cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Mechanisms of indigenous exclusion in British Columbia's environmental assessment process
Creators: name: Andrews, Hollis Katherine
Publisher: name: University of British Columbia
Year: 2017

description: Due to changes in Canadian case law, there is a growing focus on making space for Indigenous rights and interests in BC’s environmental assessment process. However, despite this increased attention, First Nations are continuing to report that their interests are poorly represented in evaluations of project effects. This disconnect is the focus of my research, and in this thesis, I discuss findings from a review of fifteen EA certificate applications approved by the provincial government between 2011 and 2016. I found that evaluations of the extent and significance of potential impacts on Indigenous rights and interests are now central (and required) components of every EA. However, the methods commonly used to carry out these evaluations often rely on settler-colonial assumptions that invalidate or obscure issues of critical concern to First Nations. This negation is so commonplace that my analysis revealed a consistent set of precise mechanisms through which project proponents systematically exclude Indigenous interests in such applications. In my research, I refer to these patterns as “mechanisms of exclusion”, and describe three: (1) failure to recognize long-standing interests (particularly non-consumptive interests associated with territory governance and land and resource management); (2) insufficient consideration of extra-material dimensions of value in characterizations of Aboriginal interests and related evaluations of project effects; and (3) a lack of appropriate thresholds and/or transparency in evaluations of impact significance. My objective in doing so is to underscore the need to look more critically at the assumptions embedded in ostensibly inclusive processes such as EA. In addition, I offer recommendations as to how we can better represent Indigenous interests in evaluations of adverse project effects.
Algebraic properties of the first-order part of a problem
Creators: name: Solda, Giovanni
name: Valenti, Manlio
Publisher: name: arXiv
Year: 2022
Subjects: subject: Logic (math.LO)
subject: Logic in Computer Science (cs.LO)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: 03D78 03D30 03D55

description: In this paper we study the notion of first-order part of a computational problem, first introduced by Dzhafarov, Solomon, and Yokoyama, which captures the "strongest computational problem with codomain $\mathbb{N}$ that is Weihrauch reducible to $f$". This operator is very useful to prove separation results, especially at the higher levels of the Weihrauch lattice. We explore the first-order part in relation with several other operators already known in the literature. We also introduce a new operator, called unbounded finite parallelization, which plays an important role in characterizing the first-order part of parallelizable problems. We show how the obtained results can be used to explicitly characterize the first-order part of several known problems.
description: 41 pages. Updated after reviewer comments
Origin of the exponential decay of the Loschmidt echo in integrable systems
Creators: name: Dubertrand, Rémy
name: Goussev, Arseni
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: 530 Physik
subject: 05.45.Mt, 03.65.Sq, 03.65.Yz

description: We address the time decay of the Loschmidt echo, measuring the sensitivity of quantum dynamics to small Hamiltonian perturbations, in one-dimensional integrable systems. Using a semiclassical analysis, we show that the Loschmidt echo may exhibit a well-pronounced regime of exponential decay, similar to the one typically observed in quantum systemswhose dynamics is chaotic in the classical limit.We derive an explicit formula for the exponential decay rate in terms of the spectral properties of the unperturbed and perturbed Hamilton operators and the initial state. In particular, we show that the decay rate, unlike in the case of the chaotic dynamics, is directly proportional to the strength of the Hamiltonian perturbation. Finally, we compare our analytical predictions against the results of a numerical computation of the Loschmidt echo for a quantum particle moving inside a one-dimensional box with Dirichlet-Robin boundary conditions, and find the two in good agreement.
Quantum black holes, localization and the topological string
Creators: name: Dabholkar, Atish
name: Gomes, Joao
name: Murthy, Sameer
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We use localization to evaluate the functional integral of string field theory on AdS_2xS^2 background corresponding to the near horizon geometry of supersymmetric black holes in 4d compactifications with N=2 supersymmetry. In particular, for a theory containing n_v + 1 vector multiplets, we show that the functional integral localizes exactly onto an ordinary integral over a finite-dimensional submanifold in the field space labeling a continuous family of instanton solutions in which auxiliary fields in the vector multiplets are excited with nontrivial dependence on AdS_2 coordinates. These localizing solutions are universal in that they follow from the off-shell supersymmetry transformations and do not depend on the choice of the action. They are parametrized by n_v +1 real parameters C^I, ; I= 0,..., n_v that correspond to the values of the auxiliary fields at the center of AdS_2. In the Type-IIA frame, assuming D-terms evaluate to zero on the solutions for reasons of supersymmetry, the classical part of the integrand equals the absolute square of the partition function of the topological string as conjectured by Ooguri, Strominger, and Vafa; however evaluated at the off-shell values of scalar fields at the center of AdS_2. In addition, there are contributions from one-loop determinants, brane-instantons, and nonperturbative orbifolds that are in principle computable. These results thus provide a concrete method to compute exact quantum entropy of these black holes including all perturbative and nonperturbative corrections and can be used to establish a precise relation between the quantum degeneracies of black holes and the topological string.
description: 52 pges; references added; revised equations in section 5, results unchanged
Visual-Tactile Multimodality for Following Deformable Linear Objects Using Reinforcement Learning
Creators: name: Pecyna, Leszek
name: Dong, Siyuan
name: Luo, Shan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Manipulation of deformable objects is a challenging task for a robot. It will be problematic to use a single sensory input to track the behaviour of such objects: vision can be subjected to occlusions, whereas tactile inputs cannot capture the global information that is useful for the task. In this paper, we study the problem of using vision and tactile inputs together to complete the task of following deformable linear objects, for the first time. We create a Reinforcement Learning agent using different sensing modalities and investigate how its behaviour can be boosted using visual-tactile fusion, compared to using a single sensing modality. To this end, we developed a benchmark in simulation for manipulating the deformable linear objects using multimodal sensing inputs. The policy of the agent uses distilled information, e.g., the pose of the object in both visual and tactile perspectives, instead of the raw sensing signals, so that it can be directly transferred to real environments. In this way, we disentangle the perception system and the learned control policy. Our extensive experiments show that the use of both vision and tactile inputs, together with proprioception, allows the agent to complete the task in up to 92% of cases, compared to 77% when only one of the signals is given. Our results can provide valuable insights for the future design of tactile sensors and for deformable objects manipulation.
description: 8 pages, 11 figures
A finite element method for fully nonlinear elliptic problems
Creators: name: Lakkis, Omar
name: Pryer, Tristan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65N30, 65Y20, 35J60,

description: We present a continuous finite element method for some examples of fully nonlinear elliptic equation. A key tool is the discretisation proposed in Lakkis & Pryer (2011, SISC) allowing us to work directly on the strong form of a linear PDE. An added benefit to making use of this discretisation method is that a recovered (finite element) Hessian is a biproduct of the solution process. We build on the linear basis and ultimately construct two different methodologies for the solution of second order fully nonlinear PDEs. Benchmark numerical results illustrate the convergence properties of the scheme for some test problems including the Monge-Ampère equation and Pucci's equation.
description: 22 pages, 31 figures
Moiré Engineering of Spin-Orbit Coupling in Twisted Platinum Diselenide
Creators: name: Klebl, Lennart
name: Xu, Qiaoling
name: Fischer, Ammon
name: Xian, Lede
name: Claassen, Martin
name: Rubio, Angel
name: Kennes, Dante M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We study the electronic structure and correlated phases of twisted bilayers of platinum diselenide using large-scale ab initio simulations combined with the functional renormalization group. PtSe$_2$ is a group-X transition metal dichalcogenide, which hosts emergent flat bands at small twist angles in the twisted bilayer. Remarkably, we find that moiré engineering can be used to tune the strength of Rashba spin-orbit interactions, altering the electronic behavior in a novel manner. We reveal that an effective triangular lattice with a twist-controlled ratio between kinetic and spin-orbit coupling scales can be realized. Even dominant spin-orbit coupling can be accessed in this way and we discuss consequences for the interaction driven phase diagram, which features pronounced exotic superconducting and entangled spin-charge density waves.
description: 13 pages, 4 figures
Isometric group actions with vanishing rate of escape on CAT(0) spaces
Creators: name: Izeki, Hiroyasu
Publisher: name: arXiv
Year: 2022
Subjects: subject: Group Theory (math.GR)
subject: Differential Geometry (math.DG)
subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 53C23, 20F65

description: Let $Γ$ be a finitely generated group equipped with a symmetric and nondegenerate probability measure $μ$ with finite second moment, and $Y$ a CAT(0) space which is either proper or of finite telescopic dimension. We show that if an isometric action of $Γ$ on $Y$ has vanishing rate of escape with respect to $μ$ and does not fix a point in the boundary at infinity of $Y$, then there exists a flat subspace in $Y$ which is left invariant under the action of $Γ$. In the proof of this result, an equivariant $μ$-harmonic map from $Γ$ into $Y$ plays an important role.
description: 67 pages, 8 figures
Visual and interactive legacy outputs
Creators: name: Keeble, Kathryn
name: Keeble, Simon
name: Fritz, Jan-Stefan
name: Verbeek, Laura
name: Reitz, Anja
name: Ketelhake, Sandra
Publisher: name: AtlantOS
Year: 2019

description: Development and dissemination of up to 6 visual / interactive outputs aimed at stakeholder groups
Dominant Andreev Reflection through Nonlinear Radio-Frequency Transport
Creators: name: Zhang, Tingyu
name: Tajima, Hiroyuki
name: Sekino, Yuta
name: Uchino, Shun
name: Liang, Haozhao
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: Superconductivity (cond-mat.supr-con)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Nuclear Theory (nucl-th)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We theoretically propose the laser-induced Andreev reflection between two-component Fermi superfluid and normal states via spatially-uniform Rabi couplings. By analyzing the tunneling current between the superfluid and normal states up to the fourth order in the Rabi couplings, we find that the Andreev current exhibits unconventional non-Ohmic transport at zero temperature. Remarkably, the Andreev current gives the only contribution in the synthetic junction system at zero detunings regardless of the ratio of the chemical potential bias to the superfluid gap, which is in sharp contrast to that in the conventional superconductor-normal metal junction. Our result may also pave a way for understanding the black hole information paradox through the Andreev reflection as a quantum-information mirror.
description: 7 pages, 5 figures
A comprehensive review and evaluation on text predictive and entertainment systems
Creators: name: Hamarashid, Hozan K.
name: Saeed, Soran A.
name: Rashid, Tarik A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: One of the most important ways to experience communication and interact with the systems is by handling the prediction of the most likely words to happen after typing letters or words. It is helpful for people with disabilities due to disabling people who could type or enter texts at a limited slow speed. Also, it is beneficial for people with dyslexia and those people who are not well with spells of words. Though, an input technology, for instance, the next word suggestion facilitates the typing process in smartphones as an example. This means that when a user types a word, then the system suggests the next words to be chosen in which the necessary word by the user. Besides, it can be used in entertainment as a gam, for example, to determine a target word and reach it or tackle it within 10 attempts of prediction. Generally, the systems depend on a text corpus, which was provided in the system to conduct the prediction. Writing every single word is time-consuming, therefore, it is vitally important to decrease time consumption by reducing efforts to input texts in the systems by offering most probable words for the user to select, this could be done via next word prediction systems. There are several techniques can be found in literature, which is utilized to conduct a variety of next word prediction systems by using different approaches. In this paper, a survey of miscellaneous techniques towards the next word prediction systems will be addressed. Besides, the evaluation of the prediction systems will be discussed. Then, a modal technique will be determined to be utilized for the next word prediction system from the perspective of easiness of implementation and obtaining a good result.
description: 42 pages
Lemaitre-Tolman-Bondi model of the universe and Hawking radiation of a dynamical horizon
Creators: name: Biswas, Ritabrata
name: Mazumder, Nairwita
name: Chakraborty, Subenoy
Publisher: name: arXiv
Year: 2011
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The paper deals with anisotropic spherically symmetric Lemaitre-Tolman-Bondi model of the universe bounded by the apparent horizon. Using Hamilton-Jacobi method for both massive and massless test particles, we are able to show that the temperature associated with the apparent horizon due to Hawking radiation is the usual Hawking Temperature. Also the usual Lemaitre-Tolman-Bondi model and the transformed r-gauge Lemaitre-Tolman-Bondi model are shown to be equivalent. Finally, the results of Tunneling approach agree with the Hamiltonian-Jacobi method.
description: have to modify the work
On the applicability of holography in thermodynamic equilibrium
Creators: name: Yang, Run-Qiu
name: Li, Li
name: Cai, Rong-Gen
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: For a strongly coupled system that has a gravity dual description, we show that the standard holographic dictionary yields a nonnegative susceptibility when the system is in thermodynamic equilibrium and the correlation function is absolutely integrable. When the system has no spontaneous condensation or has a spontaneous $\mathbb{Z}_2$-symmetry breaking, we find that the ``trace energy condition" is violated in many cases. There is a normalized grand potential density that is monotonic as accessing to lower scales, providing a candidate $c$-function characterizing the number of effective degrees of freedom. Finally, we discuss a ``paradox'' raising by the negative susceptibility in holography and its resolution.
description: The published version
Fidelity for kicked atoms with gravity near a quantum resonance
Creators: name: Dubertrand, Rémy
name: Guarneri, Italo
name: Wimberger, Sandro
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: 530 Physik
subject: 05.45.Mt, 03.65.Sq, 37.10.Jk

description: Kicked atoms under a constant Stark or gravity field are investigated for experimental setups with cold and ultracold atoms. The parametric stability of the quantum dynamics is studied using the fidelity. In the case of a quantum resonance, it is shown that the behavior of the fidelity depends on arithmetic properties of the gravity parameter. Close to a quantum resonance, the long-time asymptotics of the fidelity is studied by means of a pseudoclassical approximation introduced by Fishman et al. [J. Stat. Phys. 110, 911 (2003)]. The long-time decay of fidelity arises from the tunneling out of pseudoclassical stable islands, and a simple ansatz is proposed which satisfactorily reproduces the main features observed in numerical simulations.
Simultaneous Human-robot Matching and Routing for Multi-robot Tour Guiding under Time Uncertainty
Creators: name: Fu, Bo
name: Kathuria, Tribhi
name: Rizzo, Denise
name: Castanier, Matthew
name: Yang, X. Jessie
name: Ghaffari, Maani
name: Barton, Kira
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: Multiagent Systems (cs.MA)
subject: FOS: Computer and information sciences
subject: 93A16

description: This work presents a framework for multi-robot tour guidance in a partially known environment with uncertainty, such as a museum. In the proposed centralized multi-robot planner, a simultaneous matching and routing problem (SMRP) is formulated to match the humans with robot guides according to their selected places of interest (POIs) and generate the routes and schedules for the robots according to uncertain spatial and time estimation. A large neighborhood search algorithm is developed to efficiently find sub-optimal low-cost solutions for the SMRP. The scalability and optimality of the multi-robot planner are evaluated computationally under different numbers of humans, robots, and POIs. The largest case tested involves 50 robots, 250 humans, and 50 POIs. Then, a photo-realistic multi-robot simulation platform was developed based on Habitat-AI to verify the tour guiding performance in an uncertain indoor environment. Results demonstrate that the proposed centralized tour planner is scalable, makes a smooth trade-off in the plans under different environmental constraints, and can lead to robust performance with inaccurate uncertainty estimations (within a certain margin).
description: ASME, Journal of Autonomous Vehicles and Systems, 2022
Trace formula for chaotic dielectric resonators tested with microwave experiments
Creators: name: Bittner, S.
name: Dietz, B.
name: Dubertrand, Rémy
name: Isensee, J.
name: Miski-Oglu, M.
name: Richter, A.
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: 530 Physik
subject: 05.45.Mt, 42.55.Sa, 03.65.Sq

description: We measured the resonance spectra of two stadium-shaped dielectric microwave resonators and tested a semiclassical trace formula for chaotic dielectric resonators proposed by Bogomolny et al. [Phys. Rev. E 78, 056202 (2008)]. We found good qualitative agreement between the experimental data and the predictions of the trace formula. Deviations could be attributed to missing resonances in the measured spectra in accordance with previous experiments [Phys. Rev. E 81, 066215 (2010)]. The investigation of the numerical length spectrum showed good qualitative and reasonable quantitative agreement with the trace formula. It demonstrated, however, the need for higher-order corrections of the trace formula. The application of a curvature correction to the Fresnel reflection coefficients entering the trace formula yielded better agreement, but deviations remained, indicating the necessity of further investigations.
Fidelity of the near-resonant quantum kicked rotor
Creators: name: Probst, B.
name: Dubertrand, Rémy
name: Wimberger, S.
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: 530 Physik
subject: 03.65.Sq, 05.60.Gg, 03.75.Dg, 37.10.Vz

description: We present a perturbative result for the temporal evolution of the fidelity of the quantum kicked rotor, i.e. the overlap of the same initial state evolved with two slightly different kicking strengths, for kicking periods close to a principal quantum resonance. Based on a pendulum approximation, we describe the fidelity for rotational orbits in the pseudo-classical phase space of a corresponding classical map. Our results are compared to numerical simulations indicating the range of applicability of our analytical approximation.
Computing zeta functions of table algebra orders using local zeta integrals
Creators: name: Babei, Angelica
name: Herman, Allen
Publisher: name: arXiv
Year: 2022
Subjects: subject: Number Theory (math.NT)
subject: Rings and Algebras (math.RA)
subject: FOS: Mathematics
subject: 11R54 (Primary) 11S45, 05E30 (Secondary)

description: We investigate Solomon's zeta function for orders in the special case of orders generated by the standard basis of an integral table algebra, a special case of which is the integral adjacency algebra of an association scheme. As Solomon's elementary method for computing this zeta function runs into computational difficulties for ranks $3$ or more, a more efficient method is desired. We give several examples to illustrate how the local zeta integral approach proposed by Bushnell and Reiner can be applied to compute explicit zeta functions for these orders.
Bijective enumeration of some colored permutations given by the product of two long cycles
Creators: name: Féray, Valentin
name: Vassilieva, Ekaterina A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05A05

description: Let $γ_n$ be the permutation on $n$ symbols defined by $γ_n = (1\ 2\...\ n)$. We are interested in an enumerative problem on colored permutations, that is permutations $β$ of $n$ in which the numbers from 1 to $n$ are colored with $p$ colors such that two elements in a same cycle have the same color. We show that the proportion of colored permutations such that $γ_n β^{-1}$ is a long cycle is given by the very simple ratio $\frac{1}{n- p+1}$. Our proof is bijective and uses combinatorial objects such as partitioned hypermaps and thorn trees. This formula is actually equivalent to the proportionality of the number of long cycles $α$ such that $γ_nα$ has $m$ cycles and Stirling numbers of size $n+1$, an unexpected connection previously found by several authors by means of algebraic methods. Moreover, our bijection allows us to refine the latter result with the cycle type of the permutations.
description: 22 pages. Version 1 is a short version of 12 pages, entitled "Linear coefficients of Kerov's polynomials: bijective proof and refinement of Zagier's result", published in DMTCS proceedings of FPSAC 2010, AN, 713-724
Multiple-photon bundle emission in the $n$-photon Jaynes-Cummings model
Creators: name: Jiang, Shu-Yuan
name: Zou, Fen
name: Wang, Yi
name: Huang, Jin-Feng
name: Xu, Xun-Wei
name: Liao, Jie-Qiao
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study the multiple-photon bundle emission in the $n$-photon Jaynes-Cummings model composed of a two-level system coupled to a single-mode optical field via the $n$-photon exciting process. Here, the two-level system is strongly driven by a near-resonant monochromatic field, and hence the system can work in the Mollow regime, in which a super-Rabi oscillation between the zero-photon state and the $n$-photon state can take place under proper resonant conditions. We calculate the photon number populations and the standard equal-time high-order correlation functions, and find that the multiple-photon bundle emission can occur in this system. The multiple-photon bundle emission is also confirmed by investigating the quantum trajectories of the state populations and both the standard and generalized time-delay second-order correlation functions for multiple-photon bundle. Our work paves the way towards the study of multiple-photon quantum coherent devices, with potential application in quantum information sciences and technologies.
description: 10 pages, 6 figures
Trace formula for dielectric cavities: I. General properties
Creators: name: Bogomolny, E.
name: Dubertrand, Rémy
name: Schmit, C.
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: 530 Physik
subject: 05.45.Mt, 42.55.Sa, 03.65.Sq

description: The construction of the trace formula for open dielectric cavities is examined in detail. Using the Krein formula it is shown that the sum over cavity resonances can be written as a sum over classical periodic orbits for the motion inside the cavity. The contribution of each periodic orbit is the product of the two factors. The first is the same as in the standard trace formula and the second is connected with the product of reflection coefficients for all points of reflection with the cavity boundary. Two asymptotic terms of the smooth resonance counting function related with the area and the perimeter of a convex cavity are derived. The coefficient of the perimeter term differs from the one for closed cavities due to unusual high-energy asymptotics of the S matrix for the scattering on the cavity. Corrections to the leading semi-classical formula are briefly discussed. Obtained formulas agree well with numerical calculations for circular dielectric cavities.
Multifractality of quantum wave functions in the presence of perturbations
Creators: name: Dubertrand, Rémy
name: García-Mata, I.
name: Georgeot, B.
name: Giraud, O.
name: Lemarié, G.
name: Martin, J.
Publisher: name: Universität Regensburg
Year: 2015
Subjects: subject: 530 Physik
subject: 05.45.Df, 05.45.Mt, 71.30.+h, 05.40.−a

description: We present a comprehensive study of the destruction of quantum multifractality in the presence of perturbations. We study diverse representative models displaying multifractality, including a pseudointegrable system, the Anderson model, and a random matrix model. We apply several types of natural perturbations which can be relevant for experimental implementations. We construct an analytical theory for certain cases and perform extensive large-scale numerical simulations in other cases. The data are analyzed through refined methods including double scaling analysis. Our results confirm the recent conjecture that multifractality breaks down following two scenarios. In the first one, multifractality is preserved unchanged below a certain characteristic length which decreases with perturbation strength. In the second one, multifractality is affected at all scales and disappears uniformly for a strong-enough perturbation. Our refined analysis shows that subtle variants of these scenarios can be present in certain cases. This study could guide experimental implementations in order to observe quantum multifractality in real systems.
A PR drag origin for the Fomalhaut disk's pervasive inner dust: constraints on collisional strengths, icy composition, and embedded planets
Creators: name: Sommer, Max
name: Wyatt, Mark
name: Han, Yinuo
Publisher: name: arXiv
Year: 2025
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Recent JWST observations of the Fomalhaut debris disk have revealed a significant abundance of dust interior to the outer planetesimal belt, raising questions about its origin and maintenance. In this study, we apply an analytical model to the Fomalhaut system, that simulates the dust distribution interior to a planetesimal belt, as collisional fragments across a range of sizes are dragged inward under Poynting-Robertson (PR) drag. We generate spectral energy distributions and synthetic JWST/MIRI images of the model disks, and perform an extensive grid search for particle parameters -- pertaining to composition and collisional strength -- that best match the observations. We find that a sound fit can be found for particle properties that involve a substantial water ice component, around 50%--80% by total volume, and a catastrophic disruption threshold, $Q_D^\star$, at a particle size of $D\!\approx\!30\,$um of 2--4$\,\times\,10^6\,$erg/g. Based on the expected dynamical depletion of migrating dust by an intervening planet we discount planets with masses $>1\,M_\mathrm{Saturn}$ beyond $\sim50\,$au in the extended disk, though a planet shepherding the inner edge of the outer belt of up to $\sim2\,M_\mathrm{Saturn}$ is reconcilable with the PR-drag-maintained disk scenario, contingent upon higher collisional strengths. These results indicate that PR drag transport from the outer belt alone can account for the high interior dust contents seen in the Fomalhaut system, which may thus constitute a common phenomenon in other belt-bearing systems. This establishes a framework for interpreting mid-planetary system dust around other stars, with our results for Fomalhaut providing a valuable calibration of the models.
On the Support of Minimizers of Causal Variational Principles
Creators: name: Finster, Felix
name: Schiefeneder, Daniela
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: Functional Analysis (math.FA)
subject: Optimization and Control (math.OC)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: A class of causal variational principles on a compact manifold is introduced and analyzed both numerically and analytically. It is proved under general assumptions that the support of a minimizing measure is either completely timelike, or it is singular in the sense that its interior is empty. In the examples of the circle, the sphere and certain flag manifolds, the general results are supplemented by a more detailed and explicit analysis of the minimizers. On the sphere, we get a connection to packing problems and the Tammes distribution. Moreover, the minimal action is estimated from above and below.
description: 39 pages, LaTeX, 7 figures, introduction expanded, references added (published version)
The Hölder Inequality for KMS States
Creators: name: Jäkel, Christian D.
name: Robl, Florian
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mathematical Physics (math-ph)
subject: Operator Algebras (math.OA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We prove a Hölder inequality for KMS States, which generalises a well-known trace-inequality. Our results are based on the theory of non-commutative $L_p$-spaces.
description: 10 pages
Near integrable systems
Creators: name: Bogomolny, E.
name: Dennis, M. R.
name: Dubertrand, Rémy
Publisher: name: Universität Regensburg
Year: 2009
Subjects: subject: 530 Physik
subject: 03.65.Ge, 05.45.Mt, 03.65.Sq

description: A two-dimensional circular quantum billiard with unusual boundary conditions introduced by Berry and Dennis (2008 J. Phys. A: Math. Theor. 41 135203) is considered in detail. It is demonstrated that most of its eigenfunctions are strongly localized and the corresponding eigenvalues are close to eigenvalues of the circular billiard with Neumann boundary conditions. Deviations from strong localization are also discussed. These results agree well with numerical calculations.
Trace formula for dielectric cavities. III. TE modes
Creators: name: Bogomolny, E.
name: Dubertrand, Rémy
Publisher: name: Universität Regensburg
Year: 2012
Subjects: subject: 530 Physik
subject: 05.45.Mt, 42.55.Sa, 03.65.Sq

description: The construction of the semiclassical trace formula for resonances with transverse electric polarization for two-dimensional dielectric cavities is discussed. Special attention is given to the derivation of the two first terms of Weyl’s series for the average number of such resonances. The formulas obtained agree well with numerical calculations for dielectric cavities of different shapes.
Do Neural Networks for Segmentation Understand Insideness?
Creators: name: Villalobos, Kimberly
name: Štih, Vilim
name: Ahmadinejad, Amineh
name: Sundaram, Shobhita
name: Dozier, Jamell
name: Francl, Andrew
name: Azevedo, Frederico
name: Sasaki, Tomotake
name: Boix, Xavier
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: Neurons and Cognition (q-bio.NC)
subject: FOS: Computer and information sciences
subject: FOS: Biological sciences

description: The insideness problem is an aspect of image segmentation that consists of determining which pixels are inside and outside a region. Deep Neural Networks (DNNs) excel in segmentation benchmarks, but it is unclear if they have the ability to solve the insideness problem as it requires evaluating long-range spatial dependencies. In this paper, the insideness problem is analysed in isolation, without texture or semantic cues, such that other aspects of segmentation do not interfere in the analysis. We demonstrate that DNNs for segmentation with few units have sufficient complexity to solve insideness for any curve. Yet, such DNNs have severe problems with learning general solutions. Only recurrent networks trained with small images learn solutions that generalize well to almost any curve. Recurrent networks can decompose the evaluation of long-range dependencies into a sequence of local operations, and learning with small images alleviates the common difficulties of training recurrent networks with a large number of unrolling steps.
The quest for development in chaos : what crisis events reveal about Nigeria’s legal system
Creators: name: Olarewaju, Temitayo
Publisher: name: University of British Columbia
Year: 2017

description: The relationship between law and economic development continues to perplex generations of scholars. This thesis adds to the query by embracing the iterative relationship between legal systems and markets as postulated by Milhaupt and Pistor; thereby, departing from law and finance theory which argues that past adopted legal systems are crucial for economic development. Law and finance theory is criticized based on the causal and proxy indeterminacy of law in achieving economic development, its discrepancies with corporate law practice, and various incoherent claims on juries and law in the twenty-first century. Milhaupt and Pistor’s framework grounded on the organization of a nation’s legal system, the functions of law in support of capitalist activity, and a state’s political economy embodying the supply and demand of law is used to understand how law is wielded in Africa’s giant quest for development. Institutional autopsies are conducted on pivotal corporate governance crisis events in Nigeria’s financial and petroleum sectors—Nigeria’s 2009-2010 banking crisis and the case of Moni Pulo v Brass—to understand Nigeria’s legal system and likely path to variation. Nigeria is revealed to be a centralized legal system, where the principal role of law is to coordinate market activity and one in which personal relationships play a vital part in her governance structure. The autopsies show there is a growing role played by state approved actors resulting in increased centralized and coordinative features of Nigeria’s legal system. It is hoped that this work assists in understanding the dynamic relationship between law and economic development in developing economies and serves as a foundation for future research on Nigeria’s political economy.
SLE description of the nodal lines of random waves functions
Creators: name: Bogomolny, E.
name: Dubertrand, Rémy
name: Schmit, C.
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik
subject: 05.45.Mt, 03.65.Sq, 64.60.Ak

description: The nodal lines of random wavefunctions are investigated. We demonstrate numerically that they are well approximated by the so-called SLE6 curves which describe the continuum limit of the percolation cluster boundaries. This result gives additional support to the recent conjecture that the nodal domains of random (and chaotic) wavefunctions in the semi-classical limit are adequately described by the critical percolation theory. It is also shown that using the dipolar variant of SLE reduces significantly finite size effects.
Multi-fidelity robust controller design with gradient sampling
Creators: name: Werner, Steffen W. R.
name: Overton, Michael L.
name: Peherstorfer, Benjamin
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optimization and Control (math.OC)
subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 37N35, 37N40, 65K10, 90C30, 90C59

description: Robust controllers that stabilize dynamical systems even under disturbances and noise are often formulated as solutions of nonsmooth, nonconvex optimization problems. While methods such as gradient sampling can handle the nonconvexity and nonsmoothness, the costs of evaluating the objective function may be substantial, making robust control challenging for dynamical systems with high-dimensional state spaces. In this work, we introduce multi-fidelity variants of gradient sampling that leverage low-cost, low-fidelity models with low-dimensional state spaces for speeding up the optimization process while nonetheless providing convergence guarantees for a high-fidelity model of the system of interest, which is primarily accessed in the last phase of the optimization process. Our first multi-fidelity method initiates gradient sampling on higher fidelity models with starting points obtained from cheaper, lower fidelity models. Our second multi-fidelity method relies on ensembles of gradients that are computed from low- and high-fidelity models. Numerical experiments with controlling the cooling of a steel rail profile and laminar flow in a cylinder wake demonstrate that our new multi-fidelity gradient sampling methods achieve up to two orders of magnitude speedup compared to the single-fidelity gradient sampling method that relies on the high-fidelity model alone.
description: 28 pages, 4 figures
Erratum to: Spin density matrix elements in exclusive ω electroproduction on 1 H and 2 H targets at 27.5 GeV beam energy
Creators: name: Airapetian, A.
name: Akopov, N.
name: Akopov, Z.
name: Augustyniak, W.
name: Avetissian, A.
name: Blok, H. P.
name: Borissov, A.
name: Bryzgalov, V.
name: Capiluppi, M.
name: Capitani, G. P.
name: Cisbani, E.
name: Ciullo, G.
name: Contalbrigo, M.
name: Dalpiaz, P. F.
name: Deconinck, W.
name: De Leo, R.
name: De Sanctis, E.
name: Diefenthaler, M.
name: Di Nezza, P.
name: Düren, M.
name: Ehrenfried, M.
name: Elbakian, G.
name: Ellinghaus, F.
name: Etzelmüller, E.
name: Fabbri, R.
name: Felawka, L.
name: Frullani, S.
name: Gabbert, D.
name: Gapienko, G.
name: Gapienko, V.
name: Garibaldi, F.
name: Gavrilov, G.
name: Gharibyan, V.
name: Hartig, M.
name: Hasch, D.
name: Holler, Y.
name: Hristova, I.
name: Ivanilov, A.
name: Jackson, H. E.
name: Joosten, S.
name: Kaiser, R.
name: Karyan, G.
name: Keri, T.
name: Kinney, E.
name: Kisselev, A.
name: Korotkov, V.
name: Kozlov, V.
name: Kravchenko, P.
name: Krivokhijine, V. G.
name: Lagamba, L.
name: Lapikás, L.
name: Lehmann, I.
name: Lenisa, P.
name: Lorenzon, W.
name: Ma, B.-Q.
name: Mahon, D.
name: Manaenkov, S. I.
name: Mao, Y.
name: Marianski, B.
name: Marukyan, H.
name: Movsisyan, A.
name: Murray, M.
name: Naryshkin, Y.
name: Nass, A.
name: Nowak, W.-D.
name: Pappalardo, L. L.
name: Perez-Benito, R.
name: Petrosyan, A.
name: Reimer, P. E.
name: Reolon, A. R.
name: Riedl, C.
name: Rith, K.
name: Rostomyan, A.
name: Ryckbosch, D.
name: Schäfer, A.
name: Schnell, G.
name: Schüler, K. P.
name: Seitz, B.
name: Shibata, T.-A.
name: Stahl, M.
name: Stancari, M.
name: Statera, M.
name: Steffens, E.
name: Steijger, J. J. M.
name: Taroian, S.
name: Terkulov, A.
name: Truty, R.
name: Trzcinski, A.
name: Tytgat, M.
name: Van Haarlem, Y.
name: Van Hulse, C.
name: Vikhrov, V.
name: Vilardi, I.
name: Wang, S.
name: Yaschenko, S.
name: Yen, S.
name: Zeiler, D.
name: Zihlmann, B.
name: Zupranski, P.
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: 530 Physik

description: It has been found that three of the spin-density matrix elements (SDMEs) in Fig. 6 of the published paper were incorrectly labeled. The labels have been fixed, while none of the results or conclusions have changed.
Hydrogen-impurity induced unconventional magnetism in semiconducting molybdenum ditelluride
Creators: name: Krieger, Jonas A.
name: Tay, Daniel
name: Rusinov, Igor P.
name: Barua, Sourabh
name: Biswas, Pabitra K.
name: Korosec, Lukas
name: Prokscha, Thomas
name: Schmitt, Thorsten
name: Schröter, Niels B. M.
name: Shang, Tian
name: Shiroka, Toni
name: Suter, Andreas
name: Balakrishnan, Geetha
name: Chulkov, Evgueni V.
name: Strocov, Vladimir N.
name: Salman, Zaher
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Layered transition-metal dichalcogenides are proposed as building blocks for van der Waals (vdW) heterostructures due to their graphene-like two dimensional structure. For this purpose, a magnetic semiconductor could represent an invaluable component for various spintronics and topotronics devices. Here, we combine different local magnetic probe spectroscopies with angle-resolved photoemission and density-functional theory calculations to show that 2H-MoTe2 is on the verge of becoming magnetic. Our results present clear evidence that the magnetism can be "switched on" by a hydrogen-like impurity. We also show that this magnetic state survives up to the free surface region, demonstrating the material's potential applicability as a magnetic component for thin-film heterostructures.
description: 17 pages, 13 figures, including supplementary
Spin-spin correlation functions of the q-VBS state of an integer spin model
Creators: name: Arita, Chikashi
name: Motegi, Kohei
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mathematical Physics (math-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We consider the valence-bond-solid ground state of the q-deformed higher-spin AKLT model (q-VBS state). We investigate the eigenvalues and eigenvectors of a matrix (G matrix), which is constructed from the matrix product representation of the q-VBS state. We compute the longitudinal and transverse spin-spin correlation functions, and determine the correlation amplitudes and correlation lengths for real q.
Estimates for constant mean curvature graphs in MxR
Creators: name: Manzano, José M.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: Primary 53A10, Secondary 49Q05, 53C42

description: We will discuss some sharp estimates for CMC graphs in a Riemannian 3-manifold MxR whose boundary is contained in a slice. We will start by giving sharp lower bounds for the geodesic curvature of the boundary and improve these bounds when assuming additional restrictions on the maximum height that such a surface reaches in MxR. We will also give a lower bound for the distance from an interior point to the boundary in terms of the height at that point, and characterize when these bounds are attained.
description: 16 pages, 2 figures
Trace formula for dielectric cavities. II. Regular, pseudointegrable, and chaotic examples
Creators: name: Bogomolny, E.
name: Djellali, N.
name: Dubertrand, Rémy
name: Gozhyk, I.
name: Lebental, M.
name: Schmit, C.
name: Ulysse, C.
name: Zyss, J.
Publisher: name: Universität Regensburg
Year: 2011
Subjects: subject: 530 Physik
subject: 42.55.Sa, 05.45.Mt, 03.65.Sq, 03.65.Yz

description: Dielectric resonators are open systems particularly interesting due to their wide range of applications in optics and photonics. In a recent paper [Phys. Rev. E 78, 056202 (2008)] the trace formula for both the smooth and the oscillating parts of the resonance density was proposed and checked for the circular cavity. The present paper deals with numerous shapes which would be integrable (square, rectangle, and ellipse), pseudointegrable (pentagon), and chaotic (stadium), if the cavities were closed (billiard case). A good agreement is found between the theoretical predictions, the numerical simulations, and experiments based on organic microlasers.
Combinatorial synthesis of cation-disordered manganese tin nitride MnSnN$_2$ thin films with magnetic and semiconducting properties
Creators: name: Rom, Christopher L.
name: Smaha, Rebecca W.
name: Melamed, Celeste L.
name: Schnepf, Rekha R.
name: Heinselman, Karen N.
name: Mangum, John S.
name: Lee, Sang-Jun
name: Lany, Stephan
name: Schelhas, Laura T.
name: Greenaway, Ann L.
name: Neilson, James R.
name: Bauers, Sage R.
name: Andrew, Jennifer S.
name: Tamboli, Adele C.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Magnetic semiconductors may soon improve the energy efficiency of computers, but materials exhibiting these dual properties remain underexplored. Here, we report the computational prediction and realization of a new magnetic and semiconducting material, MnSnN$_2$, via combinatorial sputtering of thin films. Grazing incidence wide angle X-ray scattering and laboratory X-ray diffraction studies show a wide composition tolerance for this wurtzite-like MnSnN$_2$, ranging from $20\% <$ Mn/(Mn+Sn) $< 65$\% with cation disorder across this composition space. Magnetic susceptibility measurements reveal a low-temperature transition ($T^{\mathrm{*}} \approx 10$ K) for MnSnN$_2$ and strong antiferromagnetic correlations, although the ordering below this transition may be complex. This finding contrasts with bulk MnSiN$_2$ and MnGeN$_2$, which exhibited antiferromagnetic ordering above 400 K in previous studies. Spectroscopic ellipsometry identifies an optical absorption onset of 1 eV for the experimentally-synthesized phase exhibiting cation disorder, consistent with the computationally-predicted 1.2 eV bandgap for the cation-ordered structure. Electronic conductivity measurements confirm the semiconducting nature of this new phase by showing increasing conductivity with increasing temperature. This work adds to the set of known semiconductors that are paramagnetic at room temperature and will help guide future work targeted at controlling the structure and properties of semiconducting materials that exhibit magnetic behavior.
Circular dielectric cavity and its deformations
Creators: name: Dubertrand, Rémy
name: Bogomolny, E.
name: Djellali, N.
name: Lebental, M.
name: Schmit, C.
Publisher: name: Universität Regensburg
Year: 2008
Subjects: subject: 530 Physik
subject: 42.55.Sa, 03.65.Sq

description: The construction of perturbation series for slightly deformed dielectric circular cavity is discussed in detail. The obtained formulas are checked on the example of cut disks. A good agreement is found with direct numerical simulations and far-field experiments.