cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Improvement and protection of niobium surface superconductivity by Atomic Layer Deposition and heat treatment
Creators: name: Proslier, T.
name: Zasadzinski, J.
name: Moore, J.
name: Pellin, M.
name: Elam, J.
name: Cooley, L.
name: Antoine, C.
name: Norem, J.
name: Gray, K. E.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A method to treat the surface of Nb is described which potentially can improve the performance of superconducting RF cavities. We present tunneling and x-ray photoemission spectroscopy (XPS) measurements at the surface of cavity-grade niobium samples coated with a 3 nm alumina overlayer deposited by Atomic Layer Deposition (ALD). The coated samples baked in ultra high vacuum (UHV) at low temperature reveal at first degraded superconducting surface. However, at temperatures above 450C, the tunneling conductance curves show significant improvements of the superconducting density of states (DOS) compared with untreated surfaces.
description: 3 pages, 2 figures
THE USE OF MILITARY-HISTORICAL ISSUES IN RUSSIAN ANTI-UKRAINIAN PROPAGANDA
Creators: name: Ivanenko, S.
name: Bidnyi, V.
Publisher: name: Sciences of Europe
Year: 2021
Subjects: anti-Ukrainian propaganda
discourse
World War II
narrative
Nazis
image of the enemy
memorable dates
victory
fascists
fake.

description: The peculiarities of the Kremlin propaganda's use of the narrative "Great Patriotic War" to create an "image of the enemy" from Ukraine, demonization of the state leadership, personnel of the Armed Forces of Ukraine and other law enforcement agencies, as well as legitimizing Russian aggression against our state.
A note on fermions in holographic QCD
Creators: name: Heise, Rainer
name: Svendsen, Harald G
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the fermionic sector of a probe D8-brane in the supergravity background made of D4-branes compactified on a circle with supersymmetry broken explicitly by the boundary conditions. At low energies the dual field theory is effectively four-dimensional and has proved surprisingly successful in recovering qualitative and quantitative properties of QCD. We investigate fluctuations of the fermionic fields on the probe D8-brane and interpret these as mesinos (fermionic superpartners of mesons). We demonstrate that the masses of these modes are comparable to meson masses and show that their interactions with ordinary mesons are not suppressed.
description: 21+1 pp, 1 figure; v2: typos corrected, refs. added
Operation and performance of the ATLAS semiconductor tracker in LHC Run 2
Creators: name: ATLAS Collaboration
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The semiconductor tracker (SCT) is one of the tracking systems for charged particles in the ATLAS detector. It consists of 4088 silicon strip sensor modules. During Run 2 (2015$-$2018) the Large Hadron Collider delivered an integrated luminosity of 156 fb$^{-1}$ to the ATLAS experiment at a centre-of-mass $pp$ collision energy of 13 TeV. The instantaneous luminosity and pile-up conditions were far in excess of those assumed in the original design of the SCT detector. Due to improvements to the data acquisition system, the SCT operated stably throughout Run 2. It was available for 99.9% of the integrated luminosity and achieved a data-quality efficiency of 99.85%. Detailed studies have been made of the leakage current in SCT modules and the evolution of the full depletion voltage, which are used to study the impact of radiation damage to the modules.
description: 55 pages in total, author list starting page 39, 25 figures, 6 tables, submitted to JINST. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SCTD-2019-01
Dynamics of cluster deposition on Ar surface
Creators: name: Dinh, P. M.
name: Fehrer, F.
name: Reinhard, P. -G.
name: Suraud, E.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Using a combined quantum mechanical/classical method, we study the dynamics of deposition of small Na clusters on Ar(001) surface. We work out basic mechanisms by systematic variation of substrate activity, impact energy, cluster orientations, cluster sizes, and charges. The soft Ar material is found to serve as an extremely efficient shock absorber which provides cluster capture in a broad range of impact energies. Reflection is only observed in combination with destruction of the substrate. The kinetic energy of the impinging cluster is rapidly transfered at first impact. The distribution of the collision energy over the substrate proceeds very fast with velocity of sound. The full thermalization of ionic and atomic energies goes at a much slower pace with times of several ps. Charged clusters are found to have a much stronger interface interaction and thus get in significantly closer contact with the surface.
description: 10 pages, 6 figures, accepted in Euro. Phys. J. D
Mesh convolutional neural networks for wall shear stress estimation in 3D artery models
Creators: name: Suk, Julian
name: de Haan, Pim
name: Lippe, Phillip
name: Brune, Christoph
name: Wolterink, Jelmer M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: Computational fluid dynamics (CFD) is a valuable tool for personalised, non-invasive evaluation of hemodynamics in arteries, but its complexity and time-consuming nature prohibit large-scale use in practice. Recently, the use of deep learning for rapid estimation of CFD parameters like wall shear stress (WSS) on surface meshes has been investigated. However, existing approaches typically depend on a hand-crafted re-parametrisation of the surface mesh to match convolutional neural network architectures. In this work, we propose to instead use mesh convolutional neural networks that directly operate on the same finite-element surface mesh as used in CFD. We train and evaluate our method on two datasets of synthetic coronary artery models with and without bifurcation, using a ground truth obtained from CFD simulation. We show that our flexible deep learning model can accurately predict 3D WSS vectors on this surface mesh. Our method processes new meshes in less than 5 [s], consistently achieves a normalised mean absolute error of $\leq$ 1.6 [%], and peaks at 90.5 [%] median approximation accuracy over the held-out test set, comparing favourably to previously published work. This demonstrates the feasibility of CFD surrogate modelling using mesh convolutional neural networks for hemodynamic parameter estimation in artery models.
description: (MICCAI 2021) Workshop on Statistical Atlases and Computational Modelling of the Heart (STACOM). The final authenticated version is available on SpringerLink
Spin polarons and molecules in strongly-interacting atomic Fermi gases
Creators: name: Massignan, P.
name: Bruun, G. M.
name: Stoof, H. T. C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We examine pairing and molecule formation in strongly-interacting Fermi gases, and we discuss how radio-frequency (RF) spectroscopy can reveal these features. For the balanced case, the emergence of stable molecules in the BEC regime results in a two-peak structure in the RF spectrum with clearly visible medium effects on the low-energy part of the molecular wavefunction. For the highly-imbalanced case, we show the existence of a well-defined quasiparticle (a spin polaron) on both sides of the Feshbach resonance, we evaluate its lifetime, and we illustrate how its energy may be measured by RF spectroscopy.
description: 4 pages, 5 figures. Revised version accepted for publication: minor changes to Fig. 2 (added inset with the chemical potential at unitarity), to Fig. 3 (experimental data updated), and to the notation
Ghost-Free Higher Derivative Quantum Gravity, the Hierarchy and the Cosmological Constant Problems
Creators: name: Tkach, V. I.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Proposing new solution problems of the hierarchy and smallness of the cosmological constant using the Tev scale of the Standard Model in new framework of the higher-order gravity.
description: 5 pages referances added, published version
Energy Storage and Electric Vehicle Technology-Slides
Creators: Ka Eric Cheng
Publisher: name: IEEE
Year: 2020

TEC Webinar Slides
Abstract: The key components of an Electric Vehicle are the battery and the motor drive.  Energy storages such as batteries and super capacitors are now the major units.  Energy cell packaging is now a new direction.  The use of energy cells to integrate with the vehicle body has been reported and suggests good potential for energy management.  The energy management and balance is now a necessary component to manage the energy cells.   Besides the energy storage and the traction motor and drives, there are numerous motors and actuators used in modern electric vehicles.  One of them is an active suspension system to replace the conventional hydraulic system.  The in wheel motor is based on integrating the motor and wheel into a single unit that increase the power density and presents a real 4 wheel drive.  The skid steering can, therefore, be realized.  Also, the antilock braking (ABS) is an all electric braking system, and replaces the conventional hydraulic system in ABS.

In this webinar, I will give an extensive overview of the latest electric vehicle technology that could be used in the present and the future. The talk covers the major advanced components of an electric vehicle and the technology and research related to the development.  Finally, I will conclude the webinar with an outlook on future vehicles.  The webinar is suitable for researchers or engineers with a deep knowledge of electric vehicles and is also suitable for someone who is new to the field.
Divisible assets in common law Canada
Creators: name: Hand, Mary
Publisher: name: University of British Columbia
Year: 2010

description: One of the most contentious issues within the area of recent matrimonial property legislation in Canadian common law provinces concerns what part of a spouse's property is prima facie distributable between both spouses on marriage breakdown. Each provincial statute dealing with this issue contains its own definition of what is or is not a divisible asset and in every province that definition has been the subject of judicial scrutiny. This study will assess and compare the definition of "divisible asset" employed by each province, particularly in regard to how that definition has been interpreted by the judiciary. The thesis is prefaced by an introduction, which briefly outlines the purpose of the study. Chapters 1 to 9 deal with the legislation of the individual provinces. The final section of the thesis contains the general observations and recommendations of the writer. The study is based on material available up to September 1982. Efforts have been made to give the correct position in each province as of that date. Where possible, changes which occurred since the writing of the first draft have been incorporated in the text of the thesis. In other instances, such changes have been footnoted.
Higgs-mass constraints on a supersymmetric solution of the muon g-2 anomaly
Creators: name: Ke, Wenqi
name: Slavich, Pietro
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The prediction for the quartic coupling of the SM-like Higgs boson constrains the parameter space of SUSY models, even in scenarios where all of the new-particle masses are above the scale probed so far by the LHC. We study the implications of the Higgs-mass prediction on a recently-proposed SUSY model that features two pairs of Higgs doublets, and provides a solution to the g-2 anomaly thanks to a suitable enhancement of the muon Yukawa coupling.
description: 22 pages, 3 PDF figures; v2: references added, discussion of figure 2 expanded. Version to be published in EPJC
THE MEANING OF SELF-DETERMINATION AT THE NATIONAL LEVEL: RUSSIAN VIEW
Creators: name: Eremicheva, T.
Publisher: name: Sciences of Europe
Year: 2021
Subjects: Self Concept
Self Determination
International Education
Scientific Concepts
social revolutions
passionarity
social contract
linguistic component of fact
rational choice theories.

description: The article is recommended for publication in educational, philosophical and legal journals as a manual for the education of the youth and young scientists. In understanding the goals of self-determination of an individual, one cannot be limited by the tasks of "whom to be" and "what to be." It is more important to "how to live," how to build your lifestyle, which mode of intellectual, physical and emotional loads to choose, how to overcome adversity. In this regard, it was necessary to describe the peculiarities of the Russian view of this important task in terms of identifying special interest for an international audience. The author attempted to present the view on factors that might affect the self-determination of the nation and to consider other related scientific theories, and also to consider the use of some new instruments, such as internationalization and diplomacy, with regard to contemporary issues of society and education. As the basic method of research, a coordinate system in three-dimensional socio-psycho-physical space is presented. The main conclusion was the identification of the essential component of social revolutions through the influence of the linguistic component-fact on the self-determination of the nation, as well as close attention to the educational process in the country.
High-resolution FUSE and HST ultraviolet spectroscopy of the white dwarf central star of Sh 2-216
Creators: name: Rauch, T.
name: Ziegler, M.
name: Werner, K.
name: Kruk, J. W.
name: Oliveira, C. M.
name: Putte, D. Vande
name: Mignani, R. P.
name: Kerber, F.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: LS V +4621 is the DAO-type central star of the planetary nebula Sh 2-216. We perform a comprehensive spectral analysis of high-resolution, high-S/N ultraviolet observations obtained with FUSE and STIS aboard the HST as well as the optical spectrum of LS V +4621 by means of state-of-the-art NLTE model-atmosphere techniques in order to compare its photospheric properties to theoretical predictions from stellar evolution theory as well as from diffusion calculations. From the N IV - NV, O IV - O VI, Si IV - Si V, and Fe V - Fe VII ionization equilibria, we determined an effective temperature of 95 +/- 2 kK with high precision. The surface gravity is log g = 6.9 +/- 0.2. An unexplained discrepancy appears between the spectroscopic distance d = 224 +46/-58 pc and the parallax distance d = 129 +6/-5 pc of LS V +4621. For the first time, we have identified Mg IV and Ar VI absorption lines in the spectrum of a hydrogen-rich central star and determined the Mg and Ar abundances as well as the individual abundances of iron-group elements (Cr, Mn, Fe, Co, and Ni). With the realistic treatment of metal opacities up to the iron group in the model-atmosphere calculations, the so-called Balmer-line problem (found in models that neglect metal-line blanketing) vanishes. Spectral analysis by means of NLTE model atmospheres has presently arrived at a high level of sophistication, which is now hampered largely by the lack of reliable atomic data and accurate line-broadening tables. Strong efforts should be made to improve upon this situation.
description: 13 pages, 20 figures
Observations of microquasars with the MAGIC telescope
Creators: name: Rico, J.
name: Rissi, M.
name: Bordas, P.
name: Bosch-Ramon, V.
name: Cortina, J.
name: Paredes, J. M.
name: Ribo, M.
name: Torres, D. F.
name: Zanin, R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on the results from the observations in very high energy band (VHE, E_gamma > 100GeV) of the black hole X-ray binary (BHXB) Cygnus X-1. The observations were performed with the MAGIC telescope, for a total of 40 hours during 26 nights, spanning the period between June and November 2006. We report on the results of the searches for steady and variable gamma-ray signals, including the first experimental evidence for an intense flare, of duration between 1.5 and 24 hours.
description: Contribution to the 30th ICRC, Merida Mexico, July 2007 on behalf of the MAGIC Collaboration
Microrobots from Toposelective Nanoparticle Attachment
Creators: name: Bailey, Maximilian R.
name: Grillo, Fabio
name: Spencer, Nicholas D.
name: Isa, Lucio
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Microrobots hold promise for applications ranging from targeted delivery to enhanced mixing at the microscale. However, current fabrication techniques suffer from limited throughput and material selection. Here, we demonstrate a versatile route enabling the synthesis of microrobots from off-the-shelf micro- and nano-particles. Our protocol hinges on the toposelective attachment of photocatalytic nanoparticles onto microparticles, exploiting a multi-functional polymer and a Pickering-wax emulsification step, to yield large quantities of photo-responsive active Janus particles. The polymer presents both silane and nitrocatechol groups, binding silica microspheres to a range of metal oxide nanoparticles. The Pickering-wax emulsions protect part of the microspheres' surface, enabling asymmetric functionalization, as required for self-propulsion. The resulting photocatalytic microrobots display a characteristic orientation-dependent 3D active motion upon UV illumination, different to that conventionally described in the literature. By connecting the extensive library of heterogeneous nanoparticle photocatalysts with the nascent field of active matter, this versatile material platform lays the groundwork towards designer microrobots, which can swim by catalysing a broad range of chemical reactions with potential for future applications.
description: 36 pages, 4 figures, 8 supplementary figures
Defects and Dressed Boundaries in Complex Sine-Gordon Theory
Creators: name: Bowcock, Peter
name: Umpleby, James
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we constructed integrable defects in complex sine-Gordon theory. Soliton and particle interactions with the defect are analysed. Defects are used to dress Dirichlet boundaries to create a wider class of integrable boundary conditions to ones previously studied. Properties of these new boundaries including soliton and particle reflections with the boundaries are presented.
description: 33 pages, 16 figures, minor corrections
Ward-Takahashi identity for Yang-Mills theory in the Exact Renormalization Group
Creators: name: Igarashi, Yuji
name: Itoh, Katsumi
name: Sonoda, Hidenori
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We give a functional derivation of the Ward-Takahashi identity for Yang-Mills theory in the framework of the exact renormalization group. The identity realizes non-abelian gauge symmetry nontrivially despite the presence of a momentum cutoff. The cutoff deforms the gauge transformation by introducing composite operators. In our functional method, which is an extension of the method used in our previous work on QED, these composite operators are expressed in terms of the Wilson action that depends on both a UV cutoff and an IR cutoff.
description: 12 pages
Cosmology of the Twin Higgs without explicit $\mathbb{Z}_2$ breaking
Creators: name: Beauchesne, Hugues
name: Kats, Yevgeny
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The cosmology of the Twin Higgs requires the breaking of the $\mathbb{Z}_2$ symmetry, but it is still an open question whether this breaking needs to be explicit. In this paper, we study how the Mirror Twin Higgs could be modified to be compatible with current cosmological constraints without explicit $\mathbb{Z}_2$ breaking. We first present a simple toy model that can realize baryogenesis without explicit $\mathbb{Z}_2$ breaking or reaching temperatures that would lead to domain walls. The model can also either solve the $N_{\text{eff}}$ problem and bring the abundance of mirror atoms to an allowed level or provide the correct dark matter abundance. We then present another simple model that leads to mirror neutron dark matter and thus acceptable dark matter self-interactions. We also include in appendix a series of results on energy exchange between different sectors that might prove useful for other cosmological problems.
description: 46 pages, 8 figures, minor clarifications, matches with published version in JHEP
Ultrafast Optical Spectroscopy Evidence of Pseudogap and Electron-Phonon Coupling in an Iron-Based Superconductor KCa$_2$Fe$_4$As$_4$F$_2$
Creators: name: Zhang, Chen
name: Wu, Qi-Yi
name: Hong, Wen-Shan
name: Liu, Hao
name: Zhu, Shuang-Xing
name: Song, Jiao-Jiao
name: Zhao, Yin-Zou
name: Wu, Fan-Ying
name: Liu, Zi-Teng
name: Liu, Shu-Yu
name: Yuan, Ya-Hua
name: Huang, Han
name: He, Jun
name: Li, Shiliang
name: Liu, H. Y.
name: Duan, Yu-Xia
name: Luo, Hui-Qian
name: Meng, Jian-Qiao
Publisher: name: arXiv
Year: 2021
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We use ultrafast optical spectroscopy to study the nonequilibrium quasiparticle relaxation dynamics of the iron-based superconductor KCa$_2$Fe$_4$As$_4$F$_2$ with $T_c=33.5$ K. Our results reveal a possible pseudogap ($Δ_{PG}$ = 2.4 $\pm$ 0.1 meV) below $T^*\approx 50$ K but prior to the opening of a superconducting gap ($Δ_{SC}$(0) $\approx$ 4.3 $\pm$ 0.1 meV). Measurements under high pump fluence real two distinct, coherent phonon oscillations with 1.95 and 5.51 THz frequencies, respectively. The high-frequency $A_{1g}$(2) mode corresponds to the $c-$axis polarized vibrations of FeAs planes with a nominal electron-phonon coupling constant $λ_{A_{1g}(2)}$ = 0.194 $\pm$ 0.02. Our findings suggest that the pseudogap is likely a precursor of superconductivity, and the electron-phonon coupling may play an essential role in the superconducting pairing in KCa$_2$Fe$_4$As$_4$F$_2$.
description: 6 pages, 3 figure
Bright Planetary Nebulae and their Progenitors in Galaxies Without Star Formation
Creators: name: Richer, Michael G.
name: McCall, Marshall L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present chemical abundances for planetary nebulae in M32, NGC 185, and NGC 205 based upon spectroscopy obtained at the Canada-France-Hawaii Telescope using the Multi-Object Spectrograph. From these and similar data compiled from the literature for other Local Group galaxies, we consider the origin and evolution of the stellar progenitors of bright planetary nebulae in galaxies where star formation ceased long ago. The ratio of neon to oxygen abundances in bright planetary nebulae is either identical to that measured in the interstellar medium of star-forming dwarf galaxies or at most changed by a few percent, indicating that neither abundance is significantly altered as a result of the evolution of their stellar progenitors. Several planetary nebulae appear to have dredged up oxygen, but these are the exception, not the rule. The progenitors of bright planetary nebulae typically enhance their original helium abundances by less than 50%. In contrast, nitrogen enhancements can reach factors of 100. However, nitrogen often shows little or no enhancement, suggesting that nitrogen enrichment is a random process. The helium, oxygen, and neon abundances argue that the typical bright planetary nebulae in all of the galaxies considered here are the progeny of stars with initial masses of approximately 1.5 Msun or less, based upon the nucleosynthesis predictions of current theoretical models. These models, however, are unable to explain the nitrogen enrichment or its scatter. Similar conclusions hold for the bright planetary nebulae in galaxies with ongoing star formation. Thus, though composition varies significantly, there is unity in the sense that the progenitors of typical bright planetary nebulae appear to have undergone similar physical processes. (Abridged)
description: accepted for publication in the Astrophysical Journal
Comment on "Discrepancies in the resonance-fluorescence spectrum calculated with two methods"
Creators: name: Ficek, Z.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: There are two alternative methods used in literature to calculate the incoherent part of the spectrum of light scattered by an atomic system. In the first, one calculates the spectrum of the total light scattered by the system and obtains the incoherent part by subtracting the coherent part. In the second method, one introduces the fluctuation operators and obtains the incoherent part of the spectrum by taking the Fourier transform of the two time correlation function of the fluctuation operators. These two methods have been recognized for years as two completely equivalent for evaluating the incoherent part of the spectrum. In a recent paper Qing Xu et al. [Phys. Rev. A 78, 013407 (2008)] have shown that there are discrepancies between the incoherent parts of the stationary spectrum of a three-level Lambda-type system calculated with these two methods. The predicted discrepancies can be severe that over a wide rage of the Rabi frequencies and atomic decay rates, the spectrum calculated with the variance method can have negative values. This is obviously unphysical result since the fluorescence spectrum is a positively defined quantity. It represents the frequency distribution of light incoherently scattered by the atomic system. Therefore, the calculated spectrum should be positive for all frequencies independent of values of the Rabi frequencies and the damping rates. In this comment, we show that there are no discrepancies between these two methods. The equivalence of these two alternative methods leads to the same incoherent spectra that are positive for all frequencies independent of values of the parameters involved. The analytical analysis is supported by simple numerical calculations.
description: Comments on the comment are welcome
Generalized dynamical mean-field theory of two-subalttice systems with non-local interactions and its application to study charge and spin correlations in graphene
Creators: name: Katanin, A. A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We investigate magnetic and charge correlations in graphene by using the formulation of extended dynamical mean-field theory (E-DMFT) for two-sublattice systems. First, we map the average non-local interaction onto the effective static interaction between different sublattices, which is treated together with the local interaction within an effective "two-orbital" local model. The remaining part of the non-local interaction is considered by introducing an effective retarded interaction within the E-DMFT approach. The non-local susceptibilities in charge and spin channel are further evaluated in the ladder approximation. We verify the applicability of the proposed method to describe the effect of uniformly screened long-range Coulomb potential $\propto 1/r$, as well as screened realistic long-range electron interaction [T. O. Wehling et al., Phys. Rev. Lett. 106, 236805 (2011)] in graphene. We show that the developed approach describes a competition of semimetal, spin density wave (SDW), and charge-density-wave (CDW) correlations. The obtained phase diagram is in a good agreement with recent results of functional renormalization group (fRG) for finite large graphene nanoflakes and scaling analysis of quantum Monte Carlo data on finite clusters. Similarly to the previously obtained results within the fRG approach, the realistic screening of Coulomb interaction by $σ$ bands causes moderate (strong) enhancement of critical long-range interaction strength, needed for the SDW (CDW) instability, compared to the results for the uniformly screened Coulomb potential.
description: 9 pages, 5 figures
Squark Decays in MSSM Under the Cosmological Bounds
Creators: name: Aydin, Z. Z.
name: Selbuz, L.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present the numerical investigation of the fermionic two-body decays of squarks in the Minimal Supersymmetric Standard Model with complex parameters. In the analysis we particularly take into account the cosmological bounds imposed by WMAP data. We find that the phase dependences of the decay widths of the third family squarks, as well as those of the first and second families, are quite significant which can provide viable probes of additional CP sources. We plot the CP phase dependences for each fermionic two-body decay channel of squarks $\tilde q_i$ (i=1,2, q=u,d;c,s;t,b) and speculate about the branching ratios and total (two-body) decay widths.
description: 1 text(14 pages)and 6 figures(6 pages). Total 20 pages. Accepted to be published in J. Phys. G: Nucl. Part. Phys
How many species have mass M?
Creators: name: Clauset, Aaron
name: Schwab, David J.
name: Redner, Sidney
Publisher: name: arXiv
Year: 2008
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Biological Physics (physics.bio-ph)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: Within large taxonomic assemblages, the number of species with adult body mass M is characterized by a broad but asymmetric distribution, with the largest mass being orders of magnitude larger than the typical mass. This canonical shape can be explained by cladogenetic diffusion that is bounded below by a hard limit on viable species mass and above by extinction risks that increase weakly with mass. Here we introduce and analytically solve a simplified cladogenetic diffusion model. When appropriately parameterized, the diffusion-reaction equation predicts mass distributions that are in good agreement with data on 4002 terrestrial mammal from the late Quaternary and 8617 extant bird species. Under this model, we show that a specific tradeoff between the strength of within-lineage drift toward larger masses (Cope's rule) and the increased risk of extinction from increased mass is necessary to produce realistic mass distributions for both taxa. We then make several predictions about the evolution of avian species masses.
description: 7 pages, 3 figures
A word frequency distribution study of language presented to young ESL students
Creators: name: Rebane, Kim
Publisher: name: University of British Columbia
Year: 2010

description: The purpose of this study has been to assess how well ESL children are being prepared to communicate in the English language. This was done by comparing the language presented to young ESL learners with the target language (English). Word frequency was the basis of comparison in this study. The frequency distribution of words in the target language was compared with that of the ESL text series YES!. Published word frequency lists were used to determine how well the sample represented the target language. Comparisons were made on the basis of frequency distribution, high and low frequency words, and similarity to basal reading series designed for young native speakers. It was found that young ESL learners are being exposed to language that is representative of what is needed to communicate. Results also showed that this language is unlike that of basal reading series which focus on many more repetitions of individual words. Given the different experiences with which young ESL and native learners bring to the task of learning how to read such a difference in the series is necessary. The results of this study are discussed in terms of the frequency distribution of words, research in the learning of first and second language, and pedagogical implications of the findings.
Non-equilibrium coherence dynamics in one-dimensional Bose gases
Creators: name: Hofferberth, S.
name: Lesanovsky, I.
name: Fischer, B.
name: Schumm, T.
name: Schmiedmayer, J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Low-dimensional systems are beautiful examples of many-body quantum physics. For one-dimensional systems the Luttinger liquid approach provides insight into universal properties. Much is known of the equilibrium state, both in the weakly and strongly interacting regime. However, it remains a challenge to probe the dynamics by which this equilibrium state is reached. Here we present a direct experimental study of the coherence dynamics in both isolated and coupled degenerate 1d Bose gases. Dynamic splitting is used to create two 1d systems in a phase coherent state. The time evolution of the coherence is revealed in local phase shifts of the subsequently observed interference patterns. Completely isolated 1d Bose gases are observed to exhibit a universal sub-exponential coherence decay in excellent agreement with recent predictions by Burkov et al. [Phys. Rev. Lett. 98, 200404 (2007)]. For two coupled 1d Bose gases the coherence factor is observed to approach a non-zero equilibrium value as predicted by a Bogoliubov approach. This coupled-system decay to finite coherence is the matter wave equivalent of phase locking two lasers by injection. The non-equilibrium dynamics of superfluids plays an important role in a wide range of physical systems, such as superconductors, quantum-Hall systems, superfluid Helium, and spin systems. Our experiments studying coherence dynamics show that 1d Bose gases are ideally suited for investigating this class of phenomena.
description: to appear in nature
The Formation of Crystalline Dust in AGB Winds from Binary Induced Spiral Shocks
Creators: name: Edgar, R. G.
name: Nordhaus, J.
name: Blackman, E.
name: Frank, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: As stars evolve along the Asymptotic Giant Branch, strong winds are driven from the outer envelope. These winds form a shell, which may ultimately become a planetary nebula. Many planetary nebulae are highly asymmetric, hinting at the presence of a binary companion. Some post-Asymptotic Giant Branch objects are surrounded by torii of crystalline dust, but there is no generally accepted mechanism for annealing the amorphous grains in the wind to crystals. In this Letter, we show that the shaping of the wind by a binary companion is likely to lead to the formation of crystalline dust in the orbital plane of the binary.
description: Submitted to ApJL
Anomalous Magnetic Moment and Higgs Coupling of the Muon in a Sequential U(1) Gauge Model with Dark Matter
Creators: name: Adhikari, Rathin
name: Bhat, Imtiyaz Ahmad
name: Borah, Debasish
name: Ma, Ernest
name: Nanda, Dibyendu
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We study an Abelian gauge extension of the standard model with fermion families having non-universal gauge charges. The gauge charges and scalar content are chosen in such an anomaly-free way that only the third generation fermions receive Dirac masses via renormalisable couplings with the Higgs boson. Incorporating additional vector like fermions and scalars with appropriate $U(1)$ charges can lead to radiative Dirac masses of first two generations with neutral fermions going in the loop being dark matter candidates. Focusing on radiative muon mass, we constrain the model from the requirement of satisfying muon mass, recently measured muon anomalous magnetic moment by the E989 experiment at Fermilab along with other experimental bounds including the large hadron collider (LHC) limits. The anomalous Higgs coupling to muon is constrained from the LHC measurements of Higgs to dimuon decay. The singlet fermion dark matter phenomenology is discussed showing the importance of both annihilation and coannihilation effects. Incorporating all bounds lead to a constrained parameter space which can be probed at different experiments.
description: 26 pages, 7 captioned figures, accepted for publication in Phys. Rev. D
Two-photon photoassociative spectroscopy of ultracold 88-Sr
Creators: name: de Escobar, Y. N. Martinez
name: Mickelson, P. G.
name: Pellegrini, P.
name: Nagel, S. B.
name: Traverso, A.
name: Yan, M.
name: Cote, R.
name: Killian, T. C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We present results from two-photon photoassociative spectroscopy of the least-bound vibrational level of the X$^1Σ_g^+$ state of the $^{88}$Sr$_2$ dimer. Measurement of the binding energy allows us to determine the s-wave scattering length, $a_{88}=-1.4(6) a_0$. For the intermediate state, we use a bound level on the metastable $^1S_0$-$^3P_1$ potential, which provides large Franck-Condon transition factors and narrow one-photon photoassociative lines that are advantageous for observing quantum-optical effects such as Autler-Townes resonance splittings.
description: 9 pages, 9 figures
Effortless estimation of basins of attraction
Creators: name: Datseris, George
name: Wagemakers, Alexandre
Publisher: name: arXiv
Year: 2021
Subjects: subject: Dynamical Systems (math.DS)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We present a fully automated method that identifies attractors and their basins of attraction without approximations of the dynamics. The method works by defining a finite state machine on top of the system flow. The input to the method is a dynamical system evolution rule and a grid that partitions the state space. No prior knowledge of the number, location, or nature of the attractors is required. The method works for arbitrarily-high-dimensional dynamical systems, both discrete and continuous. It also works for stroboscopic maps, Poincaré maps, and projections of high-dimensional dynamics to a lower-dimensional space. The method is accompanied by a performant open-source implementation in the DynamicalSystems.jl library. The performance of the method outclasses the naive approach of evolving initial conditions until convergence to an attractor, even when excluding the task of first identifying the attractors from the comparison. We showcase the power of our implementation on several scenarios, including interlaced chaotic attractors, high-dimensional state spaces, fractal basin boundaries, and interlaced attracting periodic orbits, among others. The output of our method can be straightforwardly used to calculate concepts such as basin stability and final state sensitivity.
Quantum charge diffusion in underdamped Josephson junctions and superconducting nanowires
Creators: name: Zazunov, A.
name: Didier, N.
name: Hekking, F. W. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The effect of quantum fluctuations on the current-voltage characteristics of Josephson junctions and superconducting nanowires is studied in the underdamped limit. Quantum fluctuations induce transitions between a Coulomb--blockade and a supercurrent branch, and can significantly modify the shape of current-voltage characteristics in the case of a highly resistive environment. Owing to the phase-charge duality, our results can be directly extended to the opposite overdamped limit.
description: 6 pages, 2 figures, replaced with published version
Syntactic development in the writing of ESL students
Creators: name: Yau, Margaret Sin-Siu
Publisher: name: University of British Columbia
Year: 2010

description: The current study examined the development of syntactic maturity in a group of Chinese secondary school students learning English as a second language (ESL). The compositions of these students written in response to two tasks (a narrative assignment and an expository assignment) were analyzed-for increase on the use of three syntactic measures (T-unit length, clause length and number of clauses per T-unit) and three grammatical structures (nominals, adverbials and coordinations within T-units) across three grade levels and between two modes of writing. The scores were analyzed by ANOVA in a 3(grade) x 2(mode) factorial design. A stepwise discriminant analysis was also carried out to isolate grammatical structures that best discriminate the writing across the three grade levels and between two modes of writing. Results indicated that there were significant differences in T-unit length, clause length and number of clauses per T-unit across the three grades and there were also significant differences in T-unit length and clause length between the two modes of writing. These differences were accounted for by the increase on these measures from the lowest grade (F.3) to the highest grade (F.7) and also from the expository assignment to the narrative assignment. Moreover, there was a significant interaction between mode and grade in T-unit length and clause length, caused by the non-parallel increase with grade levels between the two modes of writing. The increase in T-unit length and clause length between F.3 and F.7 was much greater on the expository assignment than on the narrative assignment. A similar increase and interaction was found in the grammatical structures. Both the nominals and adverbials increased with grade level, and as with the syntactic measures discussed above, the increases were much greater on the expository than on the narrative assignment. There was not a significant increase in the use of coordinate structures between grade levels, supporting other researchers' claims that this is a transformation acquired early. The ESL students in the current study showed a remarkable resemblance to native English speaking students in terms of syntactic development. Not only was the increase in the syntactic measures similar to the growth trend found with native English speaking students, but the grammatical structures that distinguished the compositions at the three grade levels were also very similar to the mature structures isolated in other studies. One implication that can be drawn from this study is that the similarities between these ESL students and native speakers in the employment of syntax reflects common cognitive strategies that underlie the language learning task. Morever, since the study shows that there is a developmental trend, perhaps proven techniques (such as sentence combining) can be tried on these students to test if the syntactic growth can be speeded up.
Slides for - Infinite-Dimensional Expansion for Sound Field Estimation with Application to Spatial Audio
Creators: Dr. Natsuki Ueno and Dr. Shoichi Koyama
Publisher: name: IEEE
Year: 2021

Webinar Slides - SPS Webinar, December 20, 2021, Dr. Natsuki Ueno and Dr. Shoichi Koyama
Sound field estimation using a microphone array is a fundamental problem in acoustic signal processing, which has a wide variety of applications, such as visualization/auralization of an acoustic field, spatial audio reproduction using a loudspeaker array or headphones, and active noise cancellation in a spatial region. We recently proposed a sound field estimation method based on infinite-dimensional basis expansion of sound fields. This method can also be regarded as the kernel method for interpolation of sound fields with a constraint of the Helmholts equation under particular conditions. This new framework on the sound field estimation has many advantages over other well-established methods based on finite-dimensional basis expansion of sound fields.

This webinar will describe our studies on sound field estimation and its applications to spatial audio. We will start with background and preliminaries on sound field estimation. Then, we will introduce our proposed method based on infinite-dimensional wavefunction expansion of sound fields. Finally, we will discuss several applications on spatial audio, e.g., binaural rendering and sound field reproduction. Open-source codes of the proposed method with impulse response dataset will also be introduced.
Titan's rotational state : The effects of a forced "free" resonant wobble
Creators: name: Noyelles, B.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In Noyelles et al. (2008, Astron. Astrophys., 478, 959-970), a resonance involving the wobble of Titan is hinted. This paper studies this scenario and its consequences. The first step is to build an accurate analytical model that would help to find the likely resonances in the rotation of every synchronous body. In this model, I take the orbital eccentricity of the body into account, as well as its variable inclination with respect to Saturn's equator. Then an analytical study using the second fundamental model of the resonance is performed to study the resonance of interest. Finally, I study the dissipative consequences of this resonance. I find that this resonance may have increased the wobble of Titan by several degrees. For instance, if Titan's polar momentum C is equal to 0.355MR_T^2 (M and R_T being respectively Titan's mass and radius), the wobble might be forced to 41 degrees. Thanks to an original formula, I find that the dissipation associated with the forced wobble might not be negligible compared to the contribution of the eccentricity. I also suspect that, due to the forced wobble, Titan's period of rotation may be somewhat underestimated by observers. Finally, I use the analytical model presented in this paper to compute the periods of the free librations of the four Galilean satellites as well as the Saturnian satellite Rhea. For Io and Europa, the results are consistent with previous studies. For the other satellites, the periods of the free librations are respectively 186.37 d, 23.38 y and 30.08 y for Ganymede, 2.44 y, 209.32 y and 356.54 y for Callisto, and 51.84 d, 2.60 y and 3.59 y for Rhea.
description: accepted for publication in Celestial Mechanics and Dynamical Astronomy