cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Infinite non-causality in active cancellation of random noise
Creators: name: Friot, Emmanuel
Publisher: name: arXiv
Year: 2005
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: Active cancellation of broadband random noise requires the detection of the incoming noise with some time advance. In an duct for example this advance must be larger than the delays in the secondary path from the control source to the error sensor. In this paper it is shown that, in some cases, the advance required for perfect noise cancellation is theoretically infinite because the inverse of the secondary path, which is required for control, can include an infinite non-causal response. This is shown to be the result of two mechanisms: in the single-channel case (one control source and one error sensor), this can arise because of strong echoes in the control path. In the multi-channel case this can arise even in free field simply because of an unfortunate placing of sensors and actuators. In the present paper optimal feedforward control is derived through analytical and numerical computations, in the time and frequency domains. It is shown that, in practice, the advance required for significant noise attenuation can be much larger than the secondary path delays. Practical rules are also suggested in order to prevent infinite non-causality from appearing.
Small scale induced gravitational waves from primordial black holes, a stringent lower mass bound, and the imprints of an early matter to radiation transition
Creators: name: Bhaumik, Nilanjandev
name: Jain, Rajeev Kumar
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In all inflationary scenarios of primordial black holes (PBH) formation, amplified scalar perturbations inevitably accompany an induced stochastic gravitational waves background (ISGWB) at smaller scales. In this paper, we study the ISGWB originating from the inflationary model, introduced in our previous paper [1] wherein PBHs can be produced with a nearly monochromatic mass fraction in the asteroid mass window accounting for the total dark matter in the universe. We numerically calculate the ISGWB in our scenario for frequencies ranging from nanoHz to KHz that covers the observational scales corresponding to future space based GW observatories such as IPTA, LISA, DECIGO and ET. Interestingly, we find that ultralight PBHs ($M_{\rm PBH} \sim 10^{-20} M_\odot$) which shall completely evaporate by today with exceedingly small contribution to dark matter, would still generate an ISGWB that may be detected by a future design of the ground based Advanced LIGO detector. Using a model independent approach, we obtain a stringent lower mass limit for ultralight PBHs which would be valid for a large class of ultra slow roll inflationary models. Further, we extend our formalism to study the imprints of a reheating epoch on both the ISGWB and the derived lower mass bound. We find that any non-instantaneous reheating leads to an even stronger lower bound on PBHs mass and an epoch of a prolonged matter dominated reheating shifts the ISGWB spectrum to smaller frequencies. In particular, we show that an epoch of an early matter dominated phase leads to a secondary amplification of ISGWB at much smaller scales corresponding to the smallest comoving scale leaving the horizon during inflation or the end of inflation scale. Finally, we discuss the prospects of the ISGWB detection by the proposed and upcoming GW observatories.
description: v1: 31 pages, 5 figures; v2: 33 pages, 5 figures, title slightly changed, version accepted for publication in Phys. Rev. D
Constraining beta(z) and Omega_m from redshift-space distortions in z~3 galaxy surveys
Creators: name: da Angela, J.
name: Outram, P. J.
name: Shanks, T.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We use sample of 813 Lyman-break galaxies (LBGs) with 2.6
description: Accepted for publication in MNRAS. 8 pages, 6 figures
Reservoir Computing for Short-reach Optical Communication
Creators: name: Da Ros, Francesco
Publisher: name: Zenodo
Year: 2021
Subjects: Optical Communication
Photonics
Reservoir Computing
Neural Networks

description: We reviewed two promising NN based equalizers for IM/DD transmission links:
 1. Time delay Feedforward Neural Networks
 • Trainable with backpropagation but with size growing linearly with the required memory
 2. Reservoir computing
 • Single ridge regression training but potentially more hardware demanding (high redundancy)

 Both schemes showed good improvement especially in conjunction with a novel spectrally sliced receiver proposed

 Simplified NN based equalizers are promising tools for extending the reach of IM/DD transmission systems
description: Further supported by: Villum Foundations (VYI grant OPTIC-AI no.29344)
The classical and quantum photon field for non-compact manifolds with boundary and in possibly inhomogeneous media
Creators: name: Strohmaier, Alexander
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mathematical Physics (math-ph)
subject: Analysis of PDEs (math.AP)
subject: Spectral Theory (math.SP)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 81T20, 35Q61, 81T55, 58A14

description: In this article I give a rigorous construction of the classical and quantum photon field on non-compact manifolds with boundary and in possibly inhomogeneous media. Such a construction is complicated by the presence of zero-modes that may appear in the presence of non-trivial topology of the manifold or the boundary. An important special case is $\mathbb{R}^3$ with obstacles. In this case the zero modes have a direct interpretation in terms of the topology of the obstacle. I give a formula for the renormalised stress energy tensor in terms of an integral kernel of an operator defined by spectral calculus of the Laplace Beltrami operator on differential forms with relative boundary conditions.
description: 32 pages, 2 figures, subtantial revision
Black Rings, Boosted Strings and Gregory-Laflamme
Creators: name: Hovdebo, J. L.
name: Myers, R. C.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We investigate the Gregory-Laflamme instability for black strings carrying KK-momentum along the internal direction. We demonstrate a simple kinematical relation between the thresholds of the classical instability for the boosted and static black strings. We also find that Sorkin's critical dimension depends on the internal velocity and in fact disappears for sufficiently large boosts. Our analysis implies the existence of an analogous instability for the five-dimensional black ring of Emparan and Reall. We also use our results for boosted black strings to construct a simple model of the black ring and argue that such rings exist in any number of space-time dimensions.
description: 26 pages, 6 figures
Evaluating Parametric Integrals in the Minkowski Regime without Contour Deformation
Creators: name: Jones, Stephen
name: Olsson, Anton
name: Stone, Thomas
Publisher: name: Scuola Internazionale Superiore di Studi Avanzati (SISSA)
Year: 2024

description: We present selected examples demonstrating an alternative approach to contour deformation for
numerically computing loop integrals in the Minkowski regime. This method focuses on identify-
ing singular hypersurfaces (varieties of the F polynomial) and mapping them to known points
which can then be resolved by employing blow-ups/sector decomposition techniques, thereby
avoiding the need for contour deformation. Using this technique, we achieve improved conver-
gence properties without the need for contour deformation, which is known to significantly in-
crease the complexity of the integrand by introducing, for example, derivatives of the F poly-
nomial and complicated Jacobians. We highlight that while we have only tested the approach on
selected one-, two- and three-loop massless and one-loop massive examples, it shows promise for
practical applications, offering potential benefits over the traditional approach. Evaluation times
are compared with existing contour deformation implementations to illustrate the performance of
this alternative method.
Ferromagnetic-electrodes-induced Hall effect in topological Dirac semimetals
Creators: name: Kobayashi, Koji
name: Nomura, Kentaro
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We propose an unconventional type of Hall effect in a topological Dirac semimetal with ferromagnetic electrodes. The topological Dirac semimetal itself has time-reversal symmetry, whereas attached ferromagnetic electrodes break it, causing the large Hall response. This induced Hall effect is a characteristic of the helical surface/edge states that arise in topological materials, such as topological Dirac semimetals or quantum spin Hall insulators. We compute the Hall conductance/resistance and the Hall angle by using a lattice model with four-terminal geometry. For topological Dirac semimetals with four electrodes, the induced Hall effect occurs whether the current electrodes or the voltage electrodes are ferromagnetic. When the spins in electrodes are almost fully polarized, the Hall angle becomes as large as that of quantum Hall states or ideal magnetic Weyl semimetals. We show the robustness of the induced Hall effect against impurities and also discuss the spin injection and spin decay problems. This Hall response can be used to detect whether the magnetizations of the two ferromagnetic electrodes are parallel or antiparallel.
description: 11 pages, 12 figures, published version
Restoration of U$_A$(1) symmetry and meson spectrum in hot or dense matter
Creators: name: Costa, Pedro
name: Ruivo, M. C.
name: de Sousa, C. A.
name: Kalinovsky, Yu. L.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We explore the effects of breaking and restoration of chiral and axial symmetries using an extended three-flavor Nambu-Jona-Lasinio model that incorporates explicitly the axial anomaly through the 't Hooft interaction. We implement a temperature (density) dependence of the anomaly coefficient motivated by lattice results for the topological susceptibility. The spectrum of scalar and pseudoscalar mesons is analyzed bearing in mind the identification of chiral partners and the study of its convergence. We also concentrate on the behavior of the mixing angles that give us relevant information on the issue under discussion. The results suggest that the axial part of the symmetry is restored before the possible restoration of the full U(3)$\otimes$U(3) chiral symmetry might occur.
description: 9 pages, 5 figures. Talk given at Joint Meeting Heidelberg-Liege-Paris-Rostock (HLPR 2004), Spa, Belgium, 16-18 Dec 2004
$T\bar{T}$ deformation of random matrices
Creators: name: Rosso, Felipe
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We define and study the $T\bar{T}$ deformation of a random matrix model, showing a consistent definition requires the inclusion of both the perturbative and non-perturbative solutions to the flow equation. The deformed model is well defined for arbitrary values of the coupling, exhibiting a phase transition for the critical value in which the spectrum complexifies. The transition is between a single and a double-cut phase, typically third order and in the same universality class as the Gross-Witten transition in lattice gauge theory. The $T\bar{T}$ deformation of a double scaled model is more subtle and complicated, and we are not able to give a compelling definition, although we discuss obstacles and possible alternatives. Preliminary comparisons with finite cut-off Jackiw-Teitelboim gravity are presented.
description: 27 pages. v2: references added. v3: updated to match published version
Parsec-scale Investigation of the Magnetic Field Structure of Several AGN Jets
Creators: name: O'Sullivan, Shane P.
name: Gabuzda, Denise C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Multi-frequency (4.6, 5, 5.5, 8, 8.8, 13, 15, 22 & 43 GHz) polarization observations of 6 "blazars" were obtained on the American Very Long Baseline Array (VLBA) over a 24-hr period on 2 July 2006. Observing at several frequencies, separated by short and long intervals, enabled reliable determination of the distribution of Faraday Rotation on a range of scales. In all cases the magnitude of the RM increases in the higher frequency observations, implying that the electron density and/or magnetic field strength is increasing as we get closer to the central engine. After correcting for Faraday rotation, the polarization orientation in the jet is either parallel or perpendicular to the jet direction. A transverse Rotation Measure (RM) gradient was detected in the jet of 0954+658, providing evidence for the presence of a helical magnetic field surrounding the jet. For three of the sources (0954+658, 1418+546, 2200+420), the sign of the RM in the core region changes in different frequency-intervals, indicating that the line-of-sight component of the magnetic field is changing with distance from the base of the jet. We suggest an explanation for this in terms of bends in a relativistic jet surrounded by a helical magnetic field; where there is no clear evidence for pc-scale bends, the same effect can be explained by an accelerating/decelerating jet.
description: 4 pages, 5 figures for the proceedings of 'High Energy Phenomena In Relativistic Outflows' (September 24-28, 2007, Dublin, Ireland)
AIMx: An Extended Adaptive Integral Method for the Fast Electromagnetic Modeling of Complex Structures
Creators: name: Sharma, Shashwat
name: Triverio, Piero
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Surface integral equation (SIE) methods are of great interest for the efficient electromagnetic modeling of various devices, from integrated circuits to antenna arrays. Existing acceleration algorithms for SIEs, such as the adaptive integral method (AIM), enable the fast approximation of interactions between well-separated mesh elements. Nearby interactions involve the singularity of the kernel, and must instead be computed accurately with direct integration at each frequency of interest, which can be computationally expensive. We propose a novel algorithm for reducing the cost-per-frequency of near-region computations for both homogeneous and layered background media. In the proposed extended AIM (AIMx), the SIE operators are decomposed into a frequency-independent term containing the singularity of the kernel, and a nonsingular frequency-dependent term. Direct integration is only required for the frequency-independent term, and can be reused at each frequency, leading to significantly faster frequency sweeps. The frequency-dependent term is captured with good accuracy via fast Fourier transform (FFT)-based acceleration even in the near region, as confirmed with an error analysis. The accuracy and efficiency of the proposed method are demonstrated through numerical examples drawn from several applications, and CPU times are significantly reduced by factors ranging from three to 16.
description: 15 pages, 18 figures, accepted for publication in the IEEE Transactions on Antennas and Propagation
Diffusion and networks: A powerful combination!
Creators: name: Simonsen, Ingve
Publisher: name: arXiv
Year: 2005
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: Over the last decade, an enormous interest and activity in complex networks have been witnessed within the physics community. On the other hand, diffusion and its theory, have equipped the toolbox of the physicist for decades. In this paper, we will demonstrate how to combine these two seemingly different topics in a fruitful manner. In particular, we will review and develop further, an auxiliary diffusive process on weighted networks that represents a powerful concept and tool for studying network (community) structures. The working principle of the method is the observation that the relaxation of the diffusive process towards the stationary state is {\em non-local} and fastest in the highly connected regions of the network. This can be used to acquire non-trivial information about the structure of clustered and non-clustered networks.
description: Latex 15 pages; To appear Physica A
Compaction-Driven Black Hole Growth
Creators: name: Lapiner, Sharon
name: Dekel, Avishai
name: Dubois, Yohan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the interplay between galaxy evolution and central black-hole (BH) growth using the {NewHorizon} cosmological simulation. BH growth is slow when the dark-matter halo is below a golden mass of $M_{\rm v} \sim 10^{12} \rm M_\odot$, and rapid above it. The early suppression is primarily due to gas removal by supernova (SN) feedback in the shallow potential well, predicting that BHs of $\sim 10^5 \rm M_\odot$ tend to lie below the linear relation with bulge mass. Rapid BH growth is allowed when the halo is massive enough to lock in the SN ejecta by its deep potential well and its heated circum-galactic medium (CGM). The onset of BH growth between these two zones is triggered by a wet-compaction event, caused, e.g., by mergers or counter-rotating streams. It brings gas that lost angular momentum into the inner-$1\rm kpc$ "blue nugget" and causes major transitions in the galaxy structural, kinematic and compositional properties, including the onset of star-formation quenching. The compaction events are confined to the golden mass by the same mechanisms of SN feedback and hot CGM. The onset of BH growth is associated with its sinkage to the center due to the compaction-driven deepening of the potential well and the associated dynamical friction. The galaxy golden mass is thus imprinted as a threshold for rapid BH growth, allowing the AGN feedback to keep the CGM hot and maintain long-term quenching. AGN feedback is not causing the onset of quenching; they are both caused by a compaction event when the mass is between the SN and hot-CGM zones.
description: 20 pages, 10 figures (additional figures in appendix). Accepted to MNRAS. arXiv admin note: text overlap with arXiv:1904.08431
FARM MACHINERY ECONOMIC COSTS FOR 1997: MINNESOTA ESTIMATES WITH ADJUSTMENTS FOR USE IN CANADA
Creators: name: Lazarus, William F.
name: Lazarus, William F.
Publisher: name: Unknown
Year: 1997
Subjects: Agricultural Finance
Farm Management

description: The tables in this publication contain estimates of farm machinery operations function costs for 1997. The estimates use an economic engineering approach. The data represents an average farming industry cost for specified machines and operations.
UNDERSTANDING BASIC LINGUOCULTURAL CONCEPTS IN THE ENGLISH PICTURE OF THE WORLD
Creators: name: Mo`minova, Muhayyo
Publisher: name: Zenodo
Year: 2024

description: This thesis examines the fundamental linguocultural aspects embedded within the English language, investigating how linguistic structures, idiomatic expressions, and cultural references collectively shape the worldview of English speakers. Language is not merely a tool for communication; it serves as a reflection of the culture from which it emerges. Understanding the English language thus entails delving into the cultural, historical, and social contexts that inform its development and usage. Drawing on the ideas of notable philosophers and linguists, this study will elucidate how language encapsulates and conveys the essence of cultural identity, social values, and collective experience.
A SIMPLE PROCEDURE TO EVALUATE EX-ANTE PRODUCER WELFARE UNDER PRICE UNCERTAINTY
Creators: name: Tsur, Yacov
name: Tsur, Yacov
Publisher: name: Unknown
Year: 1991
Subjects: Research Methods/ Statistical Methods

description: We propose a simple and tractable procedure for evaluating producer welfare under price uncertainty. These properties are achieved at the cost of assuming constant absolute risk aversion, where risk attitude depends on the stock of wealth but not on the flow of income. Numerical examples corroborate the procedure's properties; the validity of the constant absolute risk aversion case as an approximation is discussed.
Nonlinear perturbations for dissipative and interacting relativistic fluids
Creators: name: Langlois, David
name: Vernizzi, Filippo
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We develop a covariant formalism to study nonlinear perturbations of dissipative and interacting relativistic fluids. We derive nonlinear evolution equations for various covectors defined as linear combinations of the spatial gradients of the local number of e-folds and of some scalar quantities characterizing the fluid, such as the energy density or the particle number density. For interacting fluids we decompose perturbations into adiabatic and entropy components and derive their coupled evolution equations, recovering and extending the results obtained in the context of the linear theory. For non-dissipative and noninteracting fluids, these evolution equations reduce to the conservation equations that we have obtained in recent works. We also illustrate geometrically the meaning of the covectors that we have introduced.
description: 21 pages. v2: minor changes, added a reference; v3: minor changes, published version
Constraining light dark matter upscattered by ultrahigh-energy cosmic rays
Creators: name: Xia, Chen
name: Xu, Yan-Hao
name: Zhou, Yu-Feng
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Light halo dark matter (DM) particles upscattered by high-energy cosmic rays (CRs) can be energetic, and become detectable by conventional direct detection experiments. The current constraints derived from space-based direct CR measurements can reach $\mathcal{O}(10^{-31})\text{ cm}^{2}$ for a constant DM-nucleon scattering cross section. We show that if the CR energy spectrum follows a power law of type $\sim E^{-3}$, the derived constraints on the scattering cross section will be highly insensitive to DM particle mass. This suggests that ultrahigh-energy CRs (UHECRs) indirectly measured by ground-based detectors can be used to place constraints on ultralight DM particles, as $E^{-3}$ is a very good approximation of the UHECR energy spectrum up to energy $\sim10^{20}\text{ eV}$. Using the recent UHECR flux data, we show that the current constraints derived from space-based CR measurements can in principle be extended to ultralight DM particles far below eV scale.
description: 25 pages, 6 figures, match the publsied version
Search for displaced leptons in $\sqrt{s} = 13$ TeV $pp$ collisions with the ATLAS detector
Creators: name: ATLAS Collaboration
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: A search for charged leptons with large impact parameters using 139 fb$^{-1}$ of $\sqrt{s} = 13$ TeV $pp$ collision data from the ATLAS detector at the LHC is presented, addressing a long-standing gap in coverage of possible new physics signatures. Results are consistent with the background prediction. This search provides unique sensitivity to long-lived scalar supersymmetric lepton-partners (sleptons). For lifetimes of 0.1 ns, selectron, smuon and stau masses up to 720 GeV, 680 GeV, and 340 GeV are respectively excluded at 95% confidence level, drastically improving on the previous best limits from LEP.
description: 30 pages in total, author list starting page 15, 2 figures, 2 tables, published in PRL. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2018-14
Metastable massive gravitons from an infinite extra dimension
Creators: name: Seahra, Sanjeev S.
Publisher: name: arXiv
Year: 2005
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Motivated by stringy considerations, Randall & Sundrum have proposed a model where all the fields and particles of physics, save gravity, are confined on a 4-dimensional brane embedded in 5-dimensional anti-deSitter space. Their scenario features a stable bound state of bulk gravity waves and the brane that reproduces standard general relativity. We demonstrate that in addition to this zero-mode, there is also a discrete set of metastable bound states that behave like massive 4-dimensional gravitons which decay by tunneling into the bulk. These are resonances of the bulk-brane system akin to black hole quasinormal modes--as such, they give rise to the dominant corrections to 4-dimensional gravity. The phenomenology of braneworld perturbations is greatly simplified when these resonant modes are taken into account, which is illustrated by considering gravitational radiation emitted from nearby sources and early universe physics.
description: 7 pages, 1 figure. This essay received an honourable mention in the 2005 Gravity Research Foundation essay competition
Charge sensitivity of a cavity-embedded Cooper pair transistor limited by single-photon shot noise
Creators: name: Kanhirathingal, S.
name: Brock, B. L.
name: Rimberg, A. J.
name: Blencowe, M. P.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Using an operator scattering approach, we analyze the quantum dynamics of an ultrasensitive electrometer -- a Cooper pair transistor embedded in a quarter-wave microwave cavity (cCPT). While the cCPT is inherently a tunable, strongly nonlinear system affording a diverse range of functionalities, we restrict our present analysis to a necessary first investigation of its linear charge sensing capabilities, limiting to low pump powers corresponding to an average cavity photon number $\lesssim 1$. Assuming realizable cCPT parameters (B. L. Brock et al., Phys. Rev. Applied, 044009), and not including noise from the subsequent amplifier chain, we predict the fundamental, photon shot noise-limited charge sensitivity to be $0.12\, μ{\mathrm{e}}/\sqrt{\mathrm{Hz}}$ when the pumped cavity has an average of one photon and the cCPT is operated close to charge degeneracy. This is to be compared with a first reported charge sensitivity value $14\, μ{\mathrm{e}}/\sqrt{\mathrm{Hz}}$ in the single-photon regime (B. L. Brock et al., arXiv:2102.05362).
description: 15 pages, 4 figures
Medium-assisted vacuum force
Creators: name: Tomas, M. S.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We discuss some implications of a very recently obtained result for the force on a slab in a planar cavity based on the calculation of the vacuum Lorentz force [C. Raabe and D.-G. Welsch, Phys. Rev. A 71, 013814 (2005)]. We demonstrate that, according to this formula, the total force on the slab consists of a medium-screened Casimir force and, in addition to it, a medium-assisted force. The sign of of the medium-assisted force is determined solely by the properties of the cavity mirrors. In the Lifshitz configuration, this force is proportional to 1/d at small distances and is very small compared with the corresponding van der Waals force. At large distances, however, it is proportional to 1/d^4 and is comparable with the Casimir force, especially for denser media. The exponents in these power laws decrease by 1 in the case of a thin slab. The formula for the medium-assisted force also describes the force on a layer of the cavity medium, which has similar properties. For dilute media, it implies an atom-mirror interaction of the Coulomb type at small and of the Casimir-Polder type at large atom-mirror distances. For a perfectly reflecting mirror, the latter force is effectively only three-times smaller than the Casimir-Polder force.
description: RevTex 4, 12 pages, 2 eps figures, small improvements and expanded discussion
Comparison of different approaches to the quasi-static approximation in Horndeski models
Creators: name: Pace, Francesco
name: Battye, Richard
name: Bellini, Emilio
name: Lombriser, Lucas
name: Vernizzi, Filippo
name: Bolliet, Boris
Publisher: name: arXiv
Year: 2020
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: A quasi-static approximation (QSA) for modified gravity can be applied in a number of ways. We consider three different analytical formulations based on applying this approximation to: (1) the field equations; (2) the equations for the two metric potentials; (3) the use of the attractor solution derived within the Equation of State (EoS) approach. We assess the veracity of these implementations on the effective gravitational constant ($μ$) and the slip parameter ($η$), within the framework of Horndeski models. In particular, for a set of models we compare cosmological observables, i.e., the matter power spectrum and the CMB temperature and lensing angular power spectra, computed using the QSA, with exact numerical solutions. To do that, we use a newly developed branch of the CLASS code: QSA_class. All three approaches agree exactly on very small scales. Typically, we find that, except for $f(R)$ models where all the three approaches lead to the same result, the quasi-static approximations differ from the numerical calculations on large scales ($k \lesssim 3 - 4 \times 10^{-3}\,h\,{\rm Mpc}^{-1}$). Cosmological observables are reproduced to within 1% up to scales ${\rm K} = k/H_0$ of the order of a few and $\ell>5$ for the approaches based on the field equations and on the EoS, and we also do not find any appreciable difference if we use the scale-dependent expressions for $μ$ and $η$ with respect to the value on small scales, showing that the formalism and the conclusions are reliable and robust, fixing the range of applicability of the formalism. We discuss why the expressions derived from the equations for the potentials have limited applicability. Our results are in agreement with previous analytical estimates and show that the QSA is a reliable tool and can be used for comparison with current and future observations to constrain models beyond $Λ$CDM.
description: The manuscript is divided into two parts: the main paper (37 pages, 3 figures, 1 table) and the Supplementary Materials (24 pages, 1 table). Improved discussion on the validity of the quasi-static approximation. Matches the published version on JCAP
Transseries for beginners
Creators: name: Edgar, G. A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Rings and Algebras (math.RA)
subject: Classical Analysis and ODEs (math.CA)
subject: History and Overview (math.HO)
subject: FOS: Mathematics
subject: 16W60, 12H05

description: From the simplest point of view, transseries are a new kind of expansion for real-valued functions. But transseries constitute much more than that--they have a very rich (algebraic, combinatorial, analytic) structure. The set of transseries is a large ordered field, extending the real number field, and endowed with additional operations such as exponential, logarithm, derivative, integral, composition. Over the course of the last 20 years or so, transseries have emerged in several areas of mathematics: asymptotic analysis, model theory, computer algebra, surreal numbers. This paper is an exposition for the non-specialist mathematician. All a mathematician needs to know in order to apply transseries.
description: 53 pages
In My Backyard - snapshot
Creators: name: Gosiaw
Publisher: name: Zenodo
Year: 2021

description: The project aims to understand and map the use of pesticides and fertilizers and sustainable alternative practices in the context of home farming and gardening. Simultaneously, it aims to disseminate information on the topic with the final aim of reducing the use of pesticides and fertilizers.
description: Research Object in Rohub2020: https://localhost.rohub2020/api/ros/6f91c820-580c-4afe-a44e-97b89ea71915/
SOCIAL SCIENCE KNOWLEDGE AND INSTITUTIONAL INNOVATION
Creators: name: Ruttan, Vernon W.
name: Ruttan, Vernon W.
Publisher: name: Unknown
Year: 2002
Subjects: Institutional and Behavioral Economics

description: In this paper I advance a model in which institutional innovation is induced by changes in resource endowments, cultural endowments and technical change. I also introduce the role of advances in social science knowledge as a source of institutional innovation. The sources of institutional innovation are illustrated by changes in land tenure and labor relations in Philippine agriculture and by the transition from command and control to market based systems of resource management in the United States. In a final section I elaborate a pattern model that maps the general equilibrium relationship among change in resource endowments, cultural endowments, technology and institutions.
Progress Report on Calcium Chloride Maintained Traffic Bound Roads
Creators: name: Laughlin, George R.
Publisher: name: Kentucky Transportation Center, University of Kentucky
Year: 1959
Subjects: subject: Transportation Engineering

description: The object of this study is to evaluate the effectiveness of calcium chloride in maintaining traffic-bound roads. Various theses propose that the use of calcium chloride will minimize the loss of granular material from the base by reducing attrition and dusting; thereby aiding in stabilization. Such theses further suggest that when the proper amount of binder or soil mortar is present, calcium chloride will preserve a more uniform moisture condition within the soil-mortar and thus hold the aggregate in place and in a more stable condition. The primary purpose of the study is not to test these theses, but rather to evaluate the practice with respect to currently routine maintenance procedures and their comparative costs.  A maximum of fifty miles of traffic-bound roads were to be programmed for the study. Projects were selected by each maintenance district in cooperation with the Research Division. The initial application of calcium chloride was to be made at the rate of l.6 lbs. per sq. yd. of the anhydrous material or 2.0 tbs. per sq. yd. of the hydrated material. Thereafter, calcium chloride was to be added twice annually: in the spring, at the rate of 0.8 lbs. per sq. yd, based upon anhydrous material; and in the fall, at the rate of 0.4 lbs. per sq. yd., based upon anhydrous material. Prior to applying the calcium chloride, the surfaces were to be re-shaped and any necessary aggregate and binder added. It was desirable, of course, that this operation be made while the surface was in a moist condition.  Since economic considerations were of primary importance in the study, all surface maintenance cost records on these projects were to be closely evaluated and, insofar as possible, compared with costs of maintaining roads of this type without the use of calcium chloride.
On 3D Hall-MHD equations with fractional Laplacians: global well-posedness
Creators: name: Zhang, Huali
name: Zhao, Kun
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35A01, 76W05

description: Cauchy problem for 3D incompressible Hall-magnetohydrodynamics (Hall-MHD) system with fractional Laplacians is studied. First, global well-posedness of small-energy solutions with general initial data in $H^s$, $s>\frac{5}{2}$, is proved. Second, a special class of large-energy initial data is constructed, with which the Cauchy problem is globally well-posed. The proofs rely upon a new global bound of energy estimates involving Littlewood-Paley decomposition and Sobolev inequalities, which enables one to overcome the $\frac{1}{2}$-order derivative loss of the magnetic field.
description: 27 pages. Welcome all comments
Campi Flegrei 2011-2012 dMODELS - snapshot
Creators: name: Gosiaw
Publisher: name: Zenodo
Year: 2021

description: The analytical model of deformation dMODELS was applied to the Campi Flegrei case study for the period 2011-2012. This RO contains the source parameters and the estimated errors committed in modeling the geophysical source by inverting GPS data; the shape of the source is considered as a sphere. More details are available in the 'documents' folder within the 'Content' section (see 'Description dModels_Campi_Flegrei.docx').
description: Research Object in Rohub2020: https://localhost.rohub2020/api/ros/4a58cd8e-e9fb-4061-89c9-693ce494af06/
HOW BIG IS MINNESOTA'S FOOD AND AGRICULTURAL INDUSTRY?
Creators: name: Lazarus, William F.
name: Lazarus, William F.
Publisher: name: Unknown
Year: 2002
Subjects: Agribusiness

description: This report shows that the state's food and agricultural industry is still a significant component of the economy, although probably less so than in earlier years due mainly to agricultural commodity price declines. Agricultural output amounted to 8 percent of the state's total output in 1999, while employment in the industry represented 5 percent of total employment and 3 percent of the labor income generated in the state. Agricultural exports out of the state were 19 percent of the state's total exports. These agricultural exports generate additional indirect sales such as feedgrains sold to pork producers and farm machinery sales to crop farms. The indirect impact measures are derived using the IMPLAN input-output software package. The food and agricultural industry accounts for 213,000 jobs, or 6 percent of the state total, when these secondary impacts of exports are considered. When all food and agricultural industry final sales for export and in-state use are used as the direct measure rather than just exports, the total number of jobs directly or indirectly generated comes to 350,000, or 11 percent of the state total. The importance of agriculture is greater on a percentage basis for the western and southeastern portions of the state. Another measure of the food and agricultural industry's contribution to the state economy is the state's strong $8 billion "trade surplus" in food and agricultural products.
title: Lean Concretes Using Kentucky's Dense Graded Aggregate
title: (Portland Cement and SS-1 Emulsified Asphalt)
titleType: Subtitle
Creators: name: Havens, James H.
name: Evans, Milton
Publisher: name: Kentucky Transportation Center, University of Kentucky
Year: 1959
Subjects: subject: Transportation Engineering

description: Since the development of dense-graded aggregate base in Kentucky about 1952, there have been various conjectures about "auto-cementations" or "setting" of these materials when compacted and cured. In some cases, particularly when the material was limestone, they have developed rather surprising strengths, in the field as well as in the laboratory. Such displays of strength seem to be directly associated with curing (slow drying) and the possibility of re-deposition of small amounts of dissolved calcium carbonate as cement. If this is so, it might be surmised that bases which have not been "fixed" by curing and drying before surfacing may never acquire strength by virtue of auto-cementation, or may loose it on re-wetting. It may be surmised, likewise, that unless auto-cementation occurs, the supporting ability of the base must be governed by the binding power of whatever moisture is present and by virtue of physical confinement. Thus, the idea of deliberately introducing cement is quite logical if inherent strength is to be assured.
D1.5 Policy feedback to the EOSC Partnership
Creators: name: Asmi, Ari
Publisher: name: Zenodo
Year: 2023

description: This deliverable answers to the Commission request for a policy feedback regarding the RDA TIGER in the wider EOSC and policy environment. It specifies the potential policy impact of the RDA TIGER supported Working Groups, and describes wider policy recommendations from the project and RDA in general.
title: Understanding microbial landscapes of the bus during the Covid-19 Pandemic: December-2021 Report
Creators: name: Roe, Emma
name: Veal, Charlotte
name: Hurley, Paul
name: Wilks, Sandra
Publisher: name: University of Southampton
Year: 2021
Subjects: Infection Prevention, Covid-19, Public Transport, Microbial Landscapes

description: This report is provided for stakeholders involved in the provision and management of public transport services where there is a risk of community transmission of COVID-19 and other infections such as seasonal colds, flu, and noroviruses. It provides analysis of everyday bus user experiences within the changing conditions of the COVID-19 public health crisis, March 2020 onwards.

Central to our thinking is the concept of microbial landscapes. This is a new term we are introducing to help describe and explain what is going on all around us, but in particular, on the bus.

Microbial landscapes describes the intertwining BETWEEN the various ways different bus passengers visualise and sense the bus environment, AND the physical, material elements like other passenger bodies, bus architecture, viral particles and microbes. These microbial landscapes are dynamic across the temporalities of day, different seasons, different passengers, and the local dominance of evolving viral strains (alpha, delta, omicron of COVID-19 virus) and cleaning regimes, hand-sanitising, mask-wearing, and windows opening.
Rate control in bi-level image coding
Creators: name: Tompkins, David Andrew Douglas
Publisher: name: University of British Columbia
Year: 2009

description: As we continue to pursue the illusive goal of a paperless society, we are increasingly digitizing our documents, and despite increases in computer speeds and capacities, the requirement for data compression is still paramount. The JBIG2 standard is the latest international bi-level image compression standard, and the first that supports lossy coding. A method is proposed that can achieve rate control while coding bi-level images with JBIG2. For compound images, the image is segmented into text and non-text regions. Non-text regions are lossy coded as generic regions with a bit-flipping approach. The bit-flipping approach has a compression limit, so for higher compression the region is coded as a halftone. For halftone regions, an appropriate grid size is selected and a reduced multi-level image is constructed. The multi-level image is lossy coded with either a bit-flipping approach or with a vector quantization approach, depending on target rate. For text regions, rate control is achieved by adjusting the number of unique symbols in the image. The symbols are a subset of the complete set in the lossless image, and are chosen to minimize the distortion. While the rate control in non-text regions is optimized in the mean squared error sense, the rate control for text regions can be adjusted for any distortion measure. To complete the rate control for a compound image, a weighting is assigned to each region so that the overall distortion is minimized. Results demonstrate that the proposed method is effective, and can produce a JBIG2 bitstream at any target compression rate for any bi-level image.
The late time evolution of Gamma-Ray Bursts: ending hyperaccretion and producing flares
Creators: name: Proga, Daniel
name: Zhang, Bing
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We consider the properties of a hyperaccretion model for gamma-ray bursts (GRBs) at the late time when the mass supply rate is expected to decrease with time. We point out that the region in the vicinity of the accretor and the accretor itself can play an important role in determining the rate and time behavior of the accretion and ultimately the energy output. Motivated by numerical simulations and theoretical results, we conjecture that the energy release can be repeatedly stopped and then restarted by the magnetic flux accumulated around the accretor. We propose that the episode or episodes when the accretion resumes correspond to X-ray flares discovered recently in a number of GRBs.
description: to appear in MNRAS Letters, revised version
Conversion Between Cubic Bezier Curves and Catmull-Rom Splines
Creators: name: Arasteh, Soroosh Tayebi
name: Kalisz, Adam
Publisher: name: arXiv
Year: 2020
Subjects: subject: Graphics (cs.GR)
subject: Computational Geometry (cs.CG)
subject: Algebraic Geometry (math.AG)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Splines are one of the main methods of mathematically representing complicated shapes, which have become the primary technique in the fields of Computer Graphics (CG) and Computer-Aided Geometric Design (CAGD) for modeling complex surfaces. Among all, Bézier and Catmull-Rom splines are the most common in the sub-fields of engineering. In this paper, we focus on conversion between cubic Bézier and Catmull-Rom curve segments, rather than going through their properties. By deriving the conversion equations, we aim at converting the original set of the control points of either of the Catmull-Rom or Bézier cubic curves to a new set of control points, which corresponds to approximately the same shape as the original curve, when considered as the set of the control points of the other curve. Due to providing simple linear transformations of control points, the method is very simple, efficient, and easy to implement, which is further validated in this paper using some numerical and visual examples.
description: Published in SN Computer Science
Observation of discrete energy levels in a quantum confined system
Creators: name: Adams, L. L. A.
name: Lang, B. W.
name: Goldman, A. M.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Low temperature scanning tunneling microscope images and spectroscopic data have been obtained on subnanometer size Pb clusters fabricated using the technique of buffer layer assisted growth. Discrete energy levels were resolved in current-voltage characteristics as current peaks rather than current steps. Distributions of peak voltage spacings and peak current heights were consistent with Wigner-Dyson and Porter-Thomas distributions respectively, suggesting the relevance of random matrix theory to the description of the electronic eigenstates of the clusters. The observation of peaks rather than steps in the current-voltage characteristics is attributed to a resonant tunneling process involving the discrete energy levels of the cluster, the tip, and the states at the interface between the cluster and the substrate surface.
description: 4 pages, 4 figures