cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Engineering axion insulator phase in superlattices with inversion symmetry breaking
Creators: name: Islam, Rajibul
name: Mardanya, Sougata
name: Lau, Alexander
name: Cuono, Giuseppe
name: Chang, Tay-Rong
name: Singh, Bahadur
name: Canali, Carlo M.
name: Dietl, Tomasz
name: Autieri, Carmine
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study theoretically the interplay between magnetism and topology in three-dimensional HgTe/MnTe superlattices stacked along the (001) axis. Our results show the evolution of the magnetic topological phases with respect to the magnetic configurations. An axion insulator phase is observed for the antiferromagnetic order with the out-of-plane Néel vector direction below a critical thickness of MnTe, which is the ground state amongst all magnetic configurations. Defining $T$ as the time-reversal symmetry, this axion insulator phase is protected by a magnetic two-fold rotational symmetry $C_2{\cdot}T$. The axion insulator phase evolves into a trivial insulator as we increase the thickness of the magnetic layers. By switching the Néel vector direction into the $ab$ plane, the system realizes different antiferromagnetic topological insulators depending on the thickness of MnTe. These phases feature gapless surface Dirac cones shifted away from high-symmetry points on surfaces perpendicular to the Néel vector direction of the magnetic layers. In the presence of ferromagnetism, the system realizes a magnetic Weyl semimetal and a ferromagnetic semimetal for out-of-plane and in-plane magnetization directions, respectively. We observe large anomalous Hall conductivity in the presence of ferromagnetism in the three-dimensional superlattice.
description: 14 pages, 13 figures
The Emergent Copenhagen Interpretation of Quantum Mechanics
Creators: name: Hollowood, Timothy J.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We introduce a new and conceptually simple interpretation of quantum mechanics based on reduced density matrices of sub-systems from which the standard Copenhagen interpretation emerges as an effective description of macroscopically large systems. Wave function collapse is seen to be a useful but fundamentally unnecessary piece of prudent book keeping which is only valid for macro-systems. The new interpretation lies in a class of modal interpretations in that it applies to quantum systems that interact with a much larger environment. However, we show that it does not suffer from the problems that have plagued similar modal interpretations like macroscopic superpositions and rapid flipping between macroscopically distinct states. We describe how the interpretation fits neatly together with fully quantum formulations of statistical mechanics and that a measurement process can be viewed as a process of ergodicity breaking analogous to a phase transition. The key feature of the new interpretation is that joint probabilities for the ergodic subsets of states of disjoint macro-systems only arise as emergent quantities. Finally we give an account of the EPR-Bohm thought experiment and show that the interpretation implies the violation of the Bell inequality characteristic of quantum mechanics but in a way that is rather novel. The final conclusion is that the Copenhagen interpretation gives a completely satisfactory phenomenology of macro-systems interacting with micro-systems.
description: 21 pages
Topological phase in Kitaev chain with spatially separated pairing processes
Creators: name: Shi, Y. B.
name: Song, Z.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The dynamic balance between pair creation and annihilation processes takes a crucial role to the topological superconductivity in Kitaev model. Here we study the effect of spatial separation of creation and annihilation terms, i.e., sources and drains of pair are arranged alternatively. In this regard, a non-Hermitian Hamiltonian is naturally considered, which may possess complex energy branches. However, when the Bardeen-Cooper-Schrieffer pair (BCS)-like pair excitation is only considered, the spectrum in such a subspace is fully real. In particular, the Zak phases extracted from the pair wave function are quantized and therefore able to characterize the different phases regardless of the breaking of time reversal symmetry. For open chain system, the corresponding Majorana lattice is investigated. We find that although there are complex modes, all the edge modes have zero energy and obey the bulk-boundary correspondence. This results in the Kramerlike degeneracy of both the real and complex levels as a signature of the topologically non-trivial phase.
description: 12 pages, 8 figures
Optimal Strategies for Simultaneous Vickrey Auctions with Perfect Substitutes
Creators: name: Gerding, Enrico H.
name: Dash, Rajdeep Kumar
name: Byde, Andrew
name: Jennings, Nicholas Robert
Publisher: name: arXiv
Year: 2014
Subjects: subject: Computer Science and Game Theory (cs.GT)
subject: FOS: Computer and information sciences

description: We derive optimal strategies for a bidding agent that participates in multiple, simultaneous second-price auctions with perfect substitutes. We prove that, if everyone else bids locally in a single auction, the global bidder should always place non-zero bids in all available auctions, provided there are no budget constraints. With a budget, however, the optimal strategy is to bid locally if this budget is equal or less than the valuation. Furthermore, for a wide range of valuation distributions, we prove that the problem of finding the optimal bids reduces to two dimensions if all auctions are identical. Finally, we address markets with both sequential and simultaneous auctions, non-identical auctions, and the allocative efficiency of the market.
Experimental Observation of a Magnetic Interfacial Effect
Creators: name: Silva, Wibson W. G.
name: Degiorgi, Sérgio V. B.
name: Holanda, José
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We observed a magnetic interfacial effect due to the coupling between two interfaces of different materials. The interface is compoust of an antiferromagnetic and other quasi-ferromagnetic material. This effect we measured through the ferromagnetic resonance technique without and with electric current.
A DFT-based Molecular Transport Implementation in ADF/BAND
Creators: name: Verzijl, C. J. O.
name: Thijssen, J. M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: We present a novel implementation of the first-principles approach to molecular charge transport using the non-equilibrium Green's function formalism in combination with the ADF/BAND periodic band-structure DFT code, together with results for several example systems. As a proof of concept, we first discuss transport calculations on 1D chains of Li and Al atoms. We then present a detailed study of BDT and archetypal molecular wires from the OPE-family, sandwiched between 3D Au contacts, comparing well with results from the literature. Our implementation further allows us to make a comparison of 3D contacts with and without periodic boundary conditions, the latter being particularly useful for modeling the needle-shaped contacts used in break-junction experiments.
Carrier and Phonon Dynamics in Multilayer WSe2 captured by Extreme Ultraviolet Transient Absorption Spectroscopy
Creators: name: Oh, Juwon
name: Chang, Hung-Tzu
name: Chen, Christopher T.
name: Aloni, Shaul
name: Schwartzberg, Adam
name: Leone, Stephen R.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Carrier and phonon dynamics in a multilayer WSe2 film are captured by extreme ultraviolet (XUV) transient absorption (TA) spectroscopy at the W N6,7, W O2,3, and Se M4,5 edges (30-60 eV). After the broadband optical pump pulse, the XUV probe directly reports on occupations of optically excited holes and phonon-induced band renormalizations. By comparing with density functional theory calculations, XUV transient absorption due to holes are identified below the W O3 edge whereas signals at the Se M4,5 edges are dominated by phonon dynamics. Therein, 0.4 ps hole relaxation time, 1.5 ps carrier recombination time, and 1.7 ps phonon heating time are extracted. The acquisition of hole and phonon-induced signals in a single experiment can facilitate the investigation of the correlations between electron and phonon dynamics. Furthermore, the simultaneous observation of signals from different elements can be further extended to explore photochemical processes in multilayers and alloys, thereby providing key information for their applications in electronics, photocatalysts, and spintronics.
description: 26 pages, 7 figures
Potts model with invisible states on a scale-free network
Creators: name: Sarkanych, P.
name: Krasnytska, M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Different models are proposed to understand magnetic phase transitions through the prism of competition between the energy and the entropy. One of such models is a $q$-state Potts model with invisible states. This model introduces $r$ invisible states such that if a spin lies in one of them, it does not interact with the rest states. We consider such a model using the mean field approximation on an annealed scale-free network where the probability of a randomly chosen vertex having a degree $k$ is governed by the power-law $P(k)\propto k^{-λ}$. Our results confirm that $q$, $r$ and $λ$ play a role of global parameters that influence the critical behaviour of the system. Depending on their values, the phase diagram is divided into three regions with different critical behaviours. However, the topological influence, presented by the marginal value of $λ_c(q)$, has proven to be dominant over the entropic influence, governed by the number of invisible states $r$.
description: 12 pages, 10 figures
Compromise and symbolic gestures: the complexity of implementing a gender equity measure in STEM organisations in Australia
Creators: name: Barnes, Susan Christine
Publisher: name: Macquarie University
Year: 2022
Subjects: Other education not elsewhere classified

description: The lack of gender diversity in science, technology, engineering, and mathematics (STEM) has been named and evidenced as a problem for decades, despite wellintentioned efforts to address. While there is clear evidence that organisational culture is a contributing factor, research remains largely focused on explorations and descriptions of the reasons why women leave STEM. Recently, academic attention has shifted toward the understudied gender equity programs, which are used by STEM organisations to address gender inequality. The programs are not delivering the expected results, and the complexities of program implementation may be one reason why gender equity programs are failing. Feminist scholars have begun to examine these programs however implementation problems have so far been overlooked, which limits the understanding of why those programs underperform. This study responds to calls from scholars for research to focus on processes and the complexity of gender equity program implementation as a potentially crucial component of sustainable and enduring change. Adopting a pragmatic research paradigm and drawing on feminist, action research, and grounded theory principles, this thesis conducts a case study of a pilot program currently underway at four STEM organisations that anonymises grant applications for access to large-scale scientific instruments. In addition to providing new insights into the complexity of implementing a gender equity measure in STEM organisations in Australia, the study provides two theoretical contributions to feminist organisational studies. Firstly, through recognising that a theory of implementation is required within the gender equity literature. Secondly, in taking the first step towards developing that theory. Finally, the research provides lessons learned from the pilot which can be integrated into future programs and shine a light on the design of gender equity programs targeting long-lasting structural and cultural change in STEM workplaces in Australia.
Machine Learning for Screening Large Organic Molecules
Creators: name: Gaul, Christopher
name: Cuesta-Lopez, Santiago
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Machine Learning (cs.LG)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: J.2
subject: 68T07

description: Organic semiconductors are promising materials for cheap, scalable and sustainable electronics, light-emitting diodes and photovoltaics. For organic photovoltaic cells, it is a challenge to find compounds with suitable properties in the vast chemical compound space. For example, the ionization energy should fit to the optical spectrum of sun light, and the energy levels must allow efficient charge transport. Here, a machine-learning model is developed for rapidly and accurately estimating the HOMO and LUMO energies of a given molecular structure. It is build upon the SchNet model (Schütt et al. (2018)) and augmented with a `Set2Set' readout module (Vinyals et al. (2016)). The Set2Set module has more expressive power than sum and average aggregation and is more suitable for the complex quantities under consideration. Most previous models have been trained and evaluated on rather small molecules. Therefore, the second contribution is extending the scope of machine-learning methods by adding also larger molecules from other sources and establishing a consistent train/validation/test split. As a third contribution, we make a multitask ansatz to resolve the problem of different sources coming at different levels of theory. All three contributions in conjunction bring the accuracy of the model close to chemical accuracy.
description: Presented at E-MRS Fall Meeting 2022, Symposium C
Strata : Mapping climate, environmental and security vulnerability hotspots
Creators: name: Space for Climate Observatory
Publisher: name: GEO Knowledge Hub
Year: 2024
Subjects: Conflict
Migration
Hotspot map
Stress factors
Climate change
Socio-economic vulnerabilities

description: Strata is a comprehensive tool that integrates spatial datasets for climate, environment, and peace and security-related stress factors. The platform aggregates these datasets with additional layers of information on population exposure and socioeconomic vulnerability, resulting in a 'hotspot' map that highlights areas where these stressors converge.
Details
Strata was developed by Earth Blox, the United Nations Environment Programme (UNEP), and the University of Edinburgh. This tool aids over 130 UN country teams by consolidating data from diverse sources into a single platform, providing clarity on where environmental and climatic stresses intersect with socio-economic vulnerabilities and insecurities. Strata demonstrates the convergence of environmental stressors, explains changes in hotspot intensity, and identifies interactions with social and economic variables that increase risks of fragility, conflict, migration, or ineffective response.
Strata's approach is based on the Intergovernmental Panel on Climate Change's (IPCC) conceptualization of risk, combining hazard, exposure, and vulnerability. Each indicator is assigned a threshold value, and surpassing this threshold marks it as a 'red flag.' The resulting hotspot map showcases the cumulative count of these red flags, highlighting regions where multiple stress factors occur simultaneously.
The project was implemented globally, with a particular focus on Somalia, and it employs data from sources such as Google Earth Engine, Sentinel-2, MODIS, SRTM, Landsat, ACLED, FEWS NET, WorldPop Global Project, VIIRS, and The Malaria Atlas Project.
More
To learn more about the application please explore Space Climate Observatory website and Strata web platform. Website is available in English and French.
Dineutron decay into sterile anti-neutrinos in neutron stars and its observable consequences
Creators: name: Hao, Yongliang
name: Ni, Dongdong
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In some extensions of the Standard Model (SM), two neutrons are allowed to decay into two sterile anti-neutrinos ($nn \rightarrow \barχ\barχ$) via new scalar bosons. This process violates both the baryon number ($\mathcal{B}$) and the lepton number ($\mathcal{L}$) by two units but conserves their difference $(\mathcal{B}-\mathcal{L})$. Neutron stars contain a large number of neutrons and thus the $nn \rightarrow \barχ\barχ$ process can be greatly enhanced inside a neutron star. This process could result in non-trivial effects that are different from the SM predictions and can be explored through astrophysical and laboratory observations. Furthermore, a large number of sterile antineutrinos, which may be dark matter candidates, can be emitted from the interior of the neutron star. The properties of the emitted particles show a particular pattern that can be uniquely determined by the mass and radius of the neutron star. In addition, the dineutron decay may contribute to the orbital-period change of the binary systems containing neutron stars. We analyze the possibility to constrain the mass of the new scalar bosons using the observations of the binary's orbital-period changes. It is found that the mass of the new scalar bosons is roughly restricted in the range from 1 TeV to several TeV, which is possibly within the reach of direct searches at the LHC or future high-energy experiments. The joint analysis which combines the astrophysics and particle phenomenology could provide an excellent opportunity for the study of the new physical effects beyond the SM.
description: 12 pages, 1 table, and 8 figures
ViTAL: Vision-Based Terrain-Aware Locomotion for Legged Robots
Creators: name: Fahmi, Shamel
name: Barasuol, Victor
name: Esteban, Domingo
name: Villarreal, Octavio
name: Semini, Claudio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: This work is on vision-based planning strategies for legged robots that separate locomotion planning into foothold selection and pose adaptation. Current pose adaptation strategies optimize the robot's body pose relative to given footholds. If these footholds are not reached, the robot may end up in a state with no reachable safe footholds. Therefore, we present a Vision-Based Terrain-Aware Locomotion (ViTAL) strategy that consists of novel pose adaptation and foothold selection algorithms. ViTAL introduces a different paradigm in pose adaptation that does not optimize the body pose relative to given footholds, but the body pose that maximizes the chances of the legs in reaching safe footholds. ViTAL plans footholds and poses based on skills that characterize the robot's capabilities and its terrain-awareness. We use the 90 kg HyQ and 140 kg HyQReal quadruped robots to validate ViTAL, and show that they are able to climb various obstacles including stairs, gaps, and rough terrains at different speeds and gaits. We compare ViTAL with a baseline strategy that selects the robot pose based on given selected footholds, and show that ViTAL outperforms the baseline.
description: IEEE Transactions on Robotics, 2022. part of dissertation arXiv:2212.00683
Adaptive Stochastic Resource Control: A Machine Learning Approach
Creators: name: Csáji, Balázs Csanád
name: Monostori, László
Publisher: name: arXiv
Year: 2014
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: The paper investigates stochastic resource allocation problems with scarce, reusable resources and non-preemtive, time-dependent, interconnected tasks. This approach is a natural generalization of several standard resource management problems, such as scheduling and transportation problems. First, reactive solutions are considered and defined as control policies of suitably reformulated Markov decision processes (MDPs). We argue that this reformulation has several favorable properties, such as it has finite state and action spaces, it is aperiodic, hence all policies are proper and the space of control policies can be safely restricted. Next, approximate dynamic programming (ADP) methods, such as fitted Q-learning, are suggested for computing an efficient control policy. In order to compactly maintain the cost-to-go function, two representations are studied: hash tables and support vector regression (SVR), particularly, nu-SVRs. Several additional improvements, such as the application of limited-lookahead rollout algorithms in the initial phases, action space decomposition, task clustering and distributed sampling are investigated, too. Finally, experimental results on both benchmark and industry-related data are presented.
Applicability of the Wide-Band Limit in DFT-Based Molecular Transport Calculations
Creators: name: Verzijl, C. J. O.
name: Seldenthuis, J. S.
name: Thijssen, J. M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Transport properties of molecular junctions are notoriously expensive to calculate with ab initio methods, primarily due to the semi-infinite electrodes. This has led to the introduction of different approximation schemes for the electrodes. For the most popular metals used in experiments, such as gold, the wide-band limit (WBL) is a particularly efficient choice. In this paper we investigate the performance of different WBL schemes relative to more sophisticated approaches including the fully self-consistent non-equilibrium Green's function (NEGF) method. We find reasonably good agreement between all schemes for systems in which the molecule (and not the metal-molecule interface) dominates the transport properties. Moreover, our implementation of the WBL requires negligible computational effort compared to the ground state DFT calculation of a molecular junction. We also present a new approximate but efficient scheme for calculating transport with a finite bias. Provided the voltage drop occurs primarily inside the molecule, this method provides results in reasonable agreement with fully self-consistent calculations.
Discover Buckinghamshire Museum, Buckinghamshire Archives, Buckinghamshire Archaeological Service, Conservation and Archaeolgy in Milton Keynes 2021
Creators: name: Mason, Sam
name: Williams, Daniel
name: Alqassar, Eliza
name: Crank, Nick A
Publisher: name: Archaeology Data Service
Year: 2023

description: Records of Buckinghamshire, 63, 261-269
FeRhCrSi: A new spin semimetal with room temperature spin-valve behavior
Creators: name: Venkateswara, Y.
name: Nag, Jadupati
name: Samatham, S. Shanmukharao
name: Patel, Akhilesh Kumar
name: Babu, P. D.
name: Varma, Manoj Raama
name: Nayak, Jayita
name: Suresh, K. G.
name: Alam, Aftab
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Spin semimetals are a recently discovered new class of spintronic materials, which exhibit a band gap in one spin channel while a semimetallic feature in the other and thus allows for tunable spin transport. Here, we present experimental verification of spin semimetallic behavior in FeRhCrSi, a quaternary Heusler alloy with saturation moment 2 $μ_B$ and Curie temperature $>$ 400 K. It crystallises in the L2$_1$ structure with 50$\%$ antisite disorder between Fe and Rh. Below 300 K, it shows a weakly temperature dependent electrical resistivity with negative temperature coefficient, indicating the normal semimetal or spin semimetal behavior. Anomalous magnetoresistance data reveals dominant contribution from asymmetric part, a clear signature of spin-valve nature, which is retained even at room temperature. \textcolor{black}{The asymmetric part of magneto-resistance shows an unusual increase with increasing temperature.} Hall measurements confirm the anomalous nature of conductivity originating from the intrinsic Berry curvature, with holes being the majority carriers. Ab-initio simulation confirms a unique long-range ferrimagnetic ordering to be the ground state, explaining the origin behind the unexpected low saturation moment. The ferrimagnetic disordered structure confirms the spin semimetallic feature of FeRhCrSi, as observed experimentally.
description: FeRhCrSi, Quaternary Heusler Alloys, Spin semimetal, Spin valve, Heusler alloys, Half metal, High T_C Heusler alloys, Fleur, FLAPW, unfolded band structure
Pengines: Web Logic Programming Made Easy
Creators: name: Lager, Torbjörn
name: Wielemaker, Jan
Publisher: name: arXiv
Year: 2014
Subjects: subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences

description: When developing a (web) interface for a deductive database, functionality required by the client is provided by means of HTTP handlers that wrap the logical data access predicates. These handlers are responsible for converting between client and server data representations and typically include options for paginating results. Designing the web accessible API is difficult because it is hard to predict the exact requirements of clients. Pengines changes this picture. The client provides a Prolog program that selects the required data by accessing the logical API of the server. The pengine infrastructure provides general mechanisms for converting Prolog data and handling Prolog non-determinism. The Pengines library is small (2000 lines Prolog, 150 lines JavaScript). It greatly simplifies defining an AJAX based client for a Prolog program and provides non-deterministic RPC between Prolog processes as well as interaction with Prolog engines similar to Paul Tarau's engines. Pengines are available as a standard package for SWI-Prolog 7.
description: To appear in Theory and Practice of Logic Programming
AtomVision: A machine vision library for atomistic images
Creators: name: Choudhary, Kamal
name: Gurunathan, Ramya
name: DeCost, Brian
name: Biacchi, Adam
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Image and Video Processing (eess.IV)
subject: FOS: Physical sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: Computer vision techniques have immense potential for materials design applications. In this work, we introduce an integrated and general-purpose AtomVision library that can be used to generate, curate scanning tunneling microscopy (STM) and scanning transmission electron microscopy (STEM) datasets and apply machine learning techniques. To demonstrate the applicability of this library, we 1) generate and curate an atomistic image dataset of about 10000 materials, 2) develop and compare convolutional and graph neural network models to classify the Bravais lattices, 3) develop fully convolutional neural network using U-Net architecture to pixelwise classify atom vs background, 4) use generative adversarial network for super-resolution, 5) curate a natural language processing based image dataset using open-access arXiv dataset, and 6) integrate the computational framework with experimental microscopy tools. AtomVision library is available at https://github.com/usnistgov/atomvision.
Molding the flow of light with a magnetic field: plasmonic cloaking and directional scattering
Creators: name: Kort-Kamp, W. J. M.
name: Rosa, F. S. S.
name: Pinheiro, F. A.
name: Farina, C.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We investigate electromagnetic scattering and plasmonic cloaking in a system composed by a dielectric cylinder coated with a magneto-optical shell. In the long-wavelength limit we demonstrate that the application of an external magnetic field can not only switch on and off the cloaking mechanism but also mitigate losses, as the absorption cross-section is shown to be minimal precisely at the cloaking operation frequency band. We also show that the angular distribution of the scattered radiation can be effectively controlled by applying an external magnetic field, allowing for a swift change in the scattering pattern. By demonstrating that these results are feasible with realistic, existing magneto-optical materials, such as graphene epitaxially grown on SiC, we suggest that magnetic fields could be used as an effective, versatile external agent to tune plasmonic cloaks and to dynamically control electromagnetic scattering in an unprecedented way, we hope that these results may find use in disruptive photonic technologies.
description: 7 pages, 8 figures
Ideal Graphene/Silicon Schottky Junction Diodes
Creators: name: Sinha, Dhiraj
name: Lee, Ji Ung
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The proper understanding of semiconductor devices begins at the metal-semiconductor interface. The metal/semiconductor interface itself can also be an important device, as Schottky junctions often forms when the doping in the semiconductors is low. Here, we extend the analysis of metal-silicon Schottky junctions by using graphene, an atomically thin semimetal. We show that a fundamentally new transport model is needed to describe the graphene-silicon Schottky junction. While the current-voltage behavior follows the celebrated ideal diode behavior, the details of the diode characteristics is best characterized by the Landauer transport formalism, suggesting that the injection rate from graphene ultimately determines the transport properties of this new Schottky junction.
description: 13 pages, 4 figures
Overcoming Auger recombination in nanocrystal quantum dot laser using spontaneous emission enhancement
Creators: name: Gupta, Shilpi
name: Waks, Edo
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We propose a method to overcome Auger recombination in nanocrystal quantum dot lasers using cavity-enhanced spontaneous emission. We derive a numerical model for a laser composed of nanocrystal quantum dots coupled to optical nanocavities with small mode-volume. Using this model, we demonstrate that spontaneous emission enhancement of the biexciton transition lowers the lasing threshold by reducing the effect of Auger recombination. We analyze a photonic crystal nanobeam cavity laser as a realistic device structure that implements the proposed approach.
description: 18 pages, 6 figures
Regularized solution of a nonlinear problem in electromagnetic sounding
Creators: name: Deidda, Gian Piero
name: Fenu, Caterina
name: Rodriguez, Giuseppe
Publisher: name: arXiv
Year: 2014
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: We propose a regularization method to solve a nonlinear ill-posed problem connected to inversion of data gathered by a ground conductivity meter.
أثر رأس المال الفكري على إنجاح تطوير منتجات منظمات الأعمال دراسة استطلاعية في منظمة Condor لصناعة الأجهزة الالكترونية والكهرومنزلية ببرج بوعريريج- الجزائر
Creators: name: Khaled, Gachi
Publisher: name: figshare
Year: 2020
Subjects: subject: 150305 Human Resources Management
subject: FOS: Economics and business

description: تناولت هذه الدراسة موضوع أثر رأس المال الفكري على إنجاح تطوير منتجات منظمات الأعمال بدراسة حالة منظمة Condor لصناعة الأجهزة الالكترونية و الكهرومنزلية، وذلك من خلال التعرف على مدى توافر رأس المال الفكري بمكوناته الثلاثة (البشري، الهيكلي، الزبوني) لدى المنظمة محل الدراسة، ودراسة العلاقة بين توافر تلك المكونات وإنجاح عملية تطوير المنتجات. وذلك من أجل الإجابة عن السؤال المحوري للدراسة المتمثل في مدى مساهمة رأس المال الفكري في إنجاح تطوير المنتجات بمنظمة Condor. تكوّن مجتمع الدراسة من جميع المدراء ونوابهم العاملين لدى منظمة Condor، والبالغ عددهم 49 موظفا. ولصغر حجم مجتمع الدراسة فقد تم استخدام أسلوب الحصر الشامل في جمع بيانات الدراسة، حيث تم توزيع استبيان تم إعداده لهذا الغرض على جميع أفراد مجتمع الدراسة، وتم استرداد 45 استبيان صالح للتحليل. أظهرت الدراسة عدة نتائج من أهمها، وجود علاقة ارتباط وأثر معنويتين بين توافر مكونات رأس المال الفكري وإنجاح تطوير المنتجات بمنظمة Condor، وأن إنجاح تطوير منتجات المنظمة يتحقق بمستوى عالي. كما أوضحت الدراسة بأن هناك تفاوت في تأثير مكونات رأس المال الفكري في إنجاح تطوير المنتجات بالمنظمة محل الدراسة. حيث أن رأس المال الهيكلي يساهم بشكل أكبر من المكونات الأخرى لرأس المال الفكري في إنجاح تطوير منتجات المنظمة المبحوثة.
Multifractality due to long-range correlation in the L-band ionospheric scintillation S4 index time series
Creators: name: Tanna, H. J.
name: Pathak, K. N.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: The earth's ionosphere is well recognized as a dynamical system and non-linearly coupled with the magnetosphere above and natural atmosphere below.The shape and time variability of the ionosphere indeed shows chaos, pattern formation, random behavior and self-organization. The present paper studies the propriety of Multifractal Detrended Fluctuation Analysis (MF-DFA) technique for the ionospheric scintillation index time series. MF-DFA is used to identify the scaling behavior of the ionospheric scintillation time-series data of two different nature.The obtained results show the robustness and the relevancy of the MF-DFA technique for the ionospheric scintillation index time series. The comparison of the MF-DFA results of original data to those of shuffled and surrogate series shows that the multifractal nature of considered time series is almost due to long-range correlations. Subsequently, the Hurst exponents derived from two parallel methods namely Re-scaled range analysis (R/S) and Auto Correlation Function (ACF) are also suggesting the presence of long range correlation. The presented results in this work may be of assistance for future modeling and simulation studies.
description: 11 Pages, 8 figures, accepted in the Astrophysics and space science. arXiv admin note: text overlap with arXiv:astro-ph/0602461, arXiv:physics/0608056 by other authors
What if young z>9 JWST galaxies hosted massive black holes?
Creators: name: Volonteri, Marta
name: Habouzit, Melanie
name: Colpi, Monica
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: JWST is discovering star forming `candidate' galaxies with photometric redshifts $z>9$ and little attenuation. We model presumptive massive black holes (MBHs) in such galaxies and find that their unobscured emission is fainter than the galaxy starlight in JWST filters, and difficult to be detected via color-color selection, and X-ray and radio observations. Only MBHs overmassive relative to expected galaxy scaling relations, accreting at high Eddington rates, would be detectable. Their discovery would point to the presence of heavy MBH seeds, but care is needed to exclude the existence of lighter seeds as only overmassive MBHs are detectable in this type of galaxies. Conversely, if no overmassive MBHs are hosted in these galaxies, either there are no heavy seeds or they are rare. The most massive/highest redshift candidate galaxies can attain stellar masses in excess of 5e10 Msun by z~6 if they grow along the SFR-mass sequence, and can nurse a MBH growing from ~1e5 Msun up to >3e7 Msun by z~6, to become hosts of some z>6 quasars. Candidate galaxies of log(M_{gal}/Msun)~8 can not grow their putative seeds fast, unless seeds are >1e6 Msun. The number density of the JWST candidate galaxies far outnumbers that of the highest-z quasar hosts and this allows for about only 1 bright z~6-7 quasar every 1000 of these galaxies.
description: Published in MNRAS
NOTES: A 13th-century bronze buckle from Stone; A late Saxon pin from Skirmett; A spindle-whorl from Weston Turville; Castle tower, Little Missenden; An Anglo-Saxon brooch from Thornborough
Creators: name: Cherry, John
name: Farley, Michael
name: O'connor Thompson, S
name: Dickinson, Tania M
Publisher: name: Archaeology Data Service
Year: 2023

description: Records of Buckinghamshire, 22, 137-142
NOTES: A fourteenth-century effigy from St Michael's Church, Thornton; The oak screen at Brudenell House, Quainton; An unsung victory for Bucks cavalry
Creators: name: Parkhouse, Jonathan
name: Chenevix Trench, John
name: Cooper, Laurie
name: Kessler, David
Publisher: name: Archaeology Data Service
Year: 2023

description: Records of Buckinghamshire, 37, 164-172
PERFORMANCE EVALUATION OF FIELD WATER APPLICATION AT TENDAHO SUGAR PROJECT, ETHIOPIA
Creators: name: TADESSE GOBENA SHONKA
Publisher: name: Zenodo
Year: 2015

description: Sugarcane is fully irrigated crop in Ethiopia. But, there is little information on the field water application performances of sugar estate farms. Open canals are the main systems for supplying irrigation water in these farms. However, most of these schemes are frequently criticized for their low conveyance and field water application efficiencies. Under the water scarce situation, improving the canals conveyance efficiency and field water application can offers an opportunity to realize field level water savings. This study was done a purpose of identifying and understanding the current level of field water application efficiencies of Tendaho sugarcane irrigation scheme using appropriate on-field irrigation performance indicators. Primary/direct field data collection and some secondary data were used to undertake planned objectives. Canal conveyance evaluation was done for tertiary canals based priority of dominant conveyance defects observed in the sugar estate. Field water application evaluations were done during the normal irrigation practice of the sugar estate considering: application efficiency, storage efficiency, and deep percolation losses. The relationships between coefficient of uniformity and distribution uniformity have also described based on opportunity time for each quarters using the linear equation. Tertiary conveyance was evaluated by using volume flow measuring method using Parshall flumes set at inlet and outlet of representative canals. From results, the mean conveyance efficiency of tertiary canal was 59.589% with high amount of water losses. From field evaluation, most of field irrigation activities were not carried out on timely schedules. These resulted in overall mean on-field water application efficiency of 56.57%, 70.30% storage efficiency and 91.93% distribution uniformity at target application depth with the overall system efficiency of to 30.81%. Other factors found to affect irrigation efficiency are cut-off time, inflow rates, soil type, and furrow shapes.
CbwLoss: Constrained Bidirectional Weighted Loss for Self-supervised Learning of Depth and Pose
Creators: name: Wang, Fei
name: Cheng, Jun
name: Liu, Penglei
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Photometric differences are widely used as supervision signals to train neural networks for estimating depth and camera pose from unlabeled monocular videos. However, this approach is detrimental for model optimization because occlusions and moving objects in a scene violate the underlying static scenario assumption. In addition, pixels in textureless regions or less discriminative pixels hinder model training. To solve these problems, in this paper, we deal with moving objects and occlusions utilizing the difference of the flow fields and depth structure generated by affine transformation and view synthesis, respectively. Secondly, we mitigate the effect of textureless regions on model optimization by measuring differences between features with more semantic and contextual information without adding networks. In addition, although the bidirectionality component is used in each sub-objective function, a pair of images are reasoned about only once, which helps reduce overhead. Extensive experiments and visual analysis demonstrate the effectiveness of the proposed method, which outperform existing state-of-the-art self-supervised methods under the same conditions and without introducing additional auxiliary information.
description: accepted by the Transactions on Intelligent Transportation Systems on February 20, 2023
NOTES: A moated site at Bower Wood, Beaconsfield; A second Penn tile kiln site; West Wycombe Romano-British cemetery radiocarbon dates
Creators: name: Rains, M
name: Broadbent, J H
name: Farley, Michael
name: Wright, Richard V S
Publisher: name: Archaeology Data Service
Year: 2023

description: Records of Buckinghamshire, 23, 125-129
Online Planning Algorithms for POMDPs
Creators: name: Ross, Stéphane
name: Pineau, Joelle
name: Paquet, Sébastien
name: Chaib-draa, Brahim
Publisher: name: arXiv
Year: 2014
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Partially Observable Markov Decision Processes (POMDPs) provide a rich framework for sequential decision-making under uncertainty in stochastic domains. However, solving a POMDP is often intractable except for small problems due to their complexity. Here, we focus on online approaches that alleviate the computational complexity by computing good local policies at each decision step during the execution. Online algorithms generally consist of a lookahead search to find the best action to execute at each time step in an environment. Our objectives here are to survey the various existing online POMDP methods, analyze their properties and discuss their advantages and disadvantages; and to thoroughly evaluate these online approaches in different environments under various metrics (return, error bound reduction, lower bound improvement). Our experimental results indicate that state-of-the-art online heuristic search methods can handle large POMDP domains efficiently.
Studying Postmerger Outflows from Magnetized Neutrino-cooled Accretion Disks
Creators: name: Nouri, Fatemeh Hossein
name: Janiuk, Agnieszka
name: Przerwa, Małgorzata
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Neutrino-cooled accretion flow around a spinning black hole, produced by a compact binary merger is a promising scenario for jet formation and launching magnetically-driven outflows. Based on GW170817 gravitational wave detection by LIGO and Virgo observatories followed by electromagnetic counterparts, this model can explain the central engine of the short duration gamma ray bursts (GRB) and kilonova radiations. Using the open-source GRMHD HARM-COOL code, we evolved several 2D magnetized accretion disk-black hole models with realistic equation of state in the fixed curved space-time background. We applied particle tracer technique to measure the properties of the outflows. The disk and black hole's initial parameters are chosen in a way to represent different possible post-merger scenarios of the merging compact objects. Our simulations show a strong correlation between black hole's spin and ejected mass. Generally, mergers producing massive disks and rapidly spinning black holes launch stronger outflows. We observed our models generate winds with moderate velocity ($v/c \sim 0.1-0.2$), and broad range of electron fraction. We use these results to estimate the luminosity and light curves of possible radioactively powered transients emitted by such systems. We found the luminosity peaks within the range of $10^{40}-10^{42}$ erg/s which agrees with previous studies for disk wind outflows.
NOTES: Bletchley demolitions; The potteries at Buckland Common; Excavations on the Romano-British villa at Latimer; Bullbeggars Lane, Great Missenden; Chalfont St Giles wall-paintings; Chalfont St Peter church restorations; Stoke Mandeville old church demolition
Creators: name: Legg, Edward
name: Brackley, H
name: Branigan, Keith
name: Bennell, John E G
Publisher: name: Archaeology Data Service
Year: 2023

description: Records of Buckinghamshire, 17 (5), 414-417
Guiding continuous operator learning through Physics-based boundary constraints
Creators: name: Saad, Nadim
name: Gupta, Gaurav
name: Alizadeh, Shima
name: Maddix, Danielle C.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Analysis of PDEs (math.AP)
subject: Operator Algebras (math.OA)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Boundary conditions (BCs) are important groups of physics-enforced constraints that are necessary for solutions of Partial Differential Equations (PDEs) to satisfy at specific spatial locations. These constraints carry important physical meaning, and guarantee the existence and the uniqueness of the PDE solution. Current neural-network based approaches that aim to solve PDEs rely only on training data to help the model learn BCs implicitly. There is no guarantee of BC satisfaction by these models during evaluation. In this work, we propose Boundary enforcing Operator Network (BOON) that enables the BC satisfaction of neural operators by making structural changes to the operator kernel. We provide our refinement procedure, and demonstrate the satisfaction of physics-based BCs, e.g. Dirichlet, Neumann, and periodic by the solutions obtained by BOON. Numerical experiments based on multiple PDEs with a wide variety of applications indicate that the proposed approach ensures satisfaction of BCs, and leads to more accurate solutions over the entire domain. The proposed correction method exhibits a (2X-20X) improvement over a given operator model in relative $L^2$ error (0.000084 relative $L^2$ error for Burgers' equation).
description: Nadim and Gaurav contributed equally in this work. 31 pages, 7 figures, 16 tables