cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Current - voltage characteristics of break junctions of high-$T_c$ superconductors
Creators: name: Gokhfeld, D M
name: Balaev, D A
name: Shaykhutdinov, K A
name: Popkov, S I
name: Petrov, M I
Publisher: name: arXiv
Year: 2007
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: The current-voltage ($I$-$V$) characteristics of break junctions of polycrystalline La$_{1.85}$Sr$_{0.15}$CuO$_4$, Y$_{0.75}$Lu$_{0.25}$Ba$_2$Cu$_3$O$_{7-δ}$, Bi$_{1.8}$Pb$_{0.3}$Sr$_{1.9}$Ca$_2$Cu$_3$O$_x$ and composite YBa$_2$Cu$_3$O$_{7-δ}$ + Ag are investigated. The experimental $I$-$V$ curves exhibit the specific peculiarities of superconductor/normal-metal/superconductor junctions. The relation between an $I$-$V$ characteristic of network of weak links and $I$-$V$ dependencies of typical weak links is suggested to describe the experimental data. The $I$-$V$ curves of typical weak links are calculated by the Kümmel - Gunsenheimer - Nicolsky model considering the multiple Andreev reflections.
description: 9 pages, 5 figures, 2 Tables
Post-hatching parental care behaviour and hormonal status in a precocial bird
Creators: name: Boos, M.
name: Zimmer, C.
name: Carriere, A.
name: Robin, J. P.
name: Petit, O.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: In birds, the link between parental care behaviour and prolactin release during incubation persists after hatching in altricial birds, but has never been precisely studied during the whole rearing period in precocial species, such as ducks. The present study aims to understand how changes in parental care after hatching are related to circulating prolactin levels in mallard hens rearing ducklings. Blood was sampled in hens over at least 13 post-hatching weeks and the behaviour of the hens and the ducklings was recorded daily until fledging. Contacts between hens and the ducklings, leadership of the ducklings and gathering of them steadily decreased over post-hatching time. Conversely, resting, preening and agonistic behaviour of hens towards ducklings increased. Plasma prolactin concentrations remained at high levels after hatching and then fell after week 6 when body mass and structural size of the young were close to those of the hen. Parental care behaviour declined linearly with brood age, showed a disruption of the hen-brood bond at week 6 post-hatching and was related to prolactin concentration according to a sigmoid function. Our results suggest that a definite threshold in circulating prolactin is necessary to promote and/or to maintain post-hatching parental care in ducks.
Constraints on the organization and information properties of DNA sequences
Creators: name: Sibbald, Peter Ramsay
Publisher: name: University of British Columbia
Year: 2010

description: In an investigation which concentrated primarily on the two completely sequenced chloroplast genomes, one from a tobacco and one from a liverwort, an attempt has been -made to discover some of the factors which produce order in DNA sequences. This was done by 1. looking in detail at doublet organization throughout the genomes, 2'. by examining the ability of different methods to predict the existence of genes, based only on sequence organization and 3. by employing information theorj' to explore various levels of ordering in these sequences. The doublet analysis was performed on seven categories of DNA: tDNA, rDNA, ribosomal proteins, open reading frames not known to be genes (URF), other protein genes, non coding regions and introns. The rDNA has the most unusual doublet properties of all categories although all categories have, to a considerable extent, similar doublet properties. I suggest that these particular doublet properties facilitate accurate replication of the genome. In addition it appears that doublets which have certain thermodynamic properties are more abundant that others, suggesting that there is a selection pressure at the level of doublets for certain thermodynamic properties. Nussinov's hypothesis, that complementary doublets have similar relative abundances due to inverted duplication events has been tested and would not seem to explain the phenomenon. Fickett's method to predict whether URFs are genes was more successful than Sheperd's method. Fickett's method was modified for use on the chloroplast genomes and its rate of successful prediction increased substantially. This modified method will be useful for other chloroplast genomes as they are sequenced and also supports Fickett's contention that the method could be improved for use on specific groups. The ability to predict genes based only on sequence data shows that the requirement to code for protein exerts a detectable amount of order on the gene sequence and that this order is distinguishable from the order in non coding regions. Nearly all URFs greater than 200 base pairs in both plants are predicted to be genes. Informational analysis showed that most order is at the level of single and double bases with a significant, lesser amount of order at the triplet and 4-plet level. This was true for both coding and noncoding regions in both plants. This is in contrast earlier work (Rowe and Trainor) which found that in viruses there was a significant difference between 4-plet ordering in coding and noncoding regions. It is suggested that DNA may be optimized for replication rather than protein production. Several new problems and experiments have been suggested.
Photon splitting in a laser field
Creators: name: Di Piazza, A.
name: Milstein, A. I.
name: Keitel, C. H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Photon splitting due to vacuum polarization in a laser field is considered. Using an operator technique, we derive the amplitudes for arbitrary strength, spectral content and polarization of the laser field. The case of a monochromatic circularly polarized laser field is studied in detail and the amplitudes are obtained as three-fold integrals. The asymptotic behavior of the amplitudes for various limits of interest are investigated also in the case of a linearly polarized laser field. Using the obtained results, the possibility of experimental observation of the process is discussed.
description: 31 pages, 4 figures
Cahiers de lexicologie. 1994-1, n° 64
Creators: name: (:Unap)
Publisher: name: Classiques Garnier
Year: 2012
Subjects: subject: Lexique
subject: Lexicographie
subject: Sémantique
subject: Traduction
subject: Linguistique historique

description: Les Cahiers de lexicologie, revue internationale de lexicologie et de lexicographie, s'intéressent au lexique dans ses relations avec les autres composantes de la langue (syntaxe, sémantique, morphologie, phonologie, discours…), tant du point de vue théorique que de leurs applications, notamment pour ce qui concerne le traitement informatique de la langue.
description: The Cahiers de lexicologie, international review of lexicology and lexicography, studies vocabulary in its relation to other aspects of language (syntax, semantics, morphology, phonology, speech...), both from a theoretical point of view and in practical applications, notably concerning computer treatment of language.
Cahiers de lexicologie. 1994-2, n° 65
Creators: name: (:Unap)
Publisher: name: Classiques Garnier
Year: 2012
Subjects: subject: Lexique
subject: Lexicographie
subject: Sémantique
subject: Traduction
subject: Linguistique historique

description: Les Cahiers de lexicologie, revue internationale de lexicologie et de lexicographie, s'intéressent au lexique dans ses relations avec les autres composantes de la langue (syntaxe, sémantique, morphologie, phonologie, discours…), tant du point de vue théorique que de leurs applications, notamment pour ce qui concerne le traitement informatique de la langue.
description: The Cahiers de lexicologie, international review of lexicology and lexicography, studies vocabulary in its relation to other aspects of language (syntax, semantics, morphology, phonology, speech...), both from a theoretical point of view and in practical applications, notably concerning computer treatment of language.
Cahiers de lexicologie. 1995-2, n° 67
Creators: name: (:Unap)
Publisher: name: Classiques Garnier
Year: 2012
Subjects: subject: Lexique
subject: Lexicographie
subject: Sémantique
subject: Traduction
subject: Linguistique historique

description: Les Cahiers de lexicologie, revue internationale de lexicologie et de lexicographie, s'intéressent au lexique dans ses relations avec les autres composantes de la langue (syntaxe, sémantique, morphologie, phonologie, discours…), tant du point de vue théorique que de leurs applications, notamment pour ce qui concerne le traitement informatique de la langue.
description: The Cahiers de lexicologie, international review of lexicology and lexicography, studies vocabulary in its relation to other aspects of language (syntax, semantics, morphology, phonology, speech...), both from a theoretical point of view and in practical applications, notably concerning computer treatment of language.
Torsional moduli of transition metal dichalcogenide nanotubes from first principles
Creators: name: Bhardwaj, Arpit
name: Sharma, Abhiraj
name: Suryanarayana, Phanish
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We calculate the torsional moduli of single-walled transition metal dichalcogenide (TMD) nanotubes using ab initio density functional theory (DFT). Specifically, considering forty-five select TMD nanotubes, we perform symmetry-adapted DFT calculations to calculate the torsional moduli for the armchair and zigzag variants of these materials in the low-twist regime and at practically relevant diameters. We find that the torsional moduli follow the trend: MS$_2$ $>$ MSe$_2$ $>$ MTe$_2$. In addition, the moduli display a power law dependence on diameter, with the scaling generally close to cubic, as predicted by the isotropic elastic continuum model. In particular, the shear moduli so computed are in good agreement with those predicted by the isotropic relation in terms of the Young's modulus and Poisson's ratio, both of which are also calculated using symmetry-adapted DFT. Finally, we develop a linear regression model for the torsional moduli of TMD nanotubes based on the nature/characteristics of the metal-chalcogen bond, and show that it is capable of making reasonably accurate predictions.
description: 20 pages, 4 figures, 1 table
Cahiers de lexicologie. 1998-1, n° 72
Creators: name: (:Unap)
Publisher: name: Classiques Garnier
Year: 2012
Subjects: subject: Lexique
subject: Lexicographie
subject: Sémantique
subject: Traduction
subject: Linguistique historique

description: Les Cahiers de lexicologie, revue internationale de lexicologie et de lexicographie, s'intéressent au lexique dans ses relations avec les autres composantes de la langue (syntaxe, sémantique, morphologie, phonologie, discours…), tant du point de vue théorique que de leurs applications, notamment pour ce qui concerne le traitement informatique de la langue.
description: The Cahiers de lexicologie, international review of lexicology and lexicography, studies vocabulary in its relation to other aspects of language (syntax, semantics, morphology, phonology, speech...), both from a theoretical point of view and in practical applications, notably concerning computer treatment of language.
Phonon instability and structural phase transition in Vanadium under high pressure
Creators: name: Verma, Ashok K.
name: Modak, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Results of the first-principles calculations are presented for the group-VB metals V, Nb and Ta up to couple of megabar pressure. An unique structural phase transition sequence BCC-->(at 60 GPa) rhombohedral (angle=110.5 degree)-->(at ~ 160 GPa)rhombohedral(angle=108.5 degree)--> (at ~ 430 GPa) BCC is predicted in V. We also find that BCC-V becomes mechanically and vibrationally unstable at around 112 GPa pressure. Similar transitions are absent in Nb and Ta.
description: 16 pages, 4 figures
CP violation due to multi Froggatt-Nielsen fields
Creators: name: Kanemura, Shinya
name: Matsuda, Koichi
name: Ota, Toshihiko
name: Petcov, Serguey
name: Shindou, Tetsuo
name: Takasugi, Eiichi
name: Tsumura, Koji
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study how to incorporate CP violation in the Froggatt--Nielsen (FN) mechanism. To this end, we introduce non-renormalizable interactions with a flavor democratic structure to the fermion mass generation sector. It is found that at least two iso-singlet scalar fields with imposed a discrete symmetry are necessary to generate CP violation due to the appearance of the relative phase between their vacuum expectation values. In the simplest model, ratios of quark masses and the Cabibbo-Kobayashi-Maskawa (CKM) matrix including the CP violating phase are determined by the CKM element |V_{us}| and the ratio of two vacuum expectation values R=|R|e^{i*alpha} (a magnitude and a phase). It is demonstrated how the angles phi_i (i=1--3) of the unitarity triangle and the CKM off-diagonal elements |V_{ub}| and |V_{cb}| are predicted as a function of |V_{us}|, |R| and α. Although the predicted value of the CP violating phase does not agree with the experimental data within the simplest model, the basic idea of our scenario would be promising to construct a more realistic model of flavor and CP violation.
description: 8 pages, no figure
Cahiers de lexicologie. 2003-2, n° 83
Creators: name: (:Unap)
Publisher: name: Classiques Garnier
Year: 2012
Subjects: subject: Lexique
subject: Lexicographie
subject: Sémantique
subject: Traduction
subject: Linguistique historique

description: Les Cahiers de lexicologie, revue internationale de lexicologie et de lexicographie, s'intéressent au lexique dans ses relations avec les autres composantes de la langue (syntaxe, sémantique, morphologie, phonologie, discours…), tant du point de vue théorique que de leurs applications, notamment pour ce qui concerne le traitement informatique de la langue.
description: The Cahiers de lexicologie, international review of lexicology and lexicography, studies vocabulary in its relation to other aspects of language (syntax, semantics, morphology, phonology, speech...), both from a theoretical point of view and in practical applications, notably concerning computer treatment of language.
Can dc voltage proportional to the persistent current be observed on segment of asymmetric mesoscopic ring?
Creators: name: Dubonos, S. V.
name: Gurtovoi, V. L.
name: Nikulov, A. V.
name: Tulin, V. A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: In order to clear up a question on possibility of a dc voltage proportional to the persistent current in normal metal and semiconductor mesoscopic loops conjectural causes of this phenomenon observed in superconductor loops is investigated.
description: 3 pages, 2 figures
An update on the two singlet Dark Matter model
Creators: name: Basak, Tanushree
name: Coleppa, Baradhwaj
name: Loho, Kousik
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We revisit the two real singlet extension of the Standard Model with a $Z_2\times Z_2^\prime$ symmetry. One of the singlet scalars $S_2$, by virtue of an unbroken $Z_2^\prime$ symmetry, plays the role of a stable dark matter candidate. The other scalar $S_1$, with spontaneously broken $Z_2$-symmetry, mixes with the SM Higgs boson and acts as the scalar mediator. We analyze the model by putting in the entire set of theoretical and recent experimental constraints. The latest bounds from direct detection Xenon1T experiment severely restricts the allowed region of parameter space of couplings. To ensure the dark matter satisfies the relic abundance criterion, we rely on the Breit-Wigner enhanced annihilation cross-section. Further, we study the viability of explaining the observed gamma-ray excess in the galactic center in this model with a dark matter of mass in the $\sim 36-51$ GeV window and present our conclusions.
description: 14 pages, 9 figures
Diffusion of a magnetic skyrmion in 2-dimensional space
Creators: name: Suzuki, Yoshishige
name: Miki, Soma
name: Tamura, Eiiti
Publisher: name: arXiv
Year: 2021
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Two-dimensional magnetic skyrmions are particle-like magnetic domains in magnetic thin films. The kinetic property of the magnetic skyrmions at finite temperature is well described by the Thiele equation, including a stochastic field and a finite mass. In this paper, the validity of the constant-mass approximation is examined by comparing the Fourier spectrum of Brownian motions described by the Thiele equation and the Landau-Lifshitz-Gilbert equation. Then, the 4-dimensional Fokker-Planck equation is derived from the Thiele equation with a mass-term. Consequently, an expression of the diffusion flow and diffusion constant in a tensor form is derived, extending Chandrasekhar's method for Thiele dynamics.
description: 13 pages, 3 figures
The Cyborg Astrobiologist: Porting from a wearable computer to the Astrobiology Phone-cam
Creators: name: Bartolo, Alexandra
name: McGuire, Patrick C.
name: Camilleri, Kenneth P.
name: Spiteri, Christopher
name: Borg, Jonathan C.
name: Farrugia, Philip J.
name: Ormo, Jens
name: Gomez-Elvira, Javier
name: Rodriguez-Manfredi, Jose Antonio
name: Diaz-Martinez, Enrique
name: Ritter, Helge
name: Haschke, Robert
name: Oesker, Markus
name: Ontrup, Joerg
Publisher: name: arXiv
Year: 2007
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Astrophysics (astro-ph)
subject: Artificial Intelligence (cs.AI)
subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Human-Computer Interaction (cs.HC)
subject: Networking and Internet Architecture (cs.NI)
subject: Robotics (cs.RO)
subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: We have used a simple camera phone to significantly improve an `exploration system' for astrobiology and geology. This camera phone will make it much easier to develop and test computer-vision algorithms for future planetary exploration. We envision that the `Astrobiology Phone-cam' exploration system can be fruitfully used in other problem domains as well.
description: 15 pages, 4 figures, accepted for publication in the International Journal of Astrobiology
Microsolvation of cationic dimers in $^4$He droplets: geometries of A$_2^+$(He)$_N$ (A=Li,Na,K) from optimized energies
Creators: name: Marinetti, F.
name: Uranga-Piña, Ll.
name: Coccia, E.
name: López-Durán, D.
name: Bodo, E.
name: Gianturco, F. A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Ab initio computed interaction forces are employed in order to describe the microsolvation of the A$_2^+(^2Σ)$ (A=Li,Na,K) molecular ion in $^4$He clusters of small variable size. The minimum energy structures are obtained by performing energy minimization based on a genetic algorithm approach. The symmetry features of the collocation of solvent adatoms around the dimeric cation are analyzed in detail, showing that the selective growth of small clusters around the two sides of the ion during the solvation process is a feature common to all three dopants.
An N-body approach to modeling debris and ejecta off small bodies: Implementation and application
Creators: name: Larson, Jennifer N.
name: Sarid, Gal
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We introduce here our new approach to modeling particle cloud evolution off surface of small bodies (asteroids and comets), following the evolution of ejected particles requires dealing with various time and spatial scales, in an efficient, accurate and modular way. In order to improve computational efficiency and accuracy of such calculations, we created an N-body modeling package as an extension to the increasingly popular orbital dynamics N-body integrator Rebound. Our code is currently a stand-alone variant of the Rebound code and is aimed at advancing a comprehensive understanding of individual particle trajectories, external forcing, and interactions, at the scale which is otherwise overlooked by other modeling approaches. The package we developed -- Rebound Ejecta Dynamics (RED) -- is a Python-based implementation with no additional dependencies. It incorporates several major mechanisms that affect the evolution of particles in low-gravity environments and enables a more straightforward simulation of combined effects. We include variable size and velocity distributions, solar radiation pressure, ellipsoidal gravitational potential, binary or triple asteroid systems, and particle-particle interactions. In this paper, we present a sample of the RED package capabilities. These are applied to a small asteroid binary system (characterized following the Didymos/Dimorphos system, which is the target for NASA's Double Asteroid Redirection Test mission)
description: 13 pages, 11 figures, 4 tables, 2 appendices. Published (advance access) on 2/15/2021, see https://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/stab408/6136266?redirectedFrom=fulltext
Restoration of randomly blurred images
Creators: name: Guan, Ling
Publisher: name: University of British Columbia
Year: 2010

description: This thesis considers the restoration of images blurred by random point spread functions. The stochastic point spread functions are represented by the sum of a deterministic blur function plus an image-dependent noise term. The stochastic properties of such systems are studied. Several linear filters are derived. These filters are based on the following criteria: the Wiener, the minimum variance unbiased, and the constrained least squares. A filter based on the geometrical mean methodology is also presented. The popular Wiener filter, and the minimum variance unbiased filter have already been applied to this problem for the one-dimensional case. We generalize these filters to the two-dimensional case. These filters are found to give good restoration results when the blur and/or the additive noise effects are not severe. When either or both of the above conditions are not satisfied, numerical instability may occur. The constrained least squares filter does not suffer from such ill conditioning. However, the performance of this method needs to be manually controlled in order to yield good restoration results. The geometrical mean filter is formed by combining the modified Wiener filter and the constrained least squares filter. This filter gives the best restoration amongst the four linear-based filters because it does not have the shortcomings the other filters have. A nonlinear filter, the maximum a posteriori filter is also derived and implemented. Since the random blur effect is a nonlinear stochastic process, we expect the nonlinear filtering scheme to simulate the reverse of the blurring process more closely. The superiority of this filter over the modified Wiener filter is demonstrated by examples. In addition, the restoration of random time-varying blurred images is also discussed. The Wiener criterion is adopted. The solution of this problem involves the processing of a huge amount of multi-image data. To circumvent this problem we present two approaches to realize this Wiener filter. One is based on the Karhunen-Loeve transformation, and the other is a direct Wiener filter implementation. These two approaches give better results than that given by processing any single frame individually. Since image restoration involves computation of very large systems, The computational effort is an important factor to consider in the implementation of all restoration algorithms. By means of the circulant matrix approximation and the fast Fourier transform, our methods are implemented in the frequency domain. The computational efforts are reduced significantly.
Toeplitz and Cesàro-Type Operators on Homogeneous Siegel Domains
Creators: name: Calzi, Mattia
name: Peloso, Marco M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 32A36 (Primary) 32A10, 32M10 (Secondary)

description: In this paper we study Toeplitz and Cesàro-type operators on holomorphic function spaces on a homogeneous Siegel domain of Type II. We prove several necessary conditions and sufficient conditions for these operators to be continuous or compact, or to belong to suitable Schatten classes.
description: 25 pages, no figures
Thermal decomposition of norbornane (bicyclo[2.2.1]heptane) dissolved in benzene. Experimental study and mechanism investigation
Creators: name: Herbinet, Olivier
name: Sirjean, Baptiste
name: Battin-Leclerc, Frédérique
name: Fournet, René
name: Marquaire, Paul-Marie
Publisher: name: arXiv
Year: 2007
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The thermal decomposition of norbornane (dissolved in benzene) has been studied in a jet stirred reactor at temperatures between 873 and 973 K, at residence times ranging from 1 to 4 s and at atmospheric pressure, leading to conversions from 0.04 to 22.6%. 25 reaction products were identified and quantified by gas chromatography, amongst which the main ones are hydrogen, ethylene and 1,3-cyclopentadiene. A mechanism investigation of the thermal decomposition of the norbornane - benzene binary mixture has been performed. Reactions involved in the mechanism have been reviewed: unimolecular initiations 1 by C-C bond scission of norbornane, fate of the generated diradicals, reactions of transfer and propagation of norbornyl radicals, reactions of benzene and cross-coupling reactions.
Stochastic light variations in hot stars from wind instability: Finding photometric signatures and testing against the TESS data
Creators: name: Krticka, Jiri
name: Feldmeier, Achim
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Line-driven wind instability is expected to cause small-scale wind inhomogeneities, X-ray emission, and wind line profile variability. The instability can already develop around the sonic point if it is initiated close to the photosphere due to stochastic turbulent motions. In such cases, it may leave its imprint on the light curve as a result of wind blanketing. We study the photometric signatures of the line-driven wind instability. We used line-driven wind instability simulations to determine the wind variability close to the star. We applied two types of boundary perturbations: a sinusoidal one that enables us to study in detail the development of the instability and a stochastic one given by a Langevin process that provides a more realistic boundary perturbation. We estimated the photometric variability from the resulting mass-flux variations. The variability was simulated assuming that the wind consists of a large number of independent conical wind sectors. We compared the simulated light curves with TESS light curves of OB stars that show stochastic variability. We find two typical signatures of line-driven wind instability in photometric data: a knee in the power spectrum of magnitude fluctuations, which appears due to engulfment of small-scale structure by larger structures, and a negative skewness of the distribution of fluctuations, which is the result of spatial dominance of rarefied regions. These features endure even when combining the light curves from independent wind sectors. The stochastic photometric variability of OB stars bears certain signatures of the line-driven wind instability. The distribution function of observed photometric data shows negative skewness and the power spectra of a fraction of light curves exhibit a knee. This can be explained as a result of the line-driven wind instability triggered by stochastic base perturbations.
description: 9 pages, accepted for publication in Astronomy & Astrophysics
The MSST Campaign: II.Effective temperature and gravity variations in the multi-periodic pulsating subdwarf B star PG1605+072
Creators: name: Tillich, A.
name: Heber, U.
name: O'Toole, S. J.
name: Østensen, R.
name: Schuh, S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Stellar oscillations are an important tool to probe the interior of a star. Subdwarf B stars are core helium burning objects, but their formation is poorly understood as neither single star nor binary evolution can fully explain their observed properties. Since 1997 an increasing number of sdB stars has been found to pulsate forming two classes of stars (the V361 Hya and V1093 Her stars). We focus on the bright V 361 Hya star PG1605+072 to characterize its frequency spectrum. While most previous studies relied on light variations, we have measured radial velocity variations for as much as 20 modes. In this paper we aim at characterizing the modes from atmospheric parameter and radial velocity variations. Time resolved spectroscopy ($\approx$9000 spectra) has been carried out to detect line profile variations from which variations of the effective temperature and gravity are extracted by means of a quantitative spectral analysis. We measured variations of effective temperatures and gravities for eight modes with semi-amplitudes ranging from $ΔT_{\rm{eff}}=880$ K to as small as 88 K and $Δ\log{g}$ of 0.08 dex to as low as 0.008 dex. Gravity and temperature vary almost in phase, whereas phase lags are found between temperature and radial velocity. This profound analysis of a unique data set serves as sound basis for the next step towards an identification of pulsation modes. As rotation may play an important role the modelling of pulsation modes is challenging but feasible.
description: 10 pages, 9 figures, Accepted for publication in A&A
Analysis of the $\overlineΞ_{cc}Ξ_{cc}$ hexaquark molecular state with the QCD sum rules
Creators: name: Wang, Zhi-Gang
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this work, we construct the color-singlet-color-singlet type six-quark pseudoscalar current to investigate the $\overlineΞ_{cc}Ξ_{cc}$ hexaquark molecular state with the QCD sum rules, the predicted mass $M_X \sim 7.2\,\rm{GeV}$ supports assigning the $X(7200)$ to be the $\overlineΞ_{cc}Ξ_{cc}$ hexaquark molecular state with the quantum numbers $J^{PC}=0^{-+}$. The $X(7200)$ can decay through fusions of the $\bar{c}c$ and $\bar{q}q$ pairs, we can search for the $X(7200)$ and explore its properties in the $J/ψJ/ψ$, $χ_{c1}χ_{c1}$, $D^*\bar{D}^*$ and $D_1\bar{D}_1$ invariant mass spectrum in the future.
description: 8 pages, 5 figures
Detailed kinetic study of the ring opening of cycloalkanes by CBS-QB3 calculations
Creators: name: Sirjean, Baptiste
name: Glaude, Pierre-Alexandre
name: Ruiz-Lopez, M. F.
name: Fournet, René
Publisher: name: arXiv
Year: 2007
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: This work reports a theoretical study of the gas phase unimolecular decomposition of cyclobutane, cyclopentane and cyclohexane by means of quantum chemical calculations. A biradical mechanism has been envisaged for each cycloalkane, and the main routes for the decomposition of the biradicals formed have been investigated at the CBS-QB3 level of theory. Thermochemical data (δH^0_f, S^0, C^0_p) for all the involved species have been obtained by means of isodesmic reactions. The contribution of hindered rotors has also been included. Activation barriers of each reaction have been analyzed to assess the 1 energetically most favorable pathways for the decomposition of biradicals. Rate constants have been derived for all elementary reactions using transition state theory at 1 atm and temperatures ranging from 600 to 2000 K. Global rate constant for the decomposition of the cyclic alkanes in molecular products have been calculated. Comparison between calculated and experimental results allowed to validate the theoretical approach. An important result is that the rotational barriers between the conformers, which are usually neglected, are of importance in decomposition rate of the largest biradicals. Ring strain energies (RSE) in transition states for ring opening have been estimated and show that the main part of RSE contained in the cyclic reactants is removed upon the activation process.
Comment on ``New Physics Contributions to the Lifetime Difference in $D^0-\bar D^{0}$ mixing''
Creators: name: Chen, Chuan-Hung
name: Geng, Chao-Qiang
name: Nam, Soo-Hyeon
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We find that in the nonmanifest left-right (LR) model, an important LR mixing effect was not considered in the paper by E. Golowich, S. Pakvasa, and A. Petrov, Phys. Rev. Lett. 98, 181801 (2007).
description: 2 pages
Resource efficient single photon source based on active frequency multiplexing
Creators: name: Massar, Serge
name: Clemmen, Stephane
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We propose a new single photon source based on the principle of active multiplexing of heralded single photons which, unlike previously reported architecture, requires a limited amount of physical resources. We discuss both its feasibility and the purity and indistinguishability of single photons as function of the key parameters of a possible implementation.
On thermal effects in solid state lasers: the case of ytterbium-doped materials
Creators: name: Chenais, Sebastien
name: Druon, Frederic
name: Forget, Sebastien
name: Balembois, Francois
name: Georges, Patrick
Publisher: name: arXiv
Year: 2007
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: A review of theoretical and experimental studies of thermal effects in solid-state lasers is presented, with a special focus on diode-pumped ytterbium-doped materials. A large part of this review provides however general information applicable to any kind of solid-state laser. Our aim here is not to make a list of the techniques that have been used to minimize thermal effects, but instead to give an overview of the theoretical aspects underneath, and give a state-of-the-art of the tools at the disposal of the laser scientist to measure thermal effects. After a presentation of some general properties of Yb-doped materials, we address the issue of evaluating the temperature map in Yb-doped laser crystals, both theoretically and experimentally. This is the first step before studying the complex problem of thermal lensing (part III). We will focus on some newly discussed aspects, like the definition of the thermo-optic coefficient: we will highlight some misleading interpretations of thermal lensing experiments due to the use of the dn/dT parameter in a context where it is not relevant. Part IV will be devoted to a state-of-the-art of experimental techniques used to measure thermal lensing. Eventually, in part V, we will give some concrete examples in Yb-doped materials, where their peculiarities will be pointed out.
Dimensional crossover of thermal conductance in nanowires
Creators: name: Wang, Jian
name: Wang, Jian-Sheng
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Dimensional dependence of thermal conductance at low temperatures in nanowires is studied using the nonequilibrium Green's function (NEGF) method. Our calculation shows a smooth dimensional crossover of thermal conductance in nanowire from one-dimensional to three-dimensional behavior with the increase of diameters. The results are consistent with the experimental findings that the temperature dependence of thermal conductance at low temperature for diameters from tens to hundreds nanometers will be close to Debye law. The calculation also suggests that universal thermal conductance is only observable in nanowires with small diameters. We also find that the interfacial thermal conductance across Si and Ge nanowire is much lower than the corresponding value in bulk materials.
description: 4 figures
A diffraction-compensating 0-25 ns free space terahertz delay line for coherent quantum control
Creators: name: Allen, D. G.
name: Persechini, L.
name: Takahashi, S.
name: Ramina, G.
name: Sherwin, M. S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Free space delay lines provide pulses of variable time spacing for optical experiments such as pump-probe spectroscopy and coherent quantum control, including spin and photon echo techniques. However, in the terahertz (THz) region of the spectrum, beam divergence due to diffraction limits the useful length of traditional free space delay lines. We present a novel double-folded variable delay line for light in the frequency range 0.24-1.2 THz, which incorporates a symmetric arrangement of lenses whose spacing can be adjusted to compensate for diffraction at each delay. Scalable for use in other wavelength regimes, the design relays an input Gaussian beam waist to the output with up to 25 ns (~8 m) total delay and is enclosed in a desiccated volume of <0.5 m^3. The delay line can deliver two or three pulses with relative amplitudes controlled via variable spacing silicon etalon beam splitters. Beam profiles of a 0.24 THz beam show good agreement with calculations at long delays, with insertion loss per delay stage of~3 dB.
Transient behavior of surface plasmon polaritons scattered at a subwavelength groove
Creators: name: Leveque, Gaetan
name: Martin, Olivier J. F.
name: Weiner, John
Publisher: name: arXiv
Year: 2007
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We present a numerical study and analytical model of the optical near-field diffracted in the vicinity of subwavelength grooves milled in silver surfaces. The Green's tensor approach permits computation of the phase and amplitude dependence of the diffracted wave as a function of the groove geometry. It is shown that the field diffracted along the interface by the groove is equivalent to replacing the groove by an oscillating dipolar line source. An analytic expression is derived from the Green's function formalism, that reproduces well the asymptotic surface plasmon polariton (SPP) wave as well as the transient surface wave in the near-zone close to the groove. The agreement between this model and the full simulation is very good, showing that the transient "near-zone" regime does not depend on the precise shape of the groove. Finally, it is shown that a composite diffractive evanescent wave model that includes the asymptotic SPP can describe the wavelength evolution in this transient near-zone. Such a semi-analytical model may be useful for the design and optimization of more elaborate photonic circuits whose behavior in large part will be controlled by surface waves.
description: 12 pages, 10 figures
Bacterial activity hinders particle sedimentation
Creators: name: Singh, Jaspreet
name: Patteson, Alison E.
name: Maldonado, Bryan O. Torres
name: Purohit, Prashant K.
name: Arratia, Paulo E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Sedimentation in active fluids has come into focus due to the ubiquity of swimming micro-organisms in natural and industrial processes. Here, we investigate sedimentation dynamics of passive particles in a fluid as a function of bacteria E. coli concentration. Results show that the presence of swimming bacteria significantly reduces the speed of the sedimentation front even in the dilute regime, in which the sedimentation speed is expected to be independent of particle concentration. Furthermore, bacteria increase the dispersion of the passive particles, which determines the width of the sedimentation front. For short times, particle sedimentation speed has a linear dependence on bacterial concentration. Mean square displacement data shows, however, that bacterial activity decays over long experimental (sedimentation) times. An advection-diffusion equation coupled to bacteria population dynamics seems to capture concentration profiles relatively well. A single parameter, the ratio of single particle speed to the bacteria flow speed can be used to predict front sedimentation speed.
description: Soft Matter, (2021). arXiv admin note: substantial text overlap with arXiv:1710.04068
Forward- and Mid-Rapidity Jet-like correlations
Creators: name: Wang, Fuqiang
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Mid-rapidity azimuthal correlations probe di-jets originating mainly from gluon-gluon hard-scattering. Measurements of such correlations have revealed significant (gluon-)jet modification in central Au+Au collisions. Azimuthal correlations of hadrons at forward rapidity with a mid-rapidity high-$\pt$ hadron, on the other hand, probe asymmetric partonic scatterings involving large-x quarks and small-x gluons. We present preliminary results from STAR on correlations of charged hadrons at forward rapidity in the forward TPCs ($2.73$ GeV/$c$) in $pp$, d+Au, and Au+Au collisions at $\snn=200$ GeV. The implications of the results for small-x gluon distributions (Color Glass Condensate formation) and the energy loss of quark jets at forward rapidity in nuclear medium are discussed. %Their measurements in d+Au collisions, separately at the d-side and the Au-side, may be sensitive to Color Glass Condensate in the Au-nucleus. Their measurements in Au+Au collisions may probe quark-jet modification in nuclear medium.
description: Invited talk at the XIth International Workshop on Correlation and Fluctuation in Multiparticle Production, Hangzhou, China, November 2007
Direct Observation of an Incommensurate Charge Density Wave in the BiS2-based Superconductor NdO1-xFxBiS2
Creators: name: Lee, Jooseop
name: Nagao, Masanori
name: Mizuguchi, Yoshikazu
name: Ruff, Jacob
Publisher: name: arXiv
Year: 2021
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The nature of superconductivity in BiS$_2$-based superconductors has been controversial while ab-initio calculations proposed this system in close proximity to a charge-density-wave (CDW) phase. Using high-energy high-flux X-ray diffraction, we reveal an intrinsic and long-range CDW phase coexisting with superconductivity in NdO$_{1-x}$F$_{x}$BiS$_2$ superconductor ($x$ = 0.37 and 0.3). The CDW wavevector in NdO$_{0.63}$F$_{0.37}$BiS$_2$ correspond Q$_{\rm{CDW}}$ = (0.17, 0.17, 0.5) and is associated with transverse atomic displacements. Interestingly, this wavevector does not match theoretical expectations based on either phonon softening or Fermi surface nesting. In NdO$_{0.7}$F$_{0.3}$BiS$_2$, where the superconducting transition temperature is highest, the CDW satellites are slightly broader and weaker compared to NdO$_{0.63}$F$_{0.37}$BiS$_2$, possibly suggesting the competition with the superconductivity. Lastly, we measure a thermal diffuse scattering across the superconducting transition temperature and find no meaningful changes in favor of the unconventional pairing mechanism. Our result suggests the importance of understanding CDW which might hold a key to the superconductivity in the BiS$_2$-based superconductor.
description: 7 pages, 3 figures, Supplementary to be uploaded
Carbon-Enhanced Hyper-metal-poor Stars and the Stellar IMF at Low Metallicity
Creators: name: Tumlinson, Jason
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The two known ``hyper-metal-poor'' (HMP) stars, HE0107-5240 and HE1327-2326, have extremely high enhancements of the light elements C, N, and O relative to Fe and appear to represent a statistically significant excess population relative to the halo metallicity distribution extrapolated from [Fe/H] > -3. This study weighs the available evidence for and against three hypothetical origins for these stars: (1) that they formed from gas enriched by a primordial ``faint supernova'', (2) that they formed from gas enriched by core-collapse supernovae and C-rich gas ejected in rotation-driven winds from massive stars, and (3) that they formed as the low-mass secondaries in binary systems at Z ~ 10^{-5.5} Zsun and acquired their light-element enhancements from an intermediate-mass companion as it passed through an AGB phase. The observations interpreted here, especially the depletion of lithium seen in HE1327-2326, favor the binary mass-transfer hypothesis. If HE0107-5240 and HE1327-2326 formed in binary systems, the statistically significant absence of isolated and/or C-normal stars at similar [Fe/H] implies that low-mass stars could form at that metallicity, but that masses M ~< 1.4 Msun were disfavored in the IMF. This result is also explained if the abundance-derived top-heavy IMF for primordial stars persists to [Fe/H] ~ -5.5. This finding indicates that low-mass star formation was possible at extremely low metallicity, and that the typical stellar mass may have had a complex dependence on metallicity rather than a sharp transition driven solely by gas cooling.
description: 11 pages emulateapj text including three figures, accepted for publication in ApJ v666 (Sept 2007). A companion paper to 0706.2903
Second-Order Eikonal Corrections for A(e,e'p)
Creators: name: Van Overmeire, B.
name: Ryckebusch, J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The first-order eikonal approximation is frequently adopted in interpreting the results of $A(e,e'p)$ measurements. Glauber calculations, for example, typically adopt the first-order eikonal approximation. We present an extension of the relativistic eikonal approach to $A(e,e'p)$ which accounts for second-order eikonal corrections. The numerical calculations are performed within the relativistic optical model eikonal approximation. The nuclear transparency results indicate that the effect of the second-order eikonal corrections is rather modest, even at $Q^{2} \approx 0.2$ (GeV/c)$^2$. The same applies to polarization observables, left-right asymmetries, and differential cross sections at low missing momenta. At high missing momenta, however, the second-order eikonal corrections are significant and bring the calculations in closer agreement with the data and/or the exact results from models adopting partial-wave expansions.
description: 16 pages, 4 figures, 1 table, submitted to Phys. Lett. B