cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
CRAFT (Cosmic Ray Acceleration From Turbulence) in Molecular Clouds
Creators: name: Gaches, Brandt A. L.
name: Walch, Stefanie
name: Lazarian, Alex
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Low-energy cosmic rays, in particular protons with energies below 1 GeV, are significant drivers of the thermochemistry of molecular clouds. However, these cosmic rays are also greatly impacted by energy losses and magnetic field transport effects in molecular gas. Explaining cosmic ray ionization rates of $10^{-16}$ s$^{-1}$ or greater in dense gas requires either a high external cosmic ray flux, or local sources of MeV-GeV cosmic ray protons. We present a new local source of low-energy cosmic rays in molecular clouds: first order Fermi-acceleration of protons in regions undergoing turbulent reconnection in molecular clouds. We show from energetic-based arguments there is sufficient energy within the magneto-hydrodynamic turbulent cascade to produce ionization rates compatible with inferred ionization rates in molecular clouds. As turbulent reconnection is a volume-filling process, the proposed mechanism can produce a near-homogeneous distribution of low-energy cosmic rays within molecular clouds.
description: Accepted for publication by ApJL
On equilibrium equations and their perturbations using three different variational formulations of nonlinear electroelastostatics
Creators: name: Saxena, Prashant
name: Sharma, Basant Lal
Publisher: name: arXiv
Year: 2019
Subjects: subject: Classical Physics (physics.class-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 74F15, 74B15

description: We derive the equations of nonlinear electroelastostatics using three different variational formulations involving the deformation function and an independent field variable representing the electric character - considering either one of the electric field $\mathbb{E}$, electric displacement $\mathbb{D}$, or electric polarization $\mathbb{P}$. The first variation of the energy functional results in the set of Euler-Lagrange partial differential equations which are the equilibrium equations, boundary conditions, { and certain constitutive equations} for the electroelastic system. The partial differential equations for obtaining the bifurcation point have been also found using the second variation based bilinear functional. We show that the well-known Maxwell stress in vacuum is a natural outcome of the derivation of equations from the variational principles and does not depend on the formulation used. As a result of careful analysis it is found that there are certain terms in the bifurcation equation which appear difficult to obtain by an ordinary perturbation based analysis of the Euler-Lagrange equation. From a practical viewpoint, the formulations based on $\mathbb{E}$ and $\mathbb{D}$ result in simpler equations and are anticipated to be more suitable for analysing problems of stability as well as post-buckling behaviour.
description: Accepted for publication in Mathematics and Mechanics of Solids
Halo Mass-Concentration Relation at High-Mass End
Creators: name: Xu, Weiwei
name: Shan, Huanyuan
name: Li, Ran
name: Wang, Chunxiang
name: Jiang, Linhua
name: Jullo, Eric
name: Favole, Ginevra
name: Kneib, Jean-Paul
name: Zhang, Chaoli
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The concentration-mass (c-M) relation encodes the key information of the assembly history of the dark matter halos, however its behavior at the high mass end has not been measured precisely in observations yet. In this paper, we report the measurement of halo c-M relation with galaxy-galaxy lensing method, using shear catalog of the Dark Energy Camera Legacy Survey (DECaLS) Data Release 8, which covers a sky area of 9500 deg^2. The foreground lenses are selected from redMaPPer, LOWZ, and CMASS catalogs, with halo mass range from 10^{13} to 10^{15} M_sun and redshift range from z=0.08 to z=0.65. We find that the concentration decreases with the halo mass from 10^{13} to 10^{14} M_sun, but shows a trend of upturn after the pivot point of ~10^{14} M_sun. We fit the measured c-M relation with the concentration model c(M)=C_0 (M/(10^{12} M_sun/h)^{-γ} [1+(M/M_0)^{0.4}], and get the values (C_0, γ, log(M_0) = (5.119_{-0.185}^{0.183}, 0.205_{-0.010}^{0.010}, 14.083_{-0.133}^{0.130}), and (4.875_{-0.208}^{0.209}, 0.221_{-0.010}^{0.010}, 13.750_{-0.141}^{0.142}) for halos with 0.08<=z<0.35 and 0.35<=z<0.65, respectively. We also show that the model including an upturn is favored over a simple power-law model. Our measurement provides important information for the recent argument of massive cluster formation process.
description: 12 pages, 5 figures, accepted by ApJ
Wave scattering on lattice structures involving array of cracks
Creators: name: Maurya, Gaurav
name: Sharma, Basant Lal
Publisher: name: arXiv
Year: 2019
Subjects: subject: Classical Physics (physics.class-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Scattering of waves due to a vertical array of equally-spaced cracks on a square lattice is studied. The convenience of Floquet periodicity reduces the study to that of scattering of specific wave-mode from single crack in a waveguide. The discrete Green's function, for the waveguide, is used to obtain semi-analytical solution for scattering problem in case of finite cracks whereas the limiting case of semi-infinite cracks is tackled by an application of Wiener--Hopf technique. Reflectance and transmittance of such an array of cracks, in terms of incident wave parameters, is analyzed. Potential applications include construction of tunable atomic scale interfaces to control energy transmission at different frequencies.
Topological properties of spin-triplet superconductors and the Fermi surface topology in the normal state
Creators: name: Sato, Masatoshi
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We report intimate relations between topological properties of full gapped spin-triplet superconductors with time-reversal invariance and the Fermi surface topology in the normal states. An efficient method to calculate the Z2 invariants and the winding number for the spin-triplet superconductors is developed, and connections between these topological invariants and the Fermi surface structures in the normal states are pointed out. We also obtain a correspondence between the Fermi surface topology and gapless surface states in the superconducting states. The correspondence is inherent to spin-triplet superconductivity.
description: 14 pages, 2 figures, 1 table, a table was added
Relic density and CMB constraints on dark matter annihilation with Sommerfeld enhancement
Creators: name: Zavala, Jesus
name: Vogelsberger, Mark
name: White, Simon D. M.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We calculate how the relic density of dark matter particles is altered when their annihilation is enhanced by the Sommerfeld mechanism due to a Yukawa interaction between the annihilating particles. Maintaining a dark matter abundance consistent with current observational bounds requires the normalization of the s-wave annihilation cross section to be decreased compared to a model without enhancement. The level of suppression depends on the specific parameters of the particle model, with the kinetic decoupling temperature having the most effect. We find that the cross section can be reduced by as much as an order of magnitude for extreme cases. We also compute the mu-type distortion of the CMB energy spectrum caused by energy injection from such Sommerfeld-enhanced annihilation. Our results indicate that in the vicinity of resonances, associated with bound states, distortions can be large enough to be excluded by the upper limit |mu|<9.0x10^(-5) found by the COBE/FIRAS experiment.
description: 10 pages, 6 figures, accepted for publication in Physical Review D. Corrections to eqs. 9,10,14 and 16. Figures updated accordingly. No major changes to previous results. Website with online tools for Sommerfeld-related calculations can be found at http://www.mpa-garching.mpg.de/~vogelsma/sommerfeld/
ANALYSIS OF RURAL SETTLEMNTS EXPANSION PATTERN: A Case Study of Sachibunia Village Under Batiaghata Upazila in Khulna District
Creators: name: Sikder, Sujit Kumar
Publisher: name: Zenodo
Year: 2021
Subjects: Rural settlement structure
Settlement expansion pattern
Coastal Bangladesh
Khulna University
Coastal settlement
urban-rural linkage
sub-urbanisation

description: Usually, settlements grow with the increase of population. The word ‘settlements’ denotes a village where a group of people have come to live and make their homes, usually where few or no people lived before. It is conspicuous that settlements are not only the built-up part made by man but all the space–natural or man-made, used by man. Expansion of rural settlement means human behaviours that are created as a physical environment in an area. The physical environment can be treated as settlement form and pattern or chronological area coverage.
 Bangladesh, with an agrarian socio-economic base, is dominated by a rural settlement structure. About 76.61% populations live in rural Bangladesh. Land pressures and land-use conflicts are seen in rural Bangladesh. Because Horizontal expansion is very common than vertical expansion. Land resource is limited. The Land-man ratio is only 26 decimal in Bangladesh. Expansion of the rural settlements make more pressure on agriculture and the agricultural land is decreasing. The settlements expansion guidelines are necessary for the optimum utilisation of limited land resources in rural areas of Bangladesh.
 In Sachibunia village the settlement has been expanding rapidly for the last fifteen years. Here the settlement area is increasing rapidly due to some responsible factors. The present study has analysed the responsible factors of settlement expansion under the following categories: a) Demographic, b) Physical, c) Economic, d) Socio-political and e) Environmental. The development of Rupsha bypass road plays a great impact on the expansion of settlement. The establishment of Khulna University and other institutions lead the growing trend of Khulna city towards southwest direction have also some influence on the expansion of settlement in Sachibunia village.
 Rapid settlements expansion make more pressure on agricultural land. So it is necessary to manage the expansion of settlements in a planned way.
description: A part of this work has been published in: https://www.amazon.com/RURAL-SETTLEMNTS-EXPANSION-PATTERN-BANGLADESH/dp/3639163559 Publisher: VDM Verlag (2010)ISBN: ISBN 10: 3639163559 / ISBN 13: 9783639163551 Edition: 2010
Stochastic Resonance in Time-delayed Bistable Systems Driven by Weak Periodic Signal
Creators: name: Shao, Rui-Hua
name: Chen, Yong
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We study theoretically a bistable systems with time-delayed feedback driven by weak periodic force. The effective potential function and the steady-state probability density are derived. The delay time and the strength of its feedback can change the shapes of the potential wells. In the adiabatic approximation, the signal-to-noise ratio (SNR) of the system with a weak periodic force is obtained. The time-delayed feedback modulates the magnitude of SNR by changing the shape of the potential and the effective strength of signal. The maximum of SNR decreases with increasing the feedback intensity $ε$. When $ε$ is negative (or positive), the time delay can suppress (or promote) the stochastic resonance phenomenon.
description: 5 pages, 3 figures. any comment are favored
Entanglement in a spin system with inverse square statistical interaction
Creators: name: Giuliano, D.
name: Sindona, A.
name: Falcone, G.
name: Plastina, F.
name: Amico, L.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We investigate the entanglement content of the ground state of a system characterized by effective elementary degrees of freedom with fractional statistics. To this end, we explicitly construct the ground state for a chain of $N$ spins with inverse square interaction (the Haldane-Shastry model) in the presence of an external uniform magnetic field. For such a system at zero temperature, we evaluate the entanglement in the ground state both at finite size and in the thermodynamic limit. We relate the behavior of the quantum correlations with the spinon condensation phenomenon occurring at the saturation field.
description: 11 pages, 7 eps figures. Submitted to New. J. Phys, special issue "Quantum Information and Many-Body Theory"(co-edited by J Eisert and M Plenio)
Symplectic $T_7$, $T_8$ singularities and Lagrangian tangency orders
Creators: name: Domitrz, Wojciech
name: Trȩbska, Żaneta
Publisher: name: arXiv
Year: 2010
Subjects: subject: Symplectic Geometry (math.SG)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: Primary 53D05. Secondary 14H20, 58K50, 58A10

description: We study the local symplectic algebra of curves. We use the method of algebraic restrictions to classify symplectic $T_7$ singularities. We define discrete symplectic invariants - the Lagrangian tangency orders. We use these invariants to distinguish symplectic singularities of classical $A-D-E$ singularities of planar curves, $S_5$ singularity and $T_7$ singularity. We also give the geometric description of these symplectic singularities.
Justifying Kubo's formula for gapped systems at zero temperature: a brief review and some new results
Creators: name: Henheik, Joscha
name: Teufel, Stefan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: 81Q15, 81Q20, 81V70

description: We first review the problem of a rigorous justification of Kubo's formula for transport coefficients in gapped extended Hamiltonian quantum systems at zero temperature. In particular, the theoretical understanding of the quantum Hall effect rests on the validity of Kubo's formula for such systems, a connection that we review briefly as well. We then highlight an approach to linear response theory based on non-equilibrium almost-stationary states (NEASS) and on a corresponding adiabatic theorem for such systems that was recently proposed and worked out by one of us in [51] for interacting fermionic systems on finite lattices. In the second part of our paper we show how to lift the results of [51] to infinite systems by taking a thermodynamic limit.
description: 25 pages, 1 figure; final version; Contribution to the proceedings of QMath14 in Aarhus 2019
The statistical mechanics of near-extremal black holes
Creators: name: Iliesiu, Luca V.
name: Turiaci, Gustavo J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: An important open question in black hole thermodynamics is about the existence of a "mass gap" between an extremal black hole and the lightest near-extremal state within a sector of fixed charge. In this paper, we reliably compute the partition function of Reissner-Nordström near-extremal black holes at temperature scales comparable to the conjectured gap. We find that the density of states at fixed charge does not exhibit a gap; rather, at the expected gap energy scale, we see a continuum of states. We compute the partition function in the canonical and grand canonical ensembles, keeping track of all the fields appearing through a dimensional reduction on $S^2$ in the near-horizon region. Our calculation shows that the relevant degrees of freedom at low temperatures are those of $2d$ Jackiw-Teitelboim gravity coupled to the electromagnetic $U(1)$ gauge field and to an $SO(3)$ gauge field generated by the dimensional reduction.
description: 54 pp; v3 Corrected statements on page 11 regarding validity of gluing procedure
A Class of Anisotropic Five-Dimensional Solutions for the Early Universe
Creators: name: de Leon, J. Ponce
name: Wesson, P. S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We solve the Ricci-flat equations of extended general relativity to obtain an interesting class of cosmological models. The solutions are analogous to the 4D ones of Bianchi type-I of Kasner type and have significant implications for astrophysics.
description: V2 has some minor editorial changes in the introduction
M2 signatures in psi(2S) radiative decays
Creators: name: Rosner, Jonathan L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The sensitivity of observables in radiative decays psi(2S) -> gamma chi_{1,2} -> gamma gamma J/psi to quadrupole (M2) admixtures in the dominant electric dipole (E1) transitions is explored. Emphasis is placed on distributions in a single angle, and several examples are given.
description: 8 pages, 4 figures, to be submitted to Phys. Rev. D. Additional data and reference
Difficulties Distinguishing Dark Energy from Modified Gravity via Redshift Distortions
Creators: name: Simpson, Fergus
name: Peacock, John A.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The bulk motion of galaxies induced by the growth of cosmic structure offers a rare opportunity to test the validity of general relativity across cosmological scales. However, modified gravity can be degenerate in its effect with the unknown values of cosmological parameters. More seriously, even the `observed' value of the RSD (redshift-space distortions) used to measure the fluctuation growth rate depends on the assumed cosmological parameters (the Alcock-Paczynski effect). We give a full analysis of these issues, showing how to combine RSD with BAO (baryon acoustic oscillations) and CMB (Cosmic Microwave Background) data, in order to obtain joint constraints on deviations from general relativity and on the equation of state of dark energy whilst allowing for factors such as non-zero curvature. In particular we note that the evolution of Omega_m(z), along with the Alcock-Paczynski effect, produces a degeneracy between the equation of state w and the modified growth parameter gamma. Typically, the total marginalized error on either of these parameters will be larger by a factor ~ 2 compared to the conditional error where one or other is held fixed. We argue that future missions should be judged by their Figure of Merit as defined in the w_p - gamma plane, and note that the inclusion of spatial curvature can degrade this value by an order of magnitude.
description: 7 pages, 4 figures, minor changes reflect published version
Null Lagrangians in linear theories of micropolar type and few other generalizations of elasticity
Creators: name: Basak, Nirupam
name: Sharma, Basant Lal
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences
subject: 74A35

description: In the context of linear theories of generalized elasticity including those for homogeneous micropolar media, quasicrystals, piezoelectric and piezomagnetic media, we explore the concept of null Lagrangians. For obtaining the family of null Lagrangians we employ the sufficient conditions of H. Rund. In some cases a non-zero null Lagrangian is found and the stored energy admits a split into a null Lagrangian and a remainder. However, the null Lagrangian vanishes whenever the relevant elasticity tensor obeys certain symmetry conditions which can be construed as an analogue of the Cauchy relations.
Eta invariants for flat manifolds
Creators: name: Szczepanski, Andrzej
Publisher: name: arXiv
Year: 2010
Subjects: subject: Differential Geometry (math.DG)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 58J28

description: Using H. Donnelly result from the article "Eta Invariants for G-Spaces" we calculate the eta invariants of the signature operator for almost all 7-dimensional flat manifolds with cyclic holonomy group. In all cases this eta invariants are an integer numbers. The article was motivated by D. D. Long and A. Reid article "On the geometric boundaries of hyperbolic 4-manifolds, Geom. Topology 4, 2000, 171-178
description: 18 pages, a new version with referees comments
Discrete scattering by two staggered semi-infinite defects: reduction of matrix Wiener-Hopf problem
Creators: name: Sharma, Basant Lal
Publisher: name: arXiv
Year: 2019
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: As an extension of the discrete Sommerfeld problems on lattices, the scattering of a time harmonic wave is considered on an infinite square lattice when there exists a pair of semi-infinite cracks or rigid constraints. Due to the presence of stagger, also called offset, in the alignment of the defect edges the asymmetry in the problem leads to a matrix Wiener-Hopf kernel that cannot be reduced to scalar Wiener-Hopf in any known way. In the corresponding continuum model the same problem is a well known formidable one which possesses certain special structure with exponentially growing elements on the diagonal of kernel. From this viewpoint the present paper tackles a discrete analogue of the same by reformulating the Wiener-Hopf problem and reducing it to a finite set of linear algebraic equations; the coefficients of which can be found by an application of the scalar Wiener-Hopf factorization. The considered discrete paradigm involving lattice waves is relevant for modern applications of mechanics and physics at small length scales.
Georges Seurat, "Une baignade à Asnières"
Creators: name: Thom, Ian MacEwan
Publisher: name: University of British Columbia
Year: 2010

description: Since its completion in 1884, Georges-Pierre Seurat's "Une Baignade à Asnières" has been regarded in formal terms. The work has been seen as an important formal study, which is an only partially successful synthesis of his artistic antecedents: the subject matter, and to a considerable extent the style of the impressionists, modified by the artist's study of Delacroix's use of colour, the theory of Ogden Rood, and Ingrist and Puvean classicism. It is the contention of this writer that this approach, which ignores such factors as the class of the figures and the location of the scene - or in short, the subject matter - in fact misses the main thesis of the work. By examining Seurat's career before the "Baignade", and the circumstances of its creation, we hope to suggest that far from being devoid of meaningful content, the work is to be seen as an ironic and critical social comment. The workingmen are here at leisure, and yet far from being free and happy; they are condemned to conditions which make their leisure worse than none at all. This idea is what Seurat intended to convey to the art-viewing boureoisie. Although the means are subtle, a careful examination of the pictorial evidence makes the conclusion inevitable.
Post-Newtonian and Numerical Calculations of the Gravitational Self-Force for Circular Orbits in the Schwarzschild Geometry
Creators: name: Blanchet, Luc
name: Detweiler, Steven
name: Tiec, Alexandre Le
name: Whiting, Bernard F.
Publisher: name: arXiv
Year: 2009
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The problem of a compact binary system whose components move on circular orbits is addressed using two different approximation techniques in general relativity. The post-Newtonian (PN) approximation involves an expansion in powers of v/c<<1, and is most appropriate for small orbital velocities v. The perturbative self-force (SF) analysis requires an extreme mass ratio m1/m2<<1 for the components of the binary. A particular coordinate-invariant observable is determined as a function of the orbital frequency of the system using these two different approximations. The post-Newtonian calculation is pushed up to the third post-Newtonian (3PN) order. It involves the metric generated by two point particles and evaluated at the location of one of the particles. We regularize the divergent self-field of the particle by means of dimensional regularization. We show that the poles proportional to 1/(d-3) appearing in dimensional regularization at the 3PN order cancel out from the final gauge invariant observable. The 3PN analytical result, through first order in the mass ratio, and the numerical SF calculation are found to agree well. The consistency of this cross cultural comparison confirms the soundness of both approximations in describing compact binary systems. In particular, it provides an independent test of the very different regularization procedures invoked in the two approximation schemes.
description: 36 pages, 3 figures; matches the published version
Wave transmission across surface interfaces in lattice structures
Creators: name: Sharma, Basant Lal
name: Eremeyev, Victor A.
Publisher: name: arXiv
Year: 2019
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: Within the lattice dynamics formulation, we present an exact solution for anti-plane surface waves in a square lattice strip with a surface row of material particles of two types separated by a linear interface. The considered problem is a discrete analog of an elastic half-space with surface stresses modelled through the simplified Gurtin-Murdoch model, where we have an interfacial line separating areas with different surface elastic properties. The main attention is paid to the transmittance and the reflectance of a wave across the interface. The presented results shed a light on the influence on surface waves of surface inhomogeneity in surface elastic properties such as grain and subgrain boundaries.
A new proof of the Voronoï summation formula
Creators: name: Egger, Sebastian
name: Steiner, Frank
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We present a short alternative proof of the Voronoï summation formula which plays an important role in Dirichlet's divisor problem and has recently found an application in physics as a trace formula for a Schrödinger operator on a non-compact quantum graph \mathfrak{G} [S. Egger né Endres and F. Steiner, J. Phys. A: Math. Theor. 44 (2011) 185202 (44pp)]. As a byproduct we give a new proof of a non-trivial identity for a particular Lambert series which involves the divisor function d(n) and is identical with the trace of the Euclidean wave group of the Laplacian on the infinite graph \mathfrak{G}.
description: Enlarged version of the published article J. Phys. A: Math. Theor. 44 (2011) 225302 (11pp)
Planetesimals on eccentric orbits erode rapidly
Creators: name: Cedenblad, Lukas
name: Schaffer, Noemi
name: Johansen, Anders
name: Mehlig, B.
name: Mitra, Dhrubaditya
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We investigate the possibility of erosion of planetesimals in a protoplanetary disk. We use theory and direct numerical simulations (Lattice Boltzmann Method) to calculate the erosion of large -- much larger than the mean-free-path of gas molecules -- bodies of different shapes in flows. We find that erosion follows a universal power-law in time, at intermediate times, independent of the Reynolds number of the flow and the initial shape of the body. Consequently, we estimate that planetesimals in eccentric orbits, of even very small eccentricity, rapidly (in about hundred years) erodes away if the semi-major axis of their orbit lies in the inner disk -- less than about $10$ au. Even planetesimals in circular orbits erode away in approximately ten thousand years if the semi-major axis of their orbits are $\lessapprox 0.6$au.
description: Accepted for publication in Astrophysical J
Growth of high $L^p$ norms for eigenfunctions: an application of geodesic beams
Creators: name: Canzani, Yaiza
name: Galkowski, Jeffrey
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics

description: This work concerns $L^p$ norms of high energy Laplace eigenfunctions, $(-Δ_g-λ^2)ϕ_λ=0$, $\|ϕ_λ\|_{L^2}=1$. In 1988, Sogge gave optimal estimates on the growth of $\|ϕ_λ\|_{L^p}$ for a general compact Riemannian manifold. The goal of this article is to give general dynamical conditions guaranteeing quantitative improvements in $L^p$ estimates for $p>p_c$, where $p_c$ is the critical exponent. We also apply previous results of the authors to obtain quantitative improvements in concrete geometric settings including all product manifolds. These are the first results improving estimates for the $L^p$ growth of eigenfunctions that only require dynamical assumptions. In contrast with previous improvements, our assumptions are local in the sense that they depend only on the geodesics passing through a shrinking neighborhood of a given set in $M$. Moreover, the article gives a structure theorem for eigenfunctions which saturate the quantitatively improved $L^p$ bound. Modulo an error, the theorem describes these eigenfunctions as finite sums of quasimodes which, roughly, approximate zonal harmonics on the sphere scaled by $1/\sqrt{\log λ}$.
description: 51 pages, 2 figures, added Theorem 2 describing the structure of near extremal eigenfunctions has been added
Contractions of product density operators of systems of identical fermions and bosons
Creators: name: Radzki, Wiktor
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Recurrence and explicit formulae for contractions (partial traces) of antisymmetric and symmetric products of identical trace class operators are derived. Contractions of product density operators of systems of identical fermions and bosons are proved to be asymptotically equivalent to, respectively, antisymmetric and symmetric products of density operators of a single particle, multiplied by a normalization integer. The asymptotic equivalence relation is defined in terms of the thermodynamic limit of expectation values of observables in the states represented by given density operators. For some weaker relation of asymptotic equivalence, concerning the thermodynamic limit of expectation values of product observables, normalized antisymmetric and symmetric products of density operators of a single particle are shown to be equivalent to tensor products of density operators of a single particle. This paper presents the results of a part of the author's thesis [W. Radzki, "Kummer contractions of product density matrices of systems of $n$ fermions and $n$ bosons" (Polish), MS thesis, Institute of Physics, Nicolaus Copernicus University, Toruń, 1999].
description: 20 pages. The manuscript has been shortened. A few typos corrected
Routing Emergency Vehicles in Arterial Road Networks using Real-time Mixed Criticality Systems*
Creators: name: Humagain, Subash
name: Sinha, Roopak
Publisher: name: arXiv
Year: 2021
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Reducing the response time of Emergency Vehicles (EVs) has an undoubted advantage in saving life and property. Implementing pre-emption can aid in achieving it. EVs get unobstructed movement via pre-emption, usually by altering traffic signals and giving a green wave throughout the route. This approach of absolute pre-emption effects adversely on regular traffic by imposing unnecessary waiting. In this paper, we propose a novel emergency vehicle pre-emption (EVP) algorithm implemented in the Vehicular Ad-hoc Network (VANET) that can reduce the imposed undesirable waiting time, but still ascertains EVs meet target response time. We introduce mixed-criticality real-time system scheduling concept where different level of emergencies is mapped with different criticality levels and assign certain success assurance level to respective criticality. We implemented the EVP algorithm for an arterial traffic network and leveraged the use of valuable information that gets transmitted via VANET to make critical decisions. The proposed algorithm can significantly reduce the average waiting time of regular traffic. It also ascertains all EVs with different level of criticality meet target response time respective to their assurance level.
description: Conference paper, 6 pages, 7 figures
Perturbed interpolation formulae and applications
Creators: name: Ramos, João P. G.
name: Sousa, Mateus
Publisher: name: arXiv
Year: 2020
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Functional Analysis (math.FA)
subject: Number Theory (math.NT)
subject: FOS: Mathematics

description: We employ functional analysis techniques in order to deduce that some classical and recent interpolation results in Fourier analysis can be suitably perturbed. As an application of our techniques, we obtain generalizations of Kadec's 1/4-theorem for interpolation formulae in the Paley-Wiener space both in the real and complex case, as well as a perturbation result on the recent Radchenko-Viazovska interpolation result and the Cohn-Kumar-Miller-Radchenko-Viazovska result for Fourier interpolation with derivatives in dimensions 8 and 24. We also provide several applications of the main results and techniques, all relating to recent contributions in interpolation formulae and uniqueness sets for the Fourier transform.
description: 53 pages
On the number of quadratic orthomorphisms that produce maximally nonassociative quasigroups
Creators: name: Drápal, Aleš
name: Wanless, Ian M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Combinatorics (math.CO)
subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics

description: Let $q$ be an odd prime power and suppose that $a,b\in\mathbb{F}_q$ are such that $ab$ and $(1{-}a)(1{-}b)$ are nonzero squares. Let $Q_{a,b} = (\mathbb{F}_q,*)$ be the quasigroup in which the operation is defined by $u*v=u+a(v{-}u)$ if $v-u$ is a square, and $u*v=u+b(v{-}u)$ is $v-u$ is a nonsquare. This quasigroup is called maximally nonassociative if it satisfies $x*(y*z) = (x*y)*z$ $\Leftrightarrow$ $x=y=z$. Denote by $σ(q)$ the number of $(a,b)$ for which $Q_{a,b}$ is maximally nonassociative. We show that there exist constants $α\approx 0.02908$ and $β\approx 0.01259$ such that if $q\equiv 1 \bmod 4$, then $\lim σ(q)/q^2 = α$, and if $q \equiv 3 \bmod 4$, then $\lim σ(q)/q^2 = β$.
Tile Embedding: A General Representation for Procedural Level Generation via Machine Learning
Creators: name: Jadhav, Mrunal
name: Guzdial, Matthew
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: In recent years, Procedural Level Generation via Machine Learning (PLGML) techniques have been applied to generate game levels with machine learning. These approaches rely on human-annotated representations of game levels. Creating annotated datasets for games requires domain knowledge and is time-consuming. Hence, though a large number of video games exist, annotated datasets are curated only for a small handful. Thus current PLGML techniques have been explored in limited domains, with Super Mario Bros. as the most common example. To address this problem, we present tile embeddings, a unified, affordance-rich representation for tile-based 2D games. To learn this embedding, we employ autoencoders trained on the visual and semantic information of tiles from a set of existing, human-annotated games. We evaluate this representation on its ability to predict affordances for unseen tiles, and to serve as a PLGML representation for annotated and unannotated games.
description: 8 pages, 5 figures, AIIDE 2021
Null Lagrangians in Cosserat elasticity
Creators: name: Sharma, Basant Lal
name: Basak, Nirupam
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: Differential Geometry (math.DG)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 74A35

description: In the framework of nonlinear theory of Cosserat elasticity, also called micropolar elasticity, we provide the complete characterization of null Lagrangians for three dimensional bodies as well as for shells. Using the Gibb's rotation vector for description of the microrotation, this task is possible by an application of a theorem stated by Olver and Sivaloganathan in `{the structure of null Lagrangians}' (Nonlinearity, {1}, 1988, pp. 389-398). A set of necessary and sufficient conditions is also provided for the elasticity tensors to correspond to a null Lagrangian in linearized micropolar theory.
Ethelurgus sodalis
Creators: name: Riedel
name: Pénigot
name: Schwarz
name: Diller
name: Johansson
name: Japoshvili, G.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Ichneumonidae
Ethelurgus
Ethelurgus sodalis

description: Ethelurgus sodalis (TASCHENBERG, 1865), det. Schwarz
M a t e r i a l e x a m i n e d: Trap 4: 1♀ 13-27.vii.
D i s t r i b u t i o n: Transpalaearctic, new record for Georgia and the Caucasus region.
description: Published as part of Riedel, Pénigot, Schwarz, Diller, Johansson & Japoshvili, G., 2023, Darwin wasps (Hymenoptera, Ichneumonidae) of the Kintrishi National Park, Sakartvelo (Georgia), with descriptions of six new species, pp. 61-153 in Linzer biologische Beiträge 55 (1) on page 122, DOI: 10.5281/zenodo.10415120
Adiabatic theorem in the thermodynamic limit: Systems with a gap in the bulk
Creators: name: Henheik, Joscha
name: Teufel, Stefan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences
subject: 81Q15, 81Q20, 81V70

description: We prove a generalised super-adiabatic theorem for extended fermionic systems assuming a spectral gap only in the bulk. More precisely, we assume that the infinite system has a unique ground state and that the corresponding GNS-Hamiltonian has a spectral gap above its eigenvalue zero. Moreover, we show that a similar adiabatic theorem also holds in the bulk of finite systems up to errors that vanish faster than any inverse power of the system size, although the corresponding finite volume Hamiltonians need not have a spectral gap.
description: 42 pages; final version
Opción National Survey: Uruguay April 1999
Creators: name: CIFRA, In Bogliaccini, Juan, And Queirolo Rosario Laboratorio De Opinión Pública And Redes Sociales En Uruguay Collection (Social Networks And Public Opinion Lab Collection)
Publisher: name: Roper Center for Public Opinion Research
Year: 2021

description: Economic situation of your family; financial expectations; important standards for voting; past voting history; political spectrum position; voting in national election; potential voting plans/choices; making voting decisions; personal effects of government on your family; voting in district election. National Agency for Research and Innovation (ANII) Collection.
Quasiparticle Nernst effect in the cuprate superconductors from the d-density wave theory of the pseudogap phase
Creators: name: Zhang, Chuanwei
name: Tewari, Sumanta
name: Chakravarty, Sudip
Publisher: name: arXiv
Year: 2009
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We consider the Nernst effect in the underdoped regime of the cuprate high temperature superconductors within the d-density wave (DDW) model of the pseudogap phase. By a combination of analytical and numerical arguments, we show that there is a robust low-temperature positive peak (i.e., maximum) in the temperature dependence of the Nernst coefficient when the DDW state is ambipolar, i.e., when the broken symmetry supports the coexistence of both electron- and hole-like quasiparticles in the excitation spectrum, and the electron pocket dominates at the low temperatures. In contrast, the Nernst coefficient is negative and there is no such positive peak if the underlying state is non-ambipolar, i.e., when it supports only one type of quasiparticles. More generally, in the ambipolar state, the sign of the Nernst coefficient can be positive or negative depending on the dominance of the electron or hole pockets, respectively, in the low temperature thermoelectric transport. By modeling the pseudogap phase by a doping-dependent DDW order parameter with a Fermi surface topology that supports both hole and electron pockets, and assuming energy-independent transport scattering times, we analyze the evolution of the Nernst effect with doping concentration at low temperatures in the cuprate phase diagram.
description: 10 pages, 6 eps figures, minor modification, accepted for publication in PRB
Creation and Evaluation of a Pre-tertiary Artificial Intelligence (AI) Curriculum
Creators: name: Chiu, Thomas K. F.
name: Meng, Helen
name: Chai, Ching-Sing
name: King, Irwin
name: Wong, Savio
name: Yam, Yeung
Publisher: name: arXiv
Year: 2021
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Contributions: The Chinese University of Hong Kong (CUHK)-Jockey Club AI for the Future Project (AI4Future) co-created an AI curriculum for pre-tertiary education and evaluated its efficacy. While AI is conventionally taught in tertiary level education, our co-creation process successfully developed the curriculum that has been used in secondary school teaching in Hong Kong and received positive feedback. Background: AI4Future is a cross-sector project that engages five major partners - CUHK Faculty of Engineering and Faculty of Education, Hong Kong secondary schools, the government and the AI industry. A team of 14 professors with expertise in engineering and education collaborated with 17 principals and teachers from 6 secondary schools to co-create the curriculum. This team formation bridges the gap between researchers in engineering and education, together with practitioners in education context. Research Questions: What are the main features of the curriculum content developed through the co-creation process? Would the curriculum significantly improve the students perceived competence in, as well as attitude and motivation towards AI? What are the teachers perceptions of the co-creation process that aims to accommodate and foster teacher autonomy? Methodology: This study adopted a mix of quantitative and qualitative methods and involved 335 student participants. Findings: 1) two main features of learning resources, 2) the students perceived greater competence, and developed more positive attitude to learn AI, and 3) the co-creation process generated a variety of resources which enhanced the teachers knowledge in AI, as well as fostered teachers autonomy in bringing the subject matter into their classrooms.
description: 8 pages 5 figures
An Escape from Vardanyan's Theorem
Creators: name: Borges, Ana de Almeida
name: Joosten, Joost J.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Logic (math.LO)
subject: FOS: Mathematics
subject: 03B45, 03B60, 03F03, 03F30, 03F45 (Primary) 03F55 (Secondary)

description: Vardanyan's Theorems state that $\mathsf{QPL}(\mathsf{PA})$ - the quantified provability logic of Peano Arithmetic - is $Π^0_2$ complete, and in particular that this already holds when the language is restricted to a single unary predicate. Moreover, Visser and de Jonge generalized this result to conclude that it is impossible to computably axiomatize the quantified provability logic of a wide class of theories. However, the proof of this fact cannot be performed in a strictly positive signature. The system $\mathsf{QRC}_1$ was previously introduced by the authors as a candidate first-order provability logic. Here we generalize the previously available Kripke soundness and completeness proofs, obtaining constant domain completeness. Then we show that $\mathsf{QRC}_1$ is indeed complete with respect to arithmetical semantics. This is achieved via a Solovay-type construction applied to constant domain Kripke models. As corollaries, we see that $\mathsf{QRC}_1$ is the strictly positive fragment of $\mathsf{QGL}$ and a fragment of $\mathsf{QPL}(\mathsf{PA})$.
description: Second installment of work presented in arXiv:2003.13651
Topologically slice knots with nontrivial Alexander polynomial
Creators: name: Hedden, Matthew
name: Livingston, Charles
name: Ruberman, Daniel
Publisher: name: arXiv
Year: 2010
Subjects: subject: Geometric Topology (math.GT)
subject: FOS: Mathematics
subject: 57M25

description: Let C_T be the subgroup of the smooth knot concordance group generated by topologically slice knots and let C_D be the subgroup generated by knots with trivial Alexander polynomial. We prove the quotient C_T/C_D is infinitely generated, and uncover similar structure in the 3-dimensional rational spin bordism group. Our methods also lead to the construction of links that are topologically, but not smoothly, concordant to boundary links.
description: 27 pages, 7 figures. Clarified discussion of Spinc structures; fixed some typos
Extending the Reach of Leptophilic Boson Searches at DUNE and MiniBooNE with Bremsstrahlung and Resonant Production
Creators: name: Capozzi, Francesco
name: Dutta, Bhaskar
name: Gurung, Gajendra
name: Jang, Wooyoung
name: Shoemaker, Ian M.
name: Thompson, Adrian
name: Yu, Jaehoon
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: New gauge bosons coupling to leptons are simple and well-motivated extensions of the Standard Model. We study the sensitivity to gauged $L_μ -L_{e}$, $L_e-L_τ$ and $L_μ -L_τ$ both with the existing beam dump mode data of MiniBooNE and with the DUNE near detector. We find that including bremsstrahlung and resonant production of $Z'$ which decays to $e^{\pm}$ and $μ^{\pm}$ final states leads to a significant improvement in existing bounds, especially for $L_μ-L_e$ and $L_e-L_τ$ for DUNE while competitive constraints can be achieved with the existing data from the MiniBooNE's beam dump run.
description: 10 pages, 4 figures