cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Transmission across non-Hermitian $\mathcal{PT}$-symmetric quantum dots and ladders
Creators: name: Soori, Abhiram
name: Sivakumar, M.
name: Subrahmanyam, V.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A non-Hermitian region connected to semi-infinite Hermitian lattices acts either as a source or as a sink and the probability current is not conserved in a scattering typically. Even a $\mathcal{P}\mathcal{T}$-symmetric region that contains both a source and a sink does not lead to current conservation plainly. We propose a model and study the scattering across a non-Hermitian $\mathcal{P}\mathcal{T}$-symmetric two-level quantum dot~(QD) connected to two semi-infinite one-dimensional lattices in a special way so that the probability current is conserved. Aharonov-Bohm type phases are included in the model, which arise from magnetic fluxes ($\hbarϕ_{L} /e,~\hbarϕ_{R} /e$) through two loops in the system. We show that when $ϕ_L=ϕ_R$, the probability current is conserved. We find that the transmission across the QD can be perfect in the $\mathcal{P}\mathcal{T}$-unbroken phase (corresponding to real eigenenergies of the isolated QD) whereas the transmission is never perfect in the $\mathcal{P}\mathcal{T}$-broken phase (corresponding to purely imaginary eigenenergies of the QD). The two transmission peaks have the same width only for special values of the fluxes (being odd multiples of $π\hbar/2e$). In the broken phase, the transmission peak is surprisingly not at zero energy. We give an insight into this feature through a four-site toy model. We extend the model to a $\mathcal{P}\mathcal{T}$-symmetric ladder connected to two semi-infinite lattices. We show that the transmission is perfect in unbroken phase of the ladder due to Fabry-Pérot type interference, that can be controlled by tuning the chemical potential. In the broken phase of the ladder, the transmission is substantially suppressed.
description: 11 pages, 10 captioned figures, 1 table
Causative Factors of Concentration Risk in Deposit Taking Rural Banks: Evidence from Ghana
Creators: name: Boohene, David
name: Adu Agyepong, Kingsley
Publisher: name: figshare
Year: 2023
Subjects: Finance
Financial economics

description: This study looks at the deposit concentration risk of rural banks in the Eastern Region of Ghana. Using a descriptive and exploratory research design, it examines the difficulties brought on by deposit risk as a result of large depositors' making unexpected and/or early withdrawals. According to the survey's findings and the F value calculated at a 5 percent level of significance, the majority of the rural banks chosen for the study had a high deposit concentration risk. Additionally, it has been found that deposit concentration risk affects how well the chosen rural banks operate. In other words, poor operational performance is likely to come from a high deposit concentration risk, whereas a low deposit concentration risk is likely to result in excellent operational performance because a low deposit concentration risk implies funding liquidity on the part of rural banks. Thus, the study found that the major causes of the deposit concentration risk experienced by the chosen rural banks were low-interest rates on investments, closely followed by a decline in customer confidence in rural banking. The impact of poor corporate governance, on the other hand, had the lowest ranking among the six factors creating deposit concentration risk.
Machine-learned control-oriented flow estimation for multiactuator multi-sensor systems exemplified for the fluidic pinball
Creators: name: Li, Songqi
name: Li, Wenpeng
name: Noack, Bernd R.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We propose the first machine-learned control-oriented flow estimation for multiple-input multiple-output plants. Starting point is constant actuation with open-loop actuation commands leading to a database with simultaneously recorded actuation commands, sensor signals and flow fields. A key enabler is an estimator input vector comprising sensor signals and actuation commands. The mapping from the sensor signals and actuation commands to the flow fields is realized in an analytically simple, data-centric and general nonlinear approach. The analytically simple estimator generalizes Linear Stochastic Estimation (LSE) for actuation commands. The data-centric approach yields flow fields from estimator inputs by interpolating from the database -- similar to Loiseau et al. (2018) for unforced flow. The interpolation is performed with k Nearest Neighbors (kNN). The general global nonlinear mapping from inputs to flow fields is obtained from a Deep Neural Network (DNN) via an iterative training approach. The estimator comparison is performed for the fluidic pinball plant, which is a multiple-input, multiple-output wake control benchmark (Deng et al. 2020) featuring rich dynamics under steady controls. We conclude that the machine learning methods clearly outperform the linear model. The performance of kNN and DNN estimators are comparable for periodic dynamics. Yet, DNN performs consistently better when the flow is chaotic. Moreover, a thorough comparison regarding to the complexity, computational cost, and prediction accuracy is presented to demonstrate the relative merits of each estimator. The proposed method can be generalized for closed-loop flow control plants.
description: 34 pages, 27 figures, 4 tables
Rejoinder to "Feature Matching in Time Series Modeling"
Creators: name: Xia, Yingcun
name: Tong, Howell
Publisher: name: arXiv
Year: 2012
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Rejoinder to "Feature Matching in Time Series Modeling" by Y. Xia and H. Tong [arXiv:1104.3073]
description: Published in at http://dx.doi.org/10.1214/11-STS345REJ the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Reducing project related uncertainty in the fuzzy front end” of innovation – A comparison of German and Japanese product innovation projects
Creators: name: Herstatt, Cornelius
name: Verworn, Birgit
name: Nagahira, Akio
Publisher: name: TUHH Universitätsbibliothek
Year: 2003
Subjects: subject: Fuzzy front end
subject: innovation risk
subject: uncertainty
subject: idea generation
subject: project selection
subject: project planning
subject: Japan
subject: Germany.
classificationCode: 85.15
subject: Forschung und Entwicklung
subject: Produktinnovation
subject: Produktentwicklung
subject: Produktforschung
subject: Operations Research

description: In this paper, we are going to report on the results of an exploratory piece of research about the typical front-end-related activities in 28 innovation projects carried out by 14 German and 13 Japanese companies to reduce project uncertainty. In all cases we observed a range of activities to reduce project specific risks and revealed differences in the practice of innovation management in both the German and Japanese companies. We interviewed managers of 13 Japanese and 14 German enterprises concerning 14 Japanese and 14 German New Product Development projects. The focus of our research was the so called “fuzzy front end”, activities and typical deliverables in the innovation process which might be affected by front end management practice.
 Overall, in the case of the German as well as the Japanese projects, the uncertainties affected by the market or technology could successfully be reduced during the “fuzzy front end” and the majority of projects achieved their objectives and efficiency targets. Nevertheless, our study revealed differences in the way such uncertainties were reduced by the companies in Japan and Germany. Generally speaking, the 14 Japanese projects relied on a thorough planning, delegation of front end activities and strict controlling mechanisms to minimize deviations from front end specifications later in the innovation process and hence, achieved efficiency. In contrast, in the majority of the 14 German projects we could neither observe such a formal planning nor such an intensive controlling procedure supported by methods and tools as in the case of the Japanese projects. Instead, the companies in our German sample integrated relevant functions like R&D, marketing, sales, production or customer service from the beginning of the innovation process, usually already during the idea generation phase, to ensure that all critical information and perspectives were taken into consideration right from the beginning, to reduce uncertainties and later deviations as well as enhancing efficiency. Responsibilities were assigned during the fuzzy front end and rarely changed during the implementation of the project.
Accelerated chemical space search using a quantum-inspired cluster expansion approach
Creators: name: Choubisa, Hitarth
name: Abed, Jehad
name: Mendoza, Douglas
name: Yao, Zhenpeng
name: Wang, Ziyun
name: Sutherland, Brandon
name: Aspuru-Guzik, Alán
name: Sargent, Edward H
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: To enable the accelerated discovery of materials with desirable properties, it is critical to develop accurate and efficient search algorithms. Quantum annealers and similar quantum-inspired optimizers have the potential to provide accelerated computation for certain combinatorial optimization challenges. However, they have not been exploited for materials discovery due to absence of compatible optimization mapping methods. Here we show that by combining cluster expansion with a quantum-inspired superposition technique, we can lever quantum annealers in chemical space exploration for the first time. This approach enables us to accelerate the search of materials with desirable properties order 10-50 times faster than genetic algorithms and bayesian optimizations, with a significant improvement in ground state prediction accuracy. Levering this, we search chemical space for discovery of acidic oxygen evolution reaction (OER) catalysts and find a promising previously unexplored chemical family of Ru-Cr-Mn-Sb-O$_2$. The best catalyst in this chemical family show a mass activity 8 times higher than state-of-art RuO$_2$ and maintain performance for 180 hours while operating at 10mA/cm$^2$ in acidic 0.5 M $H_2SO_4$ electrolyte.
title: Die Bedeutung partikel-assoziierten Cadmiums für die Bioverfügbarkeit und Bioakkumulation im Nematoden Caenorhabditis elegans
title: The importance of particle-associated cadmium on bioavailability and bioaccumulation in the nematode Caenorhabditis elegans
titleType: AlternativeTitle
Creators: name: Offermann, Kirsten
Publisher: name: TUHH Universitätsbibliothek
Year: 2009
Subjects: subject: interne Verfügbarkeit und Akkumulation von Cadmium
subject: biologische Verfügbarkeit
subject: cdr-1-Genexpression
subject: Real-Time-PCR
subject: multiple cadmium exposure
subject: internal cadmium availability
subject: cadmium bioavailability
subject: bioaccumulation
classificationCode: 43.13
subject: Umwelttoxikologie
subject: Cadmiumbelastung
subject: Bioakkumulation
subject: Caenorhabditis elegans
subject: Bioverfügbarkeit

description: Um die Bedeutung unterschiedlicher Aufnahmewege für die interne Verfügbarkeit und Akkumulation von Cadmium zu untersuchen, wurde C. elegans über verschiedene Partikel und über Medium dem Schadstoff exponiert. Die biologische Verfügbarkeit wurde anhand der veränderten cdr-1-Genexpression mittels Real-Time-PCR bestimmt. Es konnte gezeigt werden, dass für die Wirkung und Akkumulation von Cadmium die Exposition über Nahrungspartikel entscheidend ist.
description: To investigate the impact of multiple cadmium exposure pathways on internal availability and accumulation, C. elegans were exposed to different particles and to dissolved cadmium. Internal cadmium availability was determined using the transcript level of cdr-1 gene, as quantified by real-time PCR. Particle-associated cadmium exposure was the predominant contributor to cadmium bioavailability and bioaccumulation.
On the Relativistic Formulation of Matter
Creators: name: Vishwakarma, Ram Gopal
Publisher: name: arXiv
Year: 2012
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: A critical analysis of the relativistic formulation of matter reveals some surprising inconsistencies and paradoxes. Corrections are discovered which lead to the long-sought-after equality of the gravitational and inertial masses, which are otherwise different in general relativity. Realizing the potentially great impact of the discovered corrections, an overview of the situation is provided resulting from the newly discovered crisis, amid the evidences defending the theory.
description: In press with Astrophys. Space Sci. (The final publication can be seen at springerlink.com)
Small-scale Hα Jets in the Solar Chromosphere
Creators: name: Kuridze, D.
name: Mathioudakis, M.
name: Jess, D. B.
name: Shelyag, S.
name: Christian, D. J.
name: Keenan, F. P.
name: Balasubramaniam, K. S.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: High temporal and spatial resolution observations from the Rapid Oscillations in the Solar Atmosphere (ROSA) multiwavelength imager on the Dunn Solar Telescope are used to study the velocities of small-scale Hα jets in an emerging solar active region. The dataset comprises of simultaneous imaging in the Hα core, Ca II K, and G band, together with photo- spheric line-of-sight magnetograms. Time-distance techniques are employed to determine projected plane-of-sky velocities. The Hα images are highly dynamic in nature, with estimated jet velocities as high as 45 km s^{-1}. These jets are one-directional, with their origin seemingly linked to underlying Ca II K brightenings and G-band magnetic bright points. It is suggested that the siphon flow model of cool coronal loops is suitable for the interpretation of our observations. The jets are associated with small-scale explosive events, and may provide a mass outflow from the photosphere to the corona.
description: 5 pages, 5 figures, accepted in Astronomy and Astrophysics
Near Maximal Atmospheric Mixing in Neutrino Mass Matrices with Two Vanishing Minors
Creators: name: Dev, S.
name: Gupta, Shivani
name: Gautam, Radha Raman
name: Singh, Lal
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In the flavor basis there are seven cases of two vanishing minors in the neutrino mass matrix which can accommodate the present neutrino oscillation data including the recent T2K data. It is found that two of these cases, namely $B_5$ and $B_6$ predict near maximal atmospheric neutrino mixing in the limit of large effective neutrino mass. This feature remains irrespective of the values of solar and reactor mixing angles. A non-zero reactor mixing angle is naturally accommodated in these textures.
description: 14 pages, 6 figures, 1 table, accepted for publication in Phys. Lett. B
Forward and Mueller-Navelet Jets
Creators: name: Triantafyllopoulos, D. N.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We discuss the production of forward jets in high energy processes where one probes a dense hadronic wavefunction. In particular, and as a signature of parton saturation, we discuss the possibility of a strong momentum decorrelation in Mueller-Navelet jets which leads to a geometric scaling behavior.
description: 6 pages, 4 figures. To appear in the proceedings of Excited QCD 2011, 20-25 Feb 2011, Les Houches, France
Impact of Microarray on Supernumerary Marker Chromosome and Global Developmental Delay
Creators: name: Bachani, Sumitra
name: Vatsla Dadhwal
name: Deka, Deepika
Publisher: name: Zenodo
Year: 2021
Subjects: Array CGH
global developmental delay
Karyotype
marker chromosome

description: Small supernumerary marker chromosomes (sSMCs) are structurally abnormal chromosomes that are equal in size or smaller than chromosome 20 and it can be recognised or characterised by conventional karyotype analysis. The molecular characterisation of sSMCs derived from chromosome 15 in prenatal diagnosis in a 38-year-old female is presented in this paper. A combination of a detailed ultrasound examination and karyotype analysis, can provide more precise and rapid prenatal diagnosis of sSMCs.
Spectroscopic scanning tunneling microscopy insights into Fe-based superconductors
Creators: name: Hoffman, Jennifer E.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In the first three years since the discovery of Fe-based high Tc superconductors, scanning tunneling microscopy (STM) and spectroscopy have shed light on three important questions. First, STM has demonstrated the complexity of the pairing symmetry in Fe-based materials. Phase-sensitive quasiparticle interference (QPI) imaging and low temperature spectroscopy have shown that the pairing order parameter varies from nodal to nodeless s\pm within a single family, FeTe1-xSex. Second, STM has imaged C4 -> C2 symmetry breaking in the electronic states of both parent and superconducting materials. As a local probe, STM is in a strong position to understand the interactions between these broken symmetry states and superconductivity. Finally, STM has been used to image the vortex state, giving insights into the technical problem of vortex pinning, and the fundamental problem of the competing states introduced when superconductivity is locally quenched by a magnetic field. Here we give a pedagogical introduction to STM and QPI imaging, discuss the specific challenges associated with extracting bulk properties from the study of surfaces, and report on progress made in understanding Fe-based superconductors using STM techniques.
description: 36 pages, 23 figures, 229 references
Oscillations in Quantum Entanglement During Rescattering
Creators: name: Czirjak, Attila
name: Majorosi, Szilard
name: Kovacs, Judit
name: Benedict, Mihaly G.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the time evolution of quantum entanglement between an electron and its parent ion during the rescattering due to a strong few-cycle laser pulse. Based on a simple one-dimensional model, we compute the Neumann entropy during the process for several values of the carrier-envelope phase. The local maxima of the oscillations in the Neumann entropy coincide with the zero crossings of the electric field of the laser pulse. We employ the Wigner function to qualitatively explain the quantum dynamics of rescattering in the phase space.
description: 2 pages
Self radiation force on a moving monopolar source
Creators: name: Roux, Aymeric
name: Martishang, Jean-Paul
name: Baudoin, Michael
Publisher: name: arXiv
Year: 2022
Subjects: subject: Classical Physics (physics.class-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: The radiation force exerted on an object by an acoustic wave is a widely studied phenomenon since the early work of Rayleigh, Langevin and Brillouin and has led in the last decade to tremendous developments for acoustic micromanipulation. Despite extensive work on this phenomenon, the expressions of the acoustic radiation force applied on a particle have so far been derived only for a steady particle, hence neglecting the effect of its displacement on the radiated wave. In this work we study the acoustic radiation force exerted on a monopolar source translating at a constant velocity small compared to the sound speed. We demonstrate that the asymmetry of the emitted field resulting from Doppler effect induces a radiation force on the source opposite to its motion.
Random matrix theory of polarized light scattering in disordered media
Creators: name: Byrnes, Niall
name: Foreman, Matthew R.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In this work we present a method for generating random matrices describing electromagnetic scattering from disordered media containing dielectric particles with prescribed single particle scattering characteristics. Resulting scattering matrices automatically satisfy the physical constraints of unitarity, reciprocity and time reversal, whilst also incorporating the polarization properties of electromagnetic waves and scattering anisotropy. Our technique therefore enables statistical study of a variety of polarization phenomena, including depolarization rates and polarization-dependent scattering by chiral particles. In this vein, we perform numerical simulations for media containing isotropic and chiral spherical particles of different sizes for thicknesses ranging from the single to multiple scattering regime and discuss our results, drawing comparisons to established theory.
Continuum Model of the Twisted Bilayer
Creators: name: Santos, J. M. B. Lopes dos
name: Peres, N. M. R.
name: Neto, A. H. Castro
Publisher: name: arXiv
Year: 2012
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The continuum model of the twisted graphene bilayer (Phys. Rev. Lett. 99, 256802, 2007) is extended to include all types of commensurate structures. The essential ingredient of the model, the Fourier components of the spatially modulated hopping amplitudes, can be calculated analytically, for any type of commensurate structures in the low twist angle limit. We show that the Fourier components that could give rise to a gap in the SE-even structures discussed by Mele (Phys. Rev. B 81, 161405 2010) vanish linearly with angle, whereas the amplitudes that saturate to finite values, as $θ\to0$, ensure that all low angle structures share essentially the same physics. We extend our previous calculations beyond the validity of perturbation theory, to discuss the disappearance of Dirac cone structure at angles below 1^{\circ}.
description: 13 pages, 17 figures
On the properties of Alfvénic switchbacks in the expanding solar wind: three-dimensional numerical simulations
Creators: name: Johnston, Zade
name: Squire, Jonathan
name: Mallet, Alfred
name: Meyrand, Romain
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Switchbacks -- abrupt reversals of the magnetic field within the solar wind -- have been ubiquitously observed by Parker Solar Probe (PSP). Their origin, whether from processes near the solar surface or within the solar wind itself, remains under debate, and likely has key implications for solar wind heating and acceleration. Here, using three-dimensional expanding box simulations, we examine the properties of switchbacks arising from the evolution of outwards-propagating Alfvén waves in the expanding solar wind in detail. Our goal is to provide testable predictions that can be used to differentiate between properties arising from solar surface processes and those from the in-situ evolution of Alfvén waves in switchback observations by PSP. We show how the inclusion of the Parker spiral causes magnetic field deflections within switchbacks to become asymmetric, preferentially deflecting in the plane of the Parker spiral and rotating in one direction towards the radial component of the mean field. The direction of the peak of the magnetic field distribution is also shown to be different from the mean field direction due to its highly skewed nature. Compressible properties of switchbacks are also explored, with magnetic-field-strength and density fluctuations being either correlated or anticorrelated depending on the value of $β$, agreeing with predictions from theory. We also measure dropouts in magnetic-field strength and density spikes at the boundaries of these synthetic switchbacks, both of which have been observed by PSP. The agreement of these properties with observations provide further support for the Alfvén wave model of switchbacks.
description: Revised argument in Section 2D, results unchanged; typos corrected
CoPR: Towards Accurate Visual Localization With Continuous Place-descriptor Regression
Creators: name: Zaffar, Mubariz
name: Nan, Liangliang
name: Kooij, Julian Francisco Pieter
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Visual Place Recognition (VPR) is an image-based localization method that estimates the camera location of a query image by retrieving the most similar reference image from a map of geo-tagged reference images. In this work, we look into two fundamental bottlenecks for its localization accuracy: reference map sparseness and viewpoint invariance. Firstly, the reference images for VPR are only available at sparse poses in a map, which enforces an upper bound on the maximum achievable localization accuracy through VPR. We therefore propose Continuous Place-descriptor Regression (CoPR) to densify the map and improve localization accuracy. We study various interpolation and extrapolation models to regress additional VPR feature descriptors from only the existing references. Secondly, we compare different feature encoders and show that CoPR presents value for all of them. We evaluate our models on three existing public datasets and report on average around 30% improvement in VPR-based localization accuracy using CoPR, on top of the 15% increase by using a viewpoint-variant loss for the feature encoder. The complementary relation between CoPR and Relative Pose Estimation is also discussed.
description: Published in the IEEE Transactions on Robotics, April 2023
Unbounded normal operators in octonion Hilbert spaces and their spectra
Creators: name: Ludkovsky, S. V.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Functional Analysis (math.FA)
subject: Operator Algebras (math.OA)
subject: FOS: Mathematics
subject: 47A10, 47L30, 47L60, 30G35, 17A05, 17A70

description: Affiliated and normal operators in octonion Hilbert spaces are studied. Theorems about their properties and of related algebras are demonstrated. Spectra of unbounded normal operators are investigated.
description: 50 pages
KELT-1b: A Strongly Irradiated, Highly Inflated, Short Period, 27 Jupiter-mass Companion Transiting a mid-F Star
Creators: name: Siverd, Robert J.
name: Beatty, Thomas G.
name: Pepper, Joshua
name: Eastman, Jason D.
name: Collins, Karen
name: Bieryla, Allyson
name: Latham, David W.
name: Buchhave, Lars A.
name: Jensen, Eric L. N.
name: Crepp, Justin R.
name: Street, Rachel
name: Stassun, Keivan G.
name: Gaudi, B. Scott
name: Berlind, Perry
name: Calkins, Michael L.
name: DePoy, D. L.
name: Esquerdo, Gilbert A.
name: Fulton, Benjamin J.
name: Furesz, Gabor
name: Geary, John C.
name: Gould, Andrew
name: Hebb, Leslie
name: Kielkopf, John F.
name: Marshall, Jennifer L.
name: Pogge, Richard
name: Stanek, K. Z.
name: Stefanik, Robert P.
name: Szentgyorgyi, Andrew H.
name: Trueblood, Mark
name: Trueblood, Patricia
name: Stutz, Amelia M.
name: van Saders, Jennifer L.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We present the discovery of KELT-1b, the first transiting low-mass companion from the wide-field Kilodegree Extremely Little Telescope-North (KELT-North) survey. The V=10.7 primary is a mildly evolved, solar-metallicity, mid-F star. The companion is a low-mass brown dwarf or super-massive planet with mass of 27.23+/-0.50 MJ and radius of 1.110+0.037-0.024 RJ, on a very short period (P=1.21750007) circular orbit. KELT-1b receives a large amount of stellar insolation, with an equilibrium temperature assuming zero albedo and perfect redistribution of 2422 K. Upper limits on the secondary eclipse depth indicate that either the companion must have a non-zero albedo, or it must experience some energy redistribution. Comparison with standard evolutionary models for brown dwarfs suggests that the radius of KELT-1b is significantly inflated. Adaptive optics imaging reveals a candidate stellar companion to KELT-1, which is consistent with an M dwarf if bound. The projected spin-orbit alignment angle is consistent with zero stellar obliquity, and the vsini of the primary is consistent with tidal synchronization. Given the extreme parameters of the KELT-1 system, we expect it to provide an important testbed for theories of the emplacement and evolution of short-period companions, and theories of tidal dissipation and irradiated brown dwarf atmospheres.
description: 30 pages, 19 figures. Submitted to ApJ
Deterministic and Stochastic Euler-Boussinesq Convection
Creators: name: Holm, Darryl D.
name: Pan, Wei
Publisher: name: arXiv
Year: 2022
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Mathematical Physics (math-ph)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences
subject: 76U60, 86-10

description: Stochastic parametrisations of the interactions among disparate scales of motion in fluid convection are often used for estimating prediction uncertainty, which can arise due to inadequate model resolution, or incomplete observations, especially in dealing with atmosphere and ocean dynamics, where viscous and diffusive dissipation effects are negligible. This paper derives a family of three different types of stochastic parameterisations for the classical Euler-Boussinesq (EBC) equations for a buoyant incompressible fluid flowing under gravity in a vertical plane. These three stochastic models are inspired by earlier work on the effects of stochastic fluctuations on transport, see, e.g., Kraichnan [1968, 1994] and Doering et al. [1994]. They are derived here from variants of Hamilton's principle for the deterministic case when Stratonovich noise is introduced. The three models possess different variants of their corresponding Hamiltonian structures. One variant (SALT) introduces stochastic transport. Another variant (SFLT) introduces stochastic \emph{forcing}, rather than stochastic \emph{transport}. The third variant (LA SALT) introduces nonlocality in its stochastic transport, in the probabilistic sense of McKean [1966].
description: 24 pages, 10 figures
Beam splitter as quantum coherence-maker
Creators: name: Ares, Laura
name: Luis, Alfredo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The aim of this work is to answer the question of how much quantum coherence a beam splitter is able to produce. To this end we consider as the variables under study both the amount of coherence of the input states as well as the beam splitter characteristics. We conclude that there is an optimal combination of these factors making the gain of coherence maximum. In addition, the two mode squeezed vacuum arises as the studied state most capable of gaining coherence when passing through a beam splitter. These results are qualitatively equivalent for the the l1-norm of coherence and for the relative entropy of coherence.
The Rapid Rise of Severe Marine Heat Wave Systems
Creators: name: Prochaska, J. Xavier
name: Beaulieu, Claudie
name: Giamalaki, Katerina
Publisher: name: arXiv
Year: 2023
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: We introduce a new methodology to study marine heat waves, extreme events in the sea surface temperature (SST) of the global ocean. Motivated by previously large and impactful marine heat waves and by theoretical expectation that the dominant heating processes coherently affect large regions of the ocean, we introduce a methodology from computer vision to construct marine heat wave systems (MWHSs) -- the collation of SST extrema in dimensions of area and time. We identify 649,475 MHWSs in the 37 year period (1983-2019) of daily SST records and find that the duration t_dur (days), maximum area A_max (km$^2$), and total ``volume'' N_vox (days km$^2$) for the majority of MHWSs are well-described by power-law distributions: t_dur^(-3), A_max^(-2) and N_vox^(-2). These characteristics confirm SST extrema exhibit strong spatial coherence that define the formation and evolution of marine heat waves. Furthermore, the most severe MHWSs deviate from these power-laws and are the dominant manifestation of marine heat waves: extrema in ocean heating are driven by the ~200 systems with largest area and duration. We further demonstrate that the previously purported rise in the incidence of marine heat wave events over the past decade is only significant in these severe systems. A change point analysis reveals a rapid increase in days under a severe MHW in most regions of the global ocean over the period of 2000-2005. Understanding the origin and impacts of marine heat waves in the current and future ocean, therefore, should focus on the production and evolution of the largest-scale and longest-duration heating phenomena.
description: 17 pages, 8 figures; Accepted to Environmental Research: Climate
Sharp Analysis of RLS-based Digital Precoder with Limited PAPR in Massive MIMO
Creators: name: Ma, Xiuxiu
name: Kammoun, Abla
name: Alrashdi, Ayed M.
name: Ballal, Tarig
name: Al-Naffouri, Tareq Y.
name: Alouini, Mohamed-Slim
Publisher: name: arXiv
Year: 2022
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper focuses on the performance analysis of a class of limited peak-to-average power ratio (PAPR) precoders for downlink multi-user massive multiple-input multiple-output (MIMO) systems. Contrary to conventional precoding approaches based on simple linear precoders such as maximum ratio transmission (MRT) and regularized zero-forcing (RZF), the precoders in this paper are obtained by solving a convex optimization problem. To be specific, these precoders are designed so that the power of each precoded symbol entry is restricted, and the PAPR at each antenna is tunable. By using the Convex Gaussian Min-max Theorem (CGMT), we analytically characterize the empirical distribution of the precoded vector and the joint empirical distribution between the distortion and the intended symbol vector. This allows us to study the performance of these precoders in terms of per-antenna power, per-user distortion power, signal-to-noise and distortion ratio (SINAD), and bit error probability. We show that for this class of precoders, there is an optimal transmit per-antenna power that maximizes the system performance in terms of SINAD and bit error probability.
Normal Subgroup Growth of Linear Groups: the (G2; F4;E8)-Theorem
Creators: name: Larsen, Michael
name: Lubotzky, Alexander
Publisher: name: arXiv
Year: 2011
Subjects: subject: Group Theory (math.GR)
subject: FOS: Mathematics

description: Let G be a finitely generated group and M_n(G) the number of its normal subgroup subgroups of index at most n. For linear groups G we show that M_n(G) can grow polynomially in n only if the semisimple part of the Zariski closure of G has simple components only of type G2, F4 or E8 (and in this case indeed this can happened!)
description: This is an old paper, we upload it now in order for it to have an online access
Q-Kostka polynomials and spin Green polynomials
Creators: name: Jiang, Anguo
name: Jing, Naihuan
name: Liu, Ning
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Algebra (math.QA)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: Primary: 05E05, Secondary: 17B69, 05E10

description: We study the $Q$-Kostka polynomials $L_{λμ}(t)$ by the vertex operator realization of the $Q$-Hall-Littlewood functions $G_λ(x;t)$ and derive new formulae for $L_{λμ}(t)$. In particular, we have established stability property for the Q-Kostka polynomials. We also introduce spin Green polynomials $Y^λ_μ(t)$ as both an analogue of the Green polynomials and deformation of the spin irreducible characters of $\mathfrak S_n$. Iterative formulas of the spin Green polynomials are given and some favorable properties parallel to the Green polynomials are obtained. Tables of $Y^λ_μ(t)$ are included for $n\leq7.$
description: 5 tables
Adding a new site in an existing Oracle Multimaster replication without quiescing the replication
Creators: name: Paci, Hakik
name: Kajo, Elinda
name: Tafa, Igli
name: Xhuvani, Aleksander
Publisher: name: arXiv
Year: 2011
Subjects: subject: Databases (cs.DB)
subject: FOS: Computer and information sciences

description: This paper presents a new solution, which adds a new database server on an existing Oracle Multimaster Data replication system with Online Instantiation method. During this time the system is down, because we cannot execute DML statements on replication objects but we can only make queries. The time for adding the new database server depends on the number of objects, on the replication group and on the network conditions. We propose to add a new layer between replication objects and the database sessions, which contain DML statements. The layer eliminates the system down time exploiting our developed packages. The packages will be active only during the addition of a new site process and will modify all DML statements and queries based on replication objects.
description: 9 pages, 4 figures, in International Journal of Database Management Systems (IJDMS) (2011)
Mapping Dark Matter with Extragalactic Stellar Streams: the Case of Centaurus A
Creators: name: Pearson, Sarah
name: Price-Whelan, Adrian M.
name: Hogg, David W.
name: Seth, Anil C.
name: Sand, David J.
name: Hunt, Jason A. S.
name: Crnojevic, Denija
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: In the coming decade, thousands of stellar streams will be observed in the halos of external galaxies. What fundamental discoveries will we make about dark matter from these streams? As a first attempt to look at these questions, we model Magellan/Megacam imaging of the Centaurus A's (Cen A) disrupting dwarf companion Dwarf 3 (Dw3) and its associated stellar stream, to find out what can be learned about the Cen A dark-matter halo. We develop a novel external galaxy stream-fitting technique and generate model stellar streams that reproduce the stream morphology visible in the imaging. We find that there are many viable stream models that fit the data well, with reasonable parameters, provided that Cen A has a halo mass larger than M$_{200}$ $>4.70\times 10^{12}$ M$_{\odot}$. There is a second stream in Cen A's halo that is also reproduced within the context of this same dynamical model. However, stream morphology in the imaging alone does not uniquely determine the mass or mass distribution for the Cen A halo. In particular, the stream models with high likelihood show covariances between the inferred Cen A mass distribution, the inferred Dw3 progenitor mass, the Dw3 velocity, and the Dw3 line-of-sight position. We show that these degeneracies can be broken with radial-velocity measurements along the stream, and that a single radial velocity measurement puts a substantial lower limit on the halo mass. These results suggest that targeted radial-velocity measurements will be critical if we want to learn about dark matter from extragalactic stellar streams.
description: 11 figures, 23 pages, Accepted to ApJ
Optical appearance of Einstein-Æther black hole surrounded by thin disk
Creators: name: Wang, Hui-Min
name: Lin, Zi-Chao
name: Wei, Shao-Wen
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In Einstein-Æther theory, the Lorentz symmetry is locally broken in the high-energy regime due to the presence of theÆther field. This shall leave significant imprint on astronomical observation. In this paper, we investigate the optical appearance of two types of the static and spherically symmetric black holes in Einstein-Æther theory. Via Euler-Lagrange equation, we obtain the equations of motion of the photon and calculate the total deflection angle of the photon trajectory around the black hole. By classifying the light rays with the total number of orbits, we study the effects of coupling constants on the direct image, lensing ring, and photon ring. The features of the light trajectories are also investigated by comparing with the Einstein-Æther theory and general relativity. Moreover, we also show the explicit optical appearance of black holes surrounded by thin disk emissions with three characteristic emitted models. The results indicate that the direct image gives the main contribution to the total flux, and the lensing ring just gives a very small contribution, whereas the role of the photon ring is negligible. The optical appearances are also found to significantly rely on these coupling constants.
description: 19 pages, 6 figures
Tracking the surface atomic motion in a coherent phonon oscillation
Creators: name: Curcio, Davide
name: Volckaert, Klara
name: Kutnyakhov, Dmytro
name: Agustsson, Steinn Ymir
name: Bühlmann, Kevin
name: Pressacco, Federico
name: Heber, Michael
name: Dziarzhytski, Siarhei
name: Acremann, Yves
name: Demsar, Jure
name: Wurth, Wilfried
name: Sanders, Charlotte E.
name: Hofmann, Philip
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: X-ray photoelectron diffraction is a powerful tool for determining the structure of clean and adsorbate-covered surfaces. Extending the technique into the ultrafast time domain will open the door to studies as diverse as the direct determination of the electron-phonon coupling strength in solids and the mapping of atomic motion in surface chemical reactions. Here we demonstrate time-resolved photoelectron diffraction using ultrashort soft X-ray pulses from the free electron laser FLASH. We collect Se 3d photoelectron diffraction patterns over a wide angular range from optically excited Bi$_2$Se$_3$ with a time resolution of 140 fs. Combining these with multiple scattering simulations allows us to track the motion of near-surface atoms within the first 3 ps after triggering a coherent vibration of the A$_{1g}$ optical phonons. Using a fluence of 4.2 mJ/cm$^2$ from a 1.55 eV pump laser, we find the resulting coherent vibrational amplitude in the first two interlayer spacings to be on the order of 1 pm.
Discovery of shocked H2 around OH 231.8+4.2
Creators: name: Forde, K. P.
name: Gledhill, T. M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present K-band integral field observations of the circumstellar envelope of the evolved star OH 231.8+4.2. Spatial and spectral information were simultaneously acquired using the Sinfoni integral field unit, with adaptive optics, on the Very Large Telescope. The observations reveal the discovery of H2 emission (1) around the centre of the nebula and (2) located in clumps along the Western side of the Northern lobe, presumably associated with the strong shocks that stimulate the previously reported H-alpha emission at the same location. An observed H2 1-0/2-1S(1) line ratio of 8.3+/-1.9 was calculated for the central field, a value consistent with shock excitation.
description: 5 pages, 4 figures, accepted for publication in MNRAS Letters
Nonintegrability of dynamical systems near degenerate equilibria
Creators: name: Yagasaki, Kazuyuki
Publisher: name: arXiv
Year: 2022
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 37J30, 37G05, 34M35, 34C20, 34A05

description: We prove that general three- or four-dimensional systems %of differential equations are real-analytically nonintegrable near degenerate equilibria in the Bogoyavlenskij sense under additional weak conditions when the Jacobian matrices have a zero and pair of purely imaginary eigenvalues or two incommensurate pairs of purely imaginary eigenvalues at the equilibria. For this purpose, we reduce their integrability to that of the corresponding Poincare-Dulac normal forms and further to that of simple planar systems, and use a novel approach for proving the analytic nonintegrability of planar systems. Our result also implies that general three- and four-dimensional systems exhibiting fold-Hopf and double-Hopf codimension-two bifurcations, respectively, are real-analytically nonintegrable under the weak conditions. To demonstrate these results, we give two examples for the Rossler system and coupled van der Pol oscillators.
description: 19 pages
Extension the Noether's theorem to Lagrangian formulation with nonlocality
Creators: name: Huang, Zaixing
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: A Lagrangian formulation with nonlocality is investigated in this paper. The nonlocality of the Lagrangian is introduced by a new nonlocal argument that is defined as a nonlocal residual satisfying the zero mean condition. The nonlocal Euler-Lagrangian equation is derived from the Hamilton's principle. The Noether's theorem is extended to this Lagrangian formulation with nonlocality. With the help of the extended Noether's theorem, the conservation laws relevant to energy, linear momentum, angular momentum and the Eshelby tensor are determined in the nonlocal elasticity associated with the mechanically based constitutive model. The results show that the conservation laws exist only in the form of the integral over the whole domain occupied by body. The localization of the conservation laws is discussed in detail. We demonstrate that not every conservation law corresponds to a local equilibrium equation. Only when the nonlocal residual of conservation current exists, can a conservation law be transformed into a local equilibrium equation by localization.
description: 13 pages
From a feedback-controlled demon to an information ratchet in a double quantum dot
Creators: name: Bhattacharyya, Debankur
name: Jarzynski, Christopher
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present a simple strategy for constructing an information ratchet or memory-tape model of Maxwell's demon, from a feedback-controlled model. We illustrate our approach by converting the Annby-Andersson feedback-controlled double quantum dot model [Phys. Rev. B 101, 165404 (2020)] to a memory-tape model. We use the underlying network structure of the original model to design a set of bit interaction rules for the information ratchet. The new model is solved analytically in the limit of long interaction times. For finite-time interactions, semi-analytical phase diagrams of operational modes are obtained. Stochastic simulations are used to verify theoretical results.