Results for "F. K. Malinowski"

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Notch filtering the nuclear environment of a spin qubitJan 25 2016Jan 18 2017Electron spins in gate-defined quantum dots provide a promising platform for quantum computation. In particular, spin-based quantum computing in gallium arsenide takes advantage of the high quality of semiconducting materials, reliability in fabricating ... More
Notch filtering the nuclear environment of a spin qubitJan 25 2016Jul 25 2016Electron spins in gate-defined quantum dots provide a promising platform for quantum computation. In particular, spin-based quantum computing in gallium arsenide takes advantage of the high quality of semiconducting materials, reliability in fabricating ... More
A fast, low-leakage, high-fidelity two-qubit gate for a programmable superconducting quantum computerMar 06 2019A common approach to realize conditional-phase (CZ) gates in transmon qubits relies on flux control of the qubit frequency to make computational states interact with non-computational ones using a fast-adiabatic trajectory to minimize leakage. We develop ... More
Time-domain characterization and correction of on-chip distortion of control pulses in a quantum processorJul 10 2019We introduce Cryoscope, a method for sampling on-chip baseband pulses used to dynamically control qubit frequency in a quantum processor. We specifically use Cryoscope to measure the step response of the dedicated flux control lines of two-junction transmon ... More
Order closed ideals in pre-Riesz spaces and their relationship to bandsJan 30 2018In Archimedean vector lattices bands can be introduced via three different coinciding notions. First, they are order closed ideals. Second, they are precisely those ideals which equal their double disjoint complements. The third concept is that of an ... More
Conductance-matrix symmetries of a three-terminal hybrid deviceMay 14 2019We present conductance-matrix measurements of a three-terminal superconductor-semiconductor hybrid device consisting of two normal leads and one superconducting lead. Using a symmetry decomposition of the conductance, we find that the antisymmetric components ... More
Probing the limits of correlations in an indivisible quantum systemDec 18 2017Feb 15 2018We employ a trapped ion to study quantum contextual correlations in a single qutrit using the 5-observable KCBS inequality, which is arguably the most fundamental non-contextuality inequality for testing Quantum Mechanics (QM). We quantify the effect ... More
Sustained state-independent quantum contextual correlations from a single ionJun 22 2017Oct 27 2017We use a single trapped-ion qutrit to demonstrate the violation of an input-state-independent non-contextuality inequality using a sequence of randomly chosen quantum non-demolition projective measurements. We concatenate 54 million sequential measurements ... More
Ultrafast hot-electron induced quenching of Tb4f magnetic orderAug 29 2017Aug 31 2017We have investigated ultrafast quenching of the Tb4f magnetic order in Co74Tb26 alloys, induced by femtosecond hot-electrons pulses. The hot-electron pulses were produced in specific non-magnetic capping layers by infrared fs laser pulses. Our experimental ... More
Filter function formalism beyond pure dephasing and non-Markovian noise in singlet-triplet qubitsNov 23 2015Mar 19 2016The filter function formalism quantitatively describes the dephasing of a qubit by a bath that causes Gaussian fluctuations in the qubit energies with an arbitrary noise power spectrum. Here, we extend this formalism to account for more general types ... More
Two lifetimes and the pseudogap in the orbital magnetoresistance of Zn-substituted La{1.85}Sr{0.15}CuO{4}Mar 04 1999The effect of zinc doping on the anomalous temperature dependence of the magnetoresistance and the Hall effect in the normal state was studied in a series of La{1.85}Sr{0.15}Cu{1-y}Zn{y}O{4} films, with values of y between zero and 0.12. The orbital magnetoresistance ... More
Single-color, in situ photolithography marking of individual CdTe/ZnTe Quantum Dots containing a single Mn2+ ionJan 26 2015A simple, single-color method for permanent marking of the position of individual self-assembled semiconductor Quantum Dots (QDs) at cryogenic temperatures is reported. The method combines in situ photolithography with standard micro-photoluminescence ... More
Fully-Tensorial Elastic-Wave Mode-Solver in FEniCS for Stimulated Brillouin Scattering ModelingDec 05 2018Apr 27 2019A framework for simulating the elastic-wave modes in waveguides, taking into account the full tensorial nature of the stiffness tensor, is presented and implemented in the open-source finite element solver, FEniCS. Various approximations of the elastic ... More
c-axis magnetotransport in CeCoIn$_{5}$Mar 30 2005We present the results of out-of-plane electrical transport measurements on the heavy fermion superconductor CeCoIn$_{5}$ at temperatures from 40 mK to 400 K and in magnetic field up to 9 T. For $T <$ 10 K transport measurements show that the zero-field ... More
Strategies in crowd and crowd structureSep 28 2012In an emergency situation, imitation of strategies of neighbours can lead to an order-disorder phase transition, where spatial clusters of pedestrians adopt the same strategy. We assume that there are two strategies, cooperating and competitive, which ... More
A Multi-World Approach to Question Answering about Real-World Scenes based on Uncertain InputOct 01 2014May 05 2015We propose a method for automatically answering questions about images by bringing together recent advances from natural language processing and computer vision. We combine discrete reasoning with uncertain predictions by a multi-world approach that represents ... More
Deterministic ants in labirynth -- information gained by map sharingJun 12 2012A few of ant robots are dropped to a labirynth, formed by a square lattice with a small number of nodes removed. Ants move according to a deterministic algorithm designed to explore all corridors. Each ant remembers the shape of corridors which she has ... More
Symmetry in behavior of complex social systems - discussion of models of crowd evacuation organized in agreement with symmetry conditionsFeb 07 2011Aug 18 2011The evacuation of football stadium scenarios are discussed as model realizing ordered states, described as movements of individuals according to fields of displacements, calculated correspondingly to given scenario. The symmetry of the evacuation space ... More
Stationary current of a viscous compressed liquid in a cylindrical pipeSep 13 2011An attempt of solving the equations of the movement of a newton's liquid in the cylindrical co-ordinates.
Tutorial on Answering Questions about Images with Deep LearningOct 04 2016Together with the development of more accurate methods in Computer Vision and Natural Language Understanding, holistic architectures that answer on questions about the content of real-world images have emerged. In this tutorial, we build a neural-based ... More
Noise suppression and long-range exchange coupling for gallium arsenide spin qubitsJun 12 2017This thesis presents the results of the experimental study performed on spin qubits realized in gate-defined gallium arsenide quantum dots, with the focus on noise suppression and long-distance coupling.
Pervasive and weakly pervasive pre-Riesz spacesMar 19 2018Nov 08 2018Pervasive pre-Riesz spaces are defined by means of vector lattice covers. To avoid the computation of a vector lattice cover, we give two distinct intrinsic characterizations of pervasive pre-Riesz spaces. We introduce weakly pervasive pre-Riesz spaces ... More
Suppressing quasiparticle poisoning with a voltage-controlled filterFeb 07 2019We study single-electron charging events in an Al/InAs nanowire hybrid system with deliberately introduced gapless regions. The occupancy of a Coulomb island is detected using a nearby radio-frequency quantum dot as a charge sensor. We demonstrate that ... More
Hard to Cheat: A Turing Test based on Answering Questions about ImagesJan 14 2015Jan 15 2015Progress in language and image understanding by machines has sparkled the interest of the research community in more open-ended, holistic tasks, and refueled an old AI dream of building intelligent machines. We discuss a few prominent challenges that ... More
A Pooling Approach to Modelling Spatial Relations for Image Retrieval and AnnotationNov 19 2014May 05 2015Over the last two decades we have witnessed strong progress on modeling visual object classes, scenes and attributes that have significantly contributed to automated image understanding. On the other hand, surprisingly little progress has been made on ... More
Towards a Visual Turing ChallengeOct 29 2014May 05 2015As language and visual understanding by machines progresses rapidly, we are observing an increasing interest in holistic architectures that tightly interlink both modalities in a joint learning and inference process. This trend has allowed the community ... More
Learnable Pooling Regions for Image ClassificationJan 15 2013May 05 2015Biologically inspired, from the early HMAX model to Spatial Pyramid Matching, pooling has played an important role in visual recognition pipelines. Spatial pooling, by grouping of local codes, equips these methods with a certain degree of robustness to ... More
Projection bands and atoms in pervasive pre-Riesz spacesApr 23 2019In vector lattices, the concept of a projection band is a basic tool. We deal with projection bands in the more general setting of an Archimedean pre-Riesz space $X$. We relate them to projection bands in a vector lattice cover $Y$ of $X$. If $X$ is pervasive, ... More
Order continuous operators on pre-Riesz spaces and embeddingsFeb 07 2018We investigate properties of order continuous operators on pre-Riesz spaces with respect to the embedding of the range space into a vector lattice cover or, in particular, into its Dedekind completion. We show that order continuity is preserved under ... More
Fully-Tensorial Elastic-Wave Mode-Solver in FEniCS for Stimulated Brillouin Scattering ModelingDec 05 2018Dec 11 2018A framework for simulating the elastic-wave modes in waveguides, taking into account the full tensorial nature of the stiffness tensor, is presented and implemented in the open-source finite element solver, FEniCS. Various approximations of the elastic ... More
The Visual QA Devil in the Details: The Impact of Early Fusion and Batch Norm on CLEVRSep 11 2018Visual QA is a pivotal challenge for higher-level reasoning, requiring understanding language, vision, and relationships between many objects in a scene. Although datasets like CLEVR are designed to be unsolvable without such complex relational reasoning, ... More
Vector lattice covers of ideals and bands in pre-Riesz spacesJan 22 2018Nov 08 2018Pre-Riesz spaces are ordered vector spaces which can be order densely embedded into vector lattices, their so-called vector lattice covers. Given a vector lattice cover $Y$ for a pre-Riesz space $X$, we address the question how to find vector lattice ... More
Comparative study of the two versions of the Microsoft Kinect$^{\rm TM}$ sensor in regard to the analysis of human motionApr 01 2015The present paper is part of a broader programme, exploring the possibility of involving the Microsoft Kinect$^{\rm TM}$ sensor in the analysis of human motion. In this study, the output obtained from the two available versions of this sensor is critically ... More
On using the Microsoft Kinect$^{\rm TM}$ sensors to determine the lengths of the arm and leg bones of a human subject in motionMay 02 2015The present study is part of a broader programme, exploring the possibility of involving the Microsoft Kinect$^{\rm TM}$ sensor in the analysis of human motion. We examine the output obtained from the two available versions of this sensor in relation ... More
Dynamic Nuclear Overhauser Shifts in Larmor beats from a quantum wellOct 28 1999The significance of nuclear spin polarisation in time-resolved optical studies of III-V semiconductors is addressed. Electron Larmor beats in pump-probe reflectivity from a GaAs/AlGaAs quantum well show Overhauser shift of 0.7 T due to accumulated nuclear ... More
On finite elements in $f$-algebras and in product algebrasJan 25 2018Finite elements, which are well-known and studied in the framework of vector lattices, are investigated in $\ell$-algebras, preferably in $f$-algebras, and in product algebras. The additional structure of an associative multiplication leads to new questions ... More
Synthetic SXR diagnostic using GEM detectors on WEST: development in the prospect of tungsten monitoringNov 18 2016WEST (Tungsten Environment in Steady-State Tokamak) will be operating by the end of 2016 as a test bed for the ITER divertor components in long pulse operation. In this context, radiative cooling of highly ionized impurities like tungsten (W) sputtered ... More
Different Gd3+ sites in CaB6: an ESR studyJun 27 2001Jul 17 2001The local environment of Gd3+ (4f7 S=7/2) ions in single crystals of Ca1-xGdxB6 (0.0001 < x < 0.01) is studied by means of Electron Spin Resonance (ESR). The spectra for low concentration samples (x < 0.001) show a split spectrum due to cubic crystal ... More
Anisotropy of Thermal Conductivity and Possible Signature of the Fulde-Ferrell-Larkin-Ovchinnikov state in CeCoIn_5Jan 13 2004We have measured the thermal conductivity of the heavy-fermion superconductor CeCoIn_5 in the vicinity of the upper critical field, with the magnetic field perpendicular to the c axis. Thermal conductivity displays a discontinuous jump at the superconducting ... More
Magnetic-Field Induced Localization in the Normal State of Superconducting La_2-xSr_xCuo_4May 14 1997Magnetoresistance measurements of highly underdoped superconducting La_{2-x}Sr_xCuO_4 films with $x = 0.051$ and $x = 0.048$, performed in dc magnetic fields up to 20 T and at temperatures down to 40 mK, reveal a magnetic-field induced transition from ... More
Element-resolved ultrafast demagnetization rates in ferrimagnetic CoDyAug 29 2017Aug 31 2017Femtosecond laser induced ultrafast magnetization dynamics have been studied in multisublattice CoxDy1-x alloys. By performing element and time-resolved X-ray spectroscopy, we distinguish the ultrafast quenching of Co3d and Dy4f magnetic order when the ... More
Negative spin exchange in a multielectron quantum dotJun 03 2017By operating a one-electron quantum dot (fabricated between a multielectron dot and a one-electron reference dot) as a spectroscopic probe, we study the spin properties of a gate-controlled multielectron GaAs quantum dot at the transition between odd ... More
Two types of all-optical magnetization switching mechanisms using femtosecond laser pulsesFeb 26 2016Mar 01 2016Magnetization manipulation in the absence of an external magnetic field is a topic of great interest, since many novel physical phenomena need to be understood and promising new applications can be imagined. Cutting-edge experiments have shown the capability ... More
Symmetric Operation of the Resonant Exchange QubitApr 05 2017We operate a resonant exchange qubit in a highly symmetric triple-dot configuration using IQ-modulated RF pulses. At the resulting three-dimensional sweet spot the qubit splitting is an order of magnitude less sensitive to all relevant control voltages, ... More
Impurity and strain effects on the magnetotransport of La1.85Sr0.15Cu(1-y)Zn(y)O4 filmsAug 23 2001The influence of zinc doping and strain related effects on the normal state transport properties(the resistivity, the Hall angle and the orbital magneto- resistance(OMR) is studied in a series of La1.85Sr0.15Cu(1-y)Zn(y)O4 films with values of y between ... More
Magnetotransport in the Normal State of La1.85Sr0.15Cu(1-y)Zn(y)O4 FilmsAug 23 2001We have studied the magnetotransport properties in the normal state for a series of La1.85Sr0.15Cu(1-y)Zn(y)O4 films with values of y, between 0 and 0.12. A variable degree of compressive or tensile strain results from the lattice mismatch between the ... More
Metallic nonsuperconducting phase and d-wave superconductivity in Zn-substituted LaSrCuONov 10 1999Nov 23 1999Measurements of the resistivity, magnetoresistance and penetration depth were made on films of LaSrCuO with up to 12 at.% of Zn substituted for the Cu. The results show that the quadratic temperature dependence of the inverse square of the penetration ... More
Spectrum of the Nuclear Environment for GaAs Spin QubitsJan 07 2017May 05 2017Using a singlet-triplet spin qubit as a sensitive spectrometer of the GaAs nuclear spin bath, we demonstrate that the spectrum of Overhauser noise agrees with a classical spin diffusion model over six orders of magnitude in frequency, from 1 mHz to 1 ... More
Noise suppression using symmetric exchange gates in spin qubitsNov 23 2015Feb 15 2016We demonstrate a substantial improvement in the spin-exchange gate using symmetric control instead of conventional detuning in GaAs spin qubits, up to a factor-of-six increase in the quality factor of the gate. For symmetric operation, nanosecond voltage ... More
Ask Your Neurons: A Neural-based Approach to Answering Questions about ImagesMay 05 2015Oct 01 2015We address a question answering task on real-world images that is set up as a Visual Turing Test. By combining latest advances in image representation and natural language processing, we propose Neural-Image-QA, an end-to-end formulation to this problem ... More
Model of skyscraper evacuation with the use of space symmetry and fluid dynamic approximationAug 18 2011The simulation of evacuation of pedestrians from skyscraper is a situation where the symmetry analysis method and equations of fluid dynamics finds to be very useful. When applied, they strongly reduce the number of free parameters used in simulations ... More
Intrinsically Weighted Means of Marked Point ProcessesOct 04 2012For a non-stationary or non-ergodic marked point process (MPP) on $\R^d$, the definition of averages becomes ambiguous as the process might have a different stochastic behavior in different realizations (non-ergodicity) or in different areas of the observation ... More
Ask Your Neurons: A Deep Learning Approach to Visual Question AnsweringMay 09 2016We address a question answering task on real-world images that is set up as a Visual Turing Test. By combining latest advances in image representation and natural language processing, we propose Ask Your Neurons, a scalable, jointly trained, end-to-end ... More
Mean Box Pooling: A Rich Image Representation and Output Embedding for the Visual Madlibs TaskAug 09 2016We present Mean Box Pooling, a novel visual representation that pools over CNN representations of a large number, highly overlapping object proposals. We show that such representation together with nCCA, a successful multimodal embedding technique, achieves ... More
Spatio-Temporal Image Boundary ExtrapolationMay 24 2016Boundary prediction in images as well as video has been a very active topic of research and organizing visual information into boundaries and segments is believed to be a corner stone of visual perception. While prior work has focused on predicting boundaries ... More
The zero forcing number of graphs with a givenNov 20 2016In this note, we study a dynamic coloring of vertices in a simple graph $G$. In particular, one may color an initial set of vertices, with all other vertices being non-colored. Then, at each discrete time step, a colored vertex with exactly one non-colored ... More
Size dependence of the largest distance between random pointsOct 31 2013A set of $N$ points is chosen randomly in a $D$-dimensional volume $V=a^D$, with periodic boundary conditions. For each point $i$, its distance $d_i$ is found to its nearest neighbour. Then, the maximal value is found, $d_{max}=max(d_i, i=1,...,N)$. Our ... More
All-optical control of ferromagnetic thin films and nanostructuresMar 04 2014The interplay of light and magnetism has been a topic of interest since the original observations of Faraday and Kerr where magnetic materials affect the light polarization. While these effects have historically been exploited to use light as a probe ... More
Ask Your Neurons: A Deep Learning Approach to Visual Question AnsweringMay 09 2016Nov 24 2016We address a question answering task on real-world images that is set up as a Visual Turing Test. By combining latest advances in image representation and natural language processing, we propose Ask Your Neurons, a scalable, jointly trained, end-to-end ... More
Anomalous Paramagnetic Effects in the Mixed State of LuNi2B2CMay 13 2004Feb 21 2005Anomalous paramagnetic effects in dc magnetization were observed in the mixed state of LuNi2B2C, unlike any reported previously. It appears as a kink-like feature for H > 30 kOe and becomes more prominent with increasing field. A specific heat jump at ... More
Synchronization recovery and state model reduction for soft decoding of variable length codesDec 11 2006Variable length codes exhibit de-synchronization problems when transmitted over noisy channels. Trellis decoding techniques based on Maximum A Posteriori (MAP) estimators are often used to minimize the error rate on the estimated sequence. If the number ... More
On using the Microsoft Kinect$^{\rm TM}$ sensors in the analysis of human motionDec 04 2014May 27 2015The present paper aims at providing the theoretical background required for investigating the use of the Microsoft Kinect$^{\rm TM}$ (`Kinect', for short) sensors (original and upgraded) in the analysis of human motion. Our methodology is developed in ... More
Fast spin exchange between two distant quantum dotsAug 29 2018The Heisenberg exchange interaction between neighboring quantum dots allows precise voltage control over spin dynamics, due to the ability to precisely control the overlap of orbital wavefunctions by gate electrodes. This allows the study of fundamental ... More
Radio-frequency methods for Majorana-based quantum devices: fast charge sensing and phase diagram mappingFeb 02 2019Radio-frequency (RF) reflectometry is implemented in hybrid semiconductor-superconductor nanowire systems designed to probe Majorana zero modes. Two approaches are presented. In the first, hybrid nanowire-based devices are part of a resonant circuit, ... More
Spin of a multielectron quantum dot and its interaction with a neighboring electronOct 27 2017We investigate the spin of a multielectron GaAs quantum dot in a sequence of nine charge occupancies, by exchange coupling the multielectron dot to a neighboring two-electron double quantum dot. For all nine occupancies, we make use of a leakage spectroscopy ... More
Localization and Interaction Effects in Strongly Underdoped La2-xSrxCuO4Mar 16 2004The in-plane magnetoresistance (MR) in La2-xSrxCuO4 films with 0.03 < x < 0.05 has been studied in the temperature range 1.6 K to 100 K, and in magnetic fields up to 14 T, parallel and perpendicular to the CuO2 planes. The behavior of the MR is consistent ... More
Day-ahead time series forecasting: application to capacity planningNov 06 2018In the context of capacity planning, forecasting the evolution of informatics servers usage enables companies to better manage their computational resources. We address this problem by collecting key indicator time series and propose to forecast their ... More
From BOP to BOSS and Beyond: Time Series Classification with Dictionary Based ClassifiersSep 18 2018A family of algorithms for time series classification (TSC) involve running a sliding window across each series, discretising the window to form a word, forming a histogram of word counts over the dictionary, then constructing a classifier on the histograms. ... More
The Expected Linkage Disequilibrium in Finite Populations RevisitedApr 17 2013Apr 18 2013The expected level of linkage disequilibrium (LD) in a finite ideal population at equilibrium is of relevance for many applications in population and quantitative genetics. Several recursion formulae have been proposed during the last decades, whose derivations ... More
Learning dynamic polynomial proofsJun 04 2019Polynomial inequalities lie at the heart of many mathematical disciplines. In this paper, we consider the fundamental computational task of automatically searching for proofs of polynomial inequalities. We adopt the framework of semi-algebraic proof systems ... More
Modeling Bitcoin Contracts by Timed AutomataMay 08 2014Jun 27 2014Bitcoin is a peer-to-peer cryptographic currency system. Since its introduction in 2008, Bitcoin has gained noticeable popularity, mostly due to its following properties: (1) the transaction fees are very low, and (2) it is not controlled by any central ... More
Dense Bag-of-Temporal-SIFT-Words for Time Series ClassificationJan 08 2016Jan 13 2016Time series classification is an application of particular interest with the increase of data to monitor. Classical techniques for time series classification rely on point-to-point distances. Recently, Bag-of-Words approaches have been used in this context. ... More
Contextual Media Retrieval Using Natural Language QueriesFeb 16 2016The widespread integration of cameras in hand-held and head-worn devices as well as the ability to share content online enables a large and diverse visual capture of the world that millions of users build up collectively every day. We envision these images ... More
Long-Term Image Boundary PredictionNov 27 2016Nov 23 2017Boundary estimation in images and videos has been a very active topic of research, and organizing visual information into boundaries and segments is believed to be a corner stone of visual perception. While prior work has focused on estimating boundaries ... More
Estimating single molecule conductance from spontaneous evolution of a molecular contactJun 29 2017Feb 14 2018We present an original method to estimate the conductivity of a single molecule anchored to nanometric-sized metallic electrodes, using a Mechanically Controlled Break Junction (MCBJ) operated at room temperature in liquid. We record the conductance through ... More
Temperature dependence of Er3+ ionoluminescence and photoluminescence in Gd2O3:Bi nanopowderJun 27 2016Ionoluminescence (IL) and photoluminescence (PL) of trivalent erbium ions (Er3+) in Gd2O3 nanopowder host activated with Bi3+ ions has been studied in order to establish the link between changes in luminescent spectra and temperature of the sample material. ... More
Learning Visual Question Answering by Bootstrapping Hard AttentionAug 01 2018Attention mechanisms in biological perception are thought to select subsets of perceptual information for more sophisticated processing which would be prohibitive to perform on all sensory inputs. In computer vision, however, there has been relatively ... More
Infrared light emission from atomic point contactsFeb 18 2016Feb 19 2016Gold atomic point contacts are prototype systems to evidence ballistic electron transport. The typical dimension of the nanojunction being smaller than the electron-phonon interaction length, even at room temperature, electrons transfer their excess energy ... More
Long-Term Image Boundary ExtrapolationNov 27 2016Boundary prediction in images and videos has been a very active topic of research and organizing visual information into boundaries and segments is believed to be a corner stone of visual perception. While prior work has focused on predicting boundaries ... More
Dynamic Control of Particle Deposition in Evaporating Droplets by an External Point Source of VaporJan 24 2018The deposition of particles on a surface by an evaporating sessile droplet is important for phenomena as diverse as printing, thin-film deposition and self-assembly. The shape of the final deposit depends on the flows within the droplet during evaporation. ... More
How to deal with malleability of BitCoin transactionsDec 11 2013BitCoin transactions are malleable in a sense that given a transaction an adversary can easily construct an equivalent transaction which has a different hash. This can pose a serious problem in some BitCoin distributed contracts in which changing a transaction's ... More
Multi-Cue Zero-Shot Learning with Strong SupervisionMar 29 2016Scaling up visual category recognition to large numbers of classes remains challenging. A promising research direction is zero-shot learning, which does not require any training data to recognize new classes, but rather relies on some form of auxiliary ... More
Playing the Game of Universal Adversarial PerturbationsSep 20 2018Sep 25 2018We study the problem of learning classifiers robust to universal adversarial perturbations. While prior work approaches this problem via robust optimization, adversarial training, or input transformation, we instead phrase it as a two-player zero-sum ... More
Representations of max-stable processes based on single extreme eventsSep 11 2012This paper provides the basis for new methods of inference for max-stable processes \xi\ on general spaces that admit a certain incremental representation, which, in important cases, has a much simpler structure than the max-stable process itself. A corresponding ... More
Estimation of Huesler-Reiss distributions and Brown-Resnick processesJul 30 2012Sep 25 2012Estimation of extreme-value parameters from observations in the max-domain of attraction (MDA) of a multivariate max-stable distribution commonly uses aggregated data such as block maxima. Since we expect that additional information is contained in the ... More
Magnetism and unconventional superconductivity in Ce$_n$M$_m$In$_{3n+2m}$ heavy-fermion crystalsSep 04 2002We review magnetic, superconducting and non-Fermi-liquid properties of the structurally layered heavy-fermion compounds Ce$_n$M$_m$In$_{3n+2m}$ (M=Co, Rh, Ir). These properties suggest d-wave superconductivity and proximity to an antiferromagetic quantum-critical ... More
Measurement of CP-Violating Parameters in $B\to η^\prime K$ DecaysJul 15 2002Jul 25 2002We present measurements of CP-violating parameters in $B^0(\bar{B}{}^0) \to \eta^\prime K_S^0$ and $B^{\pm} \to \eta' K^{\pm}$ decays based on a 41.8 fb$^{-1}$ data sample collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy ... More
Order and Disorder Phenomena at Surfaces of Binary AlloysFeb 10 2000We present recent Monte Carlo results on surfaces of bcc-structured binary alloys which undergo an order-disorder phase transformation in the bulk. In particular, we discuss surface order and surface induced disorder at the bulk transition between the ... More
On the Formation of Massive Primordial StarsSep 21 2001We investigate the formation by accretion of massive primordial protostars in the range 10 to 300 Msun. The high accretion rate used in the models (4.4 x 10^{-3} Msun/yr) causes the structure and evolution to differ significantly from those of both present-day ... More
Formation of the First Stars by AccretionFeb 18 2003The process of star formation from metal-free gas is investigated by following the evolution of accreting protostars with emphasis on the properties of massive objects. The main aim is to establish the physical processes that determine the upper mass ... More
Lifting U-dualitiesMay 23 2002We present a novel global E_7(7) symmetry in five-dimensional maximal supergravity as well as an E_8(8) symmetry in d=4. These symmetry groups which are known to be present after reduction to d=4 and d=3, respectively, appear as conformal extensions of ... More
Charge gap in the one--dimensional dimerized Hubbard model at quarter-fillingJun 17 1994We propose a quantitative estimate of the charge gap that opens in the one-dimensional dimerized Hubbard model at quarter-filling due to dimerization, which makes the system effectively half--filled, and to repulsion, which induces umklapp scattering ... More
Wormholes with a barotropic equation of state admitting a one-parameter group of conformal motionsFeb 06 2015Mar 24 2016The theoretical construction of a traversable wormhole proposed by Morris and Thorne maintains complete control over the geometry by assigning both the shape and redshift functions, thereby leaving open the determination of the stress-energy tensor. This ... More
More on wormholes supported by small amounts of exotic matterDec 05 2005Apr 28 2006Recent papers by Fewster and Roman have emphasized that wormholes supported by arbitrarily small amounts of exotic matter will have to be incredibly fine-tuned if they are to be traversable. This paper discusses a wormhole model that strikes a balance ... More
On a time-dependent extra spatial dimensionAug 28 2006May 14 2012In the usual brane-world scenario matter fields are confined to the four-dimensional spacetime, called a 3-brane, embedded in a higher-dimensional space, usually referred to as the bulk spacetime. In this paper we assume that the 3-brane is a de Sitter ... More
Static and dynamic traversable wormhole geometries satisfying the Ford-Roman constraintsJan 07 2004Jan 13 2004It was shown by Ford and Roman in 1996 that quantum field theory severely constrains wormhole geometries on a macroscopic scale. The first part of this paper discusses a wide class of wormhole solutions that meet these constraints. The type of shape function ... More
Limits on the optical magnitude of PSR 1821-24 in M28Apr 14 2000The detection of a pulsed X-ray counterpart (RX J1824.2-2R52P) of the 3.05 ms pulsar PSR 1821-24, suggests the possibility of a part of the rotational energy loss of this high spindown rate pulsar being in the optical band. Archival HST data for M28 is ... More
Conformal symmetry wormholes and the null energy conditionMay 24 2016In this paper we seek a relationship between the assumption of conformal symmetry and the exotic matter needed to hold a wormhole open. By starting with a Morris-Thorne wormhole having a constant energy density, it is shown that the conformal factor provides ... More
Ligand effects on the electronic structure and magnetism of magnetite surfacesMay 08 2012We address the effect of functionalization on the electronic and magnetic properties of magnetite surface as an indicator of the same properties in nanoparticles too big for a direct ab-initio approach. Using well-established methods and references (namely ... More
Results for all reactions e+ e- -> 4f, 4f + gamma with nonzero fermion massesSep 28 2001Feb 20 2002We accomplish our efforts to obtain predictions for all four-fermion final states of e+ e- annihilation and the corresponding bremsstrahlung reactions which are possible in the framework of the Standard Model. For this purpose we have developed a program ... More