cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Learning knot invariants across dimensions
Creators: name: Craven, Jessica
name: Hughes, Mark
name: Jejjala, Vishnu
name: Kar, Arjun
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Machine Learning (cs.LG)
subject: Geometric Topology (math.GT)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: We use deep neural networks to machine learn correlations between knot invariants in various dimensions. The three-dimensional invariant of interest is the Jones polynomial $J(q)$, and the four-dimensional invariants are the Khovanov polynomial $\text{Kh}(q,t)$, smooth slice genus $g$, and Rasmussen's $s$-invariant. We find that a two-layer feed-forward neural network can predict $s$ from $\text{Kh}(q,-q^{-4})$ with greater than $99\%$ accuracy. A theoretical explanation for this performance exists in knot theory via the now disproven knight move conjecture, which is obeyed by all knots in our dataset. More surprisingly, we find similar performance for the prediction of $s$ from $\text{Kh}(q,-q^{-2})$, which suggests a novel relationship between the Khovanov and Lee homology theories of a knot. The network predicts $g$ from $\text{Kh}(q,t)$ with similarly high accuracy, and we discuss the extent to which the machine is learning $s$ as opposed to $g$, since there is a general inequality $|s| \leq 2g$. The Jones polynomial, as a three-dimensional invariant, is not obviously related to $s$ or $g$, but the network achieves greater than $95\%$ accuracy in predicting either from $J(q)$. Moreover, similar accuracy can be achieved by evaluating $J(q)$ at roots of unity. This suggests a relationship with $SU(2)$ Chern--Simons theory, and we review the gauge theory construction of Khovanov homology which may be relevant for explaining the network's performance.
description: v1: 35 pages, 6 figures; v2: 36 pages, 6 figures, figures updated, typos corrected
The Interaction between Inputs and Configurations fed to Software Systems: an Empirical Study
Creators: name: Lesoil, Luc
name: Acher, Mathieu
name: Blouin, Arnaud
name: Jézéquel, Jean-Marc
Publisher: name: arXiv
Year: 2021
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Widely used software systems such as video encoders are by necessity highly configurable, with hundreds or even thousands of options to choose from. Their users often have a hard time finding suitable values for these options (i.e. finding a proper configuration of the software system) to meet their goals for the tasks at hand, e.g. compress a video down to a certain size. One dimension of the problem is of course that performance depends on the input data: a video as input to an encoder like x264 or a file system fed to a tool like xz. To achieve good performance, users should therefore take into account both dimensions of (1) software variability and (2) input data. In this problem-statement paper, we conduct a large study over 8 configurable systems that quantifies the existing interactions between input data and configurations of software systems. The results exhibit that (1) inputs fed to software systems interact with their configuration options in non monotonous ways, significantly impacting their performance properties (2) tuning a software system for its input data makes it possible to multiply its performance by up to ten (3) input variability can jeopardize the relevance of performance predictive models for a field deployment.
description: 24 pages
Enhanced valley polarization in WS$_2$/LaMnO$_3$ heterostructure
Creators: name: Dang, Jianchen
name: Yang, Mingwei
name: Xie, Xin
name: Yang, Zhen
name: Dai, Danjie
name: Zuo, Zhanchun
name: Wang, Can
name: Jin, Kuijuan
name: Xu, Xiulai
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Monolayer transition metal dichalcogenides have attracted great attentions for potential applications in valleytronics. However, the valley polarization degree is usually not high because of the intervalley scattering. Here, we demonstrate a largely enhanced valley polarization up to 80\% in monolayer WS$_2$ under non-resonant excitation at 4.2 K using WS$_2$/LaMnO$_3$ thin film heterostructure, which is much higher than that for monolayer WS$_2$ on SiO$_2$/Si substrate with a valley polarization of 15\%. Furthermore, the greatly enhanced valley polarization can be maintained to a high temperature of about 160 K with a valley polarization of 53\%. The temperature dependence of valley polarization is strongly correlated with the thermomagnetic curve of LaMnO$_3$, indicating an exciton-magnon coupling between WS$_2$ and LaMnO$_3$. A simple model is introduced to illustrate the underlying mechanisms. The coupling of WS$_2$ and LaMnO$_3$ is further confirmed with an observation of two interlayer excitons with opposite valley polarizations in the heterostructure, resulting from the spin-orbit coupling induced splitting of the conduction bands in monolayer transition metal dichalcogenides. Our results provide a pathway to control the valleytronic properties of transition metal dichalcogenides by means of ferromagnetic van der Waals engineering, paving a way to practical valleytronic applications.
description: 15 pages, 5 figures
High-precision search for dark photon dark matter with the Parkes Pulsar Timing Array
Creators: name: Xue, Xiao
name: Xia, Zi-Qing
name: Zhu, Xingjiang
name: Zhao, Yue
name: Shu, Jing
name: Yuan, Qiang
name: Bhat, N. D. Ramesh
name: Cameron, Andrew D.
name: Dai, Shi
name: Feng, Yi
name: Goncharov, Boris
name: Hobbs, George
name: Howard, Eric
name: Manchester, Richard N.
name: Parthasarathy, Aditya
name: Reardon, Daniel J.
name: Russell, Christopher J.
name: Shannon, Ryan M.
name: Spiewak, Renée
name: Thyagarajan, Nithyanandan
name: Wang, Jingbo
name: Zhang, Lei
name: Zhang, Songbo
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The nature of dark matter remains obscure in spite of decades of experimental efforts. The mass of dark matter candidates can span a wide range, and its coupling with the Standard Model sector remains uncertain. All these unknowns make the etection of dark matter extremely challenging. Ultralight dark matter, with $m \sim10^{-22}$ eV, is proposed to reconcile the disagreements between observations and predictions from simulations of small-scale structures in the cold dark matter paradigm, while remaining consistent with other observations. Because of its large de Broglie wavelength and large local occupation number within galaxies, ultralight dark matter behaves like a coherently oscillating background field with an oscillating frequency dependent on its mass. If the dark matter particle is a spin-1 dark photon, such as the $U(1)_B$ or $U(1)_{B-L}$ gauge boson, it can induce an external oscillating force and lead to displacements of test masses. Such an effect would be observable in the form of periodic variations in the arrival times of radio pulses from highly stable millisecond pulsars. In this study, we search for evidence of ultralight dark photon dark matter (DPDM) using 14-year high-precision observations of 26 pulsars collected with the Parkes Pulsar Timing Array. While no statistically significant signal is found, we place constraints on coupling constants for the $U(1)_B$ and $U(1)_{B-L}$ DPDM. Compared with other experiments, the limits on the dimensionless coupling constant $ε$ achieved in our study are improved by up to two orders of magnitude when the dark photon mass is smaller than $3\times10^{-22}$~eV ($10^{-22}$~eV) for the $U(1)_{B}$ ($U(1)_{B-L}$) scenario.
description: 12 pages, 4 figures
A versatile LabVIEW and FPGA-based scanned probe microscope for in-operando electronic device characterization
Creators: name: Berger, Andrew J.
name: Page, Michael R.
name: Jacob, Jan
name: Young, Justin R.
name: Lewis, Jim
name: Wenzel, Lothar
name: Bhallamudi, Vidya P.
name: Johnston-Halperin, Ezekiel
name: Pelekhov, Denis V.
name: Hammel, P. Chris
Publisher: name: arXiv
Year: 2014
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In-operando characterization of such devices by scanned probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanned probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform the various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically-biased graphene FET device. The combination of SPM and electrical transport also enables imaging of the transport response to a localized perturbation provided by the scanned cantilever tip. Facilitated by the broad presence of LabVIEW in the experimental sciences and the openness of our software solution, our system permits a wide variety of combined scanning and transport measurements by providing standardized interfaces and flexible access to all aspects of a measurement (input and output signals, and processed data). Our system also enables precise control of timing (synchronization of scanning and transport operations) and implementation of sophisticated feedback protocols, and thus should be broadly interesting and useful to practitioners in the field.
Redox-controlled conductance of polyoxometalate molecular junctions
Creators: name: Huez, Cécile
name: Guérin, David
name: Lenfant, Stéphane
name: Volatron, Florence
name: Calame, Michel
name: Perrin, Mickael L.
name: Proust, Anna
name: Vuillaume, Dominique
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We demonstrate the reversible in situ photoreduction of molecular junctions of phosphomolybdate [PMo12O40]3- monolayer self-assembled on flat gold electrodes, connected by the tip of a conductive atomic force microscope. The conductance of the one electron reduced [PMo12O40]4- molecular junction is increased by ca. 10, this open-shell state is stable in the junction in air at room temperature. The analysis of a large current-voltage dataset by unsupervised machine learning and clustering algorithms reveals that the electron transport in the pristine phosphomolybdate junctions leads to symmetric current-voltage curves, controlled by the lowest unoccupied molecular orbital (LUMO) at 0.6 - 0.7 eV above the Fermi energy with ca. 25% of the junctions having a better electronic coupling to the electrodes than the main part of the dataset. This analysis also shows that a small fraction (ca. 18% of the dataset) of the molecules is already reduced. The UV light in situ photoreduced phosphomolybdate junctions are systematically featuring slightly asymmetric current - voltage behaviors, which is ascribed to electron transport mediated by the single occupied molecular orbital (SOMO) nearly at resonance with the Fermi energy of the electrode and by a closely located single unoccupied molecular orbital (SUMO) at ca. 0.3 eV above the SOMO with a weak electronic coupling to the electrodes (ca. 50% of the dataset) or at ca. 0.4 eV but with a better electrode coupling (ca. 50% of the dataset). These results shed lights to the electronic properties of reversible switchable redox polyoxometalates, a key point for potential applications in nanoelectronic devices.
POTENTIAL ROLE OF PRE-SOWING SEED TREATMENT WITH GLYCINEBETAINE IN ANTIOXIDANTS MACHINERY, GROWTH AND BIOCHEMICAL ATTRIBUTES OF FLAX (Linum usitatissimum L.) UNDER WATER DEFICIT CONDITIONS
Creators: name: ZYMA BASHARAT
name: MUHAMMAD SHAHBAZ
name: EJAZ AHMAD WARAICH
Publisher: name: Zenodo
Year: 2024
Subjects: Drought Stress, Flax, Glycinebetaine, ROS, Photosynthetic Pigments, Antioxidants, Yield.

description: Abstract

Water scarcity has a profound impact on crop yield and productivity, affecting numerous crop plants globally. Flax, a versatile crop with high nutritional value, is an essential oil seed and fiber crop. To combat drought stress, plants employ various mechanisms, and glycinebetaine (GB) plays a vital role as a compatible solute, mitigating stress through osmotic adjustment and membrane protection. A pot experiment was conducted at the Old Botanical Garden, University of Agriculture, Faisalabad, to investigate GB's role in flax under water stress. Two flax varieties, Roshini and Chandini, were subjected to two drought stress levels (controlled and 50% FC) and four GB levels (non-soaked, water-soaked, 10, and 20 mM) via pre-soaking seed treatment for 8 hours. Twenty seeds of each variety were sown in plastic pots, and a CRD design with four replicates was used to arrange the experiment. The results showed that drought stress significantly hampered morphological attributes, including shoot fresh weight, shoot length, and reduced chlorophyll pigments (chlorophyll a, b, total chlorophyll, and carotenoids). However, drought stress increased reactive oxygen species (ROS) like MDA and H2O2, triggering a response in enzymatic antioxidants (CAT, SOD, and POD). Exogenously applied GB as osmolytes enhanced shoot fresh weight, shoot length, and chlorophyll pigments (except chl a/b ratio), increased enzymatic antioxidants, and decreased ROS. Yield attributes were significantly improved, the Chandini variety performed better under stress conditions and 20 mM GB showing the best results in pre-soaking seed treatment.
Polarized solutions and Fermi surfaces in holographic Bose-Fermi systems
Creators: name: Nitti, Francesco
name: Policastro, Giuseppe
name: Vanel, Thomas
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We use holography to study the ground state of a system with interacting bosonic and fermionic degrees of freedom at finite density. The gravitational model consists of Einstein-Maxwell gravity coupled to a perfect fluid of charged fermions and to a charged scalar field which interact through a current-current interaction. When the scalar field is non-trivial, in addition to compact electron stars, the screening of the fermion electric charge by the scalar condensate allows the formation of solutions where the fermion fluid is made of antiparticles, as well as solutions with coexisting, separated regions of particle-like and antiparticle-like fermion fluids. We show that, when the latter solutions exist, they are thermodynamically favored. By computing the two-point Green function of the boundary fermionic operator we show that, in addition to the charged scalar condensate, the dual field theory state exhibits electron-like and/or hole-like Fermi surfaces. Compared to fluid-only solutions, the presence of the scalar condensate destroys the Fermi surfaces with lowest Fermi momenta. We interpret this as a signal of the onset of superconductivity.
description: 46 pages, 17 figures
MPEC 2023-U206 : 2023 UH6
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2023 UH6

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Nonlinear Force-Free Field Modeling of the Solar Magnetic Carpet and Comparison with SDO/HMI and Sunrise/IMaX Observations
Creators: name: Chitta, L. P.
name: Kariyappa, R.
name: van Ballegooijen, A. A.
name: DeLuca, E. E.
name: Solanki, S. K.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In the quiet solar photosphere, the mixed polarity fields form a magnetic carpet, which continuously evolves due to dynamical interaction between the convective motions and magnetic field. This interplay is a viable source to heat the solar atmosphere. In this work, we used the line-of-sight (LOS) magnetograms obtained from the Helioseismic and Magnetic Imager (HMI) on the \textit{Solar Dynamics Observatory} (\textit{SDO}), and the Imaging Magnetograph eXperiment (IMaX) instrument on the \textit{Sunrise} balloon-borne observatory, as time dependent lower boundary conditions, to study the evolution of the coronal magnetic field. We use a magneto-frictional relaxation method, including hyperdiffusion, to produce time series of three-dimensional (3D) nonlinear force-free fields from a sequence of photospheric LOS magnetograms. Vertical flows are added up to a height of 0.7 Mm in the modeling to simulate the non-force-freeness at the photosphere-chromosphere layers. Among the derived quantities, we study the spatial and temporal variations of the energy dissipation rate, and energy flux. Our results show that the energy deposited in the solar atmosphere is concentrated within 2 Mm of the photosphere and there is not sufficient energy flux at the base of the corona to cover radiative and conductive losses. Possible reasons and implications are discussed. Better observational constraints of the magnetic field in the chromosphere are crucial to understand the role of the magnetic carpet in coronal heating.
description: Accepted for publication in The Astrophysical Journal (13 pages, 10 figures)
Guide et documents d'orientation pour la mise en oeuvre du cadre et de l'instrument QualiTePE
Creators: name: Schnitzler, Christophe
name: Lefèvre, Lisa
name: Crapa, Angelo
name: Langer, Wiebke
name: Herrmann, Christian
name: Gerlach, Erin
name: Cools, Wouter
name: Adamakis, Manolis
name: Slingerland, Menno
name: Borghouts, Lars
name: Costa, João
name: O'Brien, Wesley
name: Lemling, Alina
Publisher: name: Zenodo
Year: 2024

description: À une époque d'innovation et de changement constants, la recherche de la qualité et de l'excellence est devenue cruciale. Le cadre QualiTePE répond à ce besoin en proposant une approche globale pour améliorer la qualité de l'enseignement de l'éducation physique (EP).Ce manuel est un guide pratique pour la mise en oeuvre du cadre et de l'instrument QualiTePE, contribuant à améliorer les pratiques d'enseignement quotidiennes. Il simplifie les complexités de la prestation d'une éducation physique de qualité, en fournissant des informations pratiques, des conseils étape par étape et un soutien pour donner aux individus, aux équipes et aux organisations les moyens d'atteindre l'excellence en éducation physique.
Quantum entanglement of two harmonically trapped dipolar particles
Creators: name: Koscik, Przemyslaw
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We study systems of two identical dipolar particles confined in quasi one-dimensional harmonic traps. Numerical results for the dependencies of the entanglement on the control parameters of the systems are provided and discussed in detail. In the limit of a strong interaction between the particles, the occupancies and the von Neumann entropies of the bosonic and fermionic ground states are derived in closed analytic forms by applying the harmonic approximation. The strong correlation regimes of the system with the dipolar bosons and the system with the charged ones are compared with each other in regard to aspects of their entanglement.
description: 5 pages,2 figures
Quantum field theoretic representation of Wilson surfaces: I higher coadjoint orbit theory
Creators: name: Zucchini, Roberto
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 81T20 81T45 53Z05

description: This is the first of a series of two papers devoted to the partition function realization of Wilson surfaces in strict higher gauge theory. A higher version of the Kirillov-Kostant-Souriau theory of coadjoint orbits is presented based on the derived geometric framework, which has shown its usefulness in 4--dimensional higher Chern--Simons theory. An original notion of derived coadjoint orbit is put forward. A theory of derived unitary line bundles and Poisson structures on regular derived orbits is constructed. The proper derived counterpart of the Bohr--Sommerfeld quantization condition is then identified. A version of derived prequantization is proposed. The difficulties hindering a full quantization, shared with other approaches to higher quantization, are pinpointed and a possible way--out is suggested. The theory we elaborate provide the geometric underpinning for the field theoretic constructions of the companion paper.
description: 104 pages, no figures
Canonically consistent quantum master equation
Creators: name: Becker, Tobias
name: Schnell, Alexander
name: Thingna, Juzar
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We put forth a new class of quantum master equations that correctly reproduce the asymptotic state of an open quantum system beyond the infinitesimally weak system-bath coupling limit. Our method is based on incorporating the knowledge of the reduced steady state into its dynamics. The correction not only steers the reduced system towards a correct steady state but also improves the accuracy of the dynamics, thereby refining the archetypal Born-Markov weak-coupling second-order master equations. In case of equilibrium, since a closed form for the steady state exists in terms of a mean force Gibbs state, we utilize this form to correct the Redfield quantum master equation. Using an exactly solvable harmonic oscillator system we benchmark our approach with the exact solution showing that our method also helps correcting the long-standing issue of positivity violation, albeit without complete positivity. Our method of a canonically consistent quantum master equation, opens a new perspective in the theory of open quantum systems leading to a reduced density matrix accurate beyond the commonly used Redfield and Lindblad equations, while retaining the same conceptual and numerical complexity.
A Multiple Imputation Method for Sensitivity Analyses of Time-to-Event Data with Possibly Informative Censoring
Creators: name: Koch, Gary G.
name: Ali, Mirza W.
name: Zhao, Yue
name: Zhou, Haibo
name: Herring, Amy H.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2014

description: This article presents a multiple imputation method for sensitivity analyses of time-to-event data with possibly informative censoring. The imputed time for censored values is drawn from the failure time distribution conditional on the time of follow-up discontinuation. A variety of specifications regarding the post-discontinuation tendency of having events can be incorporated in the imputation through a hazard ratio parameter for discontinuation versus continuation of follow-up. Multiple-imputed data sets are analyzed with the primary analysis method, and the results are then combined using the methods of Rubin. An illustrative example is provided.
Die Enzyklika "Fulgens Corona" zur Eröffnung des Marianischen Jahrs
Creators: name: Pius XII., Papst
Publisher: name: Herder Korrespondenz
Year: 1970

description: Herder Korrespondenz, Bd. 8 Nr. 2 (1953): Herder Korrespondenz, Band 8, Heft 2
Deciphering the Maximal Transcendentality Principle via Bootstrap
Creators: name: Guo, Yuanhong
name: Jin, Qingjun
name: Wang, Lei
name: Yang, Gang
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We prove the principle of maximal transcendentality for a class of form factors, including the general two-loop minimal form factors, the two-loop three-point form factor of ${\rm tr}(F^2)$, and the two-loop four-point form factor of ${\rm tr}(F^3)$. Our proof is based on a recently developed bootstrap method using the representation of master integral expansions, together with some unitarity cuts that are universal in general gauge theories. The maximally transcendental parts of the two-loop four-gluon form factor of $\mathrm{tr}(F^3)$ are obtained for the first time in both planar $\mathcal{N}=4$ SYM and pure YM theories. This form factor can be understood as the Higgs-plus-four-gluon amplitudes involving a dimension-seven operator in the Higgs effective theory. In this case, we find that the maximally transcendental part of the $\mathcal{N}=4$ SYM result is different from that of pure YM, and the discrepancy is due to the gluino-loop contributions in $\mathcal{N}=4$ SYM. In contrast, the scalar-loop contributions have no maximally transcendental parts. Thus, the maximal transcendentality principle still holds for the form factor results in $\mathcal{N}=4$ SYM and QCD, after a proper identification of the fundamental quarks and adjoint gluinos as $n_f \rightarrow 4N_c$. This seems to be the first example of the maximally transcendental principle that involves fermion-loop contributions. As another intriguing observation, we find that the four-point form factor of the half-BPS $\mathrm{tr}(ϕ^3)$ operator is precisely a building block in the form factor of $\mathrm{tr}(F^3)$.
description: 72 pages, 17 figures; v2: references added, minor corrections
A study of the elastic $πN$ scattering at finite baryon density
Creators: name: Han, Hyeon-dong
name: Hutauruk, Parada T. P.
name: Nam, Seung-il
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We investigate the elastic $πN$ scattering for the $I=3/2$ channel dominated by the $Δ(1232)$ resonance at finite baryon density $ρ_B$ for the symmetric nuclear matter, employing the effective Lagrangian approach at the tree-level Born approximation. The quark-meson coupling (QMC) model and linear-density approximation are employed to describe the medium modifications for the in-medium baryon properties, such as the nucleon and $Δ$ masses, and $Δ$ full decay width. We first reproduce the experimental data in vacuum by fitting the model parameters, then analyze various physical observables including total and differential cross sections, proton-spin asymmetry in medium. It turns out that the $Δ$-resonance contribution becomes diminished with respect to $ρ_B$, due to the weaker $πN$-interaction strength in medium. Beyond the $Δ$-resonance region $\sqrt{s}\gtrsim1.5$ GeV, the cross sections are almost independent of the density. The present results will be useful to understand the role of the $Δ$ resonance in the neutron-star equation of state (EoS) as well as in relativistic heavy-ion collision experiments.
description: 11 pages, 15 figures
Fine-Grained VR Sketching: Dataset and Insights
Creators: name: Luo, Ling
name: Gryaditskaya, Yulia
name: Yang, Yongxin
name: Xiang, Tao
name: Song, Yi-Zhe
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: We present the first fine-grained dataset of 1,497 3D VR sketch and 3D shape pairs of a chair category with large shapes diversity. Our dataset supports the recent trend in the sketch community on fine-grained data analysis, and extends it to an actively developing 3D domain. We argue for the most convenient sketching scenario where the sketch consists of sparse lines and does not require any sketching skills, prior training or time-consuming accurate drawing. We then, for the first time, study the scenario of fine-grained 3D VR sketch to 3D shape retrieval, as a novel VR sketching application and a proving ground to drive out generic insights to inform future research. By experimenting with carefully selected combinations of design factors on this new problem, we draw important conclusions to help follow-on work. We hope our dataset will enable other novel applications, especially those that require a fine-grained angle such as fine-grained 3D shape reconstruction. The dataset is available at tinyurl.com/VRSketch3DV21.
Realization of the Single-pair-Weyl Phonons with the Maximum Charge Number in Acoustic Crystals
Creators: name: Wang, Zhe-Qi
name: Liu, Qing-Bo
name: Yang, Xiang-Feng
name: Fu, Hua-Hua
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: To observe the Weyl phonon (WP) with the maximum charge and to design a realistic material structure containing only single-pair-WPs have long been considered two challenges in the field of topology physics. Here we have successfully designed an acoustic crystal to realize the single-pair-WPs with the maximum charge for the first time. Our theoretical simulations on acoustic band dispersions demonstrate that protected by the time-reversal symmetry ($\cal T$) and the point group symmetries, a WP with the charge -4 ($\mathcal{C}=-4$) and another WP with $\mathcal{C}=+4$ are located at the high-symmetry point $Γ$ and R, respectively, with the absence of any other kinds of WPs. Moreover, the singe-pair-WPs obtained here are designed by the simplest two-band mode, and the related quadruple-helicoid Fermi acrs can be observed clearly in experiments, since they aren't covered by any bulk bands and hybridized by other kinds of WPs. Our theoretical results provide a reliable acoustic crystal to study the topological properties of the single-pair-WPs with the maximum charge for experimentalists in this field.
description: 7 pages; 4 figures
Flexible Stopping Boundaries When Changing Primary Endpoints After Unblinded Interim Analyses
Creators: name: Chen, Liddy M.
name: Chu, Haitao
name: Ibrahim, Joseph G.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2014

description: It has been widely recognized that interim analyses of accumulating data in a clinical trial can inflate type I error. Different methods, from group sequential boundaries to flexible alpha spending functions, have been developed to control the overall type I error at pre-specified level. These methods mainly apply to testing the same endpoint in multiple interim analyses. In this paper, we consider a group sequential design with pre-planned endpoint switching after unblinded interim analyses. We extend the alpha spending function method to group sequential stopping boundaries when the parameters can be different between interim, or between interim and final analyses.
Towards Auto-Generated Code Contracts - Replication Package
Creators: name: Bühlmann, Noah
Publisher: name: Zenodo
Year: 2023
Subjects: Machine Learning
Large Language Models
Design by Contract

description: Replication package for the master thesis "Towards Auto-Generated Code Contracts" that was submitted to the Software Engineering Group at the Institute of Computer Science at the University of Bern by Noah Bühlmann in September 2023. For instructions please read the file README.md
Integrable nonunitary quantum circuits
Creators: name: Su, Lei
name: Martin, Ivar
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We show that the integrable Lindblad superoperators found recently can be used to build integrable nonunitary quantum circuits with two-site gates by demonstrating that the $\check{R}$-matrices are completely positive and trace preserving. Using the bond-site transformation, we obtain the corresponding integrable nonunitary quantum circuits with three-site gates. When restricted to the diagonals of the density matrix, these quantum models reduce to integrable classical cellular automata. This approach may pave the way for a systematic construction of integrable nonunitary quantum circuits.
description: 13 pages, 5 figures. Published version
Superradiance as a Source of Collective Decoherence in Quantum Computers
Creators: name: Yavuz, Deniz D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We argue that superradiance (collective emission) due to radiative coupling of qubit states results in non-local noise, and thus introduces an error source that cannot be corrected using current models of fault-tolerant quantum computation.
description: 11 pages, 2 figures
Ricci flow does not preserve positive sectional curvature in dimension four
Creators: name: Bettiol, Renato G.
name: Krishnan, Anusha M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53C21, 53E20

description: We find examples of cohomogeneity one metrics on $S^4$ and $\mathbb C P^2$ with positive sectional curvature that lose this property when evolved via Ricci flow. These metrics are arbitrarily small perturbations of Grove--Ziller metrics with flat planes that become instantly negatively curved under Ricci flow.
description: LaTeX2e, 18 pages, 2 figures
Doping effect on the evolution of the pairing symmetry in n-type superconductor near antiferromagnetic phase boundary
Creators: name: Charikova, T. B.
name: Shelushinina, N. G.
name: Harus, G. I.
name: Neverov, V. N.
name: Petukhov, D. S.
name: Petukhova, O. E.
name: Ivanov, A. A.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We present the investigation results of the in-plane \{rho}(T) resistivity tensor at the temperature range 0.4-40 K in magnetic fields up to 90kOe (H||c, J||ab) for electron-doped Nd{2-x}Ce{x}CuO{4+δ} with different degree of disorder near antiferromagnetic - superconducting phase boundary. We have experimentally found that for optimally doped compound both the upper critical field slope and the critical temperature decrease with increasing of the disorder parameter (d-wave pairing) while in the case of the underdoped system the critical temperature remains constant and (dHc2/dT)|Tc increases with increasing of the disorder (s-wave pairing). These features suggest a possible implementation of the complex mixture state as the (s+id)-pairing.
description: 9 pages, 2 figures
Probabilistic prediction of the time to hard freeze using seasonal weather forecasts and survival time methods
Creators: name: Roksvåg, Thea
name: Lenkoski, Alex
name: Scheuerer, Michael
name: Heinrich-Mertsching, Claudio
name: Thorarinsdottir, Thordis L.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: Agricultural food production and natural ecological systems depend on a range of seasonal climate indicators that describe seasonal patterns in climatological conditions. This paper proposes a probabilistic forecasting framework for predicting the end of the freeze-free season, or the time to a mean daily near-surface air temperature below 0 $^\circ$C (here referred to as hard freeze). The forecasting framework is based on the multi-model seasonal forecast ensemble provided by the Copernicus Climate Data Store and uses techniques from survival analysis for time-to-event data. The original mean daily temperature forecasts are statistically post-processed with a mean and variance correction of each model system before the time-to-event forecast is constructed. In a case study for a region in Fennoscandia covering Norway for the period 1993-2020, the proposed forecasts are found to outperform a climatology forecast from an observation-based data product at locations where the average predicted time to hard freeze is less than 40 days after the initialization date of the forecast on October 1.
Observation of dipole-quadrupole interaction in an ultracold gas of Rydberg atoms
Creators: name: Deiglmayr, Johannes
name: Saßmannshausen, Heiner
name: Pillet, Pierre
name: Merkt, Frédéric
Publisher: name: arXiv
Year: 2014
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We observe the direct excitation of pairs of Cs atoms from the ground state to molecular states correlating asymptotically to $ns\,n'f$ asymptotes. The molecular resonances are interpreted as originating from the dipole-quadrupole interaction between the $ns\,n'f$ pair states and close-by $np\,np$ asymptotes ($22\leq n \leq 32$). This interpretation is supported by Stark spectroscopy of the pair states and a detailed modeling of the interaction potentials. The dipole-quadrupole interaction mixes electronic states of opposite parity and thus requires a coupling between electronic and nuclear motion to conserve the total parity of the system. This non-Born-Oppenheimer coupling is facilitated by the near-degeneracy of even and odd $L$ partial waves in the atom-atom scattering which have opposite parity.
description: 5 pages, 3 figures
The Value of Help Bits in Randomized and Average-Case Complexity
Creators: name: Beigi, Salman
name: Etesami, Omid
name: Gohari, Amin
Publisher: name: arXiv
Year: 2014
Subjects: subject: Computational Complexity (cs.CC)
subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: "Help bits" are some limited trusted information about an instance or instances of a computational problem that may reduce the computational complexity of solving that instance or instances. In this paper, we study the value of help bits in the settings of randomized and average-case complexity. Amir, Beigel, and Gasarch (1990) show that for constant $k$, if $k$ instances of a decision problem can be efficiently solved using less than $k$ bits of help, then the problem is in P/poly. We extend this result to the setting of randomized computation: We show that the decision problem is in P/poly if using $\ell$ help bits, $k$ instances of the problem can be efficiently solved with probability greater than $2^{\ell-k}$. The same result holds if using less than $k(1 - h(α))$ help bits (where $h(\cdot)$ is the binary entropy function), we can efficiently solve $(1-α)$ fraction of the instances correctly with non-vanishing probability. We also extend these two results to non-constant but logarithmic $k$. In this case however, instead of showing that the problem is in P/poly we show that it satisfies "$k$-membership comparability," a notion known to be related to solving $k$ instances using less than $k$ bits of help. Next we consider the setting of average-case complexity: Assume that we can solve $k$ instances of a decision problem using some help bits whose entropy is less than $k$ when the $k$ instances are drawn independently from a particular distribution. Then we can efficiently solve an instance drawn from that distribution with probability better than $1/2$. Finally, we show that in the case where $k$ is super-logarithmic, assuming $k$-membership comparability of a decision problem, one cannot prove that the problem is in P/poly by a "black-box proof."
On unipotent radicals of motivic Galois groups
Creators: name: Eskandari, Payman
name: Murty, V. Kumar
Publisher: name: arXiv
Year: 2022
Subjects: subject: Algebraic Geometry (math.AG)
subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 14F42 (Primary) 18M25, 32G20, 11M32 (Secondary)

description: Let $\mathbf{T}$ be a neutral Tannakian category over a field of characteristic zero with unit object $\mathbf{1}$, and equipped with a filtration $W_\cdot$ similar to the weight filtration on mixed motives. Let $M$ be an object of $\mathbf{T}$, and $\underline{\mathfrak{u}}(M)\subset W_{-1}\underline{Hom}(M,M)$ the Lie algebra of the kernel of the natural surjection from the fundamental group of $M$ to the fundamental group of $Gr^WM$. A result of Deligne gives a characterization of $\underline{\mathfrak{u}}(M)$ in terms of the extensions $0\longrightarrow W_pM \longrightarrow M \longrightarrow M/W_pM \longrightarrow 0$: it states that $\underline{\mathfrak{u}}(M)$ is the smallest subobject of $W_{-1}\underline{Hom}(M,M)$ such that the sum of the aforementioned extensions, considered as extensions of $\mathbf{1}$ by $W_{-1}\underline{Hom}(M,M)$, is the pushforward of an extension of $\mathbf{1}$ by $\underline{\mathfrak{u}}(M)$. In this article, we study each of the above-mentioned extensions individually in relation to $\underline{\mathfrak{u}}(M)$. Among other things, we obtain a refinement of Deligne's result, where we give a sufficient condition for when an individual extension $0\longrightarrow W_pM \longrightarrow M \longrightarrow M/W_pM \longrightarrow 0$ is the pushforward of an extension of $\mathbf{1}$ by $\underline{\mathfrak{u}}(M)$. In the second half of the paper, we give an application to mixed motives whose unipotent radical of the motivic Galois group is as large as possible (i.e. with $\underline{\mathfrak{u}}(M)= W_{-1}\underline{Hom}(M,M)$). Using Grothedieck's formalism of \textit{extensions panachées} we prove a classification result for such motives. Specializing to the category of mixed Tate motives we obtain a classification result for 3-dimensional mixed Tate motives over $\mathbb{Q}$ with three weights and large unipotent radicals.
Coarse-graining of a discrete model for edge dislocations in the regular triangular lattice
Creators: name: Alicandro, Roberto
name: De Luca, Lucia
name: Lazzaroni, Giuliano
name: Palombaro, Mariapia
name: Ponsiglione, Marcello
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: We consider a discrete model of planar elasticity where the particles, in the reference configuration, sit on a regular triangular lattice and interact through nearest neighbor pairwise potentials, with bonds modeled as linearized elastic springs. Within this framework we introduce plastic slip fields, whose discrete circulation around each triangle detects the possible presence of an edge dislocation. We provide a $Γ$-convergence analysis, as the lattice spacing tends to zero, of the elastic energy induced by edge dislocations in the energy regime corresponding to a finite number of geometrically necessary dislocations.
Multivariate Recurrent Events in the Presence of Multivariate Informative Censoring with Applications to Bleeding and Transfusion Events in Myelodysplastic Syndrome
Creators: name: Zeng, Donglin
name: Jia, Catherine
name: Chen, Ming-Hui
name: Ibrahim, Joseph G.
name: Hu, Kuolung
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2014

description: We propose a general novel class of joint models to analyze recurrent events that has a wide variety of applications. The application of focus on this paper is to model the bleeding and transfusion events in Myelodyplastic Syndrome (MDS) studies, where patients may die or withdraw from the study early due to adverse events or other reasons, such as consent withdrawal or required alternative therapy during the study. The proposed model accommodates multiple recurrent events and multivariate informative censoring through a shared random effects model. The random effects model captures both within-subject and within-event dependence simultaneously. We construct the likelihood function for the semi-parametric joint model and develop an EM algorithm for inference. The computational burden does not increase with the number of types of recurrent events. We utilize the MDS clinical trial data to illustrate our proposed methodology. We also conduct a number of simulations to examine the performance of the proposed model.
Reconstruction in Time-Bandwidth Compression Systems
Creators: name: Chan, Jacky
name: Mahjoubfar, Ata
name: Asghari, Mohammad H.
name: Jalali, Bahram
Publisher: name: arXiv
Year: 2014
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Recently it has been shown that the intensity time-bandwidth product of optical signals can be engineered to match that of the data acquisition instrument. In particular, it is possible to slow down an ultrafast signal, resulting in compressed RF bandwidth - a similar benefit to that offered by the Time-Stretch Dispersive Fourier Transform (TS-DFT) - but with reduced temporal record length leading to time-bandwidth compression. The compression is implemented using a warped group delay dispersion leading to non-uniform time stretching of the signal's intensity envelope. Decoding requires optical phase retrieval and reconstruction of the input temporal profile, for the case where information of interest is resides in the complex field. In this paper, we present results on the general behavior of the reconstruction process and its dependence on the signal-to-noise ratio. We also discuss the role of chirp in the input signal.
description: Pre-print for Applied Physics Letters submission
Sample Size Determination in Shared Frailty Models for Multivariate Time-to-Event Data
Creators: name: Ibrahim, Joseph G.
name: Chen, Liddy M.
name: Chu, Haitao
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2014

description: The frailty model is increasingly popular for analyzing multivariate time-to-event data. The most common model is the shared frailty model. Although study design consideration is as important as analysis strategies, sample size determination methodology in studies with multivariate time-to-event data is greatly lacking in the literature. In this paper, we develop a sample size determination method for the shared frailty model to investigate the treatment effect on multivariate event times. We analyzed the data using both a parametric model and a piecewise model with unknown baseline hazard, and compare the empirical power with the calculated power. Last, we discuss the formula for testing the treatment effect on recurrent events.