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June 2019 arXiv papers — page 6

Showing 501600 of 12,804 papers

  1. José Camacho, Evrim Acar, Morten A. Rasmussen, Rasmus Bro

    Matrix factorization methods are extensively employed to understand complex data. In this paper, we introduce the cross-product penalized component analysis (XCAN), a sparse matrix factorization based on the optimization of a loss function that allows a trade-off between variance maximization and structural preservation. The approach is based on previous dev

  2. Vaden Masrani, Tuan Anh Le, Frank Wood

    We introduce the thermodynamic variational objective (TVO) for learning in both continuous and discrete deep generative models. The TVO arises from a key connection between variational inference and thermodynamic integration that results in a tighter lower bound to the log marginal likelihood than the standard variational variational evidence lower bound (EL

  3. Rares-Darius Buhai, Yoni Halpern, Yoon Kim, Andrej Risteski

    One of the most surprising and exciting discoveries in supervised learning was the benefit of overparameterization (i.e. training a very large model) to improving the optimization landscape of a problem, with minimal effect on statistical performance (i.e. generalization). In contrast, unsupervised settings have been under-explored, despite the fact that it

  4. M. V. Flamarion, A. Nachbin, R. Ribeiro-Junior

    Non-stationary rotational surface waves are considered, where the underlying current has constant vorticity. A study is presented on the robustness of a critical layer in the presence of a bottom topography, as well as on its spontaneous formation for waves generated from rest. The restriction, from previous studies, to a traveling-wave formulation is remove

  5. Paulo Chagas, Luiz Souza, Ikaro Araújo, Nayze Aldeman

    Glomeruli are histological structures of the kidney cortex formed by interwoven blood capillaries, and are responsible for blood filtration. Glomerular lesions impair kidney filtration capability, leading to protein loss and metabolic waste retention. An example of lesion is the glomerular hypercellularity, which is characterized by an increase in the number

  6. Kenny Higginbotham, Bhavesh Khamesra, Jame P. McInerney, Karan Jani

    Spurious junk radiation in the initial data for binary black hole numerical simulations has been an issue of concern. The radiation affects the masses and spins of the black holes, modifying their orbital dynamics and thus potentially compromising the accuracy of templates used in gravitational wave analysis. Our study finds that junk radiation effects are l

  7. R. F. Barros, G. B. Alves, D. S. Tasca, C. E. R. Souza

    We investigate the dynamical properties of a type-II optical parametric oscillator pumped by a structured light beam carrying orbital angular momentum. Different dynamical regimes are theoretically derived and experimentally demonstrated, depending on the anisotropy effects imposed by the nonlinear medium. In a weakly anisotropic regime, fine-tuning of the o

  8. Alessandro Muscoloni, Carlo Vittorio Cannistraci

    Analysis of 'big data' characterized by high-dimensionality such as word vectors and complex networks requires often their representation in a geometrical space by embedding. Recent developments in machine learning and network geometry have pointed out the hyperbolic space as a useful framework for the representation of this data derived by real complex phys

  9. Luca Battistella, Navid Nabijou, Dhruv Ranganathan

    We construct and study the reduced, relative, genus one Gromov--Witten theory of very ample pairs. These invariants form the principal component contribution to relative Gromov--Witten theory in genus one and are relative versions of Zinger's reduced Gromov--Witten invariants. We relate the relative and absolute theories by degeneration of the tangency condi

  10. Omer Erkan, Yakup Gulmez, Cem Hayirli, Gulay Gulmez

    In this paper, we present a programmable Ultra Low DC Current Source (ULCS) developed at T\"UB\.ITAK UME. The output current range is from 1 fA up to 100 pA with 100 aA resolution and is directly traceable to DC voltage, capacitance and time units. The principle of the device is based on applying a linear ramp voltage on standard capacitors with values betwe

  11. Marcelo F. Ciappina, Alfredo Iorio, Pablo Pais, Adamantia Zampeli

    Assuming dislocations could be meaningfully described by torsion, we propose here a scenario based on the role of time in the low-energy regime of two-dimensional Dirac materials, for which coupling of the fully antisymmetric component of the torsion with the emergent spinor is not necessarily zero. Appropriate inclusion of time is our proposal to overcome w

  12. Alexandra E. Moylett, Raúl García-Patrón, Jelmer J. Renema, Peter S. Turner

    Boson Sampling is the problem of sampling from the same distribution as indistinguishable single photons at the output of a linear optical interferometer. It is an example of a non-universal quantum computation which is believed to be feasible in the near term and cannot be simulated on a classical machine. Like all purported demonstrations of "quantum supre

  13. Elmer Ramirez Barreto, David Romero Abad

    In this work we explore the possibility to fix the number of new non-sequential chiral-type generations of fermions that could be added to the standard model by combining the condition that arise from the anomalies cancellation with the restriction in the number of flavors impose by the QCD asymptotic freedom. We found that the maximum number of new generati

  14. Mikhail Yurochkin, Amanda Bower, Yuekai Sun

    We consider training machine learning models that are fair in the sense that their performance is invariant under certain sensitive perturbations to the inputs. For example, the performance of a resume screening system should be invariant under changes to the gender and/or ethnicity of the applicant. We formalize this notion of algorithmic fairness as a vari

  15. S. Konstantinou-Rizos, G. Papamikos

    We construct birational maps that satisfy the parametric set-theoretical Yang-Baxter equation and its entwining generalisation. For this purpose, we employ Darboux transformations related to integrable Nonlinear Schr\"odinger type equations and study the refactorisation problems of the product of their associated Darboux matrices. Additionally, we study vari

  16. Yacov Kantor, Mehran Kardar

    How does removal of sites by a random walk lead to blockage of percolation? To study this problem of correlated site percolation, we consider a random walk (RW) of $N=uL^d$ steps on a $d$-dimensional hypercubic lattice of size $L^d$ (with periodic boundaries). We systematically explore dependence of the probability $\Pi_d(L,u)$ of percolation (existence of a

  17. André Eikmeier, Etienne Emmrich

    The initial value problem for a multivalued differential equation is studied, which is governed by the sum of a monotone, hemicontinuous, coercive operator fulfilling a certain growth condition and a Volterra integral operator in time of convolution type with exponential decay. The two operators act on different Banach spaces where one is not embedded in the

  18. Ben Margalit, Edo Berger, Brian D. Metzger

    Recently born magnetars are promising candidates for the engines powering fast radio bursts (FRBs). The focus thus far has been placed on millisecond magnetars born in rare core-collapse explosions, motivated by the star forming dwarf host galaxy of the repeating FRB 121102, which is remarkably similar to the hosts of superluminous supernovae (SLSNe) and lon

  19. Elizabeth R. Bennewitz, Cristian Gaidau, Thomas W. Baumgarte, Stuart L. Shapiro

    We study effects of heating by dark matter (DM) annihilation on black hole gas accretion. We observe that, for reasonable assumptions about DM densities in spikes around supermassive black holes, as well as DM masses and annihilation cross-sections within the standard WIMP model, heating by DM annihilation may have an appreciable effect on the accretion onto

  20. Astrid Lamberts, Sarah Blunt, Tyson Littenberg, Shea Garrison-Kimmel

    Short-period (P<1 hour) white dwarf binaries will be the most numerous sources for the space-based gravitational wave detector LISA. Based on thousands of resolved systems, we will be able to constrain binary evolution and provide a new map of the Milky Way and its surroundings. Here we predict the main properties of populations of different types of detache

  21. Ryan L. Sanders, Alice E. Shapley, Naveen A. Reddy, Mariska Kriek

    We present detections of [OIII]$\lambda$4363 and direct-method metallicities for star-forming galaxies at $z=1.7-3.6$. We combine new measurements from the MOSFIRE Deep Evolution Field (MOSDEF) survey with literature sources to construct a sample of 18 galaxies with direct-method metallicities at $z>1$, spanning $7.5<1$2+log(O/H$)<8.2$ and log(M$_*$/M$_{\odo

  22. Jongjun M. Lee, Chenhua Geng, Jae Whan Park, Masaki Oshikawa

    We propose a new principle to realize flatbands which are robust in real materials, based on a network superstructure of one-dimensional segments. This mechanism is naturally realized in the nearly commensurate charge-density wave of 1T-TaS${}_2$ with the honeycomb network of conducting domain walls, and the resulting flatband can naturally explain the enhan

  23. Maxim Pospelov, Surjeet Rajendran, Harikrishnan Ramani

    Inelastic dark matter and strongly interacting dark matter are poorly constrained by direct detection experiments since they both require the scattering event to deliver energy from the nucleus into the dark matter in order to have observable effects. We propose to test these scenarios by searching for the collisional de-excitation of meta-stable nuclear iso

  24. Joolee Son, Kyung-Han Kim, Y. H. Ahn, Hyun-Woo Lee

    The Berry curvature dipole is a physical quantity that is expected to allow various quantum geometrical phenomena in a range of solid-state systems. Monolayer transition metal dichalcogenides provide an exceptional platform to modulate and investigate the Berry curvature dipole through strain. Here we theoretically demonstrate and experimentally verify for m

  25. Lucas Kohn, Pietro Silvi, Matthias Gerster, Maximilian Keck

    We revisit here the Kibble-Zurek mechanism for superfluid bosons slowly driven across the transition towards the Mott-insulating phase. By means of a combination of the Time-Dependent Variational Principle and a Tree-Tensor Network, we characterize the current flowing during annealing in a ring-shaped one-dimensional Bose-Hubbard model with artificial classi

  26. Alexander Wietek, Philippe Corboz, Stefan Wessel, Bruce Normand

    The thermodynamic properties of the Shastry-Sutherland model have posed one of the longest-lasting conundrums in frustrated quantum magnetism. Over a wide range on both sides of the quantum phase transition (QPT) from the dimer-product to the plaquette-based ground state, neither analytical nor any available numerical methods have come close to reproducing t

  27. Yuri Gershtein, Simon Knapen

    We show that the phase II upgrade of the CMS tracking detector could enable the experiment to trigger on very low mass $\mathcal{O}(1\,\text{GeV})$ displaced muon pairs with minimal $p_T$ cuts. As a result, CMS can be competitive with LHCb when searching for low mass displaced exotics originating from heavy flavor decays. The method can also be applied to si

  28. Indranil Banik, Pavel Kroupa

    We consider how the trajectory of an interstellar precursor mission would be affected by the gravity of the Sun in Newtonian and Milgromian dynamics (MOND). The Solar gravity is ${\approx 50\%}$ stronger in MOND beyond a distance of ${\approx 7000}$ astronomical units, the MOND radius of the Sun. A spacecraft travelling at $0.01 \, c$ reaches this distance a

  29. J. Casares, T. Muñoz-Darias, D. Mata Sanchez, P. A. Charles

    We study the optical evolution of the 2015 outburst in V404 Cyg, with emphasis on the peculiar nebular phase and subsequent decay to quiescence. From the decay timescale of the Balmer emission associated with the nebula we measure an outflow mass M_wind~4x10^{-6} Msun. Remarkably, this is ~100 times larger than the accreted mass and ~10% of the total mass st

  30. Jean-François Fortin, Valentina Prilepina, Witold Skiba

    We compute the most general embedding space two-point function in arbitrary Lorentz representations in the context of the recently introduced formalism in arXiv:1905.00036 and arXiv:1905.00434. This work provides a first explicit application of this approach and furnishes a number of checks of the formalism. We project the general embedding space two-point f

  31. Lei Xu, Shubhra Kanti Karmaker Santu, Kalyan Veeramachaneni

    Most automation in machine learning focuses on model selection and hyper parameter tuning, and many overlook the challenge of automatically defining predictive tasks. We still heavily rely on human experts to define prediction tasks, and generate labels by aggregating raw data. In this paper, we tackle the challenge of defining useful prediction problems on

  32. Lucas Lombriser

    A significant tension has become manifest between the current expansion rate of our Universe measured from the cosmic microwave background by the Planck satellite and from local distance probes, which has prompted for interpretations of that as evidence of new physics. Within conventional cosmology a likely source of this discrepancy is identified here as a

  33. Michael Rapoport, Brian Smithling, Wei Zhang

    This is a largely expository article based on our previous work on arithmetic diagonal cycles on unitary Shimura varieties. We define a class of Shimura varieties closely related to unitary groups which represent a moduli problem of abelian varieties with additional structure, and which admit interesting algebraic cycles. We generalize to arbitrary signature

  34. Shi Pu, Alex Olshevsky, Ioannis Ch. Paschalidis

    We provide a discussion of several recent results which, in certain scenarios, are able to overcome a barrier in distributed stochastic optimization for machine learning. Our focus is the so-called asymptotic network independence property, which is achieved whenever a distributed method executed over a network of n nodes asymptotically converges to the optim

  35. Hee-Joong Chung

    We consider the Witten-Reshetikhin-Turaev invariants or Chern-Simons partition function at or around roots of unity $q=e^{2\pi i \frac{1}{K}}$ with rational level $K=\frac{r}{s}$ where $r$ and $s$ are coprime integers. From the exact expression for the $G=SU(2)$ Witten-Reshetikhin-Turaev invariants of Seifert manifolds at other roots of unity obtained by Law

  36. S. A. Osorio, M. B. Sturla, H. D. Rosales, D. C. Cabra

    Swirling topological spin configurations, known as magnetic skyrmions, are known to be stabilised in chiral ferromagnets with Dzyaloshinskii-Moriya interaction (DMI). In particular, for appropriate values of the external magnetic field they appear in a topological crystalline phase, termed Skyrmion crystal phase (SkX). A similar phenomenon is present in the

  37. Marc Barthelemy

    Cities are systems with a large number of constituents and agents interacting with each other and can be considered as emblematic of complex systems. Modeling these systems is a real challenge and triggered the interest of many disciplines such as quantitative geography, spatial economics, geomatics and urbanism, and more recently physics. (Statistical) Phys

  38. L. Bellino, G. Florio, G. Puglisi

    We deduce a fully analytical model to predict the artifacts of the measuring device handles in Single Molecule Force Spectroscopy experiments. As we show, neglecting the effects of the handle stiffness can lead to crucial overestimation or underestimation of the stability properties and transition thresholds of macromolecules.

  39. Dan Hendrycks, Mantas Mazeika, Saurav Kadavath, Dawn Song

    Self-supervision provides effective representations for downstream tasks without requiring labels. However, existing approaches lag behind fully supervised training and are often not thought beneficial beyond obviating or reducing the need for annotations. We find that self-supervision can benefit robustness in a variety of ways, including robustness to adve

  40. Don Zagier, Federico Zerbini

    In this paper we show that in perturbative string theory the genus-one contribution to formal 2-point amplitudes can be related to the genus-zero contribution to 4-point amplitudes. This is achieved by studying special linear combinations of multiple zeta values that appear as coefficients of the amplitudes. We also exploit our results to relate closed strin

  41. Chris Yakopcic, Nayim Rahman, Tanvir Atahary, Tarek M. Taha

    Cognitive agents are typically utilized in autonomous systems for automated decision making. These systems interact at real time with their environment and are generally heavily power constrained. Thus, there is a strong need for a real time agent running on a low power platform. The agent examined is the Cognitively Enhanced Complex Event Processing (CECEP)

  42. Dmitriy Smirnov, Mikhail Bessmeltsev, Justin Solomon

    Choosing the right representation for geometry is crucial for making 3D models compatible with existing applications. Focusing on piecewise-smooth man-made shapes, we propose a new representation that is usable in conventional CAD modeling pipelines and can also be learned by deep neural networks. We demonstrate its benefits by applying it to the task of ske

  43. Ahmad Salmanogli

    In this article, we design a quantum device to duplicate the Robins procedure. The Robins use a unique method to determine the migratory direction. In the procedure utilized, the important issue is the effect of the geomagnetic field on the magnetic momentum of created radical pairs (triplet-singlet states) dancing with a special frequency. To duplicate the

  44. Charles Dalang, Lucas Lombriser

    Modified gravity theories with an effective Newton constant that varies over cosmological timescales generally predict a different gravitational wave luminosity distance than General Relativity. While this holds for a uniform variation, we show that if locally screened at the source and at the observer as required to pass stringent astrophysical tests of gra

  45. Telmo Felgueira, Silvio Rodrigues, Christian S. Perone, Rui Castro

    The cost of wind energy can be reduced by using SCADA data to detect faults in wind turbine components. Normal behavior models are one of the main fault detection approaches, but there is a lack of consensus in how different input features affect the results. In this work, a new taxonomy based on the causal relations between the input features and the target

  46. M. A. Prosnikov, A. N. Smirnov, V. Yu. Davydov, Y. Araki

    Complex systems with coexisting polarity, chirality and incommensurate magnetism are of great interest because they open new degrees of freedom in interaction between different subsystems and therefore they host a plethora of intriguing physical properties. Here we report on optical properties and lattice and spin dynamics of Ni$_2$InSbO$_6$ single crystals

  47. Jin Yeong Tan, Lawrence Ong, Behzad Asadi

    For communications in the presence of eavesdroppers, random components are often used in code design to camouflage information from eavesdroppers. In broadcast channels without eavesdroppers, Marton error-correcting coding comprises random components which allow correlation between auxiliary random variables representing independent messages. In this paper,

  48. Murat Kirişci, Necip Şimşek

    In present paper, the definition of new metric space with neutrosophic numbers is given. Several topological and structural properties have been investigated. The analogues of Baire Category Theorem and Uniform Convergence Theorem are given for Neutrosophic metric spaces.

  49. Fabian Baumann, Philipp Lorenz-Spreen, Igor M. Sokolov, Michele Starnini

    Echo chambers and opinion polarization recently quantified in several sociopolitical contexts and across different social media, raise concerns on their potential impact on the spread of misinformation and on openness of debates. Despite increasing efforts, the dynamics leading to the emergence of these phenomena stay unclear. We propose a model that introdu

  50. Guandao Yang, Xun Huang, Zekun Hao, Ming-Yu Liu

    As 3D point clouds become the representation of choice for multiple vision and graphics applications, the ability to synthesize or reconstruct high-resolution, high-fidelity point clouds becomes crucial. Despite the recent success of deep learning models in discriminative tasks of point clouds, generating point clouds remains challenging. This paper proposes

  51. Marco Nugnes, Camilla Colombo, Massimo Tipaldi

    This paper introduces a new analytical method for the determination of the coverage area modeling the Earth as an oblate ellipsoid of rotation. Starting from the knowledge of the satellite's position vector and the direction of the navigation antenna line of sight, the surface generated by the intersection of the oblate ellipsoid and the assumed conical fiel

  52. Thijs Kamma, Antoon Pelsser

    We develop a dual-control method for approximating investment strategies in incomplete environments that emerge from the presence of trading constraints. Convex duality enables the approximate technology to generate lower and upper bounds on the optimal value function. The mechanism rests on closed-form expressions pertaining to the portfolio composition, fr

  53. Anastasia A. Golubtsova, Vu H. Nguyen

    We study rectangular timelike Wilson loops at long distances in the exact renormalization group flow in the context of the holographic duality. We consider the 5d holographic model with an exponential dilaton potential constructed in [arXiv:1803.06764]. To probe the RG flow backgrounds at zero and finite temperatures we calculate the minimal surfaces of the

  54. Peter Elbau, Leonidas Mindrinos, Leopold Veselka

    We consider the problem of reconstructing the position and the time-dependent optical properties of a linear dispersive medium from OCT measurements. The medium is multi-layered described by a piece-wise inhomogeneous refractive index. The measurement data are from a frequency-domain OCT system and we address also the phase retrieval problem. The parameter i

  55. Charlie Blake, Ian P. Gent

    Our ignorance of the winnability percentage of the solitaire card game `Klondike' has been described as ``one of the embarrassments of applied mathematics''. Klondike, the game in the Windows Solitaire program, is just one of many single-player card games, generically called `patience' or `solitaire' games, for which players have long wanted to know how like

  56. Denes Molnar

    We resolve the long-standing open question of how the transport model AMPT manages to generate sufficiently high elliptic flow (v2) in A+A reactions with only few-millibarn 2->2 partonic cross sections - in apparent contradiction with an early study by Molnar and Gyulassy. Through detailed comparisons with the covariant Molnar's Parton Cascade (MPC), we pinp

  57. Andrzej Mróz

    For standard algorithms verifying positive definiteness of a matrix $A\in\mathbb{M}_n(\mathbb{R})$ based on Sylvester's criterion, the computationally pessimistic case is this when $A$ is positive definite. We present two algorithms realizing the same task for $A\in\mathbb{M}_n(\mathbb{Z})$, for which the case when $A$ is positive definite is the optimistic

  58. Adam Takacs, Denes Molnar

    We investigate fluid-to-particle conversion using the usual Cooper-Frye approach but with more general local equilibrium distributions than the Boltzmann or Bose/Fermi distributions typically used. Even though we study ideal fluids (i.e., shear stress and bulk pressure are zero everywhere), we find a suppression of elliptic flow (v2) at high transverse momen

  59. Gauthier Durieux, Ilaria Brivio, Fabio Maltoni, Michael Trott

    We propose a procedure to cross-validate Monte Carlo implementations of the standard model effective field theory. It is based on the numerical comparison of squared amplitudes computed at specific phase-space and parameter points in pairs of implementations. Interactions are fully linearised in the effective field theory expansion. The squares of linear eff

  60. Yang Ni, Yuan Ji, Peter Mueller

    We present a consensus Monte Carlo algorithm that scales existing Bayesian nonparametric models for clustering and feature allocation to big data. The algorithm is valid for any prior on random subsets such as partitions and latent feature allocation, under essentially any sampling model. Motivated by three case studies, we focus on clustering induced by a D

  61. Ana Brito, Ilídio Lopes

    We study the relation between the internal structures of 10 benchmark main-sequence F-stars and their rotational properties. Stellar rotation of main-sequence F-type stars can be characterised by two distinct rotational regimes. Early-type F-stars are usually rapid rotators with periods typically below 10 days, whereas later-type F-stars have longer rotation

  62. Ville Vakkuri, Kai-Kristian Kemell, Pekka Abrahamsson

    Artificial intelligence (AI) is becoming increasingly widespread in system development endeavors. As AI systems affect various stakeholders due to their unique nature, the growing influence of these systems calls for ethical considerations. Academic discussion and practical examples of autonomous system failures have highlighted the need for implementing eth

  63. Federico Tommasi, Lorenzo Fini, Fabrizio Martelli, Stefano Cavalieri

    The peculiar characteristics of random laser emission have been studied in many different media, leading to a classification of the working regimes based on the statistics of spectral fluctuations. Alongside such studies, the possibility to constrain light propagation by L\'evy walks, i.e. with a `heavy-tailed' distribution of steps, has opened the opportuni

  64. Stephan Clémençon, Pierre Laforgue

    With the deluge of digitized information in the Big Data era, massive datasets are becoming increasingly available for learning predictive models. However, in many practical situations, the poor control of the data acquisition processes may naturally jeopardize the outputs of machine learning algorithms, and selection bias issues are now the subject of much

  65. Massimo Materassi

    The concept of stochastic Lagrangian and its use in statistical dynamics is illustrated theoretically, and with some examples. Dynamical variables undergoing stochastic differential equations are stochastic processes themselves, and their realization probability functional within a given time interval arises from the interplay between the deterministic parts

  66. Anwesh Ray

    Let $p\geq 5$ be a prime number, $\mathbb{F}$ a finite field of characteristic $p$ and let $\bar{\chi}$ be the mod-$p$ cyclotomic character. Let $\bar{\rho}:\operatorname{G}_{\mathbb{Q}}\rightarrow \operatorname{GL}_2(\mathbb{F})$ be a Galois representation such that the local representation $\bar{\rho}_{\restriction \operatorname{G}_{\mathbb{Q}_p}}$ is flat

  67. Charlotte Sleight

    We propose a Mellin space approach to the evaluation of late-time momentum-space correlation functions of quantum fields in $\left(d+1\right)$-dimensional de Sitter space. The Mellin-Barnes representation makes manifest the analytic structure of late-time correlators and, more generally, provides a convenient general $d$ framework for the study of conformal

  68. S. Metais, G. Lerosey, F. Lemoult

    An ensemble of resonators arranged on a sub-wavelength scale is usually considered as a bulk effective medium, known as a metamaterial, and can offer unusual macroscopic properties. Here, we take a different approach and limit ourselves to the study of only a few number of such elementary components and demonstrate that it still offers uncommon opportunities

  69. Andre Nachbin

    It is an established fact that a finite difference operator approximates a derivative with a fixed algebraic rate of convergence. Nevertheless, we exhibit a new finite difference operator and prove it has spectral accuracy. Its rate of convergence is not fixed and improves with the function's regularity. For example, the rate of convergence is exponential fo

  70. Man-Wai Cheung

    In this article, we use the relationship between cluster scattering diagrams and stability scattering diagrams to relate quiver representations with these diagrams. With a notion of positive crossing of a path $\gamma$, we show that if $\gamma$ has positive crossing in the scattering diagram, then it goes in the opposite direction of the Auslander-Reiten qui

  71. Jason Li, Jesper Nederlof

    In the Feedback Vertex Set problem, one is given an undirected graph $G$ and an integer $k$, and one needs to determine whether there exists a set of $k$ vertices that intersects all cycles of $G$ (a so-called feedback vertex set). Feedback Vertex Set is one of the most central problems in parameterized complexity: It served as an excellent test bed for many

  72. Esther Galby, Paloma T. Lima, Bernard Ries

    In this paper, we consider the following problem: given a connected graph $G$, can we reduce the domination number of $G$ by one by using only one edge contraction? We show that the problem is $\mathsf{NP}$-hard when restricted to $\{P_6,P_4+P_2\}$-free graphs and that it is $\mathsf{coNP}$-hard when restricted to subcubic claw-free graphs and $2P_3$-free gr

  73. Daniel Malz, J. Ignacio Cirac

    Number-resolving single-photon detectors represent a key technology for a host of quantum optics protocols, but despite significant efforts, state-of-the-art devices are limited to few photons. In contrast, state-dependent atom counting in arrays can be done with extremely high fidelity up to hundreds of atoms. We show that in waveguide QED, the problem of p

  74. Igor Dolgachev

    We explain a classical construction of a del Pezzo surface of degree d = 4 or 5 as a smooth order two congruence of lines in 3-space whose focal surface is a quartic surface $X_{20-d}$ with 20-d ordinary double points. We also show that $X_{15}$ can be realized as a hyperplane section of the Castelnuovo-Richmond-Igusa quartic hypersurface. This leads to the

  75. Dario Gatto, Paolo Facchi, Frank Narducci, Vincenzo Tamma

    We propose an interferometric scheme for the estimation of a linear combination with non-negative weights of an arbitrary number $M>1$ of unknown phase delays, distributed across an $M$-channel linear optical network, with Heisenberg-limited sensitivity. This is achieved without the need of any sources of photon-number or entangled states, photon-number reso

  76. Carlo Heissenberg, Franco Strocchi

    The aim of this paper is to propose a criterion of spontaneous symmetry breaking that makes reference to the properties of pure phases defined by a translationally invariant state. By avoiding any reference to the ground state, at the basis of the standard approach, this criterion applies to a wider class of models. An interesting application is the breaking

  77. Henrik Johansson, Alexander Ochirov

    The duality between color and kinematics was originally observed for purely adjoint massless gauge theories, and later found to hold even after introducing massive fermionic and scalar matter in arbitrary gauge-group representations. Such a generalization was critical for obtaining both loop amplitudes in pure Einstein gravity and realistic gravitational mat

  78. Jakub Czartowski, Dardo Goyeneche, Markus Grassl, Karol Życzkowski

    Discrete structures in Hilbert space play a crucial role in finding optimal schemes for quantum measurements. We solve the problem whether a complete set of five iso-entangled mutually unbiased bases exists in dimension four, providing an explicit analytical construction. The reduced density matrices of these $20$ pure states forming this generalized quantum

  79. Pietro Baldi, Emanuele Haus

    We investigate a general question about the size and regularity of the data and the solutions in implicit function problems with loss of regularity. First, we give a heuristic explanation of the fact that the optimal data size found by Ekeland and S\'er\'e with their recent non-quadratic version of the Nash-Moser theorem can also be recovered, for a large cl

  80. Utkan Güngördü, J. P. Kestner

    Achieving high-fidelity control of quantum systems is essential for realization of a practical quantum computer. Composite pulse sequences which suppress different types of errors can be nested to suppress a wide variety of errors but the result is often not optimal, especially in the presence of constraints such as bandwidth limitations. Robust smooth pulse

  81. Yizhang Chen, Egecan Cogulu, Debangsu Roy, Jinjun Ding

    We present a study of the transport properties of thermally generated spin currents in an insulating ferrimagnetic-antiferromagnetic-ferrimagnetic trilayer over a wide range of temperature. Spin currents generated by the spin Seebeck effect (SSE) in a yttrium iron garnet (YIG) YIG/NiO/YIG trilayer on a gadolinium gallium garnet (GGG) substrate were detected

  82. Federico Faedo, Pedro F. Ramirez

    We derive exact relations to all orders in the $\alpha'$ expansion for the charges of a bound system of heterotic strings, solitonic 5-branes and, optionally, a Kaluza-Klein monopole. The expressions, which differ from those of the zeroth-order supergravity approximation, coincide with the values obtained when only the corrections of quadratic order in curva

  83. David Meredith

    We introduce two algorithms, RECURSIA and RRT, designed to increase the compression factor achievable using point-set cover algorithms based on the SIA and SIATEC pattern discovery algorithms. SIA computes the maximal translatable patterns (MTPs) in a point set, while SIATEC computes the translational equivalence class (TEC) of every MTP in a point set, wher

  84. Kangkai Liang, Peng Wang, Houwen Wu, Mingtao Yang

    To make a Born-Infeld (BI) black hole thermally stable, we consider two types of boundary conditions, i.e., the asymptotically anti-de Sitter (AdS) space and a Dirichlet wall placed in the asymptotically flat space. The phase structures and transitions of these two types of BI black holes, namely BI-AdS black holes and BI black holes in a cavity, are investi

  85. Alexander D. Dörfler, Pascal Eberle, Debasish Koner, Michal Tomza

    We report a study of cold charge-transfer (CT) collisions of Rb atoms with N$_2^+$ and O$_2^+$ ions in the mK regime using a dynamic ion-neutral hybrid trapping experiment. State- and collision-energy- dependent reaction rate coefficients have been measured for both systems. We observe markedly different charge-transfer kinetics and dynamics for the differen

  86. Denis Emelin, Ivan Titov, Rico Sennrich

    The transformer is a state-of-the-art neural translation model that uses attention to iteratively refine lexical representations with information drawn from the surrounding context. Lexical features are fed into the first layer and propagated through a deep network of hidden layers. We argue that the need to represent and propagate lexical features in each l

  87. Ruming Zhang

    In this paper, we propose a new numerical method for scattering problems in periodic waveguide, based on the newly established contour integral representation of solutions in a previous paper by the author (see [Zhadf]). For this kind of problems, solutions are obtained via the Limiting Absorption Principle and we all them LAP solutions. Based on the Floquet

  88. Fredrik Sandin, Mattias Nilsson

    Spiking neural networks implemented in dynamic neuromorphic processors are well suited for spatiotemporal feature detection and learning, for example in ultra low-power embedded intelligence and deep edge applications. Such pattern recognition networks naturally involve a combination of dynamic delay mechanisms and coincidence detection. Inspired by an audit

  89. Valentin De Bortoli, Alain Durmus, Marcelo Pereyra, Ana F. Vidal

    Stochastic approximation methods play a central role in maximum likelihood estimation problems involving intractable likelihood functions, such as marginal likelihoods arising in problems with missing or incomplete data, and in parametric empirical Bayesian estimation. Combined with Markov chain Monte Carlo algorithms, these stochastic optimisation methods h

  90. Yoojin Oh, Marc Toussaint, Jim Mainprice

    In this paper we present a framework for the teleoperation of pick-and-place tasks. We define a shared control policy that allows to blend between direct user control and autonomous control based on user intent inference. One of the main challenges in shared autonomy systems is to define the arbitration function, which decides when to let the autonomous agen

  91. Philipp Kratzer, Marc Toussaint, Jim Mainprice

    Predicting human motion in unstructured and dynamic environments is difficult as humans naturally exhibit complex behaviors that can change drastically from one environment to the next. In order to alleviate this issue, we propose to encode the lower level aspects of human motion separately from the higher level geometrical aspects, which we believe will gen

  92. Leandro Soares Indrusiak, Piotr Dziurzanski, Shuai Zhao

    This volume represents the proceedings of the International Workshop on Reconfigurable and Communication-centric Cyber-Physical Systems (ReCoCyPS 2019), co-located with the 14th International Symposium on Reconfigurable Communication-centric Systems-on-Chip (ReCoSoC 2019) on July 2-3 2019, York, United Kingdom. The workshop is organised by the EU-funded SAFI

  93. Jin Xu, Natarajan Gautam

    We consider a priority queueing system where a single processor serves k classes of packets that are generated randomly following Poisson processes. Our objective is to compute the expected Peak Age of Information (PAoI) under various scenarios. In particular, we consider two situations where the buffer size at each queue is one and infinite, and in the infi

  94. Michael J. O'Brien, David G. Grier

    How far a particle moves along the optical axis in a holographic optical trap is not simply dictated by the programmed motion of the trap, but rather depends on an interplay of the trap's changing shape and the particle's material properties. For the particular case of colloidal spheres in optical tweezers, holographic video microscopy reveals that trapped p

  95. Aditi Kathpalia, Nithin Nagaraj

    Synchronization of chaos arises between coupled dynamical systems and is very well understood as a temporal phenomena which leads the coupled systems to converge or develop a dependence with time. In this work, we provide a complementary spatial perspective to this phenomenon by introducing the novel idea of causal stability. We then propose and prove a caus

  96. James Wurster, Matthew R. Bate

    Resolution studies of test problems set baselines and help define minimum resolution requirements, however, resolution studies must also be performed on scientific simulations to determine the effect of resolution on the specific scientific results. We perform a resolution study on the formation of a protostar by modelling the collapse of gas through 14 orde

  97. Gabriel C. Drummond-Cole, Philip Hackney

    The functor between operadic algebras given by restriction along an operad map generally has a left adjoint. We give a necessary and sufficient condition for the restriction functor to admit a right adjoint. The condition is a factorization axiom which roughly says that operations in the codomain operad can be written essentially uniquely as operations in ar

  98. Jiehua Chen

    We study the Reaching Stable Marriage via Divorces (DivorceSM) problem of deciding, given a Stable Marriage instance and an initial matching $M$ , whether there exists a stable matching which is reachable from $M$ by divorce operations as introduced by Knuth [12]. Towards answering an open question of Manlove [13] and Cechl\'arov\'a et al. [3], we show that

  99. B. L. Alterman, Justin C. Kasper

    We study the relationship between solar wind helium to hydrogen abundance ratio ($A_\mathrm{He}$), solar wind speed ($v_\mathrm{SW}$), and sunspot number (SSN) over solar cycles 23 and 24. This is the first full 22-year Hale cycle measured with the Wind spacecraft covering a full cycle of the solar dynamo with two polarity reversals. While previous studies h

  100. Hugo Caerols, Felipe A. Asenjo

    With only five photographs of the Sun at different dates we show that the mass of Sun can be calculated by using a telescope, a camera, and the Kepler's third law. With these photographs we are able to calculate the distance between Sun and Earth at different dates in a period of time of about three months. These distances allow us to obtain the correct elli