cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Modeling quasi-dark states with Temporal Coupled-Mode Theory
Creators: name: Souza, Mario C. M. M.
name: Rezende, Guilherme F. M.
name: Barea, Luis A. M.
name: Wiederhecker, Gustavo S.
name: Frateschi, Newton C.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Coupled resonators are commonly used to achieve tailored spectral responses and allow novel functionalities in a broad range of applications, from optical modulation and filtering in integrated photonic circuits to the study of nonlinear dynamics in arrays of resonators. The Temporal Coupled-Mode Theory (TCMT) provides a simple and general tool that is widely used to model these devices and has proved to yield very good results in many different systems of low-loss, weakly coupled resonators. Relying on TCMT to model coupled resonators might however be misleading in some circumstances due to the lumped-element nature of the model. In this article, we report an important limitation of TCMT related to the prediction of dark states. Studying a coupled system composed of three microring resonators, we demonstrate that TCMT predicts the existence of a dark state that is in disagreement with experimental observations and with the more general results obtained with the Transfer Matrix Method (TMM) and the Finite-Difference Time-Domain (FDTD) simulations. We identify the limitation in the TCMT model to be related to the mechanism of excitation/decay of the supermodes and we propose a correction that effectively reconciles the model with expected results. A comparison with TMM and FDTD allows to verify both steady-state and transient solutions of the modified-TCMT model. The proposed correction is derived from general considerations, energy conservation and the non-resonant power circulating in the system, therefore it provides good insight on how the TCMT model should be modified to eventually account for the same limitation in a different coupled-resonator design. Moreover, our discussion based on coupled microring resonators can be useful for other electromagnetic resonant systems due to the generality and far-reach of the TCMT formalism.
description: 7 pages, 4 figures
A further decline in battery storage costs can pave the way for a solar PV-dominated Indian power system
Creators: name: Ershad, Ahmad Murtaza
name: Ueckerdt, Falko
name: Pietzcker, Robert C.
name: Giannousakis, Anastasis
name: Luderer, Gunnar
Publisher: name: Elsevier BV
Year: 2021
Subjects: subject: 600 Technik, Medizin, angewandte Wissenschaften::620 Ingenieurwissenschaften::629 Andere Fachrichtungen der Ingenieurwissenschaften
subject: market value of solar PV
subject: battery storage
subject: power sector model
subject: India

description: India, mainly powered by coal, has adopted ambitious renewable energy targets and currently considers a climate neutrality target for 2050. The rapid growth of solar PV power faces challenges due to its variable generation resulting in a decline in its economic value. In this paper, we evaluate the potential of battery storage to stabilize the market value of solar PV for three scenarios of further battery costs decrease. We estimate optimal battery storage and power generating capacities and their hourly operation in a 2040 Indian wholesale electricity market using an open-source power sector model. We find that battery storage increases the optimal solar PV shares from ∼40-50 % (without batteries) to ∼65 % (90%) in our central (optimistic) battery cost scenarios, while they hardly increase in our pessimistic battery cost scenario. We conclude that if battery cost drop to below ∼200 USD/kWh (including balance-of-system costs) they could become essential in a transition to a solar PV-dominant Indian energy system.
How unusual is the cool-core radio halo cluster CL1821+643 ?
Creators: name: Kale, Ruta
name: Parekh, Viral
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Massive galaxy clusters with cool-cores typically host diffuse radio sources called mini-haloes, whereas, those with non-cool-cores host radio haloes. We attempt to understand the unusual nature of the cool-core galaxy cluster CL1821+643 that hosts a Mpc-scale radio halo using new radio observations and morphological analysis of its intra-cluster medium. We present the Giant Metrewave Radio Telescope (GMRT) 610 MHz image of the radio halo. The spectral index, $α$ defined as $S\propto ν^{-α}$, of the radio halo is $1.0\pm0.1$ over the frequency range of 323 - 610 - 1665 MHz. Archival {\it Chandra} X-ray data were used to make surface brightness and temperature maps. The morphological parameters Gini, $M_{20}$ and concentration ($C$) were calculated on X-ray surface brightness maps by including and excluding the central quasar (H1821+643) in the cluster. We find that the cluster CL1821+643, excluding the quasar, is a non-relaxed cluster as seen in the morphological parameter planes. It occupies the same region as other merging radio halo clusters in the temperature- morphology parameter plane. We conclude that this cluster has experienced a non-core-disruptive merger.
description: 8 pages, 6 figures
Topological origin of flat-bands as pseudo-Landau levels in uniaxial strained graphene nanoribbons and induced magnetic ordering due to electron-electron interactions
Creators: name: Andrade, Elias
name: López-Urías, Florentino
name: Naumis, Gerardo G.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Flat-bands play a central role in the presence of correlated phases in Moiré and other modulated two dimensional systems. In this work, flat-bands are shown to exist in uniaxially periodic strained graphene. Such strain should be produced for example by a substrate. The model is thus mapped into a one-dimensional effective Hamiltonian and this allows to find the conditions for having flat-bands, i.e., a long-wavelength modulation only on each one of the bipartite graphene sublattices, while having a tagged strain field between neighboring carbon atoms. The origin of such flat-bands is thus tracked down to the existence of topological localized wavefunctions at domain walls separating different regions, each with a non-uniform Su-Schriffer-Hegger model (SSH) type of coupling. Thereafter, the system is mapped into a continuum model allowing to explain the numerical results in terms of the Jackiw-Rebbi model and of pseudo-Landau levels. Finally, the interplay between the obtained flat-bands and electron-electron interaction is explored through the Hubbard model. The numerical results within the mean-field approximation indicate that the flat-bands induce Néel antiferromagnetic and ferromagnetic domains even for a very weak Hubbard interaction. The present model thus provides a simple platform to understand the physical origin of flat-bands, pseudo-Landau levels and the effects of the electron-electron interaction.
description: 10 pages, 9 figures
Crossarchus F. G. Cuvier 1825
Creators: name: W. Christopher Wozencraft
Publisher: name: Zenodo
Year: 1993
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Carnivora
Herpestidae
Crossarchus

description: Crossarchus F. G. Cuvier, 1825. In E. Geoffroy Saint-Hilaire and F. G. Cuvier, Hist. Nat. Mammifères, pt. 3, 5(47), "le Mangue" 3 pp., 1 pl. TYPE SPECIES: Crossarchus obscurus F. G. Cuvier, 1825, by original designation (Melville and Smith, 1987). COMMENTS: Revised by Goldman (1984). Placed in Mungos by Hill and Carter (1941). Van Rompaey and Colyn (1992) presented a key to the species.
description: Published as part of W. Christopher Wozencraft, 1993, Order Carnivora, pp. 279-348 in Mammal Species of the World (2 nd Edition), Washington and London :Smithsonian Institution Press on page 301, DOI: 10.5281/zenodo.7359191
description: {"references": ["Cuvier, F. G. 1825. Elephant d' Afrique. Pp. VI, in E. Geoffroy St. - Hilaire and F. Cuvier, Histoire Naturelle Mammiferes, 3 (52): 2.", "Melville, R. V., and J. D. D. Smith (eds.). 1987. Official lists and indexes of names and works in zoology. International Commission on Zoological Nomenclature, 366 pp.", "Goldman, C. A. 1984. Systematic revision of the African mongoose genus Crossarchus (Mammalia: Viverridae). Canadian Journal of Zoology, 62: 1618 - 1630.", "Hill, J. E., and T. D. Carter. 1941. The mammals of Angola, Africa. Bulletin of the American Museum of Natural History, 78 (1): 1 - 211.", "Van Rompaey, H., and M. Colyn. 1992. Crossarchus ansorgei. Mammalian Species, 402: 1 - 3."]}
Laboratory rotational ground state transitions of NH$_3$D$^+$ and CF$^+$
Creators: name: Stoffels, Alexander
name: Kluge, Lars
name: Schlemmer, Stephan
name: Brünken, Sandra
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Aims. This paper reports accurate laboratory frequencies of the rotational ground state transitions of two astronomically relevant molecular ions, NH3D+ and CF+. Methods. Spectra in the millimeter-wave band were recorded by the method of rotational state-selective attachment of He-atoms to the molecular ions stored and cooled in a cryogenic ion trap held at 4 K. The lowest rotational transition in the A state (ortho state) of NH$_3$D$^+$ ($J_K = 1_0 - 0_0$), and the two hyperfine components of the ground state transition of CF$^+$($J = 1 - 0$) were measured with a relative precision better than $10^{-7}$. Results. For both target ions the experimental transition frequencies agree with recent observations of the same lines in different astronomical environments. In the case of NH$_3$D$^+$ the high-accuracy laboratory measurements lend support to its tentative identification in the interstellar medium. For CF$^+$ the experimentally determined hyperfine splitting confirms previous quantum-chemical calculations and the intrinsic spectroscopic nature of a double-peaked line profile observed in the $J = 1 - 0$ transition towards the Horsehead PDR.
description: 7 pages, 2 figures
Supplementary Material from Metamaterials with Poisson's ratio discontinuity by means of fragmentation–reconstitution rotating units
Creators: name: Lim, Teik-Cheng
Publisher: name: The Royal Society
Year: 2023
Subjects: subject: Mechanical Engineering
subject: FOS: Mechanical engineering
subject: Macromolecular and Materials Chemistry not elsewhere classified

description: Poisson's ratio for in-plane compression
Reversal and amplification of zonal flows by boundary enforced thermal wind
Creators: name: Dietrich, Wieland
name: Gastine, Thomas
name: Wicht, Johannes
Publisher: name: arXiv
Year: 2016
Subjects: subject: Geophysics (physics.geo-ph)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Zonal flows in rapidly-rotating celestial objects such as the Sun, gas or ice giants form in a variety of surface patterns and amplitudes. Whereas the differential rotation on the Sun, Jupiter and Saturn features a super-rotating equatorial region, the ice giants, Neptune and Uranus harbour an equatorial jet slower than the planetary rotation. Global numerical models covering the optically thick, deep-reaching and rapidly rotating convective envelopes of gas giants reproduce successfully the prograde jet at the equator. In such models, convective columns shaped by the dominant Coriolis force typically exhibit a consistent prograde tilt. Hence angular momentum is pumped away from the rotation axis via Reynolds stresses. Those models are found to be strongly geostrophic, hence a modulation of the zonal flow structure along the axis of rotation, e.g. introduced by persistent latitudinal temperature gradients, seems of minor importance. Within our study we stimulate these thermal gradients and the resulting ageostrophic flows by applying an axisymmetric and equatorially symmetric outer boundary heat flux anomaly ($Y_{20}$) with variable amplitude and sign. Such a forcing pattern mimics the thermal effect of intense solar or stellar irradiation. Our results suggest that the ageostrophic flows are linearly amplified with the forcing amplitude $q^\star$ leading to a more pronounced dimple of the equatorial jet (alike Jupiter). The geostrophic flow contributions, however, are suppressed for weak $q^\star$, but inverted and re-amplified once $q^\star$ exceeds a critical value. The inverse geostrophic differential rotation is consistently maintained by now also inversely tilted columns and reminiscent of zonal flow profiles observed for the ice giants. Analysis of the main force balance and parameter studies further foster these results.
Wavelength-Dependent Extinction and Grain Sizes in Dippers
Creators: name: Sitko, Michael L.
name: Russell, Ray W.
name: Long, Zachary C.
name: Assani, Korash
name: Pikhartova, Monika
name: Bayyari, Ammar
name: Grady, Carol A.
name: Lisse, Carey M.
name: Marengo, Massimo
name: Wisniewski, John P.
name: Danchi, William
Publisher: name: arXiv
Year: 2023
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We have examined inter-night variability of K2-discovered Dippers that are not close to being viewed edge-on, as determined from previously-reported ALMA images, using the SpeX spectrograph and the NASA Infrared Telescope facility (IRTF). The three objects observed were EPIC 203850058, EPIC 205151387, and EPIC 204638512 (2MASS J16042165-2130284). Using the ratio of the fluxes between two successive nights, we find that for EPIC 204638512 and EPIC 205151387, we find that the properties of the dust differ from that seen in the diffuse interstellar medium and denser molecular clouds. However, the grain properties needed to explain the extinction does resemble those used to model the disks of many young stellar objects. The wavelength-dependent extinction models of both EPIC 204638512 and EPIC 205151387 includes grains at least 500 microns in size, but lacks grains smaller than 0.25 microns. The change in extinction during the dips, and the timescale for these variations to occur, imply obscuration by the surface layers of the inner disks. The recent discovery of a highly mis-inclined inner disk in EPIC 204638512 is suggests that the variations in this disk system may point to due to rapid changes in obscuration by the surface layers of its inner disk, and that other face-on Dippers might have similar geometries. The He I line at 1.083 microns in EPIC 205151387 and EPIC 20463851 were seen to change from night to night, suggesting that we are seeing He I gas mixed in with the surface dust.
description: 13 pages, 6 figures, 2 tables
Multiple magnetic transitions and complex magnetic structures in Fe$_2$SiSe$_4$ with the sawtooth lattice
Creators: name: Pan, Feihao
name: Hu, Xunwu
name: Huang, Jiale
name: Shi, Bingxian
name: Wang, Jinchen
name: Liu, Juanjuan
name: Zhang, Hongxia
name: Xu, Daye
name: Wang, Hongliang
name: Hao, Lijie
name: Cheng, Peng
name: Yao, Dao-Xin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The sawtooth lattice shares some structural similarities with the kagome lattice and may attract renewed research interest. Here, we report a comprehensive study on the physical properties of Fe$_2$SiSe$_4$, an unexplored member in the olivine chalcogenides with the sawtooth lattice of Fe. Our results show that Fe$_2$SiSe$_4$ is a magnetic semiconductor with band gap of 0.66~eV. It first undergoes an antiferromagnetic transition at T$_{m1}$=110~K, then an ferrimagnetic-like one at T$_{m2}$=50~K and finally a magnetic transition at T$_{m3}$=25~K which is likely driven by the thermal populations of spin-orbit manifold on the Fe site. Neutron diffraction analysis reveals a non-collinear antiferromagnetic structure with propagation vector $\mathbf{q_1}$=(0,0,0) at T$_{m2}$
description: 8 pages, 7 figures
The impact of environmental effects on AGN: a decline in the incidence of ionized outflows
Creators: name: Del Pino, B. Rodríguez
name: Arribas, S.
name: Chies-Santos, A. L.
name: Lamperti, I.
name: Perna, M.
name: Vílchez, J. M.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: AGN have been generally considered to be less frequent in denser environments due to the lower number of galaxy-galaxy interactions and/or the removal of their gas-rich reservoirs by the dense intergalactic medium. However, recent observational and theoretical works suggest that the effect of ram-pressure stripping might reduce the angular momentum of their gas, causing it to infall towards the super massive black hole (SMBH) at their centre, activating the AGN phase. In this work we explore the connection between environment and nuclear activity by evaluating the variation in the incidence of ionized outflows in AGN across different environments. We select a sample of $\sim3300$ optical AGN from the Sloan Digital Sky Survey Data Release 13 that we match with the group catalogue from Lim et al. 2017. We further probe their environment through the projected distance to the central galaxy of the group/cluster and the projected surface density to the 5th neighbour ($δ_5$). We find that at lower masses ($<10^{10.3}$M$_{\odot}$), the fraction of ionized outflows is significantly lower in satellite ($\sim7$%) than in isolated ($\sim22$%) AGN. The fraction of outflows in all satellite AGN decreases towards closer distances to the central, whereas only the lower-mass ones display a significant decline with $δ_5$. Although this study does not include AGN in the densest regions of galaxy clusters, our findings suggest that AGN in dense environments accrete less gas than those in the field potentially due to the removal of the gas reservoirs via stripping or starvation, consistent with a negative connection between environment and AGN activity. We propose that the observed change in the incidence of outflows towards denser regions of groups and clusters could contribute to the higher gas metallicities of cluster galaxies compared to field ones, especially at lower masses.
description: 9 pages, 6 figures, Accepted for publication in Astronomy and Astrophysics
Cosmological Constant Implementing Mach Principle in General Relativity
Creators: name: Namavarian, Nadereh
name: Farhoudi, Mehrdad
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider the fact that noticing on the operational meaning of the physical concepts played an impetus role in the appearance of general relativity (GR). Thus, we have paid more attention to the operational definition of the gravitational coupling constant in this theory as a dimensional constant which is gained through an experiment. However, as all available experiments just provide the value of this constant locally, this coupling constant can operationally be meaningful only in a local area. Regarding this point, to obtain an extension of GR for the large scale, we replace it by a conformal invariant model and then, reduce this model to a theory for the cosmological scale via breaking down the conformal symmetry through singling out a specific conformal frame which is characterized by the large scale characteristics of the universe. Finally, we come to the same field equations that historically were proposed by Einstein for the cosmological scale (GR plus the cosmological constant) as the result of his endeavor for making GR consistent with the Mach principle. However, we declare that the obtained field equations in this alternative approach do~not carry the problem of the field equations proposed by Einstein for being consistent with Mach's principle (i.e., the existence of de Sitter solution), and can also be considered compatible with this principle in the Sciama view.
description: 12 pages
Modulational instability in nonlocal Kerr media with sine-oscillatory response
Creators: name: Wang, Zhuo
name: Guo, Qi
name: Hong, Weiyi
name: Hu, Wei
Publisher: name: arXiv
Year: 2016
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We discuss the modulational instability (MI) of plane waves in nonlocal Kerr media with the sine-oscillation response function, which can model the nematic liquid crystal with negative dielectric anisotropy. The results in the framework of the nonlocal nonlinear Schrödinger equation show that the MI in this system has two extraordinary properties. First, MI exists in both cases of negative Kerr coefficient $(n_{2}<0)$ and positive Kerr coefficient $(n_{2}>0)$. Second, the maximum gain of MI is not affected by the intensity of the plane wave, and the wave number %spatial frequency of the maximum gain depends on the oscillation period of the response function. We also explore, for the first time to the best of our knowledge, the physical mechanism of MI in the framework of the four-wave mixing (FWM). %FWM interaction. By introducing a phase mismatch term $\triangle k$ and a (nonlinear) growth factor $γ$ (both of them have clear physical meanings), we find that the necessary and sufficient condition for the MI appearance is that the phase mismatching during the FWM process should be small enough such that $|\triangle k|<2|γ|$. Basing on the discover, we present a new scenario to uniformly and consistently explain why the MI can happen for the focusing local Kerr media and cannot for the defocusing local Kerr media, as well as the MI phenomena in the nonlocal cases.
How is a data-driven approach better than random choice in label space division for multi-label classification?
Creators: name: Szymański, Piotr
name: Kajdanowicz, Tomasz
name: Kersting, Kristian
Publisher: name: arXiv
Year: 2016
Subjects: subject: Machine Learning (cs.LG)
subject: Performance (cs.PF)
subject: Social and Information Networks (cs.SI)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: We propose using five data-driven community detection approaches from social networks to partition the label space for the task of multi-label classification as an alternative to random partitioning into equal subsets as performed by RAkELd: modularity-maximizing fastgreedy and leading eigenvector, infomap, walktrap and label propagation algorithms. We construct a label co-occurence graph (both weighted an unweighted versions) based on training data and perform community detection to partition the label set. We include Binary Relevance and Label Powerset classification methods for comparison. We use gini-index based Decision Trees as the base classifier. We compare educated approaches to label space divisions against random baselines on 12 benchmark data sets over five evaluation measures. We show that in almost all cases seven educated guess approaches are more likely to outperform RAkELd than otherwise in all measures, but Hamming Loss. We show that fastgreedy and walktrap community detection methods on weighted label co-occurence graphs are 85-92% more likely to yield better F1 scores than random partitioning. Infomap on the unweighted label co-occurence graphs is on average 90% of the times better than random paritioning in terms of Subset Accuracy and 89% when it comes to Jaccard similarity. Weighted fastgreedy is better on average than RAkELd when it comes to Hamming Loss.
Pricing Derivatives in a Regime Switching Market with Time Inhomogeneous Volatility
Creators: name: Das, Milan Kumar
name: Goswami, Anindya
name: Patankar, Tanmay S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Pricing of Securities (q-fin.PR)
subject: Probability (math.PR)
subject: Mathematical Finance (q-fin.MF)
subject: FOS: Economics and business
subject: FOS: Mathematics
subject: 60K15, 91B30, 91G20, 91G60

description: This paper studies pricing derivatives in an age-dependent semi-Markov modulated market. We consider a financial market where the asset price dynamics follow a regime switching geometric Brownian motion model in which the coefficients depend on finitely many age-dependent semi-Markov processes. We further allow the volatility coefficient to depend on time explicitly. Under these market assumptions, we study locally risk minimizing pricing of a class of European options. It is shown that the price function can be obtained by solving a non-local B-S-M type PDE. We establish existence and uniqueness of a classical solution of the Cauchy problem. We also find another characterization of price function via a system of Volterra integral equation of second kind. This alternative representation leads to computationally efficient methods for finding price and hedging. Finally, we analyze the PDE to establish continuous dependence of the solution on the instantaneous transition rates of semi-Markov processes. An explicit expression of quadratic residual risk is also obtained.
description: 24 pages
The Large Array Survey Telescope -- System Overview and Performances
Creators: name: Ofek, E. O.
name: Ben-Ami, S.
name: Polishook, D.
name: Segre, E.
name: Blumenzweig, A.
name: Strotjohann, N. L.
name: Yaron, O.
name: Shani, Y. M.
name: Nachshon, S.
name: Shvartzvald, Y.
name: Hershko, O.
name: Engel, M.
name: Segre, M.
name: Segev, N.
name: Zimmerman, E.
name: Nir, G.
name: Judkovsky, Y.
name: Gal-Yam, A.
name: Zackay, B.
name: Waxman, E.
name: Kushnir, D.
name: Chen, P.
name: Azaria, R.
name: Manulis, I.
name: Diner, O.
name: Vandeventer, B.
name: Franckowiak, A.
name: Weimann, S.
name: Borowska, J.
name: Garrappa, S.
name: Zenin, A.
name: Ramazani, V. Fallah
name: Konno, R.
name: Kusters, D.
name: Sadeh, I.
name: Parsons, R. D.
name: Berge, D.
name: Kowalski, M.
name: Ohm, S.
name: Arcavi, I.
name: Bruch, R.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The Large Array Survey Telescope (LAST) is a wide-field visible-light telescope array designed to explore the variable and transient sky with a high cadence. LAST will be composed of 48, 28-cm f/2.2 telescopes (32 already installed) equipped with full-frame backside-illuminated cooled CMOS detectors. Each telescope provides a field of view (FoV) of 7.4 deg^2 with 1.25 arcsec/pix, while the system FoV is 355 deg^2 in 2.9 Gpix. The total collecting area of LAST, with 48 telescopes, is equivalent to a 1.9-m telescope. The cost-effectiveness of the system (i.e., probed volume of space per unit time per unit cost) is about an order of magnitude higher than most existing and under-construction sky surveys. The telescopes are mounted on 12 separate mounts, each carrying four telescopes. This provides significant flexibility in operating the system. The first LAST system is under construction in the Israeli Negev Desert, with 32 telescopes already deployed. We present the system overview and performances based on the system commissioning data. The Bp 5-sigma limiting magnitude of a single 28-cm telescope is about 19.6 (21.0), in 20 s (20x20 s). Astrometric two-axes precision (rms) at the bright-end is about 60 (30)\,mas in 20\,s (20x20 s), while absolute photometric calibration, relative to GAIA, provides ~10 millimag accuracy. Relative photometric precision, in a single 20 s (320 s) image, at the bright-end measured over a time scale of about 60 min is about 3 (1) millimag. We discuss the system science goals, data pipelines, and the observatory control system in companion publications.
description: Submitted to PASP, 15pp
Study of Surface Damage in Silicon by Irradiation with Focused Rubidium Ions
Creators: name: Xu, S.
name: Li, Y.
name: Verheijen, M. A.
name: Kieft, E. R.
name: Vredenbregt, E. J. D.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Cold atom ion sources have been developed and commercialized as alternative sources for focused ion beams (FIB). So far, applications and related research have not been widely reported. In this paper, a prototype rubidium FIB is used to study the irradiation damage of 8.5 keV beam energy Rb$^+$ ions on silicon to examine the suitability of rubidium for nanomachining applications. Transmission electron microscopy combined with energy dispersive X-ray spectroscopy is applied to silicon samples irradiated by different doses of rubidium ions. The experimental results show a duplex damage layer consisting of an outer layer of oxidation without Rb and an inner layer containing Rb mostly at the interface to the underlying Si substrate. The steady-state damage layer is measured to be $23.2(\pm 0.3)$ nm thick with a rubidium staining level of $7(\pm1)$ atomic percentage.
description: 13 pages, 5 figures
Dynamical density functional theory for orientable colloids including inertia and hydrodynamic interactions
Creators: name: Durán-Olivencia, Miguel A.
name: Goddard, Benjamin D.
name: Kalliadasis, Serafim
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Over the last few decades, classical density-functional theory (DFT) and its dynamic extensions (DDFTs) have become powerful tools in the study of colloidal fluids. Recently, previous DDFTs for spherically-symmetric particles have been generalised to take into account both inertia and hydrodynamic interactions, two effects which strongly influence non-equilibrium properties. The present work further generalises this framework to systems of anisotropic particles. Starting from the Liouville equation and utilising Zwanzig's projection-operator techniques, we derive the kinetic equation for the Brownian particle distribution function, and by averaging over all but one particle, a DDFT equation is obtained. Whilst this equation has some similarities with DDFTs for spherically-symmetric colloids, it involves a translational-rotational coupling which affects the diffusivity of the (asymmetric) particles. We further show that, in the overdamped (high friction) limit, the DDFT is considerably simplified and is in agreement with a previous DDFT for colloids with arbitrary shape particles.
description: dynamical density functional theory ; colloidal fluids ; arbitrary-shape particles ; orientable colloids
Updates to the DScribe Library: New Descriptors and Derivatives
Creators: name: Laakso, Jarno
name: Himanen, Lauri
name: Homm, Henrietta
name: Morooka, Eiaki V.
name: Jäger, Marc O. J.
name: Todorović, Milica
name: Rinke, Patrick
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We present an update of the DScribe package, a Python library for atomistic descriptors. The update extends DScribe's descriptor selection with the Valle-Oganov materials fingerprint and provides descriptor derivatives to enable more advanced machine learning tasks, such as force prediction and structure optimization. For all descriptors, numeric derivatives are now available in DSribe. For the many-body tensor representation (MBTR) and the Smooth Overlap of Atomic Positions (SOAP), we have also implemented analytic derivatives. We demonstrate the effectiveness of the descriptor derivatives for machine learning models of Cu clusters and perovskite alloys.
description: The following article has been submitted to The Journal of Chemical Physics. After it is published, it will be found at https://aip.scitation.org/toc/jcp/current
title: Adaptive Segmentation Techniques for Object Region Extraction from Images with Complex Lighting Environment
Creators: name: Valaparla, Deepthi P.
Publisher: name: Old Dominion University
publisherIdentifier: https://ror.org/04zjtrb98
publisherIdentifierScheme: ROR
Year: 2003

description: Automated image segmentation of objects in complex lighting environments is a difficult task since it is not possible to pre-define a threshold to distinguish the object from the background. It is ascertained that an effective threshold ctite1ion for such objects depends on the negative binomial distribution of the object region with respect to the background lighting. Based on this concept, a novel adaptive threshold selection method for automatic segmentation of the lumen region in endoscopic images is presented in this thesis. More precise lumen region and boundary are obtained by an integrated neighborhood search based region growing procedure whose speed is significantly enhanced by a quad-tree structure decomposition method. A boundary thinning and connecting algorithm, employing a novel search window on the preliminary boundary, provides a single-pixel-width-connected boundary. The new method does not need a priori knowledge about the image characteristics and is completely automatic. It reduces the computation time by 36% when compared to conventional threshold selection methods and facilitates high-speed response for real-time navigation of a vision-guided micro robotic endoscope.

A new adaptive threshold selection method for skin extraction from the normalized r-g histogram of a face image is also presented in this thesis. It is observed from the spatial analysis of the r-g histogram that skin regions appear as clusters having negative binomial distribution characteristics, thus enabling accurate skin extraction from the background which is random or uniform. The textures of the candidate skin region are further analyzed using wavelet packet decomposition to obtain a set of feature vectors. Classification of the regions as face or non-face is done by evaluating the Bhattacharya distance of each feature vector to a prototype vector. The adaptive method has an improved accuracy of 9% when compared to traditional face detection techniques with images in varying lighting conditions. Research is progressing towards development of a relative variance based lighting compensation technique to segment static color images in normalized color space.
Compartmental analysis of dynamic nuclear medicine data: regularization procedure and application to physiology
Creators: name: Fabrice, Delbary
name: Sara, Garbarino
Publisher: name: arXiv
Year: 2016
Subjects: subject: Medical Physics (physics.med-ph)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Numerical Analysis (math.NA)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Compartmental models based on tracer mass balance are extensively used in clinical and pre-clinical nuclear medicine in order to obtain quantitative information on tracer metabolism in the biological tissue. This paper is the second of a series of two that deal with the problem of tracer coefficient estimation via compartmental modelling in an inverse problem framework. While the previous work was devoted to the discussion of identifiability issues for 2, 3 and n-dimension compartmental systems, here we discuss the problem of numerically determining the tracer coefficients by means of a general regularized Multivariate Gauss Newton scheme. In this paper, applications concerning cerebral, hepatic and renal functions are considered, involving experimental measurements on FDG-PET data on different set of murine models.
The late-type stellar density profile in the Galactic Center: A statistical approach
Creators: name: Chappell, Samantha N.
name: Ghez, Andrea M.
name: Do, Tuan
name: Martinez, Gregory D.
name: Yelda, Sylvana
name: Sitarski, Breann N.
name: Lu, Jessica R.
name: Morris, Mark R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The late-type stellar population in the Galactic Center was first predicted to reside in a dynamically relaxed cusp (power law slope ranging from 3/2 to 7/4). However, observations - which rely on models to correct for projection effects - have suggested a flat distribution instead. The need for this correction is due to the lack of information regarding the line-of-sight distances. With a two decade long baseline in astrometric measurements, we are now able to measure significant projected radial accelerations, six of which are newly reported here, that directly constrain line-of-sight distances. Here we present a statistical approach to take advantage of this information and more accurately constrain the shape of the radial density profile of the late-type stellar population in the Galactic Center.
description: 3 pages, 1 figure, Proceedings of IAU Symposium 322nd: The Multi-Messenger Astrophysics of the Galactic Centre; 2016 July 18 - 22, Cairns (Australia)
H$α$ emission line sources from VLT-MUSE in a low-metallicity star forming region -- Dolidze 25
Creators: name: Ashraf, Mizna
name: Jose, Jessy
name: Herczeg, Gregory
name: Fang, Min
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The process of accretion through circumstellar disks in young stellar objects is an integral part of star formation and the $Hα$ emission line is a prominent signature of accretion in low-mass stars. We present the detection and characterization of $Hα$ emission line sources in the central region of a distant, low-metallicity young stellar cluster - Dolidze 25 (at $\sim$ 4.5 kpc) - using medium-resolution optical spectra (4750-9350 Å ) obtained with the Multi-Unit Spectroscopic Explorer (MUSE) at the VLT. We have identified 14 potential accreting sources within a rectangular region of (2$'$ x 1$'$) towards the center of the cluster based on the detection of strong and broad emissions in $Hα$ as well as the presence of other emission lines such as [OI] and $Hβ$. Based on their positions in both photometric color-magnitude and color-color diagrams, we have also confirmed that these objects belong to the pre-main sequence phase of star formation. Our results were compared with the disk and diskless members of the cluster previously identified by Guarcello et al. (2021) using near-IR colors, and all sources they had identified as disks were confirmed to be accreting based on the spectroscopic characteristics.
Combined single crystal polarized XAFS and XRD at high pressure: probing the interplay between lattice distortions and electronic order at multiple length scales in high $T_c$ cuprates
Creators: name: Fabbris, Gilberto
name: Hücker, Markus
name: Gu, Genda
name: Tranquada, John M.
name: Haskel, Daniel
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Some of the most exotic material properties derive from electronic states with short correlation length (~10-500 Å), suggesting that the local structural symmetry may play a relevant role in their behavior. Here we discuss the combined use of polarized x-ray absorption fine structure and x-ray diffraction at high pressure as a powerful method to tune and probe structural and electronic orders at multiple length scales. Besides addressing some of the technical challenges associated with such experiments, we illustrate this approach with results obtained in the cuprate La$_{1.875}$Ba$_{0.125}$CuO$_4$, in which the response of electronic order to pressure can only be understood by probing the structure at the relevant length scales.
description: 11 pages, 4 figures, accepted for publication in High Pressure Research
ZnO-based scintillating bolometers: New prospects to study double beta decay of $^{64}$Zn
Creators: name: Armatol, A.
name: Broerman, B.
name: Dumoulin, L.
name: Giuliani, A.
name: Khalife, H.
name: Laubenstein, M.
name: Loaiza, P.
name: de Marcillac, P.
name: Marnieros, S.
name: Nagorny, S. S.
name: Nisi, S.
name: Nones, C.
name: Olivieri, E.
name: Pagnanini, L.
name: Pirro, S.
name: Poda, D. V.
name: Scarpaci, J. -A.
name: Zolotarova, A. S.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The first detailed study on the performance of a ZnO-based cryogenic scintillating bolometer as a detector to search for rare processes in zinc isotopes was performed. A 7.2 g ZnO low-temperature detector, containing more than 80\% of zinc in its mass, exhibits good energy resolution of baseline noise 1.0--2.7 keV FWHM at various working temperatures resulting in a low-energy threshold for the experiment, 2.0--6.0 keV. The light yield for $β$/$γ$ events was measured as 1.5(3) keV/MeV, while it varies for $α$ particles in the range of 0.2--3.0 keV/MeV. The detector demonstrate an effective identification of the $β$/$γ$ events from $α$ events using time-properties of only heat signals. %(namely, Rise time parameter). The radiopurity of the ZnO crystal was evaluated using the Inductively Coupled Plasma Mass Spectrometry, an ultra-low-background High Purity Ge $γ$-spectrometer, and bolometric measurements. Only limits were set at the level of $\mathcal{O}$(1--100) mBq/kg on activities of \Nuc{K}{40}, \Nuc{Cs}{137} and daughter nuclides from the U/Th natural decay chains. The total internal $α$-activity was calculated to be 22(2) mBq/kg, with a major contribution caused by 6(1) mBq/kg of \Nuc{Th}{232} and 12(2) mBq/kg of \Nuc{U}{234}. Limits on double beta decay (DBD) processes in \Nuc{Zn}{64} and \Nuc{Zn}{70} isotopes were set on the level of $\mathcal{O}(10^{17}$--$10^{18})$ yr for various decay modes profiting from 271 h of acquired background data in the above-ground lab. This study shows a good potential for ZnO-based scintillating bolometers to search for DBD processes of Zn isotopes, especially in \Nuc{Zn}{64}, with the most prominent spectral features at $\sim$10--20 keV, like the two neutrino double electron capture. A 10 kg-scale experiment can reach the experimental sensitivity at the level of $\mathcal{O}(10^{24})$ yr.
description: Prepared for submission to JINST; 27 pages, 9 figures, and 7 tables
Sub-picosecond energy transfer from a highly intense THz pulse to water: a computational study based on the TIP4P/2005 model
Creators: name: Mishra, Pankaj Kr.
name: Vendrell, Oriol
name: Santra, Robin
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The dynamics of ultrafast energy transfer to water clusters and to bulk water by a highly intense, sub-cycle THz pulse of duration $\approx$~150~fs is investigated in the context of force-field molecular dynamics simulations. We focus our attention on the mechanisms by which rotational and translational degrees of freedom of the water monomers gain energy from these sub-cycle pulses with an electric field amplitude of up to about 0.6~V/Å. It has been recently shown that pulses with these characteristics can be generated in the laboratory [PRL 112, 213901 (2014)]. Through their permanent dipole moment, water molecules are acted upon by the electric field and forced off their preferred hydrogen-bond network conformation. This immediately sets them in motion with respect to one another as energy quickly transfers to their relative center of mass displacements. We find that, in the bulk, the operation of these mechanisms is strongly dependent on the initial temperature and density of the system. In low density systems, the equilibration between rotational and translational modes is slow due to the lack of collisions between monomers. As the initial density of the system approaches 1~g/cm$^3$, equilibration between rotational and translational modes after the pulse becomes more efficient. In turn, low temperatures hinder the direct energy transfer from the pulse to rotational motion owing to the resulting stiffness of the hydrogen bond network. For small clusters of just a few water molecules we find that fragmentation due to the interaction with the pulse is faster than equilibration between rotations and translations, meaning that the latter remain colder than the former after the pulse.
A Seven-Day Multi-Wavelength Flare Campaign on AU Mic I: High-Time Resolution Light Curves and the Thermal Empirical Neupert Effect
Creators: name: Tristan, Isaiah I.
name: Notsu, Yuta
name: Kowalski, Adam F.
name: Brown, Alexander
name: Wisniewski, John P.
name: Osten, Rachel A.
name: Vrijmoet, Eliot H.
name: White, Graeme L.
name: Carter, Brad D.
name: Grady, Carol A.
name: Henry, Todd J.
name: Hinojosa, Rodrigo H.
name: Lomax, Jamie R.
name: Neff, James E.
name: Paredes, Leonardo A.
name: Soutter, Jack
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present light curves and flares from a seven day, multi-wavelength observational campaign of AU Mic, a young and active dM1e star with exoplanets and a debris disk. We report on 73 unique flares between the X-ray to optical data. We use high-time resolution NUV photometry and soft X-ray (SXR) data from XMM-Newton to study the empirical Neupert effect, which correlates the gradual and impulsive phase flaring emissions. We find that 65% (30 of 46) flares do not follow the Neupert effect, which is three times more excursions than seen in solar flares, and propose a four part Neupert effect classification (Neupert, Quasi-Neupert, Non-Neupert I & II) to explain the multi-wavelength responses. While the SXR emission generally lags behind the NUV as expected from the chromospheric evaporation flare models, the Neupert effect is more prevalent in larger, more impulsive flares. Preliminary flaring rate analysis with X-ray and U-band data suggests that previously estimated energy ratios hold for a collection of flares observed over the same time period, but not necessarily for an individual, multi-wavelength flare. These results imply that one model cannot explain all stellar flares and care should be taken when extrapolating between wavelength regimes. Future work will expand wavelength coverage using radio data to constrain the nonthermal empirical and theoretical Neupert effects to better refine models and bridge the gap between stellar and solar flare physics.
description: 46 pages, 18 figures, 15 tables. Accepted for publication in The Astrophysical Journal
Field theories on $ρ$-deformed Minkowski space-time
Creators: name: Hersent, Kilian
name: Wallet, Jean-Christophe
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We study one-loop perturbative properties of scalar field theories on the $ρ$-Minkowski space. The corresponding star-product, together with the involution are characterized from a combination of Weyl quantization and defining properties of the convolution algebra of the Euclidean group linked to the coordinate algebra of the $ρ$-Minkowski space. The natural integration measure linked to the Haar measure of the Euclidean group defines a trace for the star-product. One-loop properties of the 2-point and 4-point functions for families of complex-valued scalar field theories on $ρ$-Minkowski space are examined. For scalar theories with orientable interaction, the 2-point function is found to receive UV quadratically diverging one-loop corrections in 4 dimensions while no IR singularities generating UV/IR mixing appears. These however occur in the one-loop corrections to the 4-point function. As well, one-loop 2-point functions for theories with non-orientable interaction involve such IR singularities. These results are discussed.
description: 19 pages