cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Optimal experimental design: Formulations and computations
Creators: name: Huan, Xun
name: Jagalur, Jayanth
name: Marzouk, Youssef
Publisher: name: arXiv
Year: 2024
Subjects: subject: Methodology (stat.ME)
subject: Numerical Analysis (math.NA)
subject: Computation (stat.CO)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Questions of `how best to acquire data' are essential to modeling and prediction in the natural and social sciences, engineering applications, and beyond. Optimal experimental design (OED) formalizes these questions and creates computational methods to answer them. This article presents a systematic survey of modern OED, from its foundations in classical design theory to current research involving OED for complex models. We begin by reviewing criteria used to formulate an OED problem and thus to encode the goal of performing an experiment. We emphasize the flexibility of the Bayesian and decision-theoretic approach, which encompasses information-based criteria that are well-suited to nonlinear and non-Gaussian statistical models. We then discuss methods for estimating or bounding the values of these design criteria; this endeavor can be quite challenging due to strong nonlinearities, high parameter dimension, large per-sample costs, or settings where the model is implicit. A complementary set of computational issues involves optimization methods used to find a design; we discuss such methods in the discrete (combinatorial) setting of observation selection and in settings where an exact design can be continuously parameterized. Finally we present emerging methods for sequential OED that build non-myopic design policies, rather than explicit designs; these methods naturally adapt to the outcomes of past experiments in proposing new experiments, while seeking coordination among all experiments to be performed. Throughout, we highlight important open questions and challenges.
description: Appears in Acta Numerica 2024. This version contains an evolving set of post-publication additions and corrections
Searching for the QCD Axion with Gravitational Microlensing
Creators: name: Fairbairn, Malcolm
name: Marsh, David J. E.
name: Quevillon, Jérémie
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The phase transition responsible for axion dark matter production can create large amplitude isocurvature perturbations which collapse into dense objects known as axion miniclusters. We use microlensing data from the EROS survey, and from recent observations with the Subaru Hyper Suprime Cam to place constraints on the minicluster scenario. We compute the microlensing event rate for miniclusters treating them as spatially extended objects with an extended mass function. Using the published bounds on the number of microlensing events we bound the fraction of DM collapsed into miniclusters, $f_{\rm MC}$. For an axion with temperature dependent mass consistent with the QCD axion we find $f_{\rm MC}<0.22(m_a/100\,μ\text{eV})^{-0.57}$, which represents the first observational constraint on the minicluster fraction. We forecast that a high-efficiency observation of ten nights with Subaru would be sufficient to constrain $f_{\rm MC}\lesssim 0.1$ over the entire QCD axion mass range. We make various approximations to derive these constraints and dedicated analyses by the observing teams of EROS and Subaru are necessary to confirm our results. If accurate theoretical predictions for $f_{\rm MC}$ can be made in future then microlensing can be used to exclude, or discover, the QCD axion. Further details of our computations are presented in a companion paper.
description: 5 pages, 4 figures, v2 contains an improved description of our modeling of miniclusters and lensing with revised limits, matches version accepted in PRL
Wine quality under integrated, organic and biodynamic management using image-forming methods and sensory analysis
Creators: name: Fritz, Jürgen
name: Döring, Johanna
name: Athmann, Miriam
name: Meissner, Georg
name: Kauer, Randolf
name: Schultz, Hans Reiner
Publisher: name: Universität Kassel
Year: 2021
Subjects: subject: sensory analysis
subject: image-forming methods
subject: copper chloride crystallization
subject: circular chromatography
subject: wine quality
subject: integrated
subject: organic
subject: biodynamic viticulture
subject: 540
subject: 600
subject: 630
subject: Sensorische Prüfung
subject: Wein
subject: Lebensmittelqualität
subject: Biologisch-dynamische Wirtschaftsweise
subject: Messung

description: Gefördert durch den Publikationsfonds der Universität Kassel
Lorentzian Robin Universe of Gauss-Bonnet Gravity
Creators: name: Ailiga, Manishankar
name: Mallik, Shubhashis
name: Narain, Gaurav
Publisher: name: arXiv
Year: 2024
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The gravitational path-integral of Gauss-Bonnet gravity is investigated and the transition from one spacelike boundary configuration to another is analyzed. Of particular interest is the case of Neumann and Robin boundary conditions which is known to lead to a stable Universe in Einstein-Hilbert gravity in four spacetime dimensions. After setting up the variational problem and computing the necessary boundary terms, the transition amplitude is computed \emph{exactly} in the mini-superspace approximation. The $\hbar\to0$ limit brings out the dominant pieces in the path-integral which is traced to an initial configuration corresponding to Hartle-Hawking no-boundary Universe. A deeper study involving Picard-Lefschetz methods not only allow us to find the integration contour along which the path integral becomes convergent but also aids in understanding the crossover from Euclidean to Lorentzian signature. Saddle analysis further highlights the boundary configurations giving dominant contribution to the path-integral which is seen to be those corresponding to Hartle-Hawking no-boundary proposal and agrees with the exact computation. To ensure completeness, a comparison with the results from Wheeler-DeWitt equation is done.
description: v2: Published in GERG. title modified, text added at few places; one appendix, some references and a figure added
Negativity Bounds for Weyl-Heisenberg Quasiprobability Representations
Creators: name: DeBrota, John B.
name: Fuchs, Christopher A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The appearance of negative terms in quasiprobability representations of quantum theory is known to be inevitable, and, due to its equivalence with the onset of contextuality, of central interest in quantum computation and information. Until recently, however, nothing has been known about how much negativity is necessary in a quasiprobability representation. Zhu proved that the upper and lower bounds with respect to one type of negativity measure are saturated by quasiprobability representations which are in one-to-one correspondence with the elusive symmetric informationally complete quantum measurements (SICs). We define a family of negativity measures which includes Zhu's as a special case and consider another member of the family which we call "sum negativity." We prove a sufficient condition for local maxima in sum negativity and find exact global maxima in dimensions $3$ and $4$. Notably, we find that Zhu's result on the SICs does not generally extend to sum negativity, although the analogous result does hold in dimension $4$. Finally, the Hoggar lines in dimension $8$ make an appearance in a conjecture on sum negativity.
description: 21 pages. v2: journal version, added references
Low-lying baryon masses using $N_f=2$ twisted mass clover-improved fermions directly at the physical point
Creators: name: Alexandrou, Constantia
name: Kallidonis, Christos
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The masses of the low-lying baryons are evaluated using an ensemble with two degenerate light twisted mass clover-improved quarks with mass tuned to reproduce the physical pion mass. The Iwasaki improved gluonic action is employed. The coupling constant value corresponds to a lattice spacing of $a=0.0938(3)(2)$ fm, determined from the nucleon mass. We find that the clover term supresses isospin symmetry breaking as compared to our previous results using $N_f=2+1+1$ twisted mass fermions. The masses of the hyperons and charmed baryons evaluated using this ensemble are in agreement with the experimental values. We provide predictions for the mass of the doubly charmed $Ξ_{cc}^*$, as well as of the doubly and triply charmed $Ω$s that have not yet been determined experimentally.
description: arXiv admin note: text overlap with arXiv:1406.4310
Strong coupling between moving atoms and slow-light Cherenkov photons
Creators: name: Calajo, Giuseppe
name: Rabl, Peter
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We describe the coupling of moving atoms to a one dimensional photonic waveguide in the regime where the atomic velocities are comparable to the effective speed of light. Such conditions could be achieved, for example, in photonic crystals or coupled resonator arrays, where the maximal photonic group velocity is significantly reduced compared to free space. In this case the interplay between a velocity-induced directionality and the emergence of new divergencies in the photonic density of states gives rise to a range of novel phenomena and non-perturbative effects in the emission of photons and the resulting photon-mediated interactions between moving atoms. We show that apart from potential implementations with optical waveguides, Rydberg atoms flying above a coupled array of superconducting microwave resonators provide a versatile platform for exploring this new regime of atom-light interactions under experimentally accessible conditions.
description: 14 pages, 8 figures
The First Billion Years project: constraining the dust attenuation law of star-forming galaxies at z $\simeq$ 5
Creators: name: Cullen, F.
name: McLure, R. J.
name: Khochfar, S.
name: Dunlop, J. S.
name: Vecchia, C. Dalla
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the results of a study investigating the dust attenuation law at $z\simeq 5$, based on synthetic spectral energy distributions (SEDs) calculated for a sample of N=498 galaxies drawn from the First Billion Years (FiBY) simulation project. The simulated galaxies at $z\simeq 5$, which have M$_{1500} \leq -18.0$ and $7.5 \leq \rm{log(M/M}_{\odot}\rm{)} \leq 10.2$, display a mass-dependent $α$-enhancement, with a median value of $[α/\rm{Fe}]_{z=5}~\simeq~4~\times~[α/\rm{Fe}]_{Z_{\odot}}$. The median Fe/H ratio of the simulated galaxies is $0.14\pm0.05$ which, even including the effects of nebular continuum, produces steep intrinsic UV continuum slopes; $\langle β_{i} \rangle = -2.4 \pm 0.05$. Using a set of simple dust attenuation models, in which the wavelength-dependent attenuation is assumed to be of the form $A(λ) \propto λ^{n}$, we explore the parameter values which best reproduce the observed $z=5$ luminosity function (LF) and colour-magnitude relation (CMR). We find that a simple model in which the absolute UV attenuation is a linearly increasing function of log stellar mass, and the dust attenuation slope ($n$) is within the range $-0.7 \leq n \leq-0.3$, can successfully reproduce the LF and CMR over a wide range of stellar population synthesis model (SPS) assumptions. This range of attenuation curves is consistent with a power-law fit to the Calzetti attenuation law in the UV ($n=-0.55$), and other similarly `grey' star-forming galaxy attenuation curves recently derived at $z\simeq2$. In contrast, attenuation curves as steep as the Small Magellanic Cloud (SMC) extinction curve ($n=-1.24$) are formally ruled out. Finally, we show that our models are consistent with recent 1.3mm ALMA observations of the Hubble Ultra Deep Field (HUDF), and predict the form of the $z\simeq5$ IRX$-β$ relation.
description: 23 pages, 19 figures, accepted for publication in MNRAS
Quantum teleportation and information splitting via four-qubit cluster state and a Bell state
Creators: name: Ramirez, Marlon David Gonzalez
name: Falaye, Babatunde James
name: Sun, Guo-Hua
name: Cruz-Irisson, M.
name: Dong, Shi-Hai
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Quantum teleportation provides a `bodiless' way of transmitting the quantum state from one object to another, at a distant location, using a classical communication channel and a previously shared entangled state. In this paper, we present a tripartite scheme for probabilistic teleportation of an arbitrary single qubit state, without losing the information of the state being teleported, via a four-qubit cluster state of the form $\left.|ϕ\right\rangle_{1234}=\left.α|0000\right\rangle+\left.β|1010\right\rangle+\left.γ|0101\right\rangle-η\left.|1111\right\rangle$, as the quantum channel, where the nonzero real numbers $α$, $β$, $γ$, and $η$ satisfy the relation $|α|^2+|β|^2+|γ|^2+|η|^2=1$. With the introduction of an auxiliary qubit with state $\left|0\right\rangle$, using a suitable unitary transformation and a positive-operator valued measure (POVM), the receiver can recreate the state of the original qubit. An important advantage of the teleportation scheme demonstrated here is that, if the teleportation fails, it can be repeated without teleporting copies of the unknown quantum state, if the concerned parties share another pair of entangled qubit. We also present a protocol for quantum information splitting of an arbitrary two-particle system via the aforementioned cluster state and a Bell-state as the quantum channel. Problems related to security attacks were examined for both the cases and it was found that this protocol is secure. This protocol is highly efficient and easy to implement.
Anharmonic interatomic force constants and thermal conductivity from Grüneisen parameters: an application to graphene
Creators: name: Lee, Ching Hua
name: Gan, Chee Kwan
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Phonon-mediated thermal conductivity, which is of great technological relevance, fundamentally arises due to anharmonic scattering from interatomic potentials. Despite its prevalence, accurate first-principles calculations of thermal conductivity remain challenging, primarily due to the high computational cost of anharmonic interatomic force constant (IFCs) calculations. Meanwhile, the related anharmonic phenomenon of thermal expansion is much more tractable, being computable from the Grüneisen parameters associated with phonon frequency shifts due to crystal deformations. In this work, we propose a novel approach for computing the largest cubic IFCs from the Grüneisen parameter data. This allows an approximate determination of the thermal conductivity via a much less expensive route. The key insight is that although the Grüneisen parameters cannot possibly contain all the information on the cubic IFCs, being derivable from spatially uniform deformations, they can still unambiguously and accurately determine the largest and most physically relevant ones. By fitting the anisotropic Grüneisen parameter data along judiciously designed deformations, we can deduce (i.e., reverse engineer) the dominant cubic IFCs and estimate three-phonon scattering amplitudes. We illustrate our approach by explicitly computing the largest cubic IFCs and thermal conductivity of graphene, especially for its out-of-plane (flexural) modes that exhibit anomalously large anharmonic shifts and thermal conductivity contributions. Our calculations on graphene not only exhibits reasonable agreement with established DFT results, but also presents a pedagogical opportunity for introducing an elegant analytic treatment of the Grüneisen parameters of generic two-band models. Our approach can be readily extended to more complicated crystalline materials with nontrivial anharmonic lattice effects.
description: 15 pages, 5 figures
Evolution of spectral and transport quantities with doping in the SU(2) theory of cuprates
Creators: name: Morice, Corentin
name: Montiel, Xavier
name: Pépin, Catherine
Publisher: name: arXiv
Year: 2017
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Recent transport experiments in the cuprate superconductors linked the opening of the pseudogap to a change in electronic dispersion [S. Badoux et al., Nature 531, 210 (2015)]. Transport measurements showed that the carrier density sharply changes from $x$ to $1+x$ at the pseudogap critical doping, in accordance with the change from Fermi arcs at low doping to a large hole Fermi surface at high doping. The SU(2) theory of cuprates shows that antiferromagnetic short range interactions cause the arising of both charge and superconducting orders, which are related by an SU(2) symmetry. The fluctuations associated with this symmetry form a pseudogap phase. Here we derive the renormalised electronic propagator under the SU(2) dome, and calculate the spectral functions and transport quantities of the renormalised bands. We show that their evolution with doping matches both spectral and transport measurements.
Time-delay Induced Dimensional Crossover in Voter Model
Creators: name: Kim, Mina
name: Noh, Jae Dong
Publisher: name: arXiv
Year: 2016
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We investigate the ordering dynamics of the voter model with time-delayed interactions. The dynamical process in the $d$-dimensional lattice is shown to be equivalent to the first passage problem of a random walker in the $(d+1)$-dimensional strip of a finite width determined by the delay time. The equivalence reveals that the time delay leads to the dimensional crossover from the $(d+1)$-dimensional scaling behavior at short time to the $d$-dimensional scaling behavior in the long time. The scaling property in both regimes and the crossover time scale are obtained analytically, which are confirmed with the numerical simulation results.
description: 5 pages, 4 figures
Deep Koopman-based Control of Quality Variation in Multistage Manufacturing Systems
Creators: name: Chen, Zhiyi
name: Maske, Harshal
name: Upadhyay, Devesh
name: Shui, Huanyi
name: Huan, Xun
name: Ni, Jun
Publisher: name: arXiv
Year: 2024
Subjects: subject: Systems and Control (eess.SY)
subject: Machine Learning (cs.LG)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: This paper presents a modeling-control synthesis to address the quality control challenges in multistage manufacturing systems (MMSs). A new feedforward control scheme is developed to minimize the quality variations caused by process disturbances in MMSs. Notably, the control framework leverages a stochastic deep Koopman (SDK) model to capture the quality propagation mechanism in the MMSs, highlighted by its ability to transform the nonlinear propagation dynamics into a linear one. Two roll-to-roll case studies are presented to validate the proposed method and demonstrate its effectiveness. The overall method is suitable for nonlinear MMSs and does not require extensive expert knowledge.
description: The paper was in the proceeding of 2024 American Control Conference. This submitted version addresses a minor correction to one equation (Eq. 14), while the results and conclusions remain the same
VLBI ecliptic plane survey: VEPS-1
Creators: name: Shu, Fengchun
name: Petrov, Leonid
name: Jiang, Wu
name: Xia, Bo
name: Jiang, Tianyu
name: Cui, Yuzhu
name: Takefuji, Kazuhiro
name: McCallum, Jamie
name: Lovell, Jim
name: Yi, Sang-oh
name: Hao, Longfei
name: Yang, Wenjun
name: Zhang, Hua
name: Chen, Zhong
name: Li, Jinling
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We present here the results of the first part of the VLBI Ecliptic Plane Survey (VEPS) program. The goal of the program is to find all compact sources within $7.5^\circ$ of the ecliptic plane which are suitable as calibrators for anticipated phase referencing observations of spacecraft and determine their positions with accuracy at the 1.5~nrad level. We run the program in two modes: the search mode and the refining mode. In the search mode, a complete sample of all sources brighter than 50 mJy at 5 GHz listed in the Parkes-MIT-NRAO (PMN) and Green Bank 6~cm (GB6) catalogs, except those previously detected with VLBI, is observed. In the refining mode, the positions of all ecliptic plane sources, including those found in the search mode, are improved. By October 2016, thirteen 24-hr sessions that targeted all sources brighter than 100~mJy have been observed and analyzed. Among 3320 observed target sources, 555 objects have been detected. We also conducted a number of follow-up VLBI experiments in the refining mode and improved the positions of 249 ecliptic plane sources.
description: 12 pages, 5 figures, 5 tables, accepted by The Astrophysical Journal Supplement Series (ApJS)
MPEC 2023-R136 : 2023 RT4
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 RT4

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.
Mesoscale Field Theory for Quasicrystals
Creators: name: De Donno, Marcello
name: Angheluta, Luiza
name: Elder, Ken R.
name: Salvalaglio, Marco
Publisher: name: arXiv
Year: 2024
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We present a mesoscale field theory unifying the modeling of growth, elasticity, and dislocations in quasicrystals. The theory is based on the amplitudes entering their density-wave representation. We introduce a free energy functional for complex amplitudes and assume non-conserved dissipative dynamics to describe their evolution. Elasticity, including phononic and phasonic deformations, along with defect nucleation and motion, emerges self-consistently by prescribing only the symmetry of quasicrystals. Predictions on the formation of semi-coherent interfaces and dislocation kinematics are given.
description: 14 pages, 6 figures
Organización bibliográfica de libros del acervo de la biblioteca de la Academia Nacional de Medicina de México
Creators: name: Chávez-Martínez, Omar
Publisher: name: Zenodo
Year: 2020
Subjects: Bibliotecas Especializadas
Libraries, Special
Bibliotecas Médicas
Libraries, Medical
Academias e Institutos
Academies and Institutes
México
Bibliotecología
Library Science

description: Informe de estancia profesional para obtener el título de Profesional Asociado en Biblioteconomía
Multiply quantized vortices in fermionic superfluids: angular momentum, unpaired fermions, and spectral asymmetry
Creators: name: Prem, Abhinav
name: Moroz, Sergej
name: Gurarie, Victor
name: Radzihovsky, Leo
Publisher: name: arXiv
Year: 2017
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We compute the orbital angular momentum $L_z$ of an s-wave paired superfluid in the presence of an axisymmetric multiply quantized vortex. For vortices with winding number $|k| > 1$, we find that in the weak-pairing BCS regime $L_z$ is significantly reduced from its value $\hbar N k/2$ in the Bose-Einstein condensation (BEC) regime, where $N$ is the total number of fermions. This deviation results from the presence of unpaired fermions in the BCS ground state, which arise as a consequence of spectral flow along the vortex sub-gap states. We support our results analytically and numerically by solving the Bogoliubov-de-Gennes equations within the weak-pairing BCS regime.
description: 5 pages + 11 pages supplemental material. Close to published version
The design and the performance of stratospheric mission in the search for the Schumann resonances
Creators: name: Papaj, Arkadiusz
name: Weszka, Piotr
name: Bocheński, Marcin
name: Michałek, Mateusz
name: Kułak, Andrzej
name: Kołodziejczyk, Agata
name: Harasymczuk, Matt
name: Karbowniczek, Paweł
name: Ławrynowicz, Aleksandra
name: Kuźma, Joanna
name: Brol, Tomasz
name: Kycia, Radosław A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: The technical details of a balloon stratospheric mission that is aimed at measuring the Schumann resonances are described. The gondola is designed specifically for the measuring of faint effects of ELF (Extremely Low Frequency electromagnetic waves) phenomena. The prototype met the design requirements. The ELF measuring system worked properly for entire mission; however, the level of signal amplification that was chosen taking into account ground-level measurements was too high. Movement of the gondola in the Earth magnetic field induced the signal in the antenna that saturated the measuring system. This effect will be taken into account in the planning of future missions. A large telemetry dataset was gathered during the experiment and is currently under processing. The payload consists also of biological material as well as electronic equipment that was tested under extreme conditions.
description: 13 pages, 9 figures
Groups with finiteness conditions on the lower central series of non-normal subgroups
Creators: name: De Mari, Fausto
Publisher: name: arXiv
Year: 2016
Subjects: subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 20F14, 20F19

description: It is known that any locally graded group with finitely many derived subgroups of non-normal subgroups is finite-by-abelian. This result is generalized here, by proving that in a locally graded group $G$ the subgroup $γ_{k}(G)$ is finite if the set $\{γ_{k}(H)\;|\;H\ntriangleleft G\}$ is finite. Moreover, locally graded groups with finitely many $k$th terms of lower central series of infinite non-normal subgroups are also completely described.
An optical investigation of the strong spin-orbital coupled magnetic semimetal YbMnBi$_2$
Creators: name: Chaudhuri, Dipanjan
name: Cheng, Bing
name: Yaresko, Alexander
name: Gibson, Quinn D.
name: Cava, Robert J.
name: Armitage, N. Peter
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Strong spin-orbit coupling (SOC) can result in ground states with non-trivial topological properties. The situation is even richer in magnetic systems where the magnetic ordering can potentially have strong influence over the electronic band structure. The class of AMnBi$_2$ (A = Sr, Ca) compounds are important in this context as they are known to host massive Dirac fermions with strongly anisotropic dispersion that is believed to be due to the interplay between strong SOC and magnetic degrees of freedom. We report the optical conductivity of YbMnBi$_2$, a newly discovered member of this family and a proposed Weyl semi-metal (WSM) candidate with broken time reversal symmetry. Together with density functional theory (DFT) band structure calculations, we show how the complete conductivity can be interpreted as the sum of a intra-band Drude response and inter-band transitions. We argue that the canting of the magnetic moments that has been proposed to be essential for the realization of the WSM in an otherwise antiferromagnetically ordered system is not necessary to explain the optical conductivity. We believe our data is explained qualitatively by the uncanted magnetic structure with a small offset of the chemical potential from strict stochiometry. There is no definite evidence of bulk Weyl nodes, instead we see signatures of a gapped Dirac dispersion, common in other members of AMnBi$_2$ family or compounds with similar 2D network of Bi atoms.
description: Submitted to Physical Review B
Vertical temperature-boundary of the pseudogap under the superconducting dome of the Bi2Sr2CaCu2O8+d phase-diagram
Creators: name: Loret, B.
name: Sakai, S.
name: Benhabib, S.
name: Gallais, Y.
name: Cazayous, M.
name: Measson, M. A.
name: Zhong, R. D.
name: Schneeloch, J.
name: Gu, G. D.
name: Forget, A.
name: Colson, D.
name: Paul, I.
name: Civelli, M.
name: Sacuto, A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Combining electronic Raman scattering experiments with cellular dynamical mean field theory, we present evidence of the pseudogap in the superconducting state of various hole-doped cuprates. In Bi2Sr2CaCu2O8+d we track the superconducting pseudogap hallmark, a peak-dip feature, as a function of temperature T and doping p, well beyond the optimal one. We show that, at all temperatures under the superconducting dome, the pseudogap disappears at the doping pc, between 0.222 and 0.226, where also the normal-state pseudogap collapses at a Lifshitz transition. This demonstrates that the superconducting pseudogap boundary forms a vertical line in the T-p phase diagram.
description: 8 pages and 8 figures
Haldane model on the Sierpiński gasket
Creators: name: Osseweijer, Zebedeus
name: Eek, Lumen
name: Moustaj, Anouar
name: Fremling, Mikael
name: Smith, Cristiane Morais
Publisher: name: arXiv
Year: 2024
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We investigate the topological phases of the Haldane model on the Sierpiński gasket. As a consequence of the fractal geometry, multiple fractal gaps arise. Additionally, a flat band appears, and due to a complex next-nearest neighbour hopping, this band splits and multiple topological flux-induced gaps emerge. Owing to the fractal nature of the model, conventional momentum-space topological invariants cannot be used. Therefore, we characterise the system's topology in terms of a real-space Chern number. In addition, we verify the robustness of the topological states to disorder. Finally, we present phase diagrams for both a fractal gap and a flux-induced gap. Previous work on a similar system claims that fractality "squeezes" the well-known Haldane phase diagram. However, this result arises because a doubled system was considered with two Sierpiński gaskets glued together. We consider only a single copy of the Sierpiński gasket, keeping global self-similarity. In contrast with these previous results, we find intricate and complex patterns in the phase diagram of this single fractal. Our work shows that the fractality of the model greatly influences the phase space of these structures, and can drive topological phases in the multitude of fractal and flux-induced gaps, providing a richer platform than a conventional integer dimensional geometry.
description: 18 pages, 17 figures
Stationary crack propagation in a two-dimensional visco-elastic network model
Creators: name: Aoyanagi, Yuko
name: Okumura, Ko
Publisher: name: arXiv
Year: 2017
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We investigate crack propagation in a simple two-dimensional visco-elastic model and find a scaling regime in the relation between the propagation velocity and energy release rate or fracture energy, together with lower and upper bounds of the scaling regime. On the basis of our result, the existence of the lower and upper bounds is expected to be universal or model-independent: the present simple simulation model provides generic insight into the physics of crack propagation, and the model will be a first step towards the development of a more refined coarse-grained model. Relatively abrupt changes of velocity are predicted near the lower and upper bounds for the scaling regime and the positions of the bounds could be good markers for the development of tough polymers, for which we provide simple views that could be useful as guiding principles for toughening polymer-based materials.
description: 17 pages, 5 figures, Final version (proof correction reflected)
Axion detection via Topological Casimir Effect
Creators: name: Cao, ChunJun
name: Zhitnitsky, Ariel
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We propose a new table-top experimental configuration for the direct detection of dark matter axions with mass in the $(10^{-6} \rm eV - 10^{-2} \rm eV)$ range using non-perturbative effects in a system with non-trivial spatial topology. Different from most experimental setups found in literature on direct dark matter axion detection, which relies on $\dotθ$ or $\vec{\nabla}θ$, we found that our system is in principle sensitive to a static $θ\geq 10^{-14}$ and can also be used to set limit on the fundamental constant $θ_{\rm QED}$ which becomes the fundamental observable parameter of the Maxwell system if some conditions are met. Connection with Witten effect when the induced electric charge $e'$ is proportional to $θ$ and the magnetic monopole becomes the dyon with non-vanishing $e'=-e \fracθ{2π}$ is also discussed.
description: Updated to published version
Relative multiplexing for minimizing switching in linear-optical quantum computing
Creators: name: Gimeno-Segovia, Mercedes
name: Cable, Hugo
name: Mendoza, Gabriel J.
name: Shadbolt, Pete
name: Silverstone, Joshua W.
name: Carolan, Jacques
name: Thompson, Mark G.
name: O'Brien, Jeremy L.
name: Rudolph, Terry G.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Many existing schemes for linear-optical quantum computing (LOQC) depend on multiplexing (MUX), which uses dynamic routing to enable near-deterministic gates and sources to be constructed using heralded, probabilistic primitives. MUXing accounts for the overwhelming majority of active switching demands in current LOQC architectures. In this manuscript, we introduce relative multiplexing (RMUX), a general-purpose optimization which can dramatically reduce the active switching requirements for MUX in LOQC, and thereby reduce hardware complexity and energy consumption, as well as relaxing demands on performance for various photonic components. We discuss the application of RMUX to the generation of entangled states from probabilistic single-photon sources, and argue that an order of magnitude improvement in the rate of generation of Bell states can be achieved. In addition, we apply RMUX to the proposal for percolation of a 3D cluster state in [PRL 115, 020502 (2015)], and we find that RMUX allows a 2.4x increase in loss tolerance for this architecture.
description: Published version, New Journal of Physics, Volume 19, June 2017
Quasiconformal parametrization of metric surfaces with small dilatation
Creators: name: Romney, Matthew
Publisher: name: arXiv
Year: 2017
Subjects: subject: Metric Geometry (math.MG)
subject: FOS: Mathematics
subject: 30L10, 52A10

description: We verify a conjecture of Rajala: if $(X,d)$ is a metric surface of locally finite Hausdorff 2-measure admitting some (geometrically) quasiconformal parametrization by a simply connected domain $Ω\subset \mathbb{R}^2$, then there exists a quasiconformal mapping $f: X \rightarrow Ω$ satisfying the modulus inequality $2π^{-1}\text{Mod }Γ\leq \text{Mod }fΓ\leq 4π^{-1}\text{Mod }Γ$ for all curve families $Γ$ in $X$. This inequality is the best possible. Our proof is based on an inequality for the area of a planar convex body under a linear transformation which attains its Banach-Mazur distance to the Euclidean unit ball.
description: 7 pages, 2 figures, to appear in Indiana Univ. Math. J
Pulsed Beam Tests at the SANAEM RFQ Beamline
Creators: name: Turemen, G.
name: Akgun, Y.
name: Alacakir, A.
name: Kilic, I.
name: Yasatekin, B.
name: Ergenlik, E.
name: Ogur, S.
name: Sunar, E.
name: Yildiz, V.
name: Ahiska, F.
name: Cicek, E.
name: Unel, G.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: A proton beamline consisting of an inductively coupled plasma (ICP) source, two solenoid magnets, two steerer magnets and a radio frequency quadrupole (RFQ) is developed at the Turkish Atomic Energy Authority's (TAEA) Saraykoy Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of 2016, the RFQ was installed in the beamline. The high power tests of the RF power supply and the RF transmission line were done successfully. The high power RF conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was tested in two different conditions, CW and pulsed. The characterization of the proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter. Beam transverse emittance was measured in between the two solenoids of the LEBT. The measured beam is then reconstructed at the entrance of the RFQ by using computer simulations to determine the optimum solenoid currents for acceptance matching of the beam. This paper will introduce the pulsed beam test results at the SANAEM RFQ beamline. In addition, the high power RF conditioning of the RFQ will be discussed.
description: 6 pages, 6 figures. Proceedings of the International Particle Accelerator Conference 2017 (IPAC'17), May 14-19, 2017, TUPAB015, p. 1341
Mass Discrepancy-Acceleration Relation in Einstein Rings
Creators: name: Tian, Yong
name: Ko, Chung-Ming
Publisher: name: arXiv
Year: 2017
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We study the Mass Discrepancy-Acceleration Relation (MDAR) of 57 elliptical galaxies by their Einstein rings from the Sloan Lens ACS Survey (SLACS). The mass discrepancy between the lensing mass and the baryonic mass derived from population synthesis is larger when the acceleration of the elliptical galaxy lenses is smaller. The MDAR is also related to surface mass density discrepancy. At the Einstein ring, these lenses belong to high-surface-mass density galaxies. Similarly, we find that the discrepancy between the lensing and stellar surface mass density is small. It is consistent with the recent discovery of dynamical surface mass density discrepancy in disk galaxies where the discrepancy is smaller when surface density is larger. We also find relativistic modified Newtonian dynamics (MOND) can naturally explain the MDAR and surface mass density discrepancy in 57 Einstein rings. Moreover, the lensing mass, the dynamical mass and the stellar mass of these galaxies are consistent with each other in relativistic MOND.
description: 7 pages, 4 figures
What is General Relativity?
Creators: name: Coley, Alan A.
name: Wiltshire, David L.
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: General relativity is a set of physical and geometric principles, which lead to a set of (Einstein) field equations that determine the gravitational field, and to the geodesic equations that describe light propagation and the motion of particles on the background. But open questions remain, including: What is the scale on which matter and geometry are dynamically coupled in the Einstein equations? Are the field equations valid on small and large scales? What is the largest scale on which matter can be coarse grained while following a geodesic of a solution to Einstein's equations? We address these questions. If the field equations are causal evolution equations, whose average on cosmological scales is not an exact solution of the Einstein equations, then some simplifying physical principle is required to explain the statistical homogeneity of the late epoch Universe. Such a principle may have its origin in the dynamical coupling between matter and geometry at the quantum level in the early Universe. This possibility is hinted at by diverse approaches to quantum gravity which find a dynamical reduction to two effective dimensions at high energies on one hand, and by cosmological observations which are beginning to strongly restrict the class of viable inflationary phenomenologies on the other. We suggest that the foundational principles of general relativity will play a central role in reformulating the theory of spacetime structure to meet the challenges of cosmology in the 21st century.
description: 18 pages. Invited article for Physica Scripta Focus issue on 21st Century Frontiers. v2: Appendix amended, references added. v3: Small corrections, references added, matches published version
Algorithmic decision making and the cost of fairness
Creators: name: Corbett-Davies, Sam
name: Pierson, Emma
name: Feller, Avi
name: Goel, Sharad
name: Huq, Aziz
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computers and Society (cs.CY)
subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: Algorithms are now regularly used to decide whether defendants awaiting trial are too dangerous to be released back into the community. In some cases, black defendants are substantially more likely than white defendants to be incorrectly classified as high risk. To mitigate such disparities, several techniques recently have been proposed to achieve algorithmic fairness. Here we reformulate algorithmic fairness as constrained optimization: the objective is to maximize public safety while satisfying formal fairness constraints designed to reduce racial disparities. We show that for several past definitions of fairness, the optimal algorithms that result require detaining defendants above race-specific risk thresholds. We further show that the optimal unconstrained algorithm requires applying a single, uniform threshold to all defendants. The unconstrained algorithm thus maximizes public safety while also satisfying one important understanding of equality: that all individuals are held to the same standard, irrespective of race. Because the optimal constrained and unconstrained algorithms generally differ, there is tension between improving public safety and satisfying prevailing notions of algorithmic fairness. By examining data from Broward County, Florida, we show that this trade-off can be large in practice. We focus on algorithms for pretrial release decisions, but the principles we discuss apply to other domains, and also to human decision makers carrying out structured decision rules.
description: To appear in Proceedings of KDD'17
Exact Gravitational Wave Signatures from Colliding Extreme Black Holes
Creators: name: Camps, Joan
name: Hadar, Shahar
name: Manton, Nicholas S.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The low-energy dynamics of any system admitting a continuum of static configurations is approximated by slow motion in moduli (configuration) space. Here, following Ferrell and Eardley, this moduli space approximation is utilized to study collisions of two maximally charged Reissner--Nordstr{ö}m black holes of arbitrary masses, and to compute analytically the gravitational radiation generated by their scattering or coalescence. The motion remains slow even though the fields are strong, and the leading radiation is quadrupolar. A simple expression for the gravitational waveform is derived and compared at early and late times to expectations.
description: 6 pages
Gain and time resolution of 45 $μ$m thin Low Gain Avalanche Detectors before and after irradiation up to a fluence of $10^{15}$ n$_{eq}$/cm$^2$
Creators: name: Lange, J.
name: Carulla, M.
name: Cavallaro, E.
name: Chytka, L.
name: Davis, P. M.
name: Flores, D.
name: Förster, F.
name: Grinstein, S.
name: Hidalgo, S.
name: Komarek, T.
name: Kramberger, G.
name: Mandić, I.
name: Merlos, A.
name: Nozka, L.
name: Pellegrini, G.
name: Quirion, D.
name: Sykora, T.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Low Gain Avalanche Detectors (LGADs) are silicon sensors with a built-in charge multiplication layer providing a gain of typically 10 to 50. Due to the combination of high signal-to-noise ratio and short rise time, thin LGADs provide good time resolutions. LGADs with an active thickness of about 45 $μ$m were produced at CNM Barcelona. Their gains and time resolutions were studied in beam tests for two different multiplication layer implantation doses, as well as before and after irradiation with neutrons up to $10^{15}$ n$_{eq}$/cm$^2$. The gain showed the expected decrease at a fixed voltage for a lower initial implantation dose, as well as for a higher fluence due to effective acceptor removal in the multiplication layer. Time resolutions below 30 ps were obtained at the highest applied voltages for both implantation doses before irradiation. Also after an intermediate fluence of $3\times10^{14}$ n$_{eq}$/cm$^2$, similar values were measured since a higher applicable reverse bias voltage could recover most of the pre-irradiation gain. At $10^{15}$ n$_{eq}$/cm$^2$, the time resolution at the maximum applicable voltage of 620 V during the beam test was measured to be 57 ps since the voltage stability was not good enough to compensate for the gain layer loss. The time resolutions were found to follow approximately a universal function of gain for all implantation doses and fluences.
description: 17 pages
Geometric influences of a particle confined to a curved surface embedded in three-dimensional Euclidean space
Creators: name: Wang, Yong-Long
name: Jiang, Hua
name: Zong, Hong-Shi
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In the spirit of the thin-layer quantization approach, we give the formula of the geometric influences of a particle confined to a curved surface embedded in three-dimensional Euclidean space. The geometric contributions can result from the reduced commutation relation between the acted function depending on normal variable and the normal derivative. According to the formula, we obtain the geometric potential, geometric momentum, geometric orbital angular momentum, geometric linear Rashba and cubic Dresselhaus spin-orbit couplings. As an example, a truncated cone surface is considered. We find that the geometric orbital angular momentum can provide an azimuthal polarization for spin, and the sign of the geometric Dresselhaus spin-orbit coupling can be flipped through the inclination angle of generatrix.
description: 12 pages, 2 figures