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2110.12370 | Team Enigma at ArgMining-EMNLP 2021: Leveraging Pre-trained Language Models for Key Point Matching | We present the system description for our submission towards the Key Point Analysis Shared Task at ArgMining 2021. Track 1 of the shared task requires participants to develop methods to predict the match score between each pair of arguments and keypoints, provided they belong to the same topic under the same stance. We leveraged existing state of the art pre-trained language models along with incorporating additional data and features extracted from the inputs (topics, key points, and arguments) to improve performance. We were able to achieve mAP strict and mAP relaxed score of 0.872 and 0.966 respectively in the evaluation phase, securing 5th place on the leaderboard. In the post evaluation phase, we achieved a mAP strict and mAP relaxed score of 0.921 and 0.982 respectively. All the codes to generate reproducible results on our models are available on Github. | [
"Computer Science Archive->cs.CL"
]
| 2021-10-24T07:10:39Z |
cond-mat/0101435 | Cooperative Parrondo's Games | We introduce a new family of Parrondo's games of alternating losing strategies in order to get a winning result. In our version of the games we consider an ensemble of players and use "social" rules in which the probabilities of the games are defined in terms of the actual state of the neighbors of a given player. | [
"Physics Archive->cond-mat"
]
| 2001-01-29T13:41:07Z |
2007.15620 | Neural Modeling for Named Entities and Morphology (NEMO^2) | Named Entity Recognition (NER) is a fundamental NLP task, commonly formulated as classification over a sequence of tokens. Morphologically-Rich Languages (MRLs) pose a challenge to this basic formulation, as the boundaries of Named Entities do not necessarily coincide with token boundaries, rather, they respect morphological boundaries. To address NER in MRLs we then need to answer two fundamental questions, namely, what are the basic units to be labeled, and how can these units be detected and classified in realistic settings, i.e., where no gold morphology is available. We empirically investigate these questions on a novel NER benchmark, with parallel tokenlevel and morpheme-level NER annotations, which we develop for Modern Hebrew, a morphologically rich-and-ambiguous language. Our results show that explicitly modeling morphological boundaries leads to improved NER performance, and that a novel hybrid architecture, in which NER precedes and prunes morphological decomposition, greatly outperforms the standard pipeline, where morphological decomposition strictly precedes NER, setting a new performance bar for both Hebrew NER and Hebrew morphological decomposition tasks. | [
"Computer Science Archive->cs.CL"
]
| 2020-07-30T17:43:14Z |
1708.07301 | Error exponents of typical random codes | We define the error exponent of the typical random code as the long-block limit of the negative normalized expectation of the logarithm of the error probability of the random code, as opposed to the traditional random coding error exponent, which is the limit of the negative normalized logarithm of the expectation of the error probability. For the ensemble of uniformly randomly drawn fixed composition codes, we provide exact error exponents of typical random codes for a general discrete memoryless channel (DMC) and a wide class of (stochastic) decoders, collectively referred to as the generalized likelihood decoder (GLD). This ensemble of fixed composition codes is shown to be no worse than any other ensemble of independent codewords that are drawn under a permutation--invariant distribution (e.g., i.i.d. codewords). We also present relationships between the error exponent of the typical random code and the ordinary random coding error exponent, as well as the expurgated exponent for the GLD. Finally, we demonstrate that our analysis technique is applicable also to more general communication scenarios, such as list decoding (for fixed-size lists) as well as decoding with an erasure/list option in Forney's sense. | [
"Computer Science Archive->cs.IT",
"Mathematics Archive->math.IT"
]
| 2017-08-24T08:05:20Z |
1706.05250 | Contributions to the Generalized Coupon Collector and LRU Problems | Based upon inequalities on Subset Probabilities, proofs of several conjectures on the Generalized Coupon Collector Problem (i.e. CCP with unequal popularity) are presented. Then we derive a very simple asymptotic relation between the expectation of the waiting time for a partial collection in the CCP, and the Miss rate of a LRU cache. | [
"Computer Science Archive->cs.DM"
]
| 2017-06-16T12:39:23Z |
0710.3235 | Studies of CP-conserving and CP-violating Bs mixing parameters with the D0 experiment | This paper summarises the recent results of the Run IIa D0 experiment at the Tevatron Collider at Fermilab on the observable parameters of the $B_{s}$ meson. A measurement of the branching fraction $B_s->D_s^{(*)}D_s^{(*)}$ is reported, which provides an estimate of the width difference $\Delta\Gamma_{s}^{CP}/\Delta\Gamma_{s}$. Through the decay $B_{s} \to J/\psi \phi$ the width difference $\Delta\Gamma_{s}$ is extracted, and for the first time a constraint is set on the CP-violating phase $\phi_{s}$, although a four-fold ambiguity remains. This result is combined with other D0 measurements to yield $\Delta\Gamma_{s}=0.13\pm0.09 {\rm ps^{-1}}$, $\phi_{s} = -0.70^{+0.47}_{-0.39}$. | [
"Physics Archive->hep->hep-ex"
]
| 2007-10-17T08:33:13Z |
1611.06750 | Spectral stability under removal of small capacity sets and applications to Aharonov-Bohm operators | We first establish a sharp relation between the order of vanishing of a Dirichlet eigenfunction at a point and the leading term of the asymptotic expansion of the Dirichlet eigenvalue variation, as a removed compact set concentrates at that point. Then we apply this spectral stability result to the study of the asymptotic behaviour of eigenvalues of Aharonov-Bohm operators with two colliding poles moving on an axis of symmetry of the domain. | [
"Mathematics Archive->math.AP"
]
| 2016-11-21T12:14:53Z |
0809.4280 | Variational Formulation for Quaternionic Quantum Mechanics | A quaternionic version of Quantum Mechanics is constructed using the Schwinger's formulation based on measurements and a Variational Principle. Commutation relations and evolution equations are provided, and the results are compared with other formulations. | [
"Mathematics Archive->math.MP",
"Physics Archive->hep->hep-th",
"Physics Archive->math-ph",
"Physics Archive->quant-ph"
]
| 2008-09-24T20:51:54Z |
1607.07343 | Gaussian processes and Bayesian moment estimation | Given a set of moment restrictions (MRs) that overidentify a parameter $\theta$, we investigate a semiparametric Bayesian approach for inference on $\theta$ that does not restrict the data distribution $F$ apart from the MRs. As main contribution, we construct a degenerate Gaussian process prior that, conditionally on $\theta$, restricts the $F$ generated by this prior to satisfy the MRs with probability one. Our prior works even in the more involved case where the number of MRs is larger than the dimension of $\theta$. We demonstrate that the corresponding posterior for $\theta$ is computationally convenient. Moreover, we show that there exists a link between our procedure, the Generalized Empirical Likelihood with quadratic criterion and the limited information likelihood-based procedures. We provide a frequentist validation of our procedure by showing consistency and asymptotic normality of the posterior distribution of $\theta$. The finite sample properties of our method are illustrated through Monte Carlo experiments and we provide an application to demand estimation in the airline market. | [
"Mathematics Archive->math.ST",
"Statistics Archive->stat.TH"
]
| 2016-07-25T16:23:24Z |
1907.04792 | Deformation classes of real Cayley M-octads | We study 8-point configurations in the real projective space forming an intersection locus of three quadrics and containing no coplanar quadruples. We found that there exists precisely 8 mirror-pairs of deformation classes of such configurations. We describe also the mutual position of these 8 pairs and find the real monodromy groups acting on the 8-point configurations, for each deformation class. | [
"Mathematics Archive->math.AG"
]
| 2019-07-10T15:27:50Z |
1910.06188 | Q8BERT: Quantized 8Bit BERT | Recently, pre-trained Transformer based language models such as BERT and GPT, have shown great improvement in many Natural Language Processing (NLP) tasks. However, these models contain a large amount of parameters. The emergence of even larger and more accurate models such as GPT2 and Megatron, suggest a trend of large pre-trained Transformer models. However, using these large models in production environments is a complex task requiring a large amount of compute, memory and power resources. In this work we show how to perform quantization-aware training during the fine-tuning phase of BERT in order to compress BERT by $4\times$ with minimal accuracy loss. Furthermore, the produced quantized model can accelerate inference speed if it is optimized for 8bit Integer supporting hardware. | [
"Computer Science Archive->cs.CL",
"Computer Science Archive->cs.LG"
]
| 2019-10-14T14:55:19Z |
astro-ph/9909264 | The Asteroseismology Metacomputer | We have developed a specialized computational instrument for fitting models of pulsating white dwarfs to observations made with the Whole Earth Telescope. This metacomputer makes use of inexpensive PC hardware and free software, including a parallel genetic algorithm which performs a global search for the best-fit set of parameters. | [
"Physics Archive->astro-ph"
]
| 1999-09-15T15:52:46Z |
1701.08205 | Bounds on curvature in regular graphs | We study the curvature-dimension inequality in regular graphs. We develop techniques for calculating the curvature of such graphs, and we give characterizations of classes of graphs with positive, zero, and negative curvature. Our main result is to compare the curvature-dimension inequality in these classes to the so-called Ollivier curvature. A consequence of our results is that in the case that the graph contains no subgraph isomorphic to either $K_3$ or $K_{2,3}$ these curvatures usually have the same sign, and we characterize the exceptions. | [
"Mathematics Archive->math.CO"
]
| 2017-01-27T21:55:50Z |
1808.05376 | Towards Automated Data Integration in Software Analytics | Software organizations want to be able to base their decisions on the latest set of available data and the real-time analytics derived from them. In order to support "real-time enterprise" for software organizations and provide information transparency for diverse stakeholders, we integrate heterogeneous data sources about software analytics, such as static code analysis, testing results, issue tracking systems, network monitoring systems, etc. To deal with the heterogeneity of the underlying data sources, we follow an ontology-based data integration approach in this paper and define an ontology that captures the semantics of relevant data for software analytics. Furthermore, we focus on the integration of such data sources by proposing two approaches: a static and a dynamic one. We first discuss the current static approach with a predefined set of analytic views representing software quality factors and further envision how this process could be automated in order to dynamically build custom user analysis using a semi-automatic platform for managing the lifecycle of analytics infrastructures. | [
"Computer Science Archive->cs.SE"
]
| 2018-08-16T08:22:59Z |
1907.00506 | Toward Asymptotically-Optimal Inspection Planning via Efficient Near-Optimal Graph Search | Inspection planning, the task of planning motions that allow a robot to inspect a set of points of interest, has applications in domains such as industrial, field, and medical robotics. Inspection planning can be computationally challenging, as the search space over motion plans that inspect the points of interest grows exponentially with the number of inspected points. We propose a novel method, Incremental Random Inspection-roadmap Search (IRIS), that computes inspection plans whose length and set of inspected points asymptotically converge to those of an optimal inspection plan. IRIS incrementally densifies a motion planning roadmap using sampling-based algorithms, and performs efficient near-optimal graph search over the resulting roadmap as it is generated. We demonstrate IRIS's efficacy on a simulated planar 5DOF manipulator inspection task and on a medical endoscopic inspection task for a continuum parallel surgical robot in anatomy segmented from patient CT data. We show that IRIS computes higher-quality inspection paths orders of magnitudes faster than a prior state-of-the-art method. | [
"Computer Science Archive->cs.RO"
]
| 2019-07-01T01:14:05Z |
math/0011098 | Arbres de Hurwitz et automorphismes d'ordre p des disques et des couronnes p-adiques formels | Let R be a complete discrete valuation ring of mixed characteristics (0,p). Given an order p-automorphism of a formal disc (or annulus) over R, we describe the minimal semi-stable model for which the specialisations of fixed points are distincts and lie in the smooth locus of the special fiber. The description leads to a combinatorial object called Hurwitz tree. Our main result is a necessary and sufficient condition for a Hurwitz tree to arise from an order p-automorphism. | [
"Mathematics Archive->math.AG"
]
| 2000-11-15T14:47:24Z |
cmp-lg/9407024 | PRINCIPAR---An Efficient, Broad-coverage, Principle-based Parser | We present an efficient, broad-coverage, principle-based parser for English. The parser has been implemented in C++ and runs on SUN Sparcstations with X-windows. It contains a lexicon with over 90,000 entries, constructed automatically by applying a set of extraction and conversion rules to entries from machine readable dictionaries. | [
"Computer Science Archive->cs.CL"
]
| 1994-07-27T21:07:17Z |
1711.02370 | A Riemann--Kempf singularity theorem for higher rank Brill--Noether loci | Given a vector bundle $V$ over a curve $X$, we define and study a surjective rational map $\mathrm{Hilb}^d (\mathbb{P} V ) - \mathrm{Quot}^{0, d} ( V^* )$ generalising the natural map $\mathrm{Sym}^d X \to \mathrm{Quot}^{0, d} ({\mathcal O}_X)$. We then give a generalisation of the geometric Riemann--Roch theorem to vector bundles of higher rank over $X$. We use this to give a geometric description of the tangent cone to the Brill--Noether locus $B^r_{r, d}$ at a suitable bundle $E$ with $h^0 (E) = r+n$. This gives a generalisation of the Riemann--Kempf singularity theorem. As a corollary, we show that the $n$th secant variety of the rank one locus of $\mathbb{P} \mathrm{End} E$ is contained in the tangent cone. | [
"Mathematics Archive->math.AG"
]
| 2017-11-07T10:09:16Z |
1811.12076 | Emergence of active nematics in bacterial biofilms | Growing tissue and bacterial colonies are active matter systems where cell divisions and cellular motion generate active stress. Although they operate in the non-equilibrium regime, these biological systems can form large-scale ordered structures such as nematically aligned cells, topological defects, and fingerings. Mechanical instabilities also play an essential role during growth by generating large structural folding. How active matter dynamics and mechanical instabilities together develop large-scale order in growing tissue is not well understood. Here, we use chain forming Bacillus subtilis, also known as a biofilm, to study the direct relation between active stress and nematic ordering. We find that a bacterial biofilm has intrinsic length scales above which series of mechanical instabilities occur. Localized stress and friction control both linear buckling and edge instabilities. Remarkably, these instabilities develop nematically aligned cellular structures and create pairs of motile and stationary topological defects. We also observe that stress distribution across the biofilm strongly depends on the defect dynamics which can further initiate the formation of sporulation sites by creating three-dimensional structures. By investigating the development of bacterial biofilms and their mechanical instabilities we are proposing a new type of active matter system which provides a unique platform to study the essential roles of nematics in growing biological tissue. | [
"Physics Archive->cond-mat->cond-mat.soft",
"Physics Archive->physics->physics.bio-ph"
]
| 2018-11-29T11:32:09Z |
0807.1052 | Compact $AC(\sigma)$ operators | All compact $AC(\sigma)$ operators have a representation analogous to that for compact normal operators. As a partial converse we obtain conditions which allow one to construct a large number of such operators. Using the results in the paper, we answer a number of questions about the decomposition of a compact $AC(\sigma)$ into real and imaginary parts. | [
"Mathematics Archive->math.FA"
]
| 2008-07-07T15:48:37Z |
2212.09118 | Regularity of the optimal sets for a class of integral shape functionals | We prove {the first} regularity theorem for the free boundary of solutions to shape optimization problems involving integral functionals, for which the energy of a domain $\Omega$ is obtained as the integral of a cost function $j(u,x)$ depending on the solution $u$ of a certain PDE problem on $\Omega$. The main feature of these functionals is that the minimality of a domain $\Omega$ cannot be translated into a variational problem for a single (real or vector valued) state function. In this paper we focus on the case of affine cost functions $j(u,x)=-g(x)u+Q(x)$, where $u$ is the solution of the PDE $-\Delta u=f$ with Dirichlet boundary conditions. We obtain the Lipschitz continuity and the non-degeneracy of the optimal $u$ from the inwards/outwards optimality of $\Omega$ and then we use the stability of $\Omega$ with respect to variations with smooth vector fields in order to study the blow-up limits of the state function $u$. By performing a triple consecutive blow-up, we prove the existence of blow-up sequences converging to homogeneous stable solution of the one-phase Bernoulli problem and according to the blow-up limits, we decompose $\partial\Omega$ into a singular and a regular part. In order to estimate the Hausdorff dimension of the singular set of $\partial\Omega$ we give a new formulation of the notion of stability for the one-phase problem, which is preserved under blow-up limits and allows to develop a dimension reduction principle. Finally, by combining a higher order Boundary Harnack principle and a viscosity approach, we prove $C^\infty$ regularity of the regular part of the free boundary when the data are smooth. | [
"Mathematics Archive->math.AP"
]
| 2022-12-18T16:07:17Z |
1003.0388 | Moduli Redefinitions and Moduli Stabilisation | Field redefinitions occur in string compactifications at the one loop level. We review arguments for why such redefinitions occur and study their effect on moduli stabilisation and supersymmetry breaking in the LARGE volume scenario. For small moduli, although the effect of such redefinitions can be larger than that of the $\alpha'$ corrections in both the K\"ahler and scalar potentials, they do not alter the structure of the scalar potential. For the less well motivated case of large moduli, the redefinitions can dominate all other terms in the scalar potential. We also study the effect of redefinitions on the structure of supersymmetry breaking and soft terms. | [
"Physics Archive->hep->hep-th"
]
| 2010-03-01T16:41:22Z |
cond-mat/0603158 | Pressure dependence of the Boson peak in glassy As2S3 studied by Raman Scattering | A detailed pressure-dependence study of the low-energy excitations of glassy As2S3 is reported over a wide pressure range, up to 10 GPa. The spectral features of Boson peak are analysed as a function of pressure. Pressure effects on the Boson peak are manifested as an appreciable shift of its frequency to higher values, a suppression of its intensity, as well as a noticeable change of its asymmetry leading to a more symmetric shape at high pressures. The pressure-induced Boson peak frequency shift agrees very well with the predictions of the soft potential model over the whole pressure range studied. As regards the pressure dependence of the Boson peak intensity, the situation is more complicated. It is proposed that in order to reach proper conclusions the corresponding dependence of the Debye density of states must also be considered. Employing a comparison of the low energy modes of the crystalline counterpart of As2S3 as well as the experimental data concerning the pressure dependencies of the Boson peak frequency and intensity, structural or glass-to-glass transition seems to occur at the pressure ~4 GPa related to a change of local structure. Finally, the pressure-induced shape changes of the Boson peak can be traced back to the very details of the excess (over the Debye contribution) vibrational density of states. | [
"Physics Archive->cond-mat->cond-mat.dis-nn",
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
]
| 2006-03-07T12:07:35Z |
0809.2522 | Determination of characteristic muon precession and relaxation signals in FeAs and FeAs2, possible impurity phases in pnictide superconductors | We report muon-spin relaxation measurements of highly homogeneous samples of FeAs and FeAs2, both previously found as impurity phases in some samples of recently synthesized pnictide superconductors. We observe well defined muon precession in the FeAs sample with two precession frequencies of 38.2(3) and 22.7(9) MHz at 7.5 K, with the majority of the amplitude corresponding to the lower frequency component. In FeAs2 we confirm previous measurements showing that no long-ranged magnetic order occurs above 2 K and measure the muon spin relaxation rate, which increases on cooling. Our results exclude the possibility that previous muon-spin relaxation measurements of pnictide superconductors have been measuring the effect of these possible impurities. | [
"Physics Archive->cond-mat->cond-mat.str-el",
"Physics Archive->cond-mat->cond-mat.supr-con"
]
| 2008-09-15T13:28:36Z |
1611.02087 | The Space of Stability Conditions on the Projective Plane | The space of Bridgeland stability conditions on the bounded derived category of coherent sheaves on P2 has a principle connected component Stab^\dag(P2). We show that Stab^\dag(P2) is the union of geometric and algebraic stability conditions. As a consequence, we give a cell decomposition for Stab^\dag (P2) and show that Stab^\dag(P2) is contractible. | [
"Mathematics Archive->math.AG"
]
| 2016-11-07T14:57:11Z |
cond-mat/0009426 | Dislocation nucleation and vacancy formation during high-speed deformation of fcc metals | Recently, a dislocation free deformation mechanism was proposed by Kiritani et al., based on a series of experiments where thin foils of fcc metals were deformed at very high strain rates. In the experimental study, they observed a large density of stacking fault tetrahedra, but very low dislocation densities in the foils after deformation. This was interpreted as evidence for a new dislocation-free deformation mechanism, resulting in a very high vacancy production rate. In this paper we investigate this proposition using large-scale computer simulations of bulk and thin films of copper. To favour such a dislocation-free deformation mechanism, we have made dislocation nucleation very difficult by not introducing any potential dislocation sources in the initial configuration. Nevertheless, we observe the nucleation of dislocation loops, and the deformation is carried by dislocations. The dislocations are nucleated as single Shockley partials. The large stresses required before dislocations are nucleated result in a very high dislocation density, and therefore in many inelastic interactions between the dislocations. These interactions create vacancies, and a very large vacancy concentration is quickly reached. | [
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
]
| 2000-09-27T14:52:43Z |
2305.11336 | Filling in the Gaps: Can Gravitationally Unstable Discs Form the Seeds of Gas Giant Planets? | Circumstellar discs likely have a short window when they are self-gravitating and prone to the effects of disc instability, but during this time the seeds of planet formation can be sown. It has long been argued that disc fragmentation can form large gas giant planets at wide orbital separations, but its place in the planet formation paradigm is hindered by a tendency to form especially large gas giants or brown dwarfs. We instead suggest that planet formation can occur early in massive discs, through the gravitational collapse of dust which can form the seeds of giant planets. This is different from the usual picture of self-gravitating discs, in which planet formation is considered through the gravitational collapse of the gas disc into a gas giant precursor. It is familiar in the sense that the core is formed first, and gas is accreted thereafter, as is the case in the core accretion scenario. However, by forming a $\sim 1 M_{\oplus}$ seed from the gravitational collapse of dust within a self-gravitating disc there exists the potential to overcome traditional growth barriers and form a planet within a few times $10^5$ years. The accretion of pebbles is most efficient with centimetre-sized dust, but the accretion of millimetre sizes can also result in formation within a Myr. Thus, if dust can grow to these sizes, planetary seeds formed within very young, massive discs could drastically reduce the timescale of planet formation and potentially explain the observed ring and gap structures in young discs. | [
"Physics Archive->astro-ph->astro-ph.EP"
]
| 2023-05-18T22:56:50Z |
hep-ex/0011041 | Time Dependent $B_s^0 - \bar{B_s^0}$ Oscillations Using Exclusively Reconstructed $D_s^+$ Decays at SLD | We set a preliminary 95% C.L. exclusion on the oscillation frequency of $B_s^0 - \bar{B_s^0}$ mixing using a sample of 400,000 hadronic $Z^0$ decays collected by the SLD experiment at the SLC during the 1996-98 run. In this analysis, $B_s^0$ mesons are partially reconstructed by combining a fully reconstructed $D_s$ with other $B_s^0$ decay tracks. The $D_s$ decays are reconstructed via the $\phi \pi$ and $K^* K$ channels. The $b$-hadron flavor at production is determined by exploiting the large forward-backward asymmetry of polarized $Z^0 \to b \bar{b}$ decays as well as information from the hemisphere opposite to the reconstructed B decay. The flavor of the $B_s^0$ at the decay vertex is determined by the charge of the $D_s$. A total of 361 candidates passed the final event selection cuts. This analysis excludes the following values of the $B_s^0 - \bar{B_s^0}$ mixing oscillation frequency: $\Delta m_s < 1.5$ ps$^{-1}$, $2.6 < \Delta m_s < 4.9$ ps$^{-1}$, and $10.8 < \Delta m_s < 13.5$ ps$^{-1}$ at the 95% confidence level. | [
"Physics Archive->hep->hep-ex"
]
| 2000-11-14T02:24:48Z |
math/0609374 | Solutions to the conjectures of Polya-Szego and Eshelby | Eshelby showed that if an inclusion is of elliptic or ellipsoidal shape then for any uniform elastic loading the field inside the inclusion is uniform. He then conjectured that the converse is true, i.e., that if the field inside an inclusion is uniform for all uniform loadings, then the inclusion is of elliptic or ellipsoidal shape. We call this the weak Eshelby conjecture. In this paper we prove this conjecture in three dimensions. In two dimensions, a stronger conjecture, which we call the strong Eshelby conjecture, has been proved: If the field inside an inclusion is uniform for a single uniform loading, then the inclusion is of elliptic shape. We give an alternative proof of Eshelby's conjecture in two dimensions using a hodographic transformation. As a consequence of the weak Eshelby's conjecture, we prove in two and three dimensions a conjecture of Polya and Szego on the isoperimetric inequalities for the polarization tensors. The Polya-Szego conjecture asserts that the inclusion whose electrical polarization tensor has the minimal trace takes the shape of a disk or a ball. | [
"Mathematics Archive->math.AP",
"Mathematics Archive->math.OC"
]
| 2006-09-13T22:04:47Z |
0911.4210 | Frames generated by actions of countable discrete groups | We consider dual frames generated by actions of countable discrete groups on a Hilbert space. Module frames in a class of modules over a group algebra are shown to coincide with a class of ordinary frames in a representation of the group. This has applications to shift-invariant spaces and wavelet theory. One of the main findings in this paper is that whenever a shift-invariant sub space in L2(Rn) has compactly supported dual frame generators then it also has compactly supported bi-orthogonal generators. The crucial part in the proof is a theorem by Swan that states that every finitely generated projective module over the Laurent polynomials in n variables is free. | [
"Mathematics Archive->math.FA"
]
| 2009-11-23T13:51:02Z |
math/9904055 | Operads and Motives in Deformation Quantization | This paper is dedicated to the memory of Moshe Flato, and will appear in Lett. Math. Phys. 48 (1) It became clear during last 5-6 years that the algebraic world of associative algebras (abelian categories, triangulated categories, etc) has many deep connections with the geometric world of two-dimensional surfaces. One of manifestations of this is Deligne's conjecture (1993) which says that on the cohomological Hochschild complex of any associative algebra naturally acts the operad of singular chains in the little discs operad. Recently D. Tamarkin discovered that the operad of chains of the little discs operad is formal, i.e. it is homotopy equivalent to its cohomology. From this fact and from Deligne's conjecture follows almost immediately my formality result in deformation quantization. I review the situation as it looks now. Also I conjecture that the motivic Galois group acts on deformation quantizations, and speculate on possible relations of higher-dimensional algebras and of motives to quantum field theories. | [
"Mathematics Archive->math.QA"
]
| 1999-04-13T13:58:53Z |
cond-mat/0306307 | Orbital Approximation for the Reduced Bloch Equations: Fermi-Dirac Distribution for Interacting Fermions and Hartree-Fock Equation at Finite Temperature | In this paper, we solve a set of hierarchy equations for the reduced statistical density operator in a grand canonical ensemble for an identical many-body fermion system without or with two-body interaction. We take the single-particle approximation, and obtain an eigen-equation for the single-particle states. For the case of no interaction, it is an eigen-equation for the free particles, and solutions are therefore the plane waves. For the case with two-body interaction, however, it is an equation which is the extension of usual Hartre-Fock equation at zero temperature to the case of any finite temperature. The average occupation number for the single-particle states with mean field interaction is also obtained, which has the same Fermi-Dirac distribution from as that for the free fermion gas. The derivation demonstrates that even for an interacting fermion system, only the lowest $N$ orbitals, where $N$ is the number of particles, are occupied at zero temperature. In addition, their practical applications in such fields as studying the temperature effects on the average structure and electronic spectra for macromolecules are discussed. | [
"Physics Archive->cond-mat->cond-mat.stat-mech"
]
| 2003-06-11T23:41:13Z |
2210.00225 | Lipschitz Continuity of the Schr\"odinger Map in Entropic Optimal Transport | The function that maps a family of probability measures to the solution of the dual entropic optimal transport problem is known as the Schr\"odinger map. We prove that when the cost function is $\mathcal{C}^{k+1}$ with $k\in \mathbb{N}^*$ then this map is Lipschitz continuous from the $L^2$-Wasserstein space to the space of $\mathcal{C}^k$ functions. Our result holds on compact domains and covers the multi-marginal case. As applications, we prove displacement smoothness of the entropic optimal transport cost and the well-posedness of certain Wasserstein gradient flows involving this functional, including the Sinkhorn divergence and a multi-species system. | [
"Mathematics Archive->math.AP",
"Mathematics Archive->math.OC"
]
| 2022-10-01T09:01:26Z |
1910.12749 | HIDRA: Head Initialization across Dynamic targets for Robust Architectures | The performance of gradient-based optimization strategies depends heavily on the initial weights of the parametric model. Recent works show that there exist weight initializations from which optimization procedures can find the task-specific parameters faster than from uniformly random initializations and that such a weight initialization can be learned by optimizing a specific model architecture across similar tasks via MAML (Model-Agnostic Meta-Learning). Current methods are limited to populations of classification tasks that share the same number of classes due to the static model architectures used during meta-learning. In this paper, we present HIDRA, a meta-learning approach that enables training and evaluating across tasks with any number of target variables. We show that Model-Agnostic Meta-Learning trains a distribution for all the neurons in the output layer and a specific weight initialization for the ones in the hidden layers. HIDRA explores this by learning one master neuron, which is used to initialize any number of output neurons for a new task. Extensive experiments on the Miniimagenet and Omniglot data sets demonstrate that HIDRA improves over standard approaches while generalizing to tasks with any number of target variables. Moreover, our approach is shown to robustify low-capacity models in learning across complex tasks with a high number of classes for which regular MAML fails to learn any feasible initialization. | [
"Computer Science Archive->cs.LG",
"Statistics Archive->stat.ML"
]
| 2019-10-28T15:18:19Z |
1711.07917 | Measuring the Allan Variance by Sinusoidal Fitting | The Allan variance of signal and reference frequencies is measured by a least-squares fit of the output of two analog-to-digital converters (ADC's) to ideal sine waves. The difference in the fit phase of the two channels generates the timing data needed for the Allan variance. The fits are performed at the signal frequency ($\approx 10 $ MHz) without the use of heterodyning. Experimental data from a modified digital oscilloscope yields a residual Allan deviation of $3 \times 10^{-13}/\tau $, where $\tau$ is the observation time in sec. This corresponds to a standard deviation in time of $<$ 300 fs or 20 $\mu$Rad in phase. The experimental results are supported by statistical theory and Monte Carlo simulations which suggest that optimized devices may have one or two orders of magnitude better performance. | [
"Physics Archive->physics->physics.ins-det"
]
| 2017-11-21T17:06:40Z |
1110.5008 | The structure of approximate groups | Let K >= 1 be a parameter. A K-approximate group is a finite set A in a (local) group which contains the identity, is symmetric, and such that A^2 is covered by K left translates of A. The main result of this paper is a qualitative description of approximate groups as being essentially finite-by-nilpotent, answering a conjecture of H. Helfgott and E. Lindenstrauss. This may be viewed as a generalisation of the Freiman-Ruzsa theorem on sets of small doubling in the integers to arbitrary groups. We begin by establishing a correspondence principle between approximate groups and locally compact (local) groups that allows us to recover many results recently established in a fundamental paper of Hrushovski. In particular we establish that approximate groups can be approximately modeled by Lie groups. To prove our main theorem we apply some additional arguments essentially due to Gleason. These arose in the solution of Hilbert's fifth problem in the 1950s. Applications of our main theorem include a finitary refinement of Gromov's theorem, as well as a generalized Margulis lemma conjectured by Gromov and a result on the virtual nilpotence of the fundamental group of Ricci almost nonnegatively curved manifolds. | [
"Mathematics Archive->math.CO",
"Mathematics Archive->math.GR"
]
| 2011-10-22T23:53:35Z |
2301.07707 | Josephson-Current Signatures of Unpaired Floquet Majorana Bound States | We theoretically study the transport signatures of unpaired Floquet Majorana bound states in the Josephson current of weakly linked, periodically driven topological superconductors. We obtain the occupation of the Floquet Majorana modes in the presence of weak coupling to thermal leads analytically, and show that, similar to static superconductors, the Josephson current involving Floquet Majorana bound states is also $4\pi$-periodic in the phase difference across the junction, and also depends linearly on the coupling between superconductors. Moreover, unlike the static case, the amplitude of the Josephson current can be tuned by setting the unbiased chemical potential of the driven superconductors at multiple harmonics of the drive frequency. As a result, we uncover a Josephson Floquet sum rule for driven superconductors. We confirm our analytical expressions for Josephson current, the occupation of Floquet bands, and a perturbative analysis of the quasienergies with numerically exact results. | [
"Physics Archive->cond-mat->cond-mat.mes-hall"
]
| 2023-01-18T18:56:24Z |
2106.07558 | Transparent Model of Unabridged Data (TMUD) | Recent advancements in computational power and algorithms have enabled unabridged data (e.g., raw images or audio) to be used as input in some models (e.g., deep learning). However, the black box nature of such models reduces their likelihood of adoption by marketing scholars. Our paradigm of analysis, the Transparent Model of Unabridged Data (TMUD), enables researchers to investigate the inner workings of such black box models by incorporating an ex ante filtration module and an ex post experimentation module. We empirically demonstrate the TMUD by investigating the role of facial components and sexual dimorphism in face perceptions, which have implications for four marketing contexts: advertisement (perceptions of approachability, trustworthiness, and competence), brand (perceptions of whether a face represents a brand's typical customer), category (perceptions of whether a face represents a category's typical customer), and customer persona (perceptions of whether a face represents the persona of a brand's customer segment). Our results reveal new and useful findings that enrich the existing literature on face perception, most of which is based on abridged attributes (e.g., width of mouth). The TMUD has great potential to be a useful paradigm for generating theoretical insights and may encourage more marketing researchers and practitioners to use unabridged data. | [
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG"
]
| 2021-05-23T04:04:22Z |
physics/9610009 | High Luminosity Muon Collider Design | Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadrons and electron machines. They should be regarded as complementary. Parameters are given of a 4 TeV high luminosity muon-muon collider, and of a 0.5 TeV demonstration machine. We discuss the various systems in such muon collider. | [
"Physics Archive->physics->physics.acc-ph"
]
| 1996-10-09T17:51:04Z |
hep-th/9512020 | Higher-Order Differential Operators on a Lie Group and Quantization | This talk is devoted mainly to the concept of higher-order polarization on a group, which is introduced in the framework of a Group Approach to Quantization, as a powerful tool to guarantee the irreducibility of quantizations and/or representations of Lie groups in those anomalous cases where the Kostant-Kirilov co-adjoint method or the Borel-Weyl-Bott representation algorithm do not succeed. | [
"Physics Archive->hep->hep-th"
]
| 1995-12-05T12:40:12Z |
1106.4419 | Voltage percolation thresholds evidenced in the electrical behaviour of different nanostructures | Percolation phenomena are investigated and discussed in three kinds of nanostructures: first two are nanocrystalline silicon-based systems, Si nanodots embedded in amorphous SiO2 matrix and porous silicon formed by an oxidized nanowire network, and the third consisting of a multi-walled carbon nanotube network embedded in amorphous SiN. The current-voltage characteristics measured on first two systems present voltage percolation thresholds with the same shape - a saturation plateau region of the current, followed by an abrupt increase. The current-voltage and conductance-voltage curves measured on multi-walled carbon nanotube network embedded in amorphous SiN present non-periodic and temperature independent oscillations. These oscillations are interpreted as voltage percolation thresholds. | [
"Physics Archive->cond-mat->cond-mat.mes-hall"
]
| 2011-06-22T11:22:28Z |
1709.05025 | Automorphism group of plane curve computed by Galois points, II | Recently, the first author classified finite groups obtained as automorphism groups of smooth plane curves of degree $d \ge 4$ into five types. He gave an upper bound of the order of the automorphism group for each types. For one of them, the type (a-ii), that is given by $\max \left\{ 2 d (d - 2), 60 d \right\}$. In this article, we shall construct typical examples of smooth plane curve $C$ by applying the method of Galois points, whose automorphism group has order $60 d$. In fact, we determine the structure of the automorphism group of those curves. | [
"Mathematics Archive->math.AG"
]
| 2017-09-15T01:08:21Z |
nucl-th/0510037 | Baryon number and strangeness: signals of a deconfined antecedent | The correlation between baryon number and strangeness is used to discern the nature of the deconfined matter produced at vanishing chemical potential in high-energy nuclear collisions at the BNL RHIC. Comparisons of results of various phenomenological models with correlations extracted from lattice QCD calculations suggest that a quasi-particle picture applies. At finite baryon densities, such as those encountered at the CERN SPS, it is demonstrated that the presence of a first-order phase transition and the accompanying development of spinodal decomposition would significantly enhance the number of strangeness carriers and the associated fluctuations. | [
"Physics Archive->nucl->nucl-th"
]
| 2005-10-11T18:35:33Z |
2310.01449 | Elastic Interaction Energy Loss for Traffic Image Segmentation | Segmentation is a pixel-level classification of images. The accuracy and fast inference speed of image segmentation are crucial for autonomous driving safety. Fine and complex geometric objects are the most difficult but important recognition targets in traffic scene, such as pedestrians, traffic signs and lanes. In this paper, a simple and efficient geometry-sensitive energy-based loss function is proposed to Convolutional Neural Network (CNN) for multi-class segmentation on real-time traffic scene understanding. To be specific, the elastic interaction energy (EIE) between two boundaries will drive the prediction moving toward the ground truth until completely overlap. The EIE loss function is incorporated into CNN to enhance accuracy on fine-scale structure segmentation. In particular, small or irregularly shaped objects can be identified more accurately, and discontinuity issues on slender objects can be improved. Our approach can be applied to different segmentation-based problems, such as urban scene segmentation and lane detection. We quantitatively and qualitatively analyze our method on three traffic datasets, including urban scene data Cityscapes, lane data TuSimple and CULane. The results show that our approach consistently improves performance, especially when using real-time, lightweight networks as the backbones, which is more suitable for autonomous driving. | [
"Computer Science Archive->cs.CV"
]
| 2023-10-02T01:30:42Z |
0710.2246 | Probing the Slope of Cluster Mass Profile with Gravitational Einstein Rings: Application to Abell 1689 | The strong lensing modelling of gravitational ``rings'' formed around massive galaxies is sensitive to the amplitude of the external shear and convergence produced by nearby mass condensations. In current wide field surveys, it is now possible to find out a large number of rings, typically 10 gravitational rings per square degree. We propose here, to systematically study gravitational rings around galaxy clusters to probe the cluster mass profile beyond the cluster strong lensing regions. For cluster of galaxies with multiple arc systems, we show that rings found at various distances from the cluster centre can improve the modelling by constraining the slope of the cluster mass profile. We outline the principle of the method with simple numerical simulations and we apply it to 3 rings discovered recently in Abell~1689. In particular, the lens modelling of the 3 rings confirms that the cluster is bimodal, and favours a slope of the mass profile steeper than isothermal at a cluster radius $\sim 300 \kpc$. These results are compared with previous lens modelling of Abell~1689 including weak lensing analysis. Because of the difficulty arising from the complex mass distribution in Abell~1689, we argue that the ring method will be better implemented on simpler and relaxed clusters. | [
"Physics Archive->astro-ph"
]
| 2007-10-11T13:46:43Z |
2305.05013 | Beyond Diagonal Reconfigurable Intelligent Surfaces Utilizing Graph Theory: Modeling, Architecture Design, and Optimization | Recently, beyond diagonal reconfigurable intelligent surface (BD-RIS) has been proposed to generalize conventional RIS. BD-RIS has a scattering matrix that is not restricted to being diagonal and thus brings a performance improvement over conventional RIS. While different BD-RIS architectures have been proposed, it still remains an open problem to develop a systematic approach to design BD-RIS architectures achieving the optimal trade-off between performance and circuit complexity. In this work, we propose novel modeling, architecture design, and optimization for BD-RIS based on graph theory. This graph theoretical modeling allows us to develop two new efficient BD-RIS architectures, denoted as tree-connected and forest-connected RIS. Tree-connected RIS, whose corresponding graph is a tree, is proven to be the least complex BD-RIS architecture able to achieve the performance upper bound in multiple-input single-output (MISO) systems. Besides, forest-connected RIS allows us to strike a balance between performance and complexity, further decreasing the complexity over tree-connected RIS. To optimize tree-connected RIS, we derive a closed-form global optimal solution, while forest-connected RIS is optimized through a low-complexity iterative algorithm. Numerical results confirm that tree-connected (resp. forest-connected) RIS achieves the same performance as fully-connected (resp. group-connected) RIS, while reducing the complexity by up to 16.4 times. | [
"Computer Science Archive->cs.IT",
"Electrical Engineering and Systems Science Archive->eess.SP",
"Mathematics Archive->math.IT"
]
| 2023-05-08T19:33:33Z |
cond-mat/9809331 | Hydrodynamic Limit of Brownian Particles Interacting with Short and Long Range Forces | We investigate the time evolution of a model system of interacting particles, moving in a $d$-dimensional torus. The microscopic dynamics are first order in time with velocities set equal to the negative gradient of a potential energy term $\Psi$ plus independent Brownian motions: $\Psi$ is the sum of pair potentials, $V(r)+\gamma^d J(\gamma r)$, the second term has the form of a Kac potential with inverse range $\gamma$. Using diffusive hydrodynamical scaling (spatial scale $\gamma^{-1}$, temporal scale $\gamma^{-2}$) we obtain, in the limit $\gamma\downarrow 0$, a diffusive type integro-differential equation describing the time evolution of the macroscopic density profile. | [
"Physics Archive->cond-mat->cond-mat.stat-mech"
]
| 1998-09-24T13:51:17Z |
1507.00878 | Holographic thermalization and Oppenheimer-Snyder collapse | The Oppenheimer-Snyder model, which describes the gravitational collapse of a ball of dust, can be used to model thermalization of strongly coupled systems using the AdS/CFT-duality. It can be used as an alternative to the previously widely used thin-shell model in the context of holographic thermalization. We solve the dynamics of the Oppenheimer-Snyder collapse in asymptotically AdS space-times and compute the two-point function of a boundary spectator field in the geodesic approximation. As a comparison we perform the same computation in the thin-shell model and discover oscillatory solutions of the thin-shell model for certain equations of state. | [
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-th"
]
| 2015-07-03T11:20:50Z |
1310.3026 | Non-thermal WIMPs as Dark Radiation | It has been thought that only light species could behave as radiation and account for the dark radiation observed recently by Planck, WMAP9, South Pole and ATACAMA telescopes. In this work we will show that GeV scale WIMPs can plausibly account for the dark radiation as well. Heavy WIMPs might mimic the effect of a half neutrino species if some of their fraction were produced non-thermally after the thermal freeze-out. In addition, we will show how BBN, CMB and Structure Formation bounds might be circumvented. | [
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->hep->hep-ph"
]
| 2013-10-11T06:09:15Z |
astro-ph/0111526 | Chandra Observations of the Components of Clusters, Groups, and Galaxies and their Interactions | We discuss two themes from Chandra observations of galaxies, groups, and clusters. First, we review the merging process as seen through the high angular resolution of Chandra. We present examples of sharp, edge-like surface brightness structures ``cold fronts'', the boundaries of the remaining cores of merger components and the Chandra observations of CL0657, the first clear example of a strong cluster merger shock. In addition to reviewing already published work, we present observations of the cold front around the elliptical galaxy NGC1404 which is infalling into the Fornax cluster and we discuss multiple ``edges'' in ZW3146. Second, we review the effects of relativistic, radio-emitting plasmas or ``bubbles'', inflated by active galactic nuclei, on the hot X-ray emitting gaseous atmospheres in galaxies and clusters. We review published work and also discuss the unusual X-ray structures surrounding the galaxies NGC4636 and NGC507. | [
"Physics Archive->astro-ph"
]
| 2001-11-28T15:04:01Z |
gr-qc/0607051 | Quantum Corrections to the Reissner-Nordstrom and Kerr-Newman Metrics: Spin 1 | A previous evaluation of one-photon loop corrections to the energy-momentum tensor has been extended to particles with unit spin and speculations are presented concerning general properties of such forms. | [
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-ph",
"Physics Archive->hep->hep-th"
]
| 2006-07-12T15:59:21Z |
2208.03011 | Comparing Equivalent Gravities: common features and differences | We discuss equivalent representations of gravity in the framework of metric-affine geometries pointing out basic concepts from where these theories stem out. In particular, we take into account tetrads and spin connection to describe the so called {\it Geometric Trinity of Gravity}. Specifically, we consider General Relativity, constructed upon the metric tensor and based on the curvature $R$; Teleparallel Equivalent of General Relativity, formulated in terms of torsion $T$ and relying on tetrads and spin connection; Symmetric Teleparallel Equivalent of General Relativity, built up on non-metricity $Q$, constructed from metric tensor and affine connection. General Relativity is formulated as a geometric theory of gravity based on metric, whereas teleparallel approaches configure as gauge theories, where gauge choices permit not only to simplify calculations, but also to give deep insight into the basic concepts of gravitational field. In particular, we point out how foundation principles of General Relativity (i.e the Equivalence Principle and the General Covariance) can be seen from the teleparallel point of view. These theories are dynamically equivalent and this feature can be demonstrated under three different standards: (1) the variational method; (2) the field equations; (3) the solutions. | [
"Physics Archive->gr-qc",
"Physics Archive->hep->hep-th"
]
| 2022-08-05T06:58:34Z |
1104.1217 | On Conditions for Linearity of Optimal Estimation | When is optimal estimation linear? It is well known that, when a Gaussian source is contaminated with Gaussian noise, a linear estimator minimizes the mean square estimation error. This paper analyzes, more generally, the conditions for linearity of optimal estimators. Given a noise (or source) distribution, and a specified signal to noise ratio (SNR), we derive conditions for existence and uniqueness of a source (or noise) distribution for which the $L_p$ optimal estimator is linear. We then show that, if the noise and source variances are equal, then the matching source must be distributed identically to the noise. Moreover, we prove that the Gaussian source-channel pair is unique in the sense that it is the only source-channel pair for which the mean square error (MSE) optimal estimator is linear at more than one SNR values. Further, we show the asymptotic linearity of MSE optimal estimators for low SNR if the channel is Gaussian regardless of the source and, vice versa, for high SNR if the source is Gaussian regardless of the channel. The extension to the vector case is also considered where besides the conditions inherited from the scalar case, additional constraints must be satisfied to ensure linearity of the optimal estimator. | [
"Computer Science Archive->cs.IT",
"Mathematics Archive->math.IT"
]
| 2011-04-07T00:09:43Z |
0806.2724 | Conditionally identically distributed species sampling sequences | Conditional identity in distribution (Berti et al. (2004)) is a new type of dependence for random variables, which generalizes the well-known notion of exchangeability. In this paper, a class of random sequences, called Generalized Species Sampling Sequences, is defined and a condition to have conditional identity in distribution is given. Moreover, a class of generalized species sampling sequences that are conditionally identically distributed is introduced and studied: the Generalized Ottawa sequences (GOS). This class contains a '`randomly reinforced'' version of the P\'olya urn and of the Blackwell-MacQueen urn scheme. For the empirical means and the predictive means of a GOS, we prove two convergence results toward suitable mixtures of Gaussian distributions. The first one is in the sense of stable convergence and the second one in the sense of almost sure conditional convergence. In the last part of the paper we study the length of the partition induced by a GOS at time $n$, i.e. the random number of distinct values of a GOS until time $n$. Under suitable conditions, we prove a strong law of large numbers and a central limit theorem in the sense of stable convergence. All the given results in the paper are accompanied by some examples. | [
"Mathematics Archive->math.PR"
]
| 2008-06-17T08:46:17Z |
2301.03126 | Statistical Inference for Ultrahigh Dimensional Location Parameter Based on Spatial Median | Motivated by the widely used geometric median-of-means estimator in machine learning, this paper studies statistical inference for ultrahigh dimensionality location parameter based on the sample spatial median under a general multivariate model, including simultaneous confidence intervals construction, global tests, and multiple testing with false discovery rate control. To achieve these goals, we derive a novel Bahadur representation of the sample spatial median with a maximum-norm bound on the remainder term, and establish Gaussian approximation for the sample spatial median over the class of hyperrectangles. In addition, a multiplier bootstrap algorithm is proposed to approximate the distribution of the sample spatial median. The approximations are valid when the dimension diverges at an exponentially rate of the sample size, which facilitates the application of the spatial median in the ultrahigh dimensional region. The proposed approaches are further illustrated by simulations and analysis of a genomic dataset from a microarray study. | [
"Mathematics Archive->math.ST",
"Statistics Archive->stat.ME",
"Statistics Archive->stat.TH"
]
| 2023-01-09T00:18:17Z |
1406.4579 | Electromagnetic Contribution to the Proton-Neutron Mass Splitting | We study the electromagnetic contribution to the proton-neutron mass splitting by combining lattice simulations and the modified Cottingham sum rule of Walker-Loud, Carlson and Miller. This analysis yields an estimate of the isovector nucleon magnetic polarizability as a function of pion mass. The physical value, obtained by chiral extrapolation to the physical pion mass, is $\beta_{p-n}=(-1.12 \pm 0.40)\times 10^{-4}\ \mathrm{fm}^3$, which is in agreement with the empirical result, albeit with a somewhat smaller error. As a result, we find $\delta M^{\gamma}_{p-n}=1.04 \pm 0.11\ \mathrm{MeV}$, which represents a significant improvement in precision. | [
"Physics Archive->hep->hep-lat",
"Physics Archive->hep->hep-ph",
"Physics Archive->nucl->nucl-th"
]
| 2014-06-18T02:58:18Z |
astro-ph/0607009 | MILES: A Medium resolution INT Library of Empirical Spectra | A new stellar library developed for stellar population synthesis modeling is presented. The library consist of 985 stars spanning a large range in atmospheric parameters. The spectra were obtained at the 2.5m INT telescope and cover the range 3525-7500A at 2.3A (FWHM) spectral resolution. The spectral resolution, spectral type coverage, flux calibration accuracy and number of stars represent a substantial improvement over previous libraries used in population synthesis models. | [
"Physics Archive->astro-ph"
]
| 2006-07-03T10:23:56Z |
2202.11471 | Radiation hardness study on a CMOS pixel sensor for charged particle tracking | A CMOS pixel sensor, named Supix-1, is developed for a pixelated silicon tracker for the Circular Electron-Positron Collider (CEPC) project. The sensor, consisted of nine sectors varying in pixel sizes, diode sizes and geometries, is fabricated with a 180 nm CMOS Image Sensor (CIS) process to study the particle detection performance of enlarged pixels. In this work, the radiation-induced effects on the charge collection of the sensor under the fluence of 1 $\times$ 10^13 1 MeV neq/cm^2 are studied by the measurements with the radioactive source of Fe-55 and the Technology Computer Aided Design (TCAD) simulations, since the radiation hardness of 6.8 $\times$ 10^12 1 MeV neq/cm^2 per year for Non-Ionizing Energy Loss (NIEL) effects is required. In measurements, the sensor gain has been calibrated using the k-$\alpha$ peak of Fe-55 before and after irradiation. The pixel-wise equivalent noise charge (ENC), charge collection efficiency (CCE) and signal-to-noise ratio (SNR) were evaluated. The radiation-induced effects on cluster properties are studied through a self-developed reconstruction algorithm. In TCAD simulations, charge collections in 5 $\times$ 5 pixel matrixes for two typical impinging cases of incident particles were simulated with and without irradiation. Both measurements and simulations indicate that enlarged pixels with area of 21 $\mu$m $\times$ 84 $\mu$m, though suffering greater loss on sensor performance than small pixels do, still have satisfactory noise and charge collection performance after irradiation for particle tracking in the upcoming collider detectors. | [
"Physics Archive->hep->hep-ex",
"Physics Archive->physics->physics.ins-det"
]
| 2022-02-23T12:42:54Z |
1705.06658 | Band Gap Formation and Tunability in Stretchable Serpentine Interconnects | Serpentine interconnects are highly stretchable and frequently used in flexible electronic systems. In this work, we show that the undulating geometry of the serpentine interconnects will generate phononic band gaps to manipulate elastic wave propagation. The interesting effect of `bands-sticking-together' is observed. We further illustrate that the band structures of the serpentine interconnects can be tuned by applying pre-stretch deformation. The discovery offers a way to design stretchable and tunable phononic crystals by using metallic interconnects instead of the conventional design with soft rubbers and unfavorable damping. | [
"Physics Archive->physics->physics.app-ph"
]
| 2017-05-18T15:39:48Z |
2111.07004 | Fault Diagnosis of Nonlinear Systems Using a Hybrid-Degree Dual Cubature-based Estimation Scheme | In this paper, a novel hybrid-degree dual estimation approach based on cubature rules and cubature-based nonlinear filters is proposed for fault diagnosis of nonlinear systems through simultaneous state and time-varying parameter estimation. Our proposed dual nonlinear filtering scheme is developed based on case-dependent cubature rules that are motivated by the following observations and facts, namely (i) dynamic characteristics of nonlinear system states and parameters generally are distinct and posses different degrees of complexities, and (ii) performance of cubature rules depend on the system dynamics and vary due to handling of high-dimensional integrations approximations. For improving the robustness capability of our proposed methodologies modified cubature point propagation method is incorporated. The performance of our proposed dual estimation strategy is demonstrated and evaluated by application to a nonlinear gas turbine engine for addressing the component fault diagnosis problem within an integrated fault detection, isolation and identification framework. Robustness analysis is implemented to verify the capability of our proposed approaches to deal with parametric uncertainties and unmodeled dynamics. Extensive simulation case studies and discussions with respect to component fouling, erosion or abrupt faults are provided to substantiate and justify the superiority of our proposed fault diagnosis methodology when compared to other well-known alternative diagnostic techniques such as the Unscented Kalman Filters (UKF) and Particle Filters (PF) that are commonly available in the literature. | [
"Computer Science Archive->cs.SY",
"Electrical Engineering and Systems Science Archive->eess.SY"
]
| 2021-11-13T00:43:03Z |
hep-th/9809042 | Strings and the Gauge Theory of Spacetime Defects | we present a new topological invariant to describe the space-time defect which is closely related to torsion tensor in Riemann-Cartan manifold. By virtue of the topological current theory and $\phi$-mapping method, we show that there must exist many strings objects generated from the zero points of $\phi$-mapping, and these strings are topological quantized and the topological quantum numbers is the Winding numbers described by the Hopf indices and the Brouwer degrees of the $\phi$-mapping. | [
"Physics Archive->hep->hep-th"
]
| 1998-09-07T10:12:17Z |
1005.3487 | On exact solutions of the Dirac equation in a homogeneous magnetic field in the Lobachevsky space | There are constructed exact solutions of the quantum-mechanical Dirac equation for a spin S=1/2 particle in Riemannian space of constant negative curvature, hyperbolic Lobachevsky space, in presence of an external magnetic field, analogue of the homogeneous magnetic field in the Minkowski space. A generalized formula for energy levels, describing quantization of the motion of the particle in magnetic field on the background of the Lobachevsky space geometry, has been obtained. | [
"Mathematics Archive->math.MP",
"Physics Archive->hep->hep-th",
"Physics Archive->math-ph"
]
| 2010-05-19T16:50:52Z |
1511.08797 | Full quantum theory of control-not gate in ion-trap quantum computation | We investigate the exact effect on ion trap quantum computation after field quantization. First an exact expression of failure probability from field quantization after many CNOT operations in Cirac-Zoller scheme is given. It is proportional to operation number and the amplitude of $|1\rangle_x |0\rangle_y$ or $|1\rangle_x |1\rangle_y$ in initial state, and inverse proportional to mean number of photons and amplitude of $|0\rangle_x |0\rangle_y$ or $|0\rangle_x |1\rangle_y$ in initial state. Then we calculate the failure probability when the limitation to mean number of photons in sideband transition is considered. When the initial state is $|1\rangle_x |0\rangle_y$ or $|1\rangle_x |1\rangle_y$, after about $10^2$ times of CNOT operations, failure probability is no less than $10^{-2}$, while $10^{-2}$ is the known maximum threshold in fault-tolerant quantum computation. Then when the initial state is $|1\rangle_x |0\rangle_y$ or $|1\rangle_x |1\rangle_y$, the number of CNOT gates on the same pair of physical qubits should be no more than $10^2$ in one error-correction period, or else the computation cannot be implemented reliably. This conclusion can help to determine the number of CNOT operations between coding and decoding in one error-correction period in fault-tolerant quantum computation. | [
"Physics Archive->quant-ph"
]
| 2015-11-26T09:00:43Z |
math/0403150 | Asymptotic bounds for Nori's connectivity theorem | Let $Y$ be a smooth complex projective variety. We study the cohomology of smooth families of hypersurfaces $X\to B$ for $B\subset{\bf P}H^0(Y,O(d))$ a codimension $c$ subvariety. We give an asymptotically optimal bound on $c$ and $k$ for $d\to\infty$ for the space $H^k(X,\C)$ not to be spanned by the image of $H^k(Y\times B,\C)$, thus extending the validity of Lefschetz Hyperplane section Theorem and Nori's Connectivity Theorem. Next, we construct in the limit case explicit families of higher Chow groups which span the non trivial cohomology classes in $X$. We give examples of indecomposable classes. The construction suggests a conjecture predicting that in the limit case the cokernel of the restriction map $H^k(Y\times B)\to H^k(X)$ should always be algebraic, containing Nori's Connectivity Theorem and our previous work on the Noether-Lefschetz locus as special cases. | [
"Mathematics Archive->math.AG"
]
| 2004-03-09T09:46:35Z |
cond-mat/0104037 | Temperature dependence of the Kondo resonance and its satellites in CeCu_2Si_2 | We present high-resolution photoemission spectroscopy studies on the Kondo resonance of the strongly-correlated Ce system CeCu$_2$Si$_2$. Exploiting the thermal broadening of the Fermi edge we analyze position, spectral weight, and temperature dependence of the low-energy 4f spectral features, whose major weight lies above the Fermi level $E_F$. We also present theoretical predictions based on the single-impurity Anderson model using an extended non-crossing approximation (NCA), including all spin-orbit and crystal field splittings of the 4f states. The excellent agreement between theory and experiment provides strong evidence that the spectral properties of CeCu$_2$Si$_2$ can be described by single-impurity Kondo physics down to $T \approx 5$ K. | [
"Physics Archive->cond-mat->cond-mat.str-el"
]
| 2001-04-02T16:38:21Z |
2001.02748 | Rate-Constrained Shaping Codes for Structured Sources | Shaping codes are used to encode information for use on channels with cost constraints. Applications include data transmission with a power constraint and, more recently, data storage on flash memories with a constraint on memory cell wear. In the latter application, system requirements often impose a rate constraint. In this paper, we study rate-constrained fixed-to-variable length shaping codes for noiseless, memoryless costly channels and general i.i.d. sources. The analysis relies on the theory of word-valued sources. We establish a relationship between the code expansion factor and minimum average symbol cost. We then determine the expansion factor that minimizes the average cost per source symbol (total cost), corresponding to a conventional optimal source code with cost. An equivalence is established between codes minimizing average symbol cost and codes minimizing total cost, and a separation theorem is proved, showing that optimal shaping can be achieved by a concatenation of optimal compression and optimal shaping for a uniform i.i.d. source. Shaping codes often incorporate, either explicitly or implicitly, some form of non-equiprobable signaling. We use our results to further explore the connections between shaping codes and codes that map a sequence of i.i.d. source symbols into an output sequence of symbols that are approximately independent and distributed according to a specified target distribution, such as distribution matching (DM) codes. Optimal DM codes are characterized in terms of a new performance measure - generalized expansion factor (GEF) - motivated by the costly channel perspective. The GEF is used to study DM codes that minimize informational divergence and normalized informational divergence. | [
"Computer Science Archive->cs.IT",
"Mathematics Archive->math.IT"
]
| 2020-01-08T21:29:45Z |
2012.12372 | Out-distribution aware Self-training in an Open World Setting | Deep Learning heavily depends on large labeled datasets which limits further improvements. While unlabeled data is available in large amounts, in particular in image recognition, it does not fulfill the closed world assumption of semi-supervised learning that all unlabeled data are task-related. The goal of this paper is to leverage unlabeled data in an open world setting to further improve prediction performance. For this purpose, we introduce out-distribution aware self-training, which includes a careful sample selection strategy based on the confidence of the classifier. While normal self-training deteriorates prediction performance, our iterative scheme improves using up to 15 times the amount of originally labeled data. Moreover, our classifiers are by design out-distribution aware and can thus distinguish task-related inputs from unrelated ones. | [
"Computer Science Archive->cs.CV",
"Computer Science Archive->cs.LG"
]
| 2020-12-21T12:25:04Z |
1008.1197 | Polarization of thin films of barium-strontium titanate under external electric field | The Landau theory of phase transitions of Ba0.8Sr0.2TiO3 thin film under external electric field applied in the planar geometry is developed. The interfacial van-der-Waals field Ez=1.1x10^8 V/m oriented normal to the film-substrate interface was introduced in to the model calculation to explain experimentally observed behavior of the polarization as a function of planar electric field. The Ez - misfit strain phase diagram of the film is constructed and discussed. | [
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
]
| 2010-08-06T13:43:35Z |
2101.11971 | Parametrized Euler class and semicohomology theory | We extend Ghys' theory about semiconjugacy to the world of measurable cocycles. More precisely, given a measurable cocycle with values into $\text{Homeo}^+(\mathbb{S}^1)$, we can construct a $\text{L}^\infty$-parametrized Euler class in bounded cohomology. We show that such a class vanishes if and only if the cocycle can be lifted to $\text{Homeo}^+_{\mathbb{Z}}(\mathbb{R})$ and it admits an equivariant family of points. We define the notion of semicohomologous cocycles and we show that two measurable cocycles are semicohomologous if and only if they induce the same parametrized Euler class. Since for minimal cocycles, semicohomology boils down to cohomology, the parametrized Euler class is constant for minimal cohomologous cocycles. We conclude by studying the vanishing of the real parametrized Euler class and we obtain some results of elementarity. | [
"Mathematics Archive->math.GT"
]
| 2021-01-28T12:55:50Z |
0711.1561 | The Hecke group algebra of a Coxeter group and its representation theory | Let W be a finite Coxeter group. We define its Hecke-group algebra by gluing together appropriately its group algebra and its 0-Hecke algebra. We describe in detail this algebra (dimension, several bases, conjectural presentation, combinatorial construction of simple and indecomposable projective modules, Cartan map) and give several alternative equivalent definitions (as symmetry preserving operator algebra, as poset algebra, as commutant algebra, ...). In type A, the Hecke-group algebra can be described as the algebra generated simultaneously by the elementary transpositions and the elementary sorting operators acting on permutations. It turns out to be closely related to the monoid algebras of respectively nondecreasing functions and nondecreasing parking functions, the representation theory of which we describe as well. This defines three towers of algebras, and we give explicitly the Grothendieck algebras and coalgebras given respectively by their induction products and their restriction coproducts. This yields some new interpretations of the classical bases of quasi-symmetric and noncommutative symmetric functions as well as some new bases. | [
"Mathematics Archive->math.CO",
"Mathematics Archive->math.RT"
]
| 2007-11-10T00:55:27Z |
1906.02217 | A null test to probe the scale-dependence of the growth of structure as a test of General Relativity | The main science driver for the coming generation of cosmological surveys is understanding dark energy which relies on testing General Relativity on the largest scales. Once we move beyond the simplest explanation for dark energy of a cosmological constant, the space of possible theories becomes both vast and extremely hard to compute realistic observables. A key discriminator of a cosmological constant, however, is that the growth of structure is scale-invariant on large scales. By carefully weighting observables derived from distributions of galaxies and a dipole pattern in their apparent sizes, we construct a null test which vanishes for any model of gravity or dark energy where the growth of structure is scale-independent. It relies only on very few assumptions about cosmology, and does not require any modelling of the growth of structure. We show that with a survey like DESI a scale-dependence of the order of 10-20 percent can be detected at 3 sigma with the null test, which will drop by a factor of 2 for a survey like the Square Kilometre Array. We also show that the null test is very insensitive to typical uncertainties in other cosmological parameters including massive neutrinos and scale-dependent bias, making this a key null test for dark energy. | [
"Physics Archive->astro-ph->astro-ph.CO",
"Physics Archive->gr-qc"
]
| 2019-06-05T18:01:32Z |
1912.10627 | Coordinate Descent Without Coordinates: Tangent Subspace Descent on Riemannian Manifolds | We extend coordinate descent to manifold domains, and provide convergence analyses for geodesically convex and non-convex smooth objective functions. Our key insight is to draw an analogy between coordinate blocks in Euclidean space and tangent subspaces of a manifold. Hence, our method is called tangent subspace descent (TSD). The core principle behind ensuring convergence of TSD is the appropriate choice of subspace at each iteration. To this end, we propose two novel conditions, the gap ensuring and $C$-randomized norm conditions on deterministic and randomized modes of subspace selection respectively, that promise convergence for smooth functions and that are satisfied in practical contexts. We propose two subspace selection rules of particular practical interest that satisfy these conditions: a deterministic one for the manifold of square orthogonal matrices, and a randomized one for the Stiefel manifold. Our proof-of-concept numerical experiments on the orthogonal Procrustes problem demonstrate TSD's efficacy. | [
"Mathematics Archive->math.OC"
]
| 2019-12-23T05:31:39Z |
2006.02875 | Periodic surface modulation of $(LaSe)_{1.14}(NbSe_2)$ observed by scanning tunneling microscopy | Fourier transformation of atomically resolved STM topography of $(LaSe)_{1.14}(NbSe_2)$ revealed a surface modulation along the hexagonal surface lattice of $NbSe_2$ layer, but with a two times larger period. We compare it to the modified charge density wave found on plain $NbSe_2$ under strain. | [
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->cond-mat->cond-mat.supr-con"
]
| 2020-06-04T14:18:08Z |
1902.01627 | Sharp gap edges in dense planetary rings: An axisymmetric diffusion model | One of the most intriguing facets of Saturn's rings are the sharp edges of gaps in the rings where the surface density abruptly drops to zero. This is despite of the fact that the range over which a moon transfers angular momentum onto the ring material is much larger. Recent UVIS-scans of the edges of the Encke and Keeler gap show that this drop occurs over a range approximately equal to the rings' thickness. Borderies et al. (1982, 1989) show that this striking feature is likely related to the local reversal of the usually outward directed viscous transport of angular momentum in strongly perturbed regions. In this article we revise the Borderies et al. (1989) model using a granular flow model to define the shear and bulk viscosities and incorporate the angular momentum flux reversal effect into the axisymmetric diffusion model we developed for gaps in dense planetary rings (Gr\"atz et al. 2018). Finally, we apply our model to the Encke and Keeler division in order to estimate the shear and bulk viscosities in the vicinity of both gaps. | [
"Physics Archive->astro-ph->astro-ph.EP"
]
| 2019-02-05T10:15:09Z |
1112.4939 | What geometrical factors determine the in situ solar wind speed? | At present it remains to address why the fast solar wind is fast and the slow wind is slow. Recently we have shown that the field line curvature may substantially influence the wind speed $v$, thereby offering an explanation for the Arge et al. finding that $v$ depends on more than just the flow tube expansion factor. Here we show by extensive numerical examples that the correlation between $v$ and field line curvature is valid for rather general base boundary conditions and for rather general heating functions. Furthermore, the effect of field line curvature is even more pronounced when the proton-alpha particle speed difference is examined. We suggest that any solar wind model has to take into account the field line shape for any quantitative analysis to be made. | [
"Physics Archive->astro-ph->astro-ph.SR"
]
| 2011-12-21T07:43:06Z |
2111.03817 | Cubes and Boxes have Rupert's passages in every direction | It is a $300$ year old counterintuitive observation of Prince Rupert of Rhine that in cube a straight tunnel can be cut, through which a second congruent cube can be passed. Hundred years later P. Nieuwland generalized Rupert's problem and asked for the largest aspect ratio so that a larger homothetic copy of the same body can be passed. We show that cubes and in fact all rectangular boxes have Rupert's passages in every direction, which is not parallel to the faces. In case of the cube it was assumed without proof that the solution of the Nieuwland's problem is a tunnel perpendicular to the largest square contained by the cube. We prove that this unwarranted assumption is correct not only for the cube, but also for all other rectangular boxes. | [
"Mathematics Archive->math.MG"
]
| 2021-11-06T07:15:33Z |
1201.3687 | Topological Insulator and Helical Zero Mode in Silicene under Inhomogeneous Electric Field | Silicene is a monolayer of silicon atoms forming a two-dimensional honeycomb lattice, which shares almost every remarkable property with graphene. The low energy structure of silicene is described by Dirac electrons with relatively large spin-orbit interactions due to its buckled structure. The key observation is that the band structure is controllable by applying the electric field to a silicene sheet. In particular, the gap closes at a certain critical electric field. Examining the band structure of a silicene nanoribbon, we demonstrate that a topological phase transition occurs from a topological insulator to a band insulator with the increase of the electric field. We also show that it is possible to generate helical zero modes anywhere in a silicene sheet by adjusting the electric field locally to this critical value. The region may act as a quantum wire or a quantum dot surrounded by topological and/or band insulators. We explicitly construct the wave functions for some simple geometries based on the low-energy effective Dirac theory. These results are applicable also to germanene, that is a two-dimensional honeycomb structure of germanium. | [
"Physics Archive->cond-mat->cond-mat.mes-hall",
"Physics Archive->cond-mat->cond-mat.mtrl-sci"
]
| 2012-01-18T02:59:19Z |
0710.4204 | Chirality sensitive effect on surface states in chiral p-wave superconductors | We study the local density of states at the surface of a chiral p-wave superconductor in the presence of a weak magnetic field. As a result, the formation of low-energy Andreev bound states is either suppressed or enhanced by an applied magnetic field, depending on its orientation with respect to the chirality of the p-wave superconductor. Similarly, an Abrikosov vortex, which is situated not too far from the surface, leads to a zero-energy peak of the density of states, if its chirality is the same as that of the superconductor, and to a gap structure for the opposite case. We explain the underlying principle of this effect and propose a chirality sensitive test on unconventional superconductors. | [
"Physics Archive->cond-mat->cond-mat.supr-con"
]
| 2007-10-23T08:17:49Z |
1406.3842 | A brief survey of Nigel Kalton's work on interpolation and related topics | This is the third of a series of papers surveying some small part of the remarkable work of our friend and colleague Nigel Kalton. We have written it as part of a tribute to his memory. It does not contain new results. This time, rather than concentrating on one particular paper, we attempt to give a general overview of Nigel's many contributions to the theory of interpolation of Banach spaces, and also, significantly, quasi-Banach spaces. | [
"Mathematics Archive->math.FA"
]
| 2014-06-15T18:50:19Z |
1012.2882 | M5-Branes, D4-Branes and Quantum 5D super-Yang-Mills | We revisit the relation of the six-dimensional (2,0) M5-brane Conformal Field Theory compactified on a circle to 5D maximally supersymmetric Yang-Mills Gauge Theory. We show that in the broken phase 5D super-Yang-Mills contains a spectrum of soliton states that can be identified with the complete Kaluza-Klein modes of an M2-brane ending on the M5-branes. This provides evidence that the (2,0) theory on a circle is equivalent to 5D super-Yang-Mills with no additional UV degrees of freedom, suggesting that the latter is in fact a well-defined quantum theory and possibly finite. | [
"Physics Archive->hep->hep-th"
]
| 2010-12-13T21:18:02Z |
2212.12073 | A tabletop x-ray tomography instrument for nanometer-scale imaging: demonstration of the 1,000-element transition-edge sensor subarray | We report on the 1,000-element transition-edge sensor (TES) x-ray spectrometer implementation of the TOMographic Circuit Analysis Tool (TOMCAT). TOMCAT combines a high spatial resolution scanning electron microscope (SEM) with a highly efficient and pixelated TES spectrometer to reconstruct three-dimensional maps of nanoscale integrated circuits (ICs). A 240-pixel prototype spectrometer was recently used to reconstruct ICs at the 130 nm technology node, but to increase imaging speed to more practical levels, the detector efficiency needs to be improved. For this reason, we are building a spectrometer that will eventually contain 3,000 TES microcalorimeters read out with microwave superconducting quantum interference device (SQUID) multiplexing, and we currently have commissioned a 1,000 TES subarray. This still represents a significant improvement from the 240-pixel system and allows us to begin characterizing the full spectrometer performance. Of the 992 maximimum available readout channels, we have yielded 818 devices, representing the largest number of TES x-ray microcalorimeters simultaneously read out to date. These microcalorimeters have been optimized for pulse speed rather than purely energy resolution, and we measure a FWHM energy resolution of 14 eV at the 8.0 keV Cu K$\alpha$ line. | [
"Physics Archive->physics->physics.ins-det"
]
| 2022-12-22T23:07:49Z |
1107.3913 | The RMS Survey: Ammonia and water maser analysis of massive star forming regions | The Red MSX Source (RMS) survey has identified a sample of ~1200 massive young stellar objects (MYSOs), compact and ultra compact HII regions from a sample of ~2000 MSX and 2MASS colour selected sources. We have used the 100 m Green Bank telescope to search for 22-24 GHz water maser and ammonia (1,1), (2,2) and (3,3) emission towards ~600 RMS sources located within the northern Galactic plane. We have identified 308 H2O masers which corresponds to an overall detection rate of ~50%. Abridged: We detect ammonia emission towards 479 of these massive young stars, which corresponds to ~80%. Ammonia is an excellent probe of high density gas allowing us to measure key parameters such as gas temperatures, opacities, and column densities, as well as providing an insight into the gas kinematics. The average kinetic temperature, FWHM line width and total NH3 column density for the sample are approximately 22 K, 2 km/s and 2x10^{15} cm^{-2}, respectively. We find that the NH3 (1,1) line width and kinetic temperature are correlated with luminosity and finding no underlying dependence of these parameters on the evolutionary phase of the embedded sources, we conclude that the observed trends in the derived parameters are more likely to be due to the energy output of the central source and/or the line width-clump mass relationship. The velocities of the peak H2O masers and the NH3 emission are in excellent agreement with each other, which would strongly suggest an association between the dense gas and the maser emission. Moreover, we find the bolometric luminosity of the embedded source and the isotropic luminosity of the H2O maser are also correlated. We conclude from the correlations of the cloud and water maser velocities and the bolometric and maser luminosity that there is a strong dynamical relationship between the embedded young massive star and the H2O maser. | [
"Physics Archive->astro-ph->astro-ph.GA"
]
| 2011-07-20T07:53:04Z |
cond-mat/9507017 | Study of ARPES data and d-wave superconductivity using electronic models in two dimensions | We review the results of an extensive investigation of photoemission spectral weight using electronic models for the high-Tc superconductors. Here we show that some recently reported unusual features of the cuprates namely the presence of (i) flat bands, (ii) small quasiparticle bandwidths, and (iii) antiferromagnetically induced weight, have all a natural explanation within the context of holes moving in the presence of robust antiferromagnetic correlations. Introducing interactions among the hole carriers, a model is constructed which has ${\rm d_{x^2 - y^2}}$ superconductivity, an optimal doping of $\sim 15\%$ (caused by the presence of a large density of states at the top of the valence band), and a critical temperature $\sim 100K$. | [
"Physics Archive->cond-mat"
]
| 1995-07-06T19:45:05Z |
2111.13092 | The SU(N) running coupling in the twisted gradient flow scheme and volume independence | We report on an ongoing study of the running coupling of SU(N) pure Yang-Mills theory in the twisted gradient flow scheme (TGF). The study exploits the idea that twisted boundary conditions reduce finite volume effects, leading to an effective size in the twisted plane that combines the number of colours and the torus period. We test this hypothesis by computing the TGF running coupling and the SU(N) $\Lambda-$ parameter on asymmetric lattices of size $(NL)^2L^2$ for various gauge groups. Finite volume effects are monitored by analyzing the coupling in different planes and by comparing results at different number of colours. | [
"Physics Archive->hep->hep-lat"
]
| 2021-11-25T14:08:32Z |
1702.08351 | Regular $t$-balanced Cayley maps on split metacyclic 2-groups | A regular $t$-balanced Cayley map on a group $\Gamma$ is an embedding of a Cayley graph on $\Gamma$ into a surface with certain special symmetric properties. We completely classify regular $t$-balanced Cayley maps for a class of split metacyclic $2$-groups. | [
"Mathematics Archive->math.CO",
"Mathematics Archive->math.GR"
]
| 2017-02-27T16:12:12Z |
1607.01756 | Protocol for an Observational Study on the Effects of Playing High School Football on Later Life Cognitive Functioning and Mental Health | A potential causal relationship between head injuries sustained by NFL players and later-life neurological decline may have broad implications for participants in youth and high school football programs. However, brain trauma risk at the professional level may be different than that at the youth and high school levels and the long-term effects of participation at these levels is as-yet unclear. To investigate the effect of playing high school football on later life depression and cognitive functioning, we propose a retrospective observational study using data from the Wisconsin Longitudinal Study (WLS) of graduates from Wisconsin high schools in 1957. We compare 1,153 high school males who played varsity football to 2,751 male students who did not. 1,951 of the control subjects did not play any sport and the remaining 800 controls played a non-contact sport. We focus on two primary outcomes measured at age 65: a composite cognitive outcome measuring verbal fluency and memory and the modified CES-D depression score. To control for potential confounders we adjust for pre-exposure covariates such as IQ with matching and model-based covariate adjustment. We will conduct an ordered testing procedure that uses all 2,751 controls while controlling for possible unmeasured differences between students who played sports and those who did not. We will quantitatively assess the sensitivity of the results to potential unmeasured confounding. The study will also consider several secondary outcomes of clinical interest such as aggression and heavy drinking. The rich set of pre-exposure variables, relatively unbiased sampling, and longitudinal nature of the WLS dataset make the proposed analysis unique among related studies that rely primarily on convenience samples of football players with reported neurological symptoms. | [
"Statistics Archive->stat.AP"
]
| 2016-07-06T19:37:18Z |
2107.07200 | Real-Time Grasping Strategies Using Event Camera | Robotic vision plays a key role for perceiving the environment in grasping applications. However, the conventional framed-based robotic vision, suffering from motion blur and low sampling rate, may not meet the automation needs of evolving industrial requirements. This paper, for the first time, proposes an event-based robotic grasping framework for multiple known and unknown objects in a cluttered scene. Compared with standard frame-based vision, neuromorphic vision has advantages of microsecond-level sampling rate and no motion blur. Building on that, the model-based and model-free approaches are developed for known and unknown objects' grasping respectively. For the model-based approach, event-based multi-view approach is used to localize the objects in the scene, and then point cloud processing allows for the clustering and registering of objects. Differently, the proposed model-free approach utilizes the developed event-based object segmentation, visual servoing and grasp planning to localize, align to, and grasp the targeting object. The proposed approaches are experimentally validated with objects of different sizes, using a UR10 robot with an eye-in-hand neuromorphic camera and a Barrett hand gripper. Moreover, the robustness of the two proposed event-based grasping approaches are validated in a low-light environment. This low-light operating ability shows a great advantage over the grasping using the standard frame-based vision. Furthermore, the developed model-free approach demonstrates the advantage of dealing with unknown object without prior knowledge compared to the proposed model-based approach. | [
"Computer Science Archive->cs.RO"
]
| 2021-07-15T09:04:07Z |
2009.11158 | Dissipative dynamics at first-order quantum transitions | We investigate the effects of dissipation on the quantum dynamics of many-body systems at quantum transitions, especially considering those of the first order. This issue is studied within the paradigmatic one-dimensional quantum Ising model. We analyze the out-of-equilibrium dynamics arising from quenches of the Hamiltonian parameters and dissipative mechanisms modeled by a Lindblad master equation, with either local or global spin operators acting as dissipative operators. Analogously to what happens at continuous quantum transitions, we observe a regime where the system develops a nontrivial dynamic scaling behavior, which is realized when the dissipation parameter $u$ (globally controlling the decay rate of the dissipation within the Lindblad framework) scales as the energy difference $\Delta$ of the lowest levels of the Hamiltonian, i.e., $u\sim \Delta$. However, unlike continuous quantum transitions where $\Delta$ is power-law suppressed, at first-order quantum transitions $\Delta$ is exponentially suppressed with increasing the system size (provided the boundary conditions do not favor any particular phase). | [
"Physics Archive->cond-mat->cond-mat.stat-mech",
"Physics Archive->quant-ph"
]
| 2020-09-23T14:08:21Z |
astro-ph/0006439 | Probing the galactic center by gravitational lensing | The nature of Galactic Center could be probed by lensing experiments capable of testing the spatial and velocity distributions of stars nearby and beyond it. Several hypotheses are possible (e.g. massive neutrino condensation, boson star) which avoid the shortcomings of the supermassive black hole model. | [
"Physics Archive->astro-ph"
]
| 2000-06-30T09:30:44Z |
1708.07924 | Quadrupolar quantum criticality on a fractal | We study the ground state ordering of quadrupolar ordered $S=1$ magnets as a function of spin dilution probability $p$ on the triangular lattice. In sharp contrast to the ordering of $S=1/2$ dipolar N\'eel magnets on percolating clusters, we find that the quadrupolar magnets are quantum disordered at the percolation threshold, $p=p^*$. Further we find that long-range quadrupolar order is present for all $p<p^*$ and vanishes first exactly at $p^*$. Strong evidence for scaling behavior close to $p^*$ points to an unusual quantum criticality without fine tuning that arises from an interplay of quantum fluctuations and randomness. | [
"Physics Archive->cond-mat->cond-mat.str-el"
]
| 2017-08-26T03:11:34Z |
2209.02738 | Nonlinear Color-Metallicity Relations of Globular Clusters. XI. Nonlinearity Effect Revealed by NGC 5128 (Centaurus A) and NGC 4594 (Sombrero) Galaxies | Metallicity distributions (MDs) of globular clusters (GCs) provide crucial clues for the assembly and star formation history of their host galaxies. GC colors, when GCs are old, have been used as a proxy of GC metallicities. Bimodal GC color distributions (CDs) observed in most early-type galaxies have been interpreted as bimodal MDs for decades, suggesting the presence of merely two GC subpopulations within single galaxies. However, the conventional view has been challenged by a new theory that nonlinear metallicity-to-color conversion can cause bimodal CDs from unimodal MDs. The unimodal MDs seem natural given that MDs involved many thousand protogalaxies. The new theory has been tested and corroborated by various observational and theoretical studies. Here we examine the nonlinear nature of GC color-metallicity relations (CMRs) using photometric and spectroscopic GC data of NGC 5128 (Centaurus A) and NGC 4594 (Sombrero), in comparison with stellar population simulations. We find that, with a slight offset in color, the overall shapes of observed and modeled CMRs agree well for all available colors. Diverse color-depending morphologies of GC CDs of the two galaxies are well reproduced based on their observed spectroscopic MDs via our CMR models. The results corroborate the nonlinear CMR interpretation of the GC color bimodality, shedding further light on theories of galaxy formation. | [
"Physics Archive->astro-ph->astro-ph.GA"
]
| 2022-09-06T18:02:02Z |
2309.12076 | Super-resolution and super-sensitivity of quantum LiDAR with multi-photonic state and binary outcome photon counting measurement | Here we are investigating the enhancement in phase sensitivity and resolution in Mach-Zehnder interferometer (MZI) based quantum LiDAR. We are using multi-photonic state (MPS), superposition of four coherent states [1], as the input state and binary outcome parity photon counting measurement and binary outcome zero-nonzero photon counting measurement as the measurement schemes. We thoroughly investigate the results in lossless as well as in lossy cases. We found enhancement in resolution and phase sensitivity in comparison to the coherent state and even coherent superposition state (ECSS) based quantum LiDAR. Our analysis shows that MPS may be an alternative nonclassical resource in the field of quantum imaging and quantum sensing technologies, like in quantum LiDAR. | [
"Physics Archive->physics->physics.optics",
"Physics Archive->quant-ph"
]
| 2023-09-21T13:46:26Z |
1712.03908 | `Sinking' in a bed of grains activated by shearing | We show how a weak force, $f$, enables intruder motion through dense granular materials subject to external mechanical excitations, in the present case stepwise shearing. A force acts on a Teflon disc in a two dimensional system of photoelastic discs. This force is much smaller than the smallest force needed to move the disc without any external excitation. In a cycle, material + intruder are sheared quasi-statically from $\gamma = 0$ to $\gamma_{max}$, and then backwards to $\gamma = 0$. During various cycle phases, fragile and jammed states form. Net intruder motion, $\delta$, occurs during fragile periods generated by shear reversals. $\delta$ per cycle, e.g. the quasistatic rate $c$, is constant, linearly dependent on $\gamma_{max}$ and $f$. It vanishes as, $c \propto (\phi_c - \phi)^a$, with $a \simeq 3$ and $\phi_c \simeq \phi_J$, reflecting the stiffening of granular systems under shear as $\phi \rightarrow \phi_J$. The intruder motion induces large scale grain circulation. In the intruder frame, this motion is a granular analogue to fluid flow past a cylinder, where $f$ is the drag force exerted by the flow. | [
"Physics Archive->cond-mat->cond-mat.soft",
"Physics Archive->cond-mat->cond-mat.stat-mech"
]
| 2017-12-11T17:33:14Z |
astro-ph/0008471 | Physical Diagnostics from a Narrow Fe-Kalpha Emission Line Detected by Chandra in the Seyfert 1 Galaxy NGC 5548 | We report the detection of a narrow Fe-K emission line in the Seyfert 1 galaxy NGC 5548 with the Chandra High-Energy Transmission Gratings. In the galaxy frame we measure a center energy of 6.40 \pm 0.03 keV, a FWHM of 4515 (+3525,-2645) km/s, and an equivalent width of 133 (+62,-54) eV. The line energy is consistent with an origin in cold, neutral matter, but ionization states up to ~Fe XVIII are not ruled out. Assuming Keplerian motion, the velocity width is consistent with the line being produced in the outer optical/UV broad-line region (BLR) at about a light-month from the central X-ray source. We cannot rule out some contribution to the Fe-K line from a putative, parsec-scale obscuring torus. The continuum intensity during the Chandra observation was a factor ~2 less than typical historical levels. If the X-ray continuum was > than a factor 2 higher in the recent past before the Chandra observation and the narrow Fe-K line intensity had not yet responded, then the predicted line equivalent width and intensity for an origin in the BLR is within the 90% measurement errors. Retroactive spectral fitting of archival ASCA data shows evidence that the narrow Fe-K has a variable intensity. It will be important to measure the non-disk component of the Fe-K line in other AGN to obtain a more complete understanding of the total Fe-K line emission. Measurement of the narrow-line parameters provides powerful diagnostics of conditions beyond the accretion disk and is necessary to properly deconvolve the broad, relativistic Fe-K line. | [
"Physics Archive->astro-ph"
]
| 2000-08-30T00:46:07Z |
0904.2854 | Probing semiclassical magneto-oscillations in the low-field quantum Hall effect | The low-field quantum Hall effect is investigated on a two-dimensional electron system in an AlGaAs/GaAs heterostructure. Magneto-oscillations following the semiclassical Shubnikov-de Haas formula are observed even when the emergence of the mobility gap shows the importance of quantum localization effects. Moreover, the Lifshitz-Kosevich formula can survive as the oscillating amplitude becomes large enough for the deviation to the Dingle factor. The crossover from the semiclassical transport to the description of quantum diffusion is discussed. From our study, the difference between the mobility and cyclotron gaps indicates that some electron states away from the Landau-band tails can be responsible for the semiclassical behaviors under low-field Landau quantization. | [
"Physics Archive->cond-mat->cond-mat.dis-nn"
]
| 2009-04-18T13:39:16Z |
0806.1146 | Comment to: "A note on failure of the ladder approximation to QCD" [Phys. Lett. B 640 (2006) 196 ] | In the paper [Hong-Shi Zong, Wei-Min Sun, Phys. Lett. B 640 (2006) 196], the authors claim that our proof of the inconsistency of the ladder approximation to QCD [Phys. Lett. B 611 (2005) 129] was incorrect. However, their claim is based on a derivation which contains a rough mathematical mistake, namely the unjustified change of variables in the divergent (though regularized) integrals. In this comment I will show this explicitly, so our conclusion that the ladder approximation to QCD is inconsistent remains, of course, correct. | [
"Physics Archive->hep->hep-ph",
"Physics Archive->hep->hep-th"
]
| 2008-06-06T12:41:08Z |
astro-ph/0312656 | Keck IR Spectroscopy of WZ Sge: Detection of Molecular Emission from the Accretion Disk | Time-resolved IR spectroscopy of WZ Sge was obtained using NIRSPEC on Keck II. We detect CO and H$_{\rm 2}$ emission from the accretion disk placing WZ Sge into a rarefied class of astronomical objects including YSOs and high luminosity early-type stars. During the eclipse phase, the molecular emission greatly weakens but no firm evidence for the secondary star is seen allowing new limits on its luminosity to be determined. The detection of molecular emission provides physical properties within the outer disk of T=3000K and N$_H$$>10^{10}$ cm$^{-3}$. Such a cool, dense region, not associated with areas of H I and He I emission, provides the first observational confirmation of predictions made by accretion disk models. | [
"Physics Archive->astro-ph"
]
| 2003-12-31T18:05:57Z |
2009.06465 | Conformally invariant complete metrics | For a domain $G$ in the one-point compactification $\overline{\mathbb{R}}^n = \mathbb{R}^n \cup \{ \infty\}$ of $\mathbb{R}^n, n \ge 2$, we characterize the completeness of the modulus metric $\mu_G$ in terms of a potential-theoretic thickness condition of $\partial G\,,$ Martio's $M$-condition. Next, we prove that $\partial G$ is uniformly perfect if and only if $\mu_G$ admits a minorant in terms of a M\"obius invariant metric. Several applications to quasiconformal maps are given. | [
"Mathematics Archive->math.CV"
]
| 2020-09-14T14:22:57Z |
2002.02174 | Superconductivity of Carbon Compounds with Sodalite Structure | We investigate the superconductivity of carbon compounds with a sodalite structure, which are similar to hydrogen compounds showing the high-temperature superconductivity. A systematic analysis by first-principles calculations is carried out, including examination of mechanical and dynamic instabilities under external pressure $P$. These instabilities are classified on the phase diagram for the effective doping charge versus the lattice constant of the system. We also present the superconducting transition temperature $T_{\rm c}$ as a function of $P$ for many carbon compounds and a pure carbon system with the sodalite structure. Some of them have $T_{\rm c}$ of up to about 100 K at $P > \sim 30$ GPa, and the results suggest that the sodalite structure of carbon may be a key to producing phonon-mediated high-$T_{\rm c}$ superconductivity. | [
"Physics Archive->cond-mat->cond-mat.supr-con"
]
| 2020-02-06T09:47:55Z |
1003.5114 | Sunspot umbra atmosphere from full Stokes inversion | Sunspots are prominent manifestations of the solar cycle and provide key constraints for understanding its operation. Also, knowing internal structure of sunspots allows us to gain insights on the energy transport in strong magnetic fields and, thus, on the processes inside the convection zone, where solar magnetic fields are generated and amplified before emerging at the surface on various scales, even during solar minima. In this paper, we present results of a spectropolarimetric analysis of a sunspot observed during the declining phase of the solar cycle 23. By inversion of full Stokes spectra observed in several spectral regions in the optical at the THEMIS facility we infer the height dependence of physical quantities such as the temperature and the magnetic field strength for different sunspot regions. The simultaneous use of atomic (Fe{\sc i} 5250.2 and 5250.6 \AA) and highly temperature sensitive molecular (TiO 7055 \AA and MgH 5200 \AA) lines allow us to improve a model of the sunspot umbra. | [
"Physics Archive->astro-ph->astro-ph.SR"
]
| 2010-03-26T11:02:39Z |
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