties of MHD waves in the neighbourhood of coronal null points. This topic is a fundamental plasma process and results so far have also lead to critical insights into reconnection, mode-coupling, quasi-periodic pulsations and phase-mixing.
description: 34 pages, 5 figures, invited review in Space Science Reviews => Note this is a 2011 paper, not a 2010 paper
A sub-Riemannian curvature-dimension inequality, volume doubling property and the Poincaré inequality
Creators: name: Baudoin, Fabrice
name: Bonnefont, Michel
name: Garofalo, Nicola
Publisher: name: arXiv
Year: 2010
Subjects: subject: Differential Geometry (math.DG)
subject: Analysis of PDEs (math.AP)
subject: Probability (math.PR)
subject: FOS: Mathematics

description: Let $\mathbb{M}$ be a smooth connected manifold endowed with a smooth measure $μ$ and a smooth locally subelliptic diffusion operator $L$ satisfying $L1=0$, and which is symmetric with respect to $μ$. We show that if $L$ satisfies, with a non negative curvature parameter, the generalized curvature inequality introduced by the first and third named authors in \cite{BG}, then the following properties hold: 1 The volume doubling property; 2 The Poincaré inequality; 3 The parabolic Harnack inequality. The key ingredient is the study of dimensional reverse log-Sobolev inequalities for the heat semigroup and corresponding non-linear reverse Harnack type inequalities. Our results apply in particular to all Sasakian manifolds whose horizontal Webster-Tanaka-Ricci curvature is non negative, all Carnot groups with step two, and to wide subclasses of principal bundles over Riemannian manifolds whose Ricci curvature is non negative.
Low lying spectrum of weak-disorder quantum waveguides
Creators: name: Borisov, Denis
name: Veselic', Ivan
Publisher: name: arXiv
Year: 2010
Subjects: subject: Spectral Theory (math.SP)
subject: Mathematical Physics (math-ph)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 35P15, 35C20, 60H25, 82B44

description: We study the low-lying spectrum of the Dirichlet Laplace operator on a randomly wiggled strip. More precisely, our results are formulated in terms of the eigenvalues of finite segment approximations of the infinite waveguide. Under appropriate weak-disorder assumptions we obtain deterministic and probabilistic bounds on the position of the lowest eigenvalue. A Combes-Thomas argument allows us to obtain so-called 'initial length scale decay estimates' at they are used in the proof of spectral localization using the multiscale analysis.
description: Accepted for publication in Journal of Statistical Physics http://www.springerlink.com/content/0022-4715
Non-Coplanar Magnetic Orders in Classical Square-Kagome Antiferromagnets
Creators: name: Gembé, Martin
name: Schmidt, Heinz-Jürgen
name: Hickey, Ciarán
name: Richter, Johannes
name: Iqbal, Yasir
name: Trebst, Simon
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Motivated by the recent synthesis of a number of Mott insulating square-kagome materials, we explore the rich phenomenology of frustrated magnetism induced by this lattice geometry, also referred to as the squagome or shuriken lattice. On the classical level, square-kagome antiferromagnets are found to exhibit extensive degeneracies, order-by-disorder, and non-coplanar ordering tendencies, which we discuss for an elementary, classical Heisenberg model with nearest-neighbor and cross-plaquette interactions. Having in mind that upon introducing quantum fluctuations non-coplanar order can melt into chiral quantum spin liquids, we provide detailed information on the multitude of non-coplanar orders, including some which break rotational symmetry (possibly leading to nematic quantum orders), as well as a number of (incommensurate) spin spiral phases. Using extensive numerical simulations, we also discuss the thermodynamic signatures of these phases, which often show multi-step thermal ordering. Our comprehensive discussion of the classical square-kagome Heisenberg model, often drawing comparisons to the conventional kagome antiferromagnet, sets the stage for future explorations of quantum analogs of the various phases, either conceptually such as in quantum spin-1/2 generalizations of our model or experimentally such as in the Cu-based candidate materials.
description: 24 pages, 27 figures
The effects of calibration errors and foreground filters on the CHIME power spectrum measurement : a study with simulations and real data
Creators: name: Höfer, Carolin
Publisher: name: University of British Columbia
Year: 2022

description: The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a drift-scan radio telescope designed to map large-scale structure in the universe using the redshifted 21 cm line emitted by neutral hydrogen. By observing the 400 MHz to 800 MHz frequency band, CHIME will measure the expansion rate of the universe in the redshift range z = 0.8 – 2.5 to constrain the nature of dark energy. In this frequency range, astrophysical foregrounds from the Galaxy and extragalactic point sources are much brighter than the 21 cm emission. This requires aggressive foreground filtering. We developed a new implementation of the Karhunen-Loeve transform that correctly tracks the signal and noise power in our data to enable us to filter bright foregrounds. Moreover, we significantly improved the foreground model by modelling the point source sky component based on source count models for both the clustered and Poisson distributed sources with a parameterized maximum flux density cut for point sources which have not been explicitly subtracted from the data. The data volumes for CHIME are extremely large, therefore we developed an upgraded parallelized power spectrum estimation pipeline which is able to forecast the Fisher information matrix and estimate power spectra for three times the frequency range and five times the number of unique baselines by distributing the power spectrum bands across nodes. This allows us to scale the Monte-Carlo simulations to arrays almost as large as CHIME. Due to the bright astrophysical foregrounds CHIME has very stringent calibration requirements. We wrote an end-to-end simulation pipeline and studied various realistic sources of calibration uncertainties with it. The calibration requirements are very stringent and CHIME currently does not quite meet the requirements when using the Karhunen-Loeve foreground filter. We investigated different processing choices on power spectrum estimation with CHIME data in the 610 MHz to 680 MHz band with a selection of short baselines to ensure quick computation times. Even with our currently best calibration procedures our power spectrum estimates are several orders of magnitude higher than the expected from the 21 cm signal. Using a delay filter as an intermediate processing step reduces the power further.
On the Degrees of Freedom Achievable Through Interference Alignment in a MIMO Interference Channel
Creators: name: Razaviyayn, Meisam
name: Lyubeznik, Gennady
name: Luo, Zhi-Quan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Information Theory (cs.IT)
subject: Algebraic Geometry (math.AG)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Consider a K-user flat fading MIMO interference channel where the k-th transmitter (or receiver) is equipped with M_k (respectively N_k) antennas. If a large number of statistically independent channel extensions are allowed either across time or frequency, the recent work [1] suggests that the total achievable degrees of freedom (DoF) can be maximized via interference alignment, resulting in a total DoF that grows linearly with K even if M_k and N_k are bounded. In this work we consider the case where no channel extension is allowed, and establish a general condition that must be satisfied by any degrees of freedom tuple (d_1, d2, ..., d_K) achievable through linear interference alignment. For a symmetric system with M_k = M, N_k = N, d_k = d for all k, this condition implies that the total achievable DoF cannot grow linearly with K, and is in fact no more than K(M + N)=(K + 1). We also show that this bound is tight when the number of antennas at each transceiver is divisible by the number of data streams.
Charge orderings and phase separations in the atomic limit of the extended Hubbard model with intersite density-density interactions
Creators: name: Kapcia, Konrad
name: Klobus, Waldemar
name: Robaszkiewicz, Stanislaw
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: A simple effective model of charge ordered insulators is studied. The tight binding Hamiltonian consists of the effective on-site interaction U and the intersite density-density interactions Wij (both: nearest-neighbour and next-nearest-neighbour). In the analysis of the phase diagrams we have adopted the variational approach, which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation. The phase separated states have not been taken into account in previous analyses. Our investigations of two cases of the on-site interaction: attraction (U/(-W_Q)=-10) and repulsion (U/(-W_Q)=1.1) show that, depending on the values of the next-nearest-neighbour attraction, the system can exhibit not only homogeneous phases: charge ordered (CO) and nonordered (NO), but also various phase separated states (CO--NO, CO--CO).
description: 3 pages, 2 figures, presented at the 14th National School of Superconductivity - Superconductivity and heterogeneous condensed systems, Ostrow Wielkopolski, Poland, October 13-17, 2009; final version, pdf-ReVTeX, corrected typos
Divergences on projective modules and non-commutative integrals
Creators: name: Brzeziński, Tomasz
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Algebra (math.QA)
subject: FOS: Mathematics
subject: 58B32, 16W25

description: A method of constructing (finitely generated and projective) right module structure on a finitely generated projective left module over an algebra is presented. This leads to a construction of a first order differential calculus on such a module which admits a hom-connection or a divergence. Properties of integrals associated to this divergence are studied, in particular the formula of integration by parts is derived. Specific examples include inner calculi on a noncommutative algebra, the Berezin integral on the supercircle and integrals on Hopf algebras.
description: 13 pages; v2 construction of projective modules has been generalised
Geometric construction of D-branes in WZW models
Creators: name: Horcajada, G.
name: Ruiz, F. Ruiz
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The geometric description of D-branes in WZW models is pushed forward. Our starting point is a gluing condition\, $J_{+}=FJ_-$ that matches the model's chiral currents at the worldsheet boundary through a linear map $F$ acting on the WZW Lie algebra. The equivalence of boundary and gluing conditions of this type is studied in detail. The analysis involves a thorough discussion of Frobenius integrability, shows that $F$ must be an isometry, and applies to both metrically degenerate and nondegenerate D-branes. The isometry $F$ need not be a Lie algebra automorphism nor constantly defined over the brane. This approach, when applied to isometries of the form $F=R$ with $R$ a constant Lie algebra automorphism, validates metrically degenerate $R$-twined conjugacy classes as D-branes. It also shows that no D-branes exist in semisimple WZW models for constant\, $F=-R$.
description: 23 pages, discussion of limitations of the gluing condition approach added
Nonlinear sigma models for monitored dynamics of free fermions
Creators: name: Fava, Michele
name: Piroli, Lorenzo
name: Swann, Tobias
name: Bernard, Denis
name: Nahum, Adam
Publisher: name: arXiv
Year: 2023
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We derive field theory descriptions for measurement-induced phase transitions in free fermion systems. We focus on a multi-flavor Majorana chain, undergoing Hamiltonian evolution with continuous monitoring of local fermion parity operators. Using the replica trick, we map the dynamics to the imaginary time evolution of an effective spin chain, and use the number of flavors as a large parameter for a controlled derivation of the effective field theory. This is a nonlinear sigma model for an orthogonal $N\times N$ matrix, in the replica limit $N\to 1$. (On a boundary of the phase diagram, another sigma model with higher symmetry applies.) Together with known results for the renormalization-group beta function, this derivation establishes the existence of stable phases -- nontrivially entangled and disentangled respectively -- in the physically-relevant replica limit $N\to 1$. In the nontrivial phase, an asymptotically exact calculation shows that the bipartite entanglement entropy for a system of size $L$ scales as $(\log L)^2$, in contrast to findings in previously-studied models. Varying the relative strength of Hamiltonian evolution and monitoring, as well as a dimerization parameter, the model's phase diagram contains transitions out of the nontrivial phase, which we map to vortex-unbinding transitions in the sigma model, and also contains separate critical points on the measurement-only axis. We highlight the close analogies as well as the differences with the replica approach to Anderson transitions in disordered systems.
description: Version accepted for publication; added discussion of the phase diagram for more than one flavor. 33 pages, 9 figures
Metamaterial branes
Creators: name: Alves-Junior, F. A. P.
name: Barreto, A. B.
name: Moraes, F.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: In this article, we propose metamaterials analog brane models based on the geometric optics approach. We show how to model the Randall-Sundrum thin brane model and the Gremm model for a thick brane. We incorporate the Yukawa-like confinement mechanics for thick branes in the analog system and show an asymmetrical analog brane model with and without the confinement mechanisms.
Improved Inner Approximation for Aggregating Power Flexibility in Active Distribution Networks and its Applications
Creators: name: Wen, Yilin
name: Hu, Zechun
name: He, Jinhua
name: Guo, Yi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Concise and reliable modeling for aggregating power flexibility of distributed energy resources in active distribution networks (ADNs) is a crucial technique for coordinating transmission and distribution networks. Our recent research has successfully derived an explicit expression for the exact aggregation model (EAM) of power flexibility at the substation level under linearized distribution network constraints. The EAM, however, is impractical for decision-making purposes due to its exponential complexity. In this paper, we propose an inner approximation method for aggregating flexibility in ADNs that utilizes the properties of the EAM to improve performance. Specifically, the geometric prototype of the inner approximation model is defined according to a subset of the coefficient vector set of the EAM, which enhances the accuracy. On the other hand, the computation efficiency of the inner approximation is also significantly improved by exploiting the regularity of coefficient vectors in the EAM in the parameter calculation process. The inner approximated flexibility model of ADNs is further incorporated into the security-constrained unit commitment problem as an application. Numerical simulations verify the effectiveness of the proposed method.
description: 10 pages
Braids and linked periodic orbits of disc homeomorphisms
Creators: name: Liu, Xiang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Dynamical Systems (math.DS)
subject: Algebraic Topology (math.AT)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 37E30, 55M20, 20F36

description: This paper concerns on linked periodic orbits of orientation-preserving homeomorphisms of the $2$-disc in the sense of Gambaudo. We interpret the linking of periodic orbits by using their induced braids. Then based on the forcing relation of braids, we present a method for finding periodic orbits which are linked with a given one. In particular, for $3$-periodic orbits of pseudo-Anosov braid types, we provide new examples of linked orbits of periods at most $4$.
description: 14 pages, 2 figures
On the range of a random walk in a torus and random interlacements
Creators: name: Procaccia, Eviatar B.
name: Shellef, Eric
Publisher: name: arXiv
Year: 2010
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: Let a simple random walk run inside a torus of dimension three or higher for a number of steps which is a constant proportion of the volume. We examine geometric properties of the range, the random subgraph induced by the set of vertices visited by the walk. Distance and mixing bounds for the typical range are proven that are a $k$-iterated log factor from those on the full torus for arbitrary $k$. The proof uses hierarchical renormalization and techniques that can possibly be applied to other random processes in the Euclidean lattice. We use the same technique to bound the heat kernel of a random walk on random interlacements.
description: Published in at http://dx.doi.org/10.1214/14-AOP924 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Polymer acrylic hydrogels with protein filler: Synthesis and characterization
Creators: name: Baidakova, M.
name: Sitnikova, V.
name: Uspenskaya, M.
name: Olekhnovich, R.
name: Kremenevskaya, M.
Publisher: name: Agronomy Research
Year: 2019
Subjects: hydrogel
radical polymerization
filler
protein hydrolysate
article

description: The water-retention hydrogel composites were synthesized by the free-radical polymerization depending on the order of addition filler of the protein hydrolysate. As the filler was used protein hydrolysate, ‘Biostim’, obtained by processing cattle hides. The influence of gelation time on the synthesis parameters of hydrogel compositions was investigated. It is found that the gelation time of the sample without filler is 2–2.5 times longer than filled of hydrogel compositions. The structural characteristics of polymer composition by TGA, DSC and atomic force microscopy were determined. FTIR spectra found decrease in the intensity of vibrations of (-COO-) groups, indicating about additional ionic interactions. Decrease the beginning evaporation temperature of polymer composites with increase concentration of protein filler, indicating the destruction of the ordered structure of the polymer material revealed by thermogravimetric analysis (TGA). The influence of various media, such as distilled water, saline solution, and buffer solutions at differents pH on the swelling behavior of hydrogels was also assessed. Maximum swelling capacity showed sample prepared with order of addition filler at the end of synthesis (Scheme I). The kinetics of the release protein hydrolysate from the polymer matrix was measurement by spectrophotometric method. The synthesized hydrogel composites with protein hydrolysate and improved physicochemical properties are of practical interest as water-retaining materials for increasing of crop the yield in agricultural.
Quantum (in)stability of maximally symmetric space-times
Creators: name: Ghosh, Jewel K.
name: Kiritsis, Elias
name: Nitti, Francesco
name: Nourry, Valentin
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Classical gravity coupled to a CFT$_4$ (matter) is considered. The effect of the quantum dynamics of matter on gravity is studied around maximally symmetric spaces (flat, de Sitter and Anti de Sitter). The structure of the graviton propagator is modified and non-trivial poles appear due to matter quantum effects. The position and residues of such poles are mapped as a function of the relevant parameters, the central charge of the CFT$_4$, the two $R^2$ couplings of gravity as well as the curvature of the background space-time. The instabilities induced are determined. Such instabilities can be important in cosmology as they trigger the departure from de Sitter space and in some regions of parameters are more important than the well-known scalar instabilities. It is also determined when the presence of such instabilities is unreliable if the associated scales are larger than the ``species" cutoff of the gravitational theory.
description: 99 pages + appendix, 24 figures + appendix
Feshbach resonances in the 6Li-40K Fermi-Fermi mixture: Elastic versus inelastic interactions
Creators: name: Naik, D.
name: Trenkwalder, A.
name: Kohstall, C.
name: Spiegelhalder, F. M.
name: Zaccanti, M.
name: Hendl, G.
name: Schreck, F.
name: Grimm, R.
name: Hanna, T. M.
name: Julienne, P. S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We present a detailed theoretical and experimental study of Feshbach resonances in the 6Li-40K mixture. Particular attention is given to the inelastic scattering properties, which have not been considered before. As an important example, we thoroughly investigate both elastic and inelastic scattering properties of a resonance that occurs near 155 G. Our theoretical predictions based on a coupled channels calculation are found in excellent agreement with the experimental results. We also present theoretical results on the molecular state that underlies the 155G resonance, in particular concerning its lifetime against spontaneous dissociation. We then present a survey of resonances in the system, fully characterizing the corresponding elastic and inelastic scattering properties. This provides the essential information to identify optimum resonances for applications relying on interaction control in this Fermi-Fermi mixture.
description: Submitted to EPJD, EuroQUAM special issues "Cold Quantum Matter - Achievements and Prospects", v2 with updated calibration of magnetic field (+4mG correction) and updated figures 4 and 6
Estonian dairy farms’ technical efficiency and factors predicting it
Creators: name: Luik-Lindsaar, Helis
name: Põldaru, Reet
name: Roots, Jüri
Publisher: name: Agronomy Research
Year: 2019
Subjects: data envelopment analysis
classification and regression tree
dairy farms’ efficiency
article

description: Milk production is a complex process whose efficiency depends directly on the inputoutput ratio and indirectly on the decisions made at farm and animal level. Decisions made about farm hygiene, dairy cows’ milk yield, cows’ age at first calving etc. affect farms’ efficiency. The aim of this study is to provide an understanding of the factors that affect dairy farms’ technical efficiency. A two-stage approach was used in this study, consisting of a data envelopment analysis (DEA) in the first stage, and classification and regression tree (CART) in the second stage. DEA determined technical efficiency scores (TE), and CART enabled to detect the main factors that influenced efficiency in dairy farms. The analysis studied at the Estonian national level FADN dataset and Estonian Livestock Performance Recording data. 147 Estonian dairy farms were included in this analysis, all of which are specialized in dairy production. DEA results demonstrated that more than half of the farms (55%) were operating efficiently or rather efficiently (TE ≥ 0.900). CART results revealed that the main variables determining efficiency are milk yield per cow's lifetime (kg day-1 ), feed costs (€ kg milk-1 ), and somatic cell count (SCC; 103 ml-1 ). Milk yield per cow's lifetime is a complicated factor as it is influenced by a lot of components (e.g. milk yield, number of lactations, age at first calving, and calving interval), but if it is known at farm level, it is also a useful variable for predicting efficiency. Feed costs per milk kg is an economic variable, i.e. lower costs are related with higher efficiency. Better hygiene (lower SCC) is also related with higher efficiency. The analysis showed that integrating farm accounts data, herd-level genetic information, and milk quality attributes enables to use more specific factors to explain the variation of TE between dairy farms.
Multiple adaptive substitutions during evolution in novel environments
Creators: name: Jain, Kavita
name: Seetharaman, Sarada
Publisher: name: arXiv
Year: 2011
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: We consider an asexual population under strong selection-weak mutation conditions evolving on rugged fitness landscapes with many local fitness peaks. Unlike the previous studies in which the initial fitness of the population is assumed to be high, here we start the adaptation process with a low fitness corresponding to a population in a stressful novel environment. For generic fitness distributions, using an analytic argument we find that the average number of steps to a local optimum varies logarithmically with the genotype sequence length and increases as the correlations amongst genotypic fitnesses increase. When the fitnesses are exponentially or uniformly distributed, using an evolution equation for the distribution of population fitness, we analytically calculate the fitness distribution of fixed beneficial mutations and the walk length distribution.
New approaches at crossroads between molecular physics and machine learning
Creators: name: Asnaashari, Kasra
Publisher: name: University of British Columbia
Year: 2022

description: This thesis explores the interplay of machine learning and molecular physics, demonstrating how developments in one field lead to advances in the other. We show this using two examples. First, we illustrate how improvements made to a machine learning model of molecular PES and FF can significantly increase its generalization accuracy. Gradient domain machine learning (GDML) models produce accurate results for high-dimensional molecular systems with a small number of ab initio calculations. The present work extends GDML to models with composite kernels built to maximize inference from a small number of molecular geometries. We illustrate that GDML models can be improved by increasing the complexity of underlying kernels through a greedy search algorithm using Bayesian information criterion as the model selection metric. We show that this requires including anisotropy into kernel functions and produces models with significantly smaller generalization errors. The results are presented for ethanol, uracil, malonaldehyde and aspirin. For aspirin, the model with composite kernels trained by forces at 1000 randomly sampled molecular geometries produces a global 57-dimensional PES with the mean absolute error 0.177 kcal/mol (61.9 cm⁻¹) and FFs with the mean absolute error 0.457 kcal/mol Å⁻¹. Second, we propose a procedure to perform quantum computation in the form of quantum annealing using a crossing between Zeeman states of different parity in the rotational and fine structure of open-shell molecules in a Σ electronic state. These crossings become avoided in the presence of an electric field. We propose an algorithm that encodes Ising models into qubits defined by pairs of ²Σ molecules sharing an excitation near these avoided crossings. This can be used to realize a transverse field Ising model tunable by an external electric or magnetic field, suitable for quantum annealing applications. We perform dynamical calculations for several examples with 1D and 2D connectivities. Our results demonstrate that the probability of obtaining valid annealing solutions is high and can be optimized by varying the annealing times.
Additional file 1 of Predictive effect of triglyceride-glucose index on clinical events in patients with acute ischemic stroke and type 2 diabetes mellitus
Creators: name: Liu, Dong
name: Yang, Kaixuan
name: Gu, Hongqiu
name: Li, Zixiao
name: Wang, Yongjun
name: Wang, Yilong
Publisher: name: figshare
Year: 2023
Subjects: subject: Medicine
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Chemical Sciences not elsewhere classified
subject: Biological Sciences not elsewhere classified
subject: Hematology

description: Additional file 1: Table S1. Pearson correlation between TyG index and HBG, FBG, TC, TG, HDL, LDL in in acute ischemic stroke patients with type-2 diabetes mellitus included in this analysis.
Comment on "Absence of Off-Diagonal Long- Range Order in hcp $^4$He Dislocation Cores"
Creators: name: Boninsegni, M.
name: Kuklov, A.
name: Pollet, L.
name: Prokof'ev, N.
name: Svistunov, B.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We contend that the arguments provided in Phys. Rev. Lett. 130, 016001 (2023), purporting to show the absence of off-diagonal long-range order in hcp $^4$He dislocation cores are misleading and incorrect. In particular, the one-body density matrix averaged over the whole crystalline sample provides no useful information on the possible superfluid behavior inside the quasi-one-dimensional core of a dislocation in the crystal.
Symmetric approximations of pseudo-Boolean functions with applications to influence indexes
Creators: name: Marichal, Jean-Luc
name: Mathonet, Pierre
Publisher: name: arXiv
Year: 2010
Subjects: subject: Optimization and Control (math.OC)
subject: Discrete Mathematics (cs.DM)
subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 41A10, 93E24 (Primary) 62G30, 90B25, 91A12 (Secondary)

description: We introduce an index for measuring the influence of the k-th smallest variable on a pseudo-Boolean function. This index is defined from a weighted least squares approximation of the function by linear combinations of order statistic functions. We give explicit expressions for both the index and the approximation and discuss some properties of the index. Finally, we show that this index subsumes the concept of system signature in engineering reliability and that of cardinality index in decision making.
title: Οι επιπτώσεις της πανδημίας covid-19 στις στρατηγικές του τουριστικού μάρκετινγκ

title: The effects of the covid-19 pandemic on tourism marketing strategies
Creators: name: Αρχοντακη Αντωνια
Publisher: name: Technical University of Crete
Year: 2023

description: Στην παρούσα διπλωματική εργασία αποτυπώνονται οι επιπτώσεις της πανδημίας COVID-19 και της παγκόσμιας υγειονομικής κρίσης που αυτή προξένησε στις στρατηγικές του τουριστικού μάρκετινγκ, τόσο διεθνώς όσο και στην Ελλάδα. Παρουσιάζεται η θέση του τουρισμού στην παγκόσμια αλλά κι εθνική μας οικονομία, όπως και η επίδραση της παγκόσμιας υγειονομικής κρίσης στα τουριστικά μεγέθη. Παρατίθενται οι γενικότερες έννοιες της έρευνας και τα μεθοδολογικά εργαλεία με τα οποία διεξήχθη η παρούσα μελέτη και τα οποία επικεντρώθηκαν στην εφαρμογή της επιστήμης των συστημάτων στη διαχείριση πληροφορίας. Παρουσιάζονται οι οικονομικές και κοινωνικές επιπτώσεις της πανδημίας COVID-19 στην οικονομία, την αγορά εργασίας και τον τουρισμό τόσο στην Ελλάδα όσο και διεθνώς. Περιγράφονται οι στρατηγικές μάρκετινγκ που προτάθηκαν κι εφαρμόστηκαν από την ελληνική και διεθνή επιχειρηματική κοινότητα του τουρισμού, προκειμένου να αντιμετωπιστεί η υγειονομική κρίση και να ανακάμψει η παγκόσμια τουριστική κίνηση. Τέλος, αξιολογούνται οι παραπάνω στρατηγικές με την οπτική της επιστήμης των συστημάτων και διατυπώνονται κάποια γενικά συμπεράσματα.
description: This dissertation reflects the effects of the COVID-19 pandemic and the global health crisis it caused on tourism marketing strategies, both internationally and in Greece. It presents the position of tourism in the global and our national economy, as well as the effect of the global health crisis on tourism figures. The general concepts of the research and the methodological tools are listed, with which the present study was conducted and which focused on the application of systems science in information management. The dissertation presents the economic and social effects of the COVID-19 pandemic on the economy, the labor market and tourism in Greece and internationally. The marketing strategies proposed and implemented by the Greek and international tourism business community are described, in order to deal with the health crisis and to recover the global tourism movement. Finally, the above strategies are evaluated from the perspective of systems science and some general conclusions are formulated.
Revisiting Bloch electrons in magnetic field: Hofstadter physics via hybrid Wannier states
Creators: name: Wang, Xiaoyu
name: Vafek, Oskar
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We revisit the Hofstadter butterfly for a subset of topologically trivial Bloch bands arising from a continuum free electron Hamiltonian in a periodic lattice potential. We employ the recently developed procedure -- which was previously used to analyze the case of topologically non-trivial bands [\href{https://journals.aps.org/prb/abstract/10.1103/PhysRevB.106.L121111}{Phys. Rev. B \textbf{106}, L121111 (2022)}] -- to construct the finite field Hilbert space from the zero-field hybrid Wannier basis states. Such states are Bloch extended along one direction and exponentially localized along the other. The method is illustrated for square and triangular lattice potentials and is shown to reproduce all the main features of the Hofstadter spectrum obtained from a numerically exact Landau level expansion method.
 In the regime when magnetic length is much longer than the spatial extent of the hybrid Wannier state in the localized direction we recover the well known Harper equation. Because the method applies to both topologically trivial and non-trivial bands, it provides an alternative and efficient approach to moiré materials in magnetic field.
description: added an appendix E comparing Peierls substitution method to hWS method; added journal ref
Break-even point of the quantum repetition code
Creators: name: Rozgonyi, Áron
name: Széchenyi, Gábor
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Enhancing the lifetime of qubits with quantum code-based memories on different quantum hardware is a significant step towards fault-tolerant quantum computing. We theoretically show that the break-even point, i.e., preserving arbitrary quantum information longer than the lifetime of a single idle qubit, can be beaten even with the quantum phase-flip repetition code in a dephasing-time-limited system. Applying circuit-based analytical calculation, we determine the efficiency of the phase-flip code as a quantum memory in the presence of relaxation, dephasing, and faulty quantum gates. Considering current platforms for quantum computing, we identify the gate error probabilities and optimal repetition number of quantum error correction cycles to reach the break-even point.
description: 9 pages, 4 figures
Set families and Foulkes modules
Creators: name: Paget, Rowena
name: Wildon, Mark
Publisher: name: arXiv
Year: 2010
Subjects: subject: Representation Theory (math.RT)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 20C30 (primary) 20C15 (secondary)

description: We construct a new family of homomorphisms from Specht modules into Foulkes modules for the symmetric group. These homomorphisms are used to give a combinatorial description of the minimal partitions (in the dominance order) which label irreducible characters appearing as summands of the characters of Foulkes modules. The homomorphisms are defined using certain families of subsets of the natural numbers. These families are of independent interest; we prove a number of combinatorial results concerning them.
description: 22 pages, 3 figures, final published version
A catalogue of cataclysmic variables from 20 years of the Sloan Digital Sky Survey with new classifications, periods, trends and oddities
Creators: name: Inight, Keith
name: Gänsicke, Boris
name: Breedt, Elmé
name: Israel, Henry
name: Littlefair, Stuart
name: Manser, Christopher
name: Marsh, Thomas
name: Mulvany, Timothy
name: Pala, Anna
name: Thorstensen, John
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present a catalogue of 507 cataclysmic variables (CVs) observed in SDSS I to IV including 70 new classifications collated from multiple archival data sets. This represents the largest sample of CVs with high-quality and homogeneous optical spectroscopy. We have used this sample to derive unbiased space densities and period distributions for the major sub-types of CVs. We also report on some peculiar CVs, period bouncers and also CVs exhibiting large changes in accretion rates. We report 70 new CVs, 59 new periods, 178 unpublished spectra and 262 new or updated classifications. From the SDSS spectroscopy, we also identified 18 systems incorrectly identified as CVs in the literature. We discuss the observed properties of 13 peculiar CVS, and we identify a small set of eight CVs that defy the standard classification scheme. We use this sample to investigate the distribution of different CV sub-types, and we estimate their individual space densities, as well as that of the entire CV population. The SDSS I to IV sample includes 14 period bounce CVs or candidates. We discuss the variability of CVs across the Hertzsprung-Russell diagram, highlighting selection biases of variability-based CV detection. Finally, we searched for, and found eight tertiary companions to the SDSS CVs. We anticipate that this catalogue and the extensive material included in the Supplementary Data will be useful for a range of observational population studies of CVs.
description: Published by MNRAS (including 2 corrections published on 7 December 2023). Includes supplementary material including machine readable version
Additional file 2 of Predictive effect of triglyceride-glucose index on clinical events in patients with acute ischemic stroke and type 2 diabetes mellitus
Creators: name: Liu, Dong
name: Yang, Kaixuan
name: Gu, Hongqiu
name: Li, Zixiao
name: Wang, Yongjun
name: Wang, Yilong
Publisher: name: figshare
Year: 2023
Subjects: subject: Medicine
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Chemical Sciences not elsewhere classified
subject: Biological Sciences not elsewhere classified
subject: Hematology

description: Additional file 2: Table S2. HRs (95% CIs) for risk of events in pre-diabetes patients with acute ischemic stroke according to TyG index quartiles in this study.
Crossover to the KPZ equation
Creators: name: Gonçalves, Patrícia
name: Jara, Milton
Publisher: name: arXiv
Year: 2010
Subjects: subject: Probability (math.PR)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 60K35

description: We characterize the crossover regime to the KPZ equation for a class of one-dimensional weakly asymmetric exclusion processes. The crossover depends on the strength asymmetry $an^{2-γ}$ ($a,γ>0$) and it occurs at $γ=1/2$. We show that the density field is a solution of an Ornstein-Uhlenbeck equation if $γ\in(1/2,1]$, while for $γ=1/2$ it is an energy solution of the KPZ equation. The corresponding crossover for the current of particles is readily obtained.
description: Published by Annales Henri Poincare Volume 13, Number 4 (2012), 813-826