cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Computer algebra calculations in supersymmetric electrodynamics
Creators: name: Shirokov, Ilya
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Symbolic Computation (cs.SC)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: We propose a new symbolic algorithm and a C++ program for generating and calculating supersymmetric Feynman diagrams for ${\cal N}=1$ supersymmetric electrodynamics regularized by higher derivatives in four dimensions. According to standard rules, the program generates all diagrams that are necessary to calculate a specific contribution to the two-point Green function of matter superfields in the needed order, and then reduces the answer to the sum of Euclidean momentum integrals. At the moment, the program was used to calculate the anomalous dimension in ${\cal N}=1$ supersymmetric quantum electrodynamics, regularized by higher derivatives, in the three-loop approximation.
description: 14 pages, 1 figure, accepted for publication in "Programming and Computer Software"
The Problem of Contextuality and the Impossibility of Experimental Metaphysics Thereof
Creators: name: Hermens, Ronnie
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Recently a new impulse has been given to the experimental investigation of contextuality. In this paper we show that for a widely used definition of contextuality there can be no decisive experiment on the existence of contextuality. To this end, we give a clear presentation of the hidden variable models due to Meyer, Kent and Clifton (MKC), which would supposedly nullify the Kochen-Specker Theorem. Although we disagree with this last statement, the models play a significant role in the discussion on the meaning of contextuality. In fact, we introduce a specific MKC-model of which we show that it is non-contextual and completely in agreement with quantum mechanical predictions. We also investigate the possibility of other definitions of non-contextuality --with an emphasis on operational definitions-- and argue that any useful definition relies on the specification of a theoretical framework. It is therefore concluded that no experimental test can yield any conclusions about contextuality on a metaphysical level.
Communication-efficient Quantum Algorithm for Distributed Machine Learning
Creators: name: Tang, Hao
name: Li, Boning
name: Wang, Guoqing
name: Xu, Haowei
name: Li, Changhao
name: Barr, Ariel
name: Cappellaro, Paola
name: Li, Ju
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The growing demands of remote detection and increasing amount of training data make distributed machine learning under communication constraints a critical issue. This work provides a communication-efficient quantum algorithm that tackles two traditional machine learning problems, the least-square fitting and softmax regression problem, in the scenario where the data set is distributed across two parties. Our quantum algorithm finds the model parameters with a communication complexity of $O(\frac{\log_2(N)}ε)$, where $N$ is the number of data points and $ε$ is the bound on parameter errors. Compared to classical algorithms and other quantum algorithms that achieve the same output task, our algorithm provides a communication advantage in the scaling with the data volume. The building block of our algorithm, the quantum-accelerated estimation of distributed inner product and Hamming distance, could be further applied to various tasks in distributed machine learning to accelerate communication.
Quantum entanglement: The unitary 8-vertex braid matrix with imaginary rapidity
Creators: name: Chakrabarti, Amitabha
name: Chakraborti, Anirban
name: Jedidi, Aymen
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study quantum entanglements induced on product states by the action of 8-vertex braid matrices, rendered unitary with purely imaginary spectral parameters (rapidity). The unitarity is displayed via the "canonical factorization" of the coefficients of the projectors spanning the basis. This adds one more new facet to the famous and fascinating features of the 8-vertex model. The double periodicity and the analytic properties of the elliptic functions involved lead to a rich structure of the 3-tangle quantifying the entanglement. We thus explore the complex relationship between topological and quantum entanglement.
description: 4 pages in REVTeX format, 2 figures
Structures of photosynthetic reaction centers with alternative cofactors
Creators: name: Hardjasa, Amelia
Publisher: name: University of British Columbia
Year: 2015

description: Rhodobacter sphaeroides is a model organism for the study of bacterial photosynthesis. The R. sphaeroides photosynthetic reaction centre (RC) is the primary site of electron transfer, which is mediated by the photosynthetic pigments bacteriochlorophyll a (BChl) and bacteriopheophytin (BPhe). The substitution of key amino acid residues can change the type of cofactors present in the RC. In particular, studies have shown that when the leucine residue in position 214 of the M subunit [(M)L214] is converted into a histidine, the BPhe normally present in the neighbouring position (HA) is replaced with a BChl. This study investigated the hypothesis that steric exclusion by the coordinating residue causes dechelation of the central magnesium ion in BChl, producing BPhe. Crystal structures of RCs where (M)L214 is substituted for glycine and alanine were determined, which demonstrated that the presence of BPhe in the HA pocket is unchanged despite decreasing the size of the residue in position (M)214. A crystal structure of an RC where (M)L214 is substituted for asparagine was also determined and showed that the replacement of BPhe with BChl at HA occurs if residue (M)214 includes an amide moiety. In the R. sphaeroides Δbchd strain, which lacks the ability to make BChl, it is believed that the RC cofactor sites are populated exclusively with zinc-bacteriochlorophyll (Zn-BChl). The crystal structures of this Zn-BChl containing RC (Zn-RC) and a Zn-RC with the (M)L214H substitution (Zn-β-RC) were solved for the first time. These structures confirmed the presence of Zn-BChl in every cofactor position and the tetracoordination of the HA Zn-BChl in the Zn-β-RC, as well as revealing that the occupancy of the HB cofactor was much lower than that of all other cofactors.
The Influence of Disk Composition on the Evolution of Stars in the Disks of Active Galactic Nuclei
Creators: name: Dittmann, Alexander J.
name: Jermyn, Adam S.
name: Cantiello, Matteo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Disks of gas accreting onto supermassive black holes, powering active galactic nuclei (AGN), can capture stars from nuclear star clusters or form stars in situ via gravitational instability. The density and thermal conditions of these disks can result in rapid accretion onto embedded stars, dramatically altering their evolution in comparison to stars in the interstellar medium. Theoretical models predict that, when subjected to sufficiently rapid accretion, fresh gas replenishes hydrogen in the cores of these stars as quickly as it is burned into helium, reaching a quasi-steady state. Such massive, long-lived ("immortal") stars may be capable of dramatically enriching AGN disks with helium, and would increase the helium abundance in AGN broad-line regions relative to that in the corresponding narrow-line regions and hosts. We investigate how the helium abundance of AGN disks alters the evolution of stars embedded therein. We find, in agreement with analytical arguments, that stars at a given mass are more luminous at higher helium mass fractions, and so undergo more radiation-driven mass-loss. We further find that embedded stars tend to be less massive in disks with higher helium mass fractions, and that immortal stars are less common in such disks. Thus, disk composition can alter the rates of electromagnetic and gravitational wave transients as well as further chemical enrichment by embedded stars.
description: 13 pages, 6 figures. Submitted to ApJ, comments welcome
Additional file 13 of Gene regulation network analyses of pistil development in papaya
Creators: name: Liao, Zhenyang
name: Dong, Fei
name: Liu, Juan
name: Xu, Lele
name: Marshall-Colon, Amy
name: Ming, Ray
Publisher: name: figshare
Year: 2022
Subjects: subject: Genetics
subject: FOS: Biological sciences
subject: Plant Biology

description: Additional file 13. Bubble chart of GO enrichment analysis of gene regulatory network in different stages. Different bubbles visually show the sharing and unique pathways of different networks.
Spin spirals in ordered and disordered solids
Creators: name: Mankovsky, S.
name: Fecher, G. H.
name: Ebert, H.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: A scheme to calculate the electronic structure of systems having a spiral magnetic structure is presented. The approach is based on the KKR (Korringa-Kohn-Rostoker) Green's function formalism which allows in combination with CPA (Coherent Potential Approximation) alloy theory to deal with chemically disordered materials. It is applied to the magnetic random alloys Fe$_x$Ni$_{1-x}$, Fe$_x$Co$_{1-x}$ and Fe$_x$Mn$_{1-x}$. For these systems the stability of their magnetic structure was analyzed. For Fe$_x$Ni$_{1-x}$ the spin stiffness for was determined as a function of concentration that was found in satisfying agreement with experiment. Performing spin spiral calculations the longitudinal momentum-dependent magnetic susceptibility was calculated for pure elemental systems (Cr, Ni) being in non-magnetic state as well as for random alloys (Ag$_x$Pt$_{1-x}$). The obtained susceptibility was used to analyze the stability of the paramagnetic state of these systems.
description: 8 figures
What are the benefits and challenges of large scale, arts based community partnership projects in an elementary school?
Creators: name: Draper, Rhonda Lee
Publisher: name: University of British Columbia
Year: 2015

description: This study explored the benefits and challenges of a large-scale, arts-based, community partnership project with an elementary school. It was called the Canada Show/Symphony Orchestra (SO) experience. This project drew across the arts, integrated multiple disciplines and involved a high quality community partnership. A case study formed the inquiry of this thesis to study the significances for all involved. Conceptually, this research was informed by my "artography" (Irwin & de Cosson, 2004), my concomitant position as an artist, researcher, teacher. Turning to constructivist traditions and informed by Dewey's (1938) philosophy of experience, a case study provided the means to systematically document the Canada Show/SO experience. Data sources included 70 grade six student performers, three of their teachers and two administrators via questionnaires featuring nine open-ended questions during three stages: 1) at the end of the final dress rehearsal; 2) at the end of the final of six performances; 3) a month after the performances had taken place. Data was also gathered from our community partner, participants in a symphony orchestra. Their questionnaires were given at one stage only – at the end of the final of six performances. Additionally eight randomly selected students digitally recorded their experiences at all stages throughout the process. The final source of data was my own journal and digital recordings documenting throughout what was encountered as artist, researcher, teacher. The findings from this study foreground the importance of arts-based interdisciplinary projects that develop multiple competencies. The majority of participants involved in this project stated that, in spite of challenges, it benefitted them socially and emotionally, helped them to develop arts-based competencies while teaching them about their Canadian history. Many participants found this large-scale, arts-based community partnership project to be transformational to them – their ideas about themselves, about others and about curriculum.
General theory for longitudinal nonreciprocal charge transport
Creators: name: Zhao, Hong Jian
name: Tao, Lingling
name: Fu, Yuhao
name: Bellaiche, Laurent
name: Ma, Yanming
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The longitudinal nonreciprocal charge transport (NCT) in crystalline materials is a highly non-trivial phenomenon, motivating the design of next generation two-terminal rectification devices (e.g., semiconductor diodes beyond PN junctions). The practical application of such devices is built upon crystalline materials whose longitudinal NCT occurs at room temperature and under low magnetic field. However, materials of this type are rather rare and elusive, and theory guiding the discovery of these materials is lacking. Here, we develop such a theory within the framework of semiclassical Boltzmann transport theory. By symmetry analysis, we classify the complete 122 magnetic point groups with respect to the longitudinal NCT phenomenon. The symmetry-adapted Hamiltonian analysis further uncovers a previously overlooked mechanism for this phenomenon. Our theory guides the first-principles prediction of longitudinal NCT in multiferroic ε-Fe2O3 semiconductor that possibly occurs at room temperature, without the application of external magnetic field. These findings advance our fundamental understandings of longitudinal NCT in crystalline materials, and aid the corresponding materials discoveries.
description: 6 pages, 2 figures
Entanglement entropy of local gravitational quenches
Creators: name: David, Justin R.
name: Mukherjee, Jyotirmoy
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the time dependence of Rényi/entanglement entropies of locally excited states created by fields with integer spins $s \leq 2$ in $4$ dimensions. For spins 0, 1 these states are characterised by localised energy densities of a given width which travel as a spherical wave at the speed of light. For the spin 2 case, in the absence of a local gauge invariant stress tensor, we probe these states with the Kretschmann scalar and show they represent localised curvature densities which travel at the speed of light. We consider the reduced density matrix of the half space with these excitations and develop methods which include a convenient gauge choice to evaluate the time dependence of Rényi/entanglement entropies as these quenches enter the half region. In all cases, the entanglement entropy grows in time and saturates at $\log 2 $. In the limit, the width of these excitations tends to zero, the growth is determined by order $2s+1$ polynomials in the ratio of the distance from the co-dimension-2 entangling surface and time. The polynomials corresponding to quenches created by the fields can be organised in terms of their representations under the $SO(2)_T\times SO(2)_L$ symmetry preserved by the presence of the co-dimension 2 entangling surface. For fields transforming as scalars under this symmetry, the order $2s+1$ polynomial is completely determined by the spin.
description: References added
Additional file 4 of Forest malaria and prospects for anti-malarial chemoprophylaxis among forest goers: findings from a qualitative study in Lao PDR
Creators: name: Jongdeepaisal, Monnaphat
name: Inthasone, Soulixay
name: Khonputsa, Panarasri
name: Malaphone, Vilayvone
name: Pongsoipetch, Kulchada
name: Pongvongsa, Tiengkham
name: Mayxay, Mayfong
name: Chindavongsa, Keobouphaphone
name: Pell, Christopher
name: Maude, Richard J.
Publisher: name: figshare
Year: 2022
Subjects: subject: Medicine
subject: Biotechnology
subject: Cancer
subject: Infectious Diseases
subject: FOS: Health sciences
subject: Computational Biology

description: Additional file 4. Policymaker IDI guide.
Denudatine-type diterpenoid alkaloids from an aqueous extract of the lateral root of Aconitum carmichaelii
Creators: name: Liu, Hui
name: Shao, Shuai
name: Xia, Huan
name: Wu, Yu-Zhuo
name: Zhu, Cheng-Gen
name: Xu, Cheng-Bo
name: Zhang, Tian-Tai
name: Guo, Qing-Lan
name: Shi, Jian-Gong
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biochemistry
subject: Pharmacology
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: FOS: Biological sciences
subject: Biological Sciences not elsewhere classified
subject: Cancer

description: Five new denudatine-type diterpenoid alkaloids (1–5), along with the known analogue aconicarmine (6), were isolated from an aqueous decoction of the lateral roots of Aconitum carmichaelii (fu-zi). Their structures were determined by spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Compound 5 is the first denudatine-type diterpenoid alcohol iminium alkaloid, which could be partially transformed into the aza acetal form in pyridine-d5. Compound 5 inhibited mice writhing in an acetic acid-induced writhing assay.
Disorder driven cluster glass state in a geometrically frustrated hexagonal perovskite
Creators: name: Chakravarty, Shruti
name: Fjellvåg, Øystein Slagtern
name: Bhattacharyya, Arpan
name: Keller, Lukas
name: Nair, Sunil
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report the observation of cluster glass-like properties in a double perovskite ruthenate Ba$_2$CoRuO$_6$ through structural (neutron and synchrotron X-ray diffraction), magnetic and transport measurements. The system exhibits classic glassy characteristics like a frequency dependence in ac Susceptibility, aging and memory effects along with persistance of short-range correlations upto room temperature. The significant ($\sim30\%$) anti-site disorder on the dimer sites, coupled with the inherent geometrical frustration, allows a variety of exchange (both antiferro- and ferromagnetic) interactions to be distributed randomly across the lattice. On cooling, locally dominant interactions cause spins to nucleate and form local, short-range ordered clusters which grow in size until a global freezing occurs at about $T_f \sim 43K$.
CoRoT-10b: a giant planet in a 13.24 day eccentric orbit
Creators: name: Bonomo, A. S.
name: Santerne, A.
name: Alonso, R.
name: Gazzano, J. -C.
name: Havel, M.
name: Aigrain, S.
name: Auvergne, M.
name: Baglin, A.
name: Barbieri, M.
name: Barge, P.
name: Benz, W.
name: Bordé, P.
name: Bouchy, F.
name: Bruntt, H.
name: Cabrera, J.
name: Cameron, A. C.
name: Carone, L.
name: Carpano, S.
name: Csizmadia, Sz.
name: Deleuil, M.
name: Deeg, H. J.
name: Dvorak, R.
name: Erikson, A.
name: Ferraz-Mello, S.
name: Fridlund, M.
name: Gandolfi, D.
name: Gillon, M.
name: Guenther, E.
name: Guillot, T.
name: Hatzes, A.
name: Hébrard, G.
name: Jorda, L.
name: Lammer, H.
name: Lanza, A. F.
name: Léger, A.
name: Llebaria, A.
name: Mayor, M.
name: Mazeh, T.
name: Moutou, C.
name: Ollivier, M.
name: Pätzold, M.
name: Pepe, F.
name: Queloz, D.
name: Rauer, H.
name: Rouan, D.
name: Samuel, B.
name: Schneider, J.
name: Tingley, B.
name: Udry, S.
name: Wuchterl, G.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The space telescope CoRoT searches for transiting extrasolar planets by continuously monitoring the optical flux of thousands of stars in several fields of view. We report the discovery of CoRoT-10b, a giant planet on a highly eccentric orbit (e=0.53 +/- 0.04) revolving in 13.24 days around a faint (V=15.22) metal-rich K1V star. We use CoRoT photometry, radial velocity observations taken with the HARPS spectrograph, and UVES spectra of the parent star to derive the orbital, stellar and planetary parameters. We derive a radius of the planet of 0.97 +/- 0.07 R_Jup and a mass of 2.75 +/- 0.16 M_Jup. The bulk density, rho_pl=3.70 +/- 0.83 g/cm^3, is ~2.8 that of Jupiter. The core of CoRoT-10b could contain up to 240 M_Earth of heavy elements. Moving along its eccentric orbit, the planet experiences a 10.6-fold variation in insolation. Owing to the long circularisation time, tau_circ > 7 Gyr, a resonant perturber is not required to excite and maintain the high eccentricity of CoRoT-10b.
description: 9 pages, 9 figures, accepted for publication by Astronomy and Astrophysics
Ultrahigh Stability of O-Sublattice in $β$-Ga$_2$O$_3$
Creators: name: He, Ru
name: Zhao, Junlei
name: Byggmästar, Jesper
name: He, Huan
name: Djurabekova, Flyura
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Recently reported remarkably high radiation tolerance of $γ$/$β$-Ga$_2$O$_3$ double-polymorphic structure brings this ultrawide bandgap semiconductor to the frontiers of power electronics applications that are able to operate in challenging environments. Understanding the mechanism of radiation tolerance is crucial for further material modification and tailoring of the desired properties. In this study, we employ machine-learning-enhanced atomistic simulations to assess the stability of both the gallium (Ga) and oxygen (O) sublattices under various levels of damage. Our study uncovers the remarkable resilience and stability of the O-sublattice, attributing this property to the strong tendency of recovery of the O defects, especially within the stronger disordered regions. Interestingly, we observe the opposite behavior of the Ga defects that display enhanced stability in the same regions of increased disorder. Moreover, we observe that highly defective $β$-Ga$_2$O$_3$ is able to transform into $γ$-Ga$_2$O$_3$ upon annealing due to preserved lattice organization of the O-sublattice. This result clearly manifests that the ultrahigh stability of the O-sublattice provides the backbone for the exceptional radiation tolerance of the $γ$/$β$ double-polymorphic structure. These computational insights closely align with experimental observations, opening avenues for further exploration of polymorphism in Ga$_2$O$_3$ and potentially in analogous polymorphic families spanning a broad range of diverse materials of complex polymorphic nature.
KernJC: Automated Vulnerable Environment Generation for Linux Kernel Vulnerabilities
Creators: name: Ruan, Bonan
name: Liu, Jiahao
name: Zhang, Chuqi
name: Liang, Zhenkai
Publisher: name: arXiv
Year: 2024
Subjects: subject: Cryptography and Security (cs.CR)
subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Linux kernel vulnerability reproduction is a critical task in system security. To reproduce a kernel vulnerability, the vulnerable environment and the Proof of Concept (PoC) program are needed. Most existing research focuses on the generation of PoC, while the construction of environment is overlooked. However, establishing an effective vulnerable environment to trigger a vulnerability is challenging. Firstly, it is hard to guarantee that the selected kernel version for reproduction is vulnerable, as the vulnerability version claims in online databases can occasionally be spurious. Secondly, many vulnerabilities can not be reproduced in kernels built with default configurations. Intricate non-default kernel configurations must be set to include and trigger a kernel vulnerability, but less information is available on how to recognize these configurations.
 To solve these challenges, we propose a patch-based approach to identify real vulnerable kernel versions and a graph-based approach to identify necessary configs for activating a specific vulnerability. We implement these approaches in a tool, KernJC, automating the generation of vulnerable environments for kernel vulnerabilities. To evaluate the efficacy of KernJC, we build a dataset containing 66 representative real-world vulnerabilities with PoCs from kernel vulnerability research in the past five years. The evaluation shows that KernJC builds vulnerable environments for all these vulnerabilities, 48.5% of which require non-default configs, and 4 have incorrect version claims in the National Vulnerability Database (NVD). Furthermore, we conduct large-scale spurious version detection on kernel vulnerabilities and identify 128 vulnerabilities which have spurious version claims in NVD. To foster future research, we release KernJC with the dataset in the community.
description: To appear in the 27th International Symposium on Research in Attacks, Intrusions and Defenses (RAID 2024)
Modular implementation of the linear and cubic-scaling orbital minimization methods in electronic structure codes using atomic orbitals
Creators: name: Lebedeva, Irina V.
name: Garcia, Alberto
name: Artacho, Emilio
name: Ordejon, Pablo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We present a code modularization approach to design efficient and massively parallel cubic and linear-scaling solvers for electronic structure calculations using atomic orbitals. The modular implementation of the orbital minimization method, in which linear algebra and parallelization issues are handled via external libraries, is demonstrated in the SIESTA code. The DBCSR and ScaLAPACK libraries are used for algebraic operations with sparse and dense matrices, respectively. The MatrixSwitch and libOMM libraries, recently developed within the Electronic Structure Library, facilitate switching between different matrix formats and implement the energy minimization. We show results comparing the performance of several cubic-scaling algorithms, and also demonstrate the parallel performance of the linear-scaling solvers, and their supremacy over the cubic-scaling solvers for insulating systems with sizes of several hundreds of atoms.
description: 13 pages, 10 figures
Interaction effects in a 1D flat band at a topological crystalline step edge
Creators: name: Wagner, Glenn
name: Das, Souvik
name: Jung, Johannes
name: Odobesko, Artem
name: Küster, Felix
name: Keller, Florian
name: Korczak, Jedrzej
name: Szczerbakow, Andrzej
name: Story, Tomasz
name: Parkin, Stuart
name: Thomale, Ronny
name: Neupert, Titus
name: Bode, Matthias
name: Sessi, Paolo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Step edges of topological crystalline insulators can be viewed as predecessors of higher-order topology, as they embody one-dimensional edge channels embedded in an effective three-dimensional electronic vacuum emanating from the topological crystalline insulator. Using scanning tunneling microscopy and spectroscopy we investigate the behaviour of such edge channels in Pb$_{1-x}$Sn$_{x}$Se under doping. Once the energy position of the step edge is brought close to the Fermi level, we observe the opening of a correlation gap. The experimental results are rationalized in terms of interaction effects which are enhanced since the electronic density is collapsed to a one-dimensional channel. This constitutes a unique system to study how topology and many-body electronic effects intertwine, which we model theoretically through a Hartree-Fock analysis.
description: 8 pages, 5 figures (main text) and 5 pages, 6 figures (Supplementary Material)
Nematic phase without Heisenberg physics in FeAs planes
Creators: name: Capati, M.
name: Grilli, M.
name: Lorenzana, J.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We use Monte Carlo simulations and analytical arguments to analyze a frustrated Ising model with nearest neighbour antiferromagnetic coupling $J_1$ and next nearest neighbour coupling $J_2$. The model is inspired on the physics of pnictide superconductors and to some extent we argue that it can be more representative of this physics than the Heisenberg counterpart. Parameters are chosen such that the ground state is a columnar or striped state, as observed experimentally, but is close to the transition to the simple Neel ordered antiferromagnetic state $R = J_2/|J_1|\gtrsim 0.5$. We find that a nematic phase is induced close to $R = 0.5$ by finite size effects and argue that this explains experiments in imperfect samples which find a more robust nematic state as the quality of the sample decreases [A. Jesche et al., Phys. Rev. B 81, 134525 (2010)]. Including the effect of a weak coupling with the lattice we find that a structural transition occurs associated with a nematic phase, with a magnetic transition occurring at a lower temperature. These two transitions merge into a single structural and magnetic transition with a stronger first-order character for larger spin-lattice couplings. These two situations are in agreement with the different phenomenologies found in different families of pnictides.
description: 11 pages, 11 figures
Using ‘off the shelf ideas’ to plan and design a unit of work in STEM
Creators: name: Kaur, Balbir
Publisher: name: Brunel University London
Year: 2020
Subjects: Education

description: Primary and Early Years settings have had insufficient access to resources and professional development to integrate STEM education as part of a curriculum program. The aim of this case study was to explore the understanding and transformation required to modify a commercial STEM resource into a curriculum plan that addressed real-world issues grounded in the Sustainable Development Goals.This small-scale action research used interviews, document analysis, questionnaires and group discussions to examine the subject knowledge required across the disciplines to plan and teach a STEM- focused curriculum. Lee Shulman’s ‘Model of Pedagogical Reasoning and Action was used as a theoretical framework’ to reflect on the curriculum plan. My findings show that a commercially prepared plan provided a valuable scaffold enabling practitioners to consider the content and pedagogical knowledge required for a STEM-focused curriculum. The contribution of subject specialists during the planning process enabled the interdisciplinary approach to create a STEM plan. MIE Journal – Mauritius Institute of Education
Air filtration : predicting and improving indoor air quality and energy performance
Creators: name: Montgomery, James
Publisher: name: University of British Columbia
Year: 2015

description: Air filtration is used to reduce particle concentrations in the indoor environment to provide improved occupant health due to reduced exposure. Increased focus on occupant health in emerging design standards is leading to the installation of higher efficiency filtration systems. These systems generally have higher resistance to flow and therefore impose a greater energy penalty. Previous air filter models have used simplified assumptions with regards to the dynamics of filter operation, which have limited the potential to determine energy efficiency or optimization approaches to system design and operation. This dissertation focuses on developing an improved air filter model to investigate the potential for system modifications to reduce energy consumption and improve indoor air quality (IAQ) within commercial buildings. A new air filter performance model was developed using generalizable results from ASHRAE Standard 52.2-2012 and validated against laboratory and real-world experiments. The results showed better agreement with laboratory tests than with real operation. The filter model was combined with existing indoor particle dynamics and epidemiological models to determine the impacts of changes to system operation through monetization of operation costs and health benefits. Laboratory experiments were performed to evaluate the role that particle properties and relative humidity play in determining the filter performance changes with the aim of better understanding the reasons for discrepancies in operation between laboratory and field filter tests. Operation can now be optimized by accounting for dynamic characteristics of filter performance. Benefits of improved filtration efficiency were found to outweigh added costs. Adopting specific indoor particle concentration limits is recommended to replace existing specifications relying on filter efficiency. System designs can then be optimized to account for local particle concentration and energy costs. A number of system design changes have been highlighted that allow for simultaneous reduction in operation cost and indoor particle concentrations. Relative humidity has been identified as a critical parameter in filter performance and standardized tests should be modified to account for variability in relative humidity and particle characteristics typical of real operation to allow for improvements to future model predictions.
TEXNIK OLIY О'QUV YURTLARIDA "MUXANDISLIK  GRAFIKASI"  FANINI О'QITISH JARAYONIDA  YANGI INNOVATSION TEXNOLOGIYALARINI QО'LLASH
Creators: name: Abduraximova, F.A.
Publisher: name: Zenodo
Year: 2023

description: Maqolada "Muhandislik va kompyuter grafikasi" fanini oʻrganishda oliy texnik taʼlim muassasalarida yangi innovatsion texnologiyalardan foydalanish keng yoritilgan.
Using blogs to make peer-reviewed research more accessible
Creators: name: Young, Nicholas T.
name: Lewis, Briley L.
name: Kerr, Emily
name: Nair, Prasanth H.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: Discipline-based education researchers produce knowledge that aims to help instructors improve student learning and educational outcomes. Yet, the information produced may not even reach the educators it is intended to influence. Prior work has found that instructors often face barriers to implementing practices in peer-reviewed literature. Some of these barriers are related to accessing the knowledge in the first place such as difficulty finding and understanding research and a lack of time to do so. To lower these barriers, we created an online blog, PERbites, that summarizes recent discipline-based education research in short posts that use plain language. Having covered nearly 100 papers to date, we conducted a survey to see if we were addressing the need we had originally set out to address. We posted a 23-item survey on our website and received 24 usable responses. The results suggested that readers do generally agree that we are meeting our original goals. Readers reported that our articles were easier to understand and used more plain language than a typical discipline-based education research (DBER) journal article. At the same time, readers thought that all the important information was still included. Finally, readers said that this approach helped them keep up with DBER studies and read about papers they otherwise would not have. However, most readers did not indicate they changed their teaching and research practice as a result of reading our blog. Our results suggest that alternative methods of sharing research (e.g., non-peer reviewed publications or conference talks) can be an effective method of connecting research with practitioners, and future work should consider how we as a community might build on these efforts to ensure education research can make meaningful changes in the classroom.
description: Published in the Proceedings of the 2022 Physics Education Research Conference, Grand Rapids, MI, US July 13th - July 14th
The 2008 October Swift detection of X-ray bursts/outburst from the transient SGR-like AXP 1E 1547.0-5408
Creators: name: Israel, G. L.
name: Esposito, P.
name: Rea, N.
name: Dall'Osso, S.
name: Senziani, F.
name: Romano, P.
name: Mangano, V.
name: Götz, D.
name: Zane, S.
name: Tiengo, A.
name: Palmer, D. M.
name: Krimm, H.
name: Gehrels, N.
name: Mereghetti, S.
name: Stella, L.
name: Turolla, R.
name: Campana, S.
name: Perna, R.
name: Angelini, L.
name: De Luca, A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We report on the detailed study of the 2008 October outburst from the anomalous X-ray pulsar (AXP) 1E 1547.0-5408 discovered through the Swift/Burst Alert Telescope (BAT) detection of SGR-like short X-ray bursts on 2008 October 3. The Swift/X-ray Telescope (XRT) started observing the source after less than 100 s since the BAT trigger, when the flux (about 6E-11 erg/cm^2/s in the 2-10 keV range) was >50 times higher than its quiescent level. Swift monitored the outbursting activity of 1E 1547.0-5408 on a daily basis for approximately three weeks. This strategy allowed us to find a phase-coherent solution for the source pulsations after the burst, which, besides period and period derivative, requires a positive Period second derivative term (spin-down increase). The time evolution of the pulse shape is complex and variable, with the pulsed fraction increasing from 20% to 50% within the Swift observational window. The XRT spectra can be fitted well by means of a single component, either a power-law (PL) or a blackbody (BB). During the very initial phases of the outburst the spectrum is hard, with a PL photon index about 2 (or kT about 1.4 keV) which steepens to about 4 (or kT about 0.8 keV) within one day from the BAT trigger, though the two components are likely present simultaneously during the first day spectra. An INTEGRAL observation carried out five days after the trigger provided an upper limit of about 2E-11 erg/cm^2/s to the emission of 1E 1547.0-5408 in the 18-60 keV band.
description: 10 pages, 2 tables, 6 figures; accepted for publication in MNRAS
Transport in reservoir computing
Creators: name: Manjunath, G
name: Ortega, Juan-Pablo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: Dynamical Systems (math.DS)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Reservoir computing systems are constructed using a driven dynamical system in which external inputs can alter the evolving states of a system. These paradigms are used in information processing, machine learning, and computation. A fundamental question that needs to be addressed in this framework is the statistical relationship between the input and the system states. This paper provides conditions that guarantee the existence and uniqueness of asymptotically invariant measures for driven systems and shows that their dependence on the input process is continuous when the set of input and output processes are endowed with the Wasserstein distance. The main tool in these developments is the characterization of those invariant measures as fixed points of naturally defined Foias operators that appear in this context and which have been profusely studied in the paper. Those fixed points are obtained by imposing a newly introduced stochastic state contractivity on the driven system that is readily verifiable in examples. Stochastic state contractivity can be satisfied by systems that are not state-contractive, which is a need typically evoked to guarantee the echo state property in reservoir computing. As a result, it may actually be satisfied even if the echo state property is not present.
description: 33 pages, 5 figures
Slavnov-Taylor constraints for non-trivial backgrounds
Creators: name: Binosi, Daniele
name: Quadri, Andrea
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We devise an algebraic procedure for the evaluation of Green's functions in SU(N) Yang-Mills theory in the presence of a non-trivial background field. In the ghost-free sector the dependence of the vertex functional on the background is shown to be uniquely determined by the Slavnov-Taylor identities in terms of a certain 1-PI correlator of the covariant derivatives of the ghost and the anti-ghost fields. At non-vanishing background this amplitude is shown to encode the quantum deformations to the tree-level background-quantum splitting. The approach only relies on the functional identities of the model (Slavnov-Taylor identities, $b$-equation, anti-ghost equation) and thus it is valid beyond perturbation theory, and in particular in a lattice implementation of the background field method. As an example of the formalism we analyze the ghost two-point function and the Kugo-Ojima function in an instanton background in SU(2) Yang-Mills theory, quantized in the background Landau gauge.
description: 33 pages
Anomalous hydrodynamics with triangular point group in 2 + 1 dimensions
Creators: name: Qi, Marvin
name: Guo, Jinkang
name: Lucas, Andrew
Publisher: name: arXiv
Year: 2022
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We present a theory of hydrodynamics for a vector U(1) charge in 2+1 dimensions, whose rotational symmetry is broken to the point group of an equilateral triangle. We show that it is possible for this U(1) to have a chiral anomaly. The hydrodynamic consequence of this anomaly is the introduction of a ballistic contribution to the dispersion relation for the hydrodynamic modes. We simulate classical Markov chains and find compelling numerical evidence for the anomalous hydrodynamic universality class. Generalizations of our theory to other symmetry groups are also discussed.
The Joker effect: cooperation driven by destructive agents
Creators: name: Arenas, Alex
name: Camacho, Juan
name: Cuesta, José A.
name: Requejo, Rubén
Publisher: name: arXiv
Year: 2011
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Biological Physics (physics.bio-ph)
subject: Quantitative Methods (q-bio.QM)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Understanding the emergence of cooperation is a central issue in evolutionary game theory. The hardest setup for the attainment of cooperation in a population of individuals is the Public Goods game in which cooperative agents generate a common good at their own expenses, while defectors "free-ride" this good. Eventually this causes the exhaustion of the good, a situation which is bad for everybody. Previous results have shown that introducing reputation, allowing for volunteer participation, punishing defectors, rewarding cooperators or structuring agents, can enhance cooperation. Here we present a model which shows how the introduction of rare, malicious agents -that we term jokers- performing just destructive actions on the other agents induce bursts of cooperation. The appearance of jokers promotes a rock-paper-scissors dynamics, where jokers outbeat defectors and cooperators outperform jokers, which are subsequently invaded by defectors. Thus, paradoxically, the existence of destructive agents acting indiscriminately promotes cooperation.
description: Accepted for publication in the Journal of Theoretical Biology (JTB)
Concept Embedding Models: Beyond the Accuracy-Explainability Trade-Off
Creators: name: Zarlenga, Mateo Espinosa
name: Barbiero, Pietro
name: Ciravegna, Gabriele
name: Marra, Giuseppe
name: Giannini, Francesco
name: Diligenti, Michelangelo
name: Shams, Zohreh
name: Precioso, Frederic
name: Melacci, Stefano
name: Weller, Adrian
name: Lio, Pietro
name: Jamnik, Mateja
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences
subject: I.2.6
subject: 68T07

description: Deploying AI-powered systems requires trustworthy models supporting effective human interactions, going beyond raw prediction accuracy. Concept bottleneck models promote trustworthiness by conditioning classification tasks on an intermediate level of human-like concepts. This enables human interventions which can correct mispredicted concepts to improve the model's performance. However, existing concept bottleneck models are unable to find optimal compromises between high task accuracy, robust concept-based explanations, and effective interventions on concepts -- particularly in real-world conditions where complete and accurate concept supervisions are scarce. To address this, we propose Concept Embedding Models, a novel family of concept bottleneck models which goes beyond the current accuracy-vs-interpretability trade-off by learning interpretable high-dimensional concept representations. Our experiments demonstrate that Concept Embedding Models (1) attain better or competitive task accuracy w.r.t. standard neural models without concepts, (2) provide concept representations capturing meaningful semantics including and beyond their ground truth labels, (3) support test-time concept interventions whose effect in test accuracy surpasses that in standard concept bottleneck models, and (4) scale to real-world conditions where complete concept supervisions are scarce.
description: To appear at NeurIPS 2022
CHEX-MATE: pressure profiles of 6 galaxy clusters as seen by SPT and Planck
Creators: name: Oppizzi, Filippo
name: De Luca, Federico
name: Bourdin, Hervé
name: Mazzotta, Pasquale
name: Ettori, Stefano
name: Gastaldello, Fabio
name: Kay, Scott
name: Lovisari, Lorenzo
name: Maughan, Ben J.
name: Pointecouteau, Etienne
name: Pratt, Gabriel W.
name: Rossetti, Mariachiara
name: Sayers, Jack
name: Sereno, Mauro
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Pressure profiles are sensitive probes of the thermodynamic conditions and the internal structure of galaxy clusters. The intra-cluster gas resides in hydrostatic equilibrium within the Dark Matter gravitational potential. However, this equilibrium may be perturbed, e.g. as a consequence of thermal energy losses, feedback and non-thermal pressure supports. Accurate measures of the gas pressure over the cosmic times are crucial to constrain the cluster evolution as well as the contribution of astrophysical processes. In this work we presented a novel algorithm to derive the pressure profiles of galaxy clusters from the Sunyaev-Zeldovich (SZ) signal measured on a combination of Planck and South Pole Telescope (SPT) observations. The synergy of the two instruments made it possible to track the profiles on a wide range of spatial scales. We exploited the sensitivity to the larger scales of the Planck High-Frequency Instrument to observe the faint peripheries, and the higher spatial resolution of SPT to solve the innermost regions. We developed a two-step pipeline to take advantage of the specifications of each instrument. We first performed a component separation on the two data-sets separately to remove the background (CMB) and foreground (galactic emission) contaminants. Then we jointly fitted a parametric pressure profile model on a combination of Planck and SPT data. We validated our technique on a sample of 6 CHEX-MATE clusters detected by SPT. We compare the results of the SZ analysis with profiles derived from X-ray observations with XMM-Newton. We find an excellent agreement between these two independent probes of the gas pressure structure.
description: 19 pages, 13 figures, submitted to A&A