Results for "F. Niel"

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A degree bound for families of rational curves on surfacesFeb 11 2014Feb 20 2018We give an upper bound for the degree of rational curves in a family that covers a given birational ruled surface in projective space. The upper bound is stated in terms of the degree, sectional genus and arithmetic genus of the surface. We introduce ... More
Photonic nanowire-based single-photon source with polarization controlMay 23 2016This document describes a modal method for optical simulations of structures with elliptical cross sections and its application to the design of the photonic nanowire (NW)-based single-photon source (SPS). The work was carried out in the framework of ... More
Self force on a scalar charge in Kerr spacetime: inclined circular orbitsAug 13 2014Feb 02 2015Accurately modeling astrophysical extreme-mass-ratio-insprials requires calculating the gravitational self-force for orbits in Kerr spacetime. The necessary calculation techniques are typically very complex and, consequently, toy scalar-field models are ... More
Bounded Hochschild cohomology of Banach algebras with a matrix-like structureNov 28 2003Let B be a unital Banach algebra. A projection in B which is equivalent to the identitity may give rise to a matrix-like structure on any two-sided ideal A in B. In this set-up we prove a theorem to the effect that the bounded Hochschild cohomology H^n(A,A^*) ... More
Density of quasismooth hypersurfaces in simplicial toric varietiesSep 23 2014Mar 23 2016This paper investigates the density of hypersurfaces in a projective normal simplicial toric variety over a finite field having a quasismooth intersection with a given quasismooth subscheme. The result generalizes the formula found by B. Poonen for smooth ... More
Deriving the Gross-Pitaevskii equationApr 17 2014In experiments, Bose-Einstein condensates are prepared by cooling a dilute Bose gas in a trap. After the phase transition has been reached, the trap is switched off and the evolution of the condensate observed. The evolution is macroscopically described ... More
Nonparametric likelihood based estimation of linear filters for point processesApr 01 2013Feb 12 2014We consider models for multivariate point processes where the intensity is given nonparametrically in terms of functions in a reproducing kernel Hilbert space. The likelihood function involves a time integral and is consequently not given in terms of ... More
Klein's double discontinuity revisited: what use is university mathematics to high school calculus?Jun 29 2013Mar 10 2014Much effort and research has been invested into understanding and bridging the gaps which many students experience in terms of contents and expectations as they begin university studies with a heavy component of mathematics, typically in the form of calculus ... More
Cyclic structures in algebraic (co)homology theoriesNov 15 2010This note discusses the cyclic cohomology of a left Hopf algebroid ($\times_A$-Hopf algebra) with coefficients in a right module-left comodule, defined using a straightforward generalisation of the original operators given by Connes and Moscovici for ... More
Black Holes in Higher-Dimensional GravityFeb 04 2008These lectures review some of the recent progress in uncovering the phase structure of black hole solutions in higher-dimensional vacuum Einstein gravity. The two classes on which we focus are Kaluza-Klein black holes, i.e. static solutions with an event ... More
Air-clad fibers: pump absorption assisted by chaotic wave dynamics?Jul 09 2007Wave chaos is a concept which has already proved its practical usefulness in design of double-clad fibers for cladding-pumped fiber lasers and fiber amplifiers. In general, classically chaotic geometries will favor strong pump absorption and we address ... More
Sub-Poissonian Phonon Lasing in Three-Mode OptomechanicsFeb 13 2015We propose to use the resonant enhancement of the parametric instability in an optomechanical system of two optical modes coupled to a mechanical oscillator to prepare mechanical states with sub-Poissonian phonon statistics. Strong single photon coupling ... More
Note sur la détermination algébrique du groupe fondamental pro-résoluble d'une courbe affineAug 01 2007May 07 2008Let X be a smooth projective algebraic curve of genus g minus $r\geq 1$ points defined over an algebraically closed field k of characteristic $p\geq 0$. The structure of the largest prime to p quotient of the \'etale fundamental group is well known by ... More
Semi-analytical approach to short-wavelength dispersion and modal properties of photonic crystal fibersJan 17 2005Feb 14 2005We consider photonic crystal fibers made from arbitrary base materials and derive a unified semi-analytical approach for the dispersion and modal properties which applies to the short-wavelength regime. In particular we calculate the dispersion and the ... More
The maximum of a random walk reflected at a general barrierMar 09 2006We define the reflection of a random walk at a general barrier and derive, in case the increments are light tailed and have negative mean, a necessary and sufficient criterion for the global maximum of the reflected process to be finite a.s. If it is ... More
Recurrence relations for Wronskian Laguerre polynomialsMay 29 2019The 3-term recurrence relation for Hermite polynomials was recently generalized to a recurrence relation for Wronskians of Hermite polynomials. In this note, a similar generalization for Laguerre polynomials is obtained.
Short wave length approximation of a boundary integral operator for homogeneous and isotropic elastic bodiesAug 17 2006We derive a short wave length approximation of a boundary integral operator for two-dimensional isotropic and homogeneous elastic bodies of arbitrary shape. Trace formulae for elastodynamics can be deduced in this way from first principles starting directly ... More
Wave chaos in the elastic discSep 03 2002The relation between the elastic wave equation for plane, isotropic bodies and an underlying classical ray dynamics is investigated. We study in particular the eigenfrequencies of an elastic disc with free boundaries and their connection to periodic rays ... More
Parabolic sheaves on logarithmic schemesJan 04 2010Oct 25 2012We show how the natural context for the definition of parabolic sheaves on a scheme is that of logarithmic geometry. The key point is a reformulation of the concept of logarithmic structure in the language of symmetric monoidal categories, which might ... More
K-theory for algebras of operators on Banach spacesJan 23 1997It is proved that, for each pair (m,n) of non-negative integers, there is a Banach space X for which the group K_0(B(X)) is isomorphic to m copies of the integers and the group K_1(B(X)) is isomorphic to n copies of the integers. Along the way we compute ... More
Molecular complexity on disk-scales uncovered by ALMA: The chemical composition of the high-mass protostar AFGL 4176Jun 14 2019The chemical composition of high-mass protostars reflects the physical evolution associated with different stages of star formation. In this study, the molecular inventory of the forming high-mass star AFGL 4176 is studied in detail at high angular resolution ... More
Brownian Motion after Einstein: Some new applications and new experimentsMar 17 2006The first half of this chapter describes the development in mathematical models of Brownian motion after Einstein's seminal papers and current applications to optical tweezers. This instrument of choice among single-molecule biophysicists is also an instrument ... More
The unreasonable accuracy of the Jastrow approach in many-body physicsJul 14 2003We investigate in a simple model whether a Jastrow-based approach for a many-body system containing two-body interactions can be exact. By comparison with recent assertions to the contrary, we find that in general the exact wave function is \emph{not} ... More
Magnetic Bloch Oscillations and domain wall dynamics in a near-Ising ferromagnetic chainJun 27 2019When charged particles in periodic lattices are subjected to a constant electric field, they respond by oscillating. Here we demonstrate that the magnetic analogue of these Bloch oscillations are realised in a one-dimensional ferromagnetic easy axis chain. ... More
Degrees of freedom for nonlinear least squares estimationFeb 12 2014Dec 12 2014We give a general result on the effective degrees of freedom for nonlinear least squares estimation, which relates the degrees of freedom to the divergence of the estimator. We show that in a general framework, the divergence of the least squares estimator ... More
Langevin dynamics in inhomogeneous media: Re-examining the Itô-Stratonovich DilemmaMay 28 2013Dec 16 2013The diffusive dynamics of a particle in a medium with space-dependent friction coefficient is studied within the framework of the inertial Langevin equation. In this description, the ambiguous interpretation of the stochastic integral, known as the It\^{o}-Stratonovich ... More
The extended coupled cluster method and the pairing problemNov 23 2010We study the application of various forms of the coupled cluster method to systems with paired fermions. The novel element of the analysis is the study of the breaking and eventual restoration of particle number in the CCM variants. We specifically include ... More
Calculation of optical-waveguide grating characteristics using Green's functions and the Dyson's equationJul 24 2006We present a method for calculating the transmission spectra, dispersion, and time delay characteristics of optical-waveguide gratings based on Green's functions and Dyson's equation. Starting from the wave equation for transverse electric modes we show ... More
Non-perturbative approach to high-index-contrast variations in electromagnetic systemsNov 23 2005We present a method that formally calculates \emph{exact} frequency shifts of an electromagnetic field for arbitrary changes in the refractive index. The possible refractive index changes include both anisotropic changes and boundary shifts. Degenerate ... More
Improved Ahead-of-Time Compilation of Stack-Based JVM Bytecode on Resource-Constrained DevicesDec 15 2017Dec 18 2017Many virtual machines exist for sensor nodes with only a few KB RAM and tens to a few hundred KB flash memory. They pack an impressive set of features, but suffer from a slowdown of one to two orders of magnitude compared to optimised native code, reducing ... More
Interaction between point charges, dipoles and graphene layersMay 26 2016We analyse the interaction between charges and graphene layers. The electric polarisability of graphene induces a force, that can be described by an image charge. The analysis shows that graphene can be described as an imperfect conductor with a finite ... More
Morita theory for Hopf algebroids, principal bibundles, and weak equivalencesJul 28 2014Feb 13 2017We show that two flat commutative Hopf algebroids are Morita equivalent if and only if they are weakly equivalent and if and only if there exists a principal bibundle connecting them. This gives a positive answer to a conjecture due to Hovey and Strickland. ... More
Description of resonances in light nuclei using a microscopic cluster modelNov 23 2004We investigate resonances in light halo nuclei using a fully microscopic cluster model and the complex scaling method. We make use of the hermitian representation of the complex scaling method. The general structure of the cluster model is that of a correlation ... More
1/N-expansions in non-relativistic quantum mechanicsFeb 13 2003An extensive number of numerical computations of energy 1/$N$ series using a recursive Taylor series method are presented in this paper. The series are computed to a high order of approximation and their behaviour on increasing the order of approximation ... More
Quantum gravity, effective fields and string theoryOct 10 2004We look at the various aspects of treating general relativity as a quantum theory. It is briefly studied how to consistently quantize general relativity as an effective field theory. A key achievement here is the long-range low-energy leading quantum ... More
Variational Monte Carlo for Microscopic Cluster ModelsJun 15 2004We examine the application of the Variational Monte Carlo (VMC) method to a cluster model for halo nuclei. Particular attention is paid to the error estimate in the presence of correlations in the underlying random walk. We analyse the required steps ... More
Side-gate modulation of critical current in mesoscopic Josephson junctionMay 24 2000May 25 2000We study the normal state conductance and the Josephson current in a superconductor-2DEG-superconductor structure where the size/shape of the 2DEG-region can be modified by an additional side-gate electrode. The considered transport properties follow ... More
On algebraic torsion forms and their spin holonomy algebrasAug 21 2006We study holonomy algebras generated by an algebraic element of the Clifford algebra, or equivalently, the holonomy algebras of certain spin connections in flat space. We provide series of examples in arbitrary dimensions and establish general properties ... More
Ancient mean curvature flows and their spacetime tracksJan 16 2019Feb 26 2019We study properly immersed ancient solutions of the codimension one mean curvature flow in $n$-dimensional Euclidean space, and classify the convex hulls of the subsets of space reached by any such flow. In particular, it follows that any compact convex ... More
Proposal of highly sensitive optofluidic sensors based on dispersive photonic crystal waveguidesMar 06 2007Optofluidic sensors based on highly dispersive two-dimensional photonic crystal waveguides are theoretically studied. Results show that these structures are strongly sensitive to the refractive index of the infiltrated liquid (nl), which is used to tune ... More
Rigidity of conformal functionals on spheresFeb 24 2009In this paper we investigate the nature of stationary points of functionals on the space of Riemannian metrics on a smooth compact manifold. Special cases are spectral invariants associated with Laplace or Dirac operators such as functional determinants, ... More
Large Amplitude Collective Motion in Nuclei and Metallic Clusters: Applicability of adiabatic theory for a pairing modelOct 01 1997A model Hamiltonian describing a two-level system with a crossing plus a pairing force is investigated using technique of large-amplitude collective motion. The collective path, which is determined by the decoupling conditions, is found to be almost identical ... More
From quantum to classical modelling of radiation reaction: a focus on stochasticity effectsJul 09 2017Feb 08 2018Radiation-reaction in the interaction of ultra-relativistic electrons with a strong external electromagnetic field is investigated using a kinetic approach in the weakly quantum regime ($\chi \lesssim 1$, with $\chi$ the electron quantum parameter). Three ... More
Towards a Unified Quark-Hadron Matter Equation of State for Applications in Astrophysics and Heavy-Ion CollisionsApr 26 2018May 28 2018We outline an approach to a unified equation of state for quark-hadron matter on the basis of a $\Phi-$derivable approach to the generalized Beth-Uhlenbeck equation of state for a cluster decomposition of thermodynamic quantities like the density. To ... More
Assumptions and Axioms: Mathematical Structures to Describe the Physics of Rigid BodiesMay 05 2010This paper challenges some of the common assumptions underlying the mathematics used to describe the physical world. We start by reviewing many of the assumptions underlying the concepts of real, physical, rigid bodies and the translational and rotational ... More
Factorization of the identity through operators with large diagonalSep 10 2015Nov 08 2017Given a Banach space~$X$ with an unconditional basis, we consider the following question: does the identity on~$X$ factor through every operator on~$X$ with large diagonal relative to the unconditional basis? We show that on Gowers' unconditional Banach ... More
Diagnostics for insufficiencies of posterior calculations in Bayesian signal inferenceJul 15 2013Nov 04 2013We present an error-diagnostic validation method for posterior distributions in Bayesian signal inference, an advancement of a previous work. It transfers deviations from the correct posterior into characteristic deviations from a uniform distribution ... More
On the nature of the phase transitions in two-dimensional type II superconductorsJun 05 2013Aug 27 2013We have simulated the thermodynamics of vortices in a thin film of a type-II superconductor. We make the lowest Landau level approximation, and use quasi-periodic boundary conditions. Our work is consistent with the results of previous simulations where ... More
New Strategy for B_s Branching Ratio Measurements and the Search for New Physics in B^0_s -> mu^+ mu^-Apr 22 2010Sep 02 2010The LHCb experiment at CERN's Large Hadron Collider will soon allow us to enter a new era in the exploration of B_s decays. A particularly promising channel for the search of "new physics" is B^0_s -> mu^+ mu^-. The systematic key uncertainty affecting ... More
Boosting electronic transport in carbon nanotubes by isotopic disorderMay 19 2009The current/voltage curve of metallic carbon nanotubes (CNTs) displays at high bias a sudden increase of the resistivity due to the scattering of electrons with phonons having an anomalously-high population (hot phonons). Here, we show that it is possible ... More
Meso-scale computer modeling of lipid-DNA complexes for gene therapySep 05 2005We report on a molecular simulation method which captures the self-assembly of cationic lipid-DNA (CL-DNA) gene delivery complexes. Computational efficiency required for large length- and time-scale simulations is achieved through a coarse-grained representation ... More
Resolving isospectral "drums" by counting nodal domainsApr 24 2005Several types of systems were put forward during the past decades to show that there exist {\it isospectral} systems which are {\it metrically} different. One important class consists of Laplace Beltrami operators for pairs of flat tori in $\mathbb{R}^n$ ... More
Isothermal Langevin dynamics in systems with power-law spatially-dependent frictionJun 28 2016We study the dynamics of Brownian particles in a heterogeneous one-dimensional medium with a spatially-dependent diffusion coefficient of the form $D(x)\sim |x|^c$, at constant temperature. The particle's probability distribution function (PDF) is calculated ... More
The Euclidean distribution of Fast Radio BurstsApr 13 2016Jun 20 2016We investigate whether current data on the distribution of observed flux densities of Fast Radio Bursts (FRBs) are consistent with a constant source density in Euclidean space. We use the number of FRBs detected in two surveys with different characteristics ... More
The G-JF Thermostat for Accurate Configurational Sampling in Soft-Matter SimulationsFeb 17 2016We implement the statistically sound G-JF thermostat for Langevin Dynamics simulations into the ESPREesSo molecular package for large-scale simulations of soft matter systems. The implemented integration method is tested against the integrator currently ... More
Lifshitz Hydrodynamics from Lifshitz Black Branes with Linear MomentumJun 30 2016We construct a new class of 4-dimensional z=2 Lifshitz black branes that have a nonzero linear momentum. These are solutions of an Einstein-Proca-dilaton model that can be obtained by Scherk-Schwarz circle reduction of AdS_5 gravity coupled to a free ... More
Gravitational Tension, Spacetime Pressure and Black Hole VolumeDec 30 2015Sep 01 2016We study the first law of black hole thermodynamics in the presence of surrounding gravitational fields and argue that variations of these fields are naturally incorporated in the first law by defining gravitational tension or gravitational binding energy. ... More
Optical runaway evaporation for multi-BEC productionSep 16 2014Oct 28 2014We report on parallel production of Bose-Einstein condensates (BECs) in steerable, multi-plexed crossed optical dipole traps. Using a conventional trap-weakening evaporation scheme, where the optical trapping power is lowered, we obtain an array of up ... More
Mode areas and field energy distribution in honeycomb photonic bandgap fibersJul 16 2003The field energy distributions and effective mode areas of silica-based photonic bandgap fibers with a honeycomb airhole structure in the cladding and an extra airhole defining the core are investigated. We present a generalization of the common effective ... More
Renormalization of Hamiltonian Field Theory; a non-perturbative and non-unitarity approachDec 13 2002Dec 17 2003Renormalization of Hamiltonian field theory is usually a rather painful algebraic or numerical exercise. By combining a method based on the coupled cluster method, analysed in detail by Suzuki and Okamoto, with a Wilsonian approach to renormalization, ... More
Modeling of realistic cladding structures for air-core photonic band-gap fibersOct 30 2003Cladding structures of photonic band-gap fibers often have air-holes of non-circular shape and, typically, close-to-hexagonal air holes with curved corners are observed. We study photonic band-gaps in such structures by aid of a two-parameter representation ... More
Linked-cluster Tamm-Dancoff Field TheoryJun 17 2003To solve the relativistic bound-state problem one needs to systematically and simultaneously decouple the high-energy from the low-energy modes and the many-body from the few-particle states using a consistent renormalization scheme. In a recent paper ... More
Near-field to far-field transition of photonic crystal fibers: symmetries and interference phenomenaMay 28 2002The transition from the near to the far field of the fundamental mode radiating out of a photonic crystal fiber is investigated experimentally and theoretically. It is observed that the hexagonal shape of the near field rotates two times by pi/6 when ... More
Direct simulation of ion beam induced stressing and amorphization of siliconJan 27 1999May 18 1999Using molecular dynamics (MD) simulation, we investigate the mechanical response of silicon to high dose ion-irradiation. We employ a realistic and efficient model to directly simulate ion beam induced amorphization. Structural properties of the amorphized ... More
An Efficient Molecular Dynamics Scheme for the Calculation of Dopant Profiles due to Ion ImplantationJan 28 1999We present a highly efficient molecular dynamics scheme for calculating the concentration depth profile of dopants in ion irradiated materials. The scheme incorporates several methods for reducing the computational overhead, plus a rare event algorithm ... More
Gravity between Newton and EinsteinApr 11 2019Jun 11 2019Statements about relativistic effects are often subtle. In this essay we will demonstrate that the three classical tests of general relativity, namely perihelion precession, deflection of light and gravitational redshift, are passed perfectly by an extension ... More
Fast Self-forced InspiralsFeb 14 2018Jul 26 2018We present a new, fast method for computing the inspiral trajectory and gravitational waves from extreme mass-ratio inspirals that can incorporate all known (and future) self-force results. Using near-identity (averaging) transformations we formulate ... More
Electronic bandwidth and pinning of Fermi energy to van Hove singularities in twisted bilayer graphene: a self consistent approachJun 25 2019Jun 26 2019The emergence of flat bands in twisted bilayer graphene leads to an enhancement of interaction effects, and thus to insulating and superconducting phases at low temperatures, even though the exact mechanism is still widely debated. The position and splitting ... More
Factorization of the identity through operators with large diagonalSep 10 2015Given a Banach space $X$ with an unconditional basis, we consider the following question: does the identity on $X$ factor through every bounded operator on $X$ with large diagonal relative to the unconditional basis? We show that on Gowers' space with ... More
(Co-)homology of Rees semigroup algebrasJul 26 2010Let $S$ be a Rees semigroup, and let $\ell^1(S)$ be its convolution semigroup algebra. Using Morita equivalence we show that bounded Hochschild homology and cohomology of $\ell^1(S)$ is isomorphic to those of the underlying discrete group algebra.
Heralded dissipative preparation of nonclassical states in a Kerr oscillatorJun 12 2019We present a heralded state preparation scheme for driven nonlinear open quantum systems. The protocol is based on a continuous photon counting measurement of the system's decay channel. When no photons are detected for a period of time, the system has ... More
Mean-Field Dynamics of Fermions with Relativistic DispersionNov 25 2013We extend the derivation of the time-dependent Hartree-Fock equation recently obtained in [2] to fermions with a relativistic dispersion law. The main new ingredient is the propagation of semiclassical commutator bounds along the pseudo-relativistic Hartree-Fock ... More
The relations between volume ratios and new concepts of gl constantsJun 11 1997In this paper we investigate a property named GL(p,q) which is closely related to the Gordon-Lewis property. Our results on GL(p,q) are then used to estimate volume ratios relative to $\ell_p$, $1<p \le\infty$, of unconditional direct sums of Banach spaces. ... More
Liquid-infiltrated photonic crystals - enhanced light-matter interactions for lab-on-a-chip applicationsJul 09 2007Optical techniques are finding widespread use in analytical chemistry for chemical and bio-chemical analysis. During the past decade, there has been an increasing emphasis on miniaturization of chemical analysis systems and naturally this has stimulated ... More
Liquid-infiltrated photonic crystals: Ohmic dissipation and broadening of modesFeb 21 2007The pronounced light-matter interactions in photonic crystals make them interesting as opto-fludic "building blocks" for lab-on-a-chip applications. We show how conducting electrolytes cause dissipation and smearing of the density-of-states, thus altering ... More
Splitting The Gluon?Apr 05 2005Aug 22 2005In the strongly correlated environment of high-temperature cuprate superconductors, the spin and charge degrees of freedom of an electron seem to separate from each other. A similar phenomenon may be present in the strong coupling phase of Yang-Mills ... More
From quantum to classical modelling of radiation reaction: a focus on the radiation spectrumFeb 08 2018Soon available multi petawatt ultra-high-intensity (UHI) lasers will allow us to probe high-amplitude electromagnetic fields interacting with either ultra-relativistic electron beams or hot plasmas in the so-called moderately quantum regime. The correct ... More
In flight performance and first results of FREGATEFeb 28 2002The gamma-ray detector of HETE-2, called FREGATE, has been designed to detect gamma-ray bursts in the energy range [6-400] keV. Its main task is to alert the other instruments of the occurrence of a gamma-ray burst (GRB) and to provide the spectral coverage ... More
A classical statistical model for distributions of escape events in swept-bias Josephson junctionsMar 02 2012We have developed a model for experiments in which the bias current applied to a Josephson junction is slowly increased from zero until the junction switches from its superconducting zero-voltage state, and the bias value at which this occurs is recorded. ... More
Current-induced forces in mesoscopic systems: a scattering matrix approachSep 27 2011Apr 10 2012Nanoelectromechanical systems are characterized by an intimate connection between electronic and mechanical degrees of freedom. Due to the nanoscopic scale, current flowing through the system noticeably impacts the vibrational dynamics of the device, ... More
Renormalization group, dimer-dimer scattering, and three-body forcesNov 24 2009Mar 30 2010We study the ratio between the fermion-fermion scattering length and the dimer-dimer scattering length for systems of nonrelativistic fermions, using the same functional renormalisation technique as previously applied to fermionic matter. We find a strong ... More
Investigation of resonant and transient phenomena in Josephson junction flux qubitsOct 27 2008Feb 18 2009We present an analytical and computational study of resonances and transient responses in a classical Josephson junction system. A theoretical basis for resonances in a superconducting loop with three junctions is presented, outlining both the direct ... More
Current-voltage characteristics of graphene devices: interplay between Zener-Klein tunneling and defectsMar 10 2010We report a theoretical/experimental study of current-voltage characteristics (I-V) of graphene devices near the Dirac point. The I-V can be described by a power law (I \propto V^\alpha, with 1< \alpha <= 1.5). The exponent is higher when the mobility ... More
The distribution of quantum fidelitiesJul 30 2008When applied to different input states, an imperfect quantum operation yields output states with varying fidelities, defined as the absolute square of their overlap with the desired states. We present an expression for the distribution of fidelities for ... More
Simulating Ramsey-Type Fringes in a Pulsed Microwave-Driven Classical Josephson JunctionApr 04 2006Apr 13 2006We present evidence for a close analogy between the nonlinear behavior of a pulsed microwave-driven Josephson junction at low temperature and the experimentally observed behavior of Josephson systems operated below the quantum transition temperature under ... More
Deep Learning for Video Game PlayingAug 25 2017Feb 18 2019In this article, we review recent Deep Learning advances in the context of how they have been applied to play different types of video games such as first-person shooters, arcade games, and real-time strategy games. We analyze the unique requirements ... More
Adaptive Reduced-Order Modeling for Non-Linear Fluid-Structure InteractionFeb 14 2017We present an adaptive reduced-order model for the efficient time-resolved simulation of fluid-structure interaction problems with complex and non-linear deformations. The model is based on repeated linearizations of the structural balance equations. ... More
Synchronization of an optomechanical system to an external driveMar 13 2017May 25 2017Optomechanical systems driven by an effective blue detuned laser can exhibit self-sustained oscillations of the mechanical oscillator. These self-oscillations are a prerequisite for the observation of synchronization. Here, we study the synchronization ... More
Robust quantum optimizer with full connectivitySep 20 2016Quantum phenomena have the potential to speed up the solution of hard optimization problems. For example quantum annealing, based on the quantum tunneling effect, has recently been shown to scale exponentially better with system size as compared with ... More
Varying-coefficient models with isotropic Gaussian process priorsAug 28 2015Oct 14 2015We study learning problems in which the conditional distribution of the output given the input varies as a function of additional task variables. In varying-coefficient models with Gaussian process priors, a Gaussian process generates the functional relationship ... More
Elasticity and mechanical instability of charged lipid bilayers in ionic solutionsJul 14 2014We use coarse-grained Monte Carlo simulations to study the elastic properties of charged membranes in solutions of monovalent and pentavalent counterions. The simulation results of the two cases reveal trends opposite to each other. The bending rigidity ... More
Null-Wave Giant Gravitons from Thermal Spinning Brane ProbesJun 11 2013We construct and analyze thermal spinning giant gravitons in type II/M-theory based on spherically wrapped black branes, using the method of thermal probe branes originating from the blackfold approach. These solutions generalize in different directions ... More
Fidelity of quantum operationsJan 19 2007Feb 05 2007We present a derivation and numerous applications of a compact explicit formula for the average fidelity of a quantum operation on a finite dimensional quantum system. The formula can be applied to averages over particularly relevant subspaces; it is ... More
Mode-locking in driven vortex lattices with transverse ac-drive and random pinningDec 17 2001We find mode-locking steps in simulated current-voltage characteristics of driven vortex lattices with {\it random} pinning when an applied ac-current is {\it perpendicular} to the dc-current. For low frequencies there is mode-locking only above a non-zero ... More
Dynamical ordering in the c-axis in 3D driven vortex latticesFeb 01 2000We present molecular dynamics simulations of driven vortices in layered superconductors in the presence of an external homogeneous force and point disorder. We use a model introduced by J.R.Clem for describing 3D vortex lines as stacks of 2D pancake vortices ... More
Optimal policy design for the sugar taxOct 16 2018Healthy nutrition promotions and regulations have long been regarded as a tool for increasing social welfare. One of the avenues taken in the past decade is sugar consumption regulation by introducing a sugar tax. Such a tax increases the price of extensive ... More
Minimal degree rational curves on real surfacesJun 13 2018We classify real families of minimal degree rational curves that cover an embedded rational surface. A corollary is that if the projective closure of a smooth surface is not biregular isomorphic to the projective closure of the unit-sphere, then the set ... More
Euclidean sums and Hamiltonian products of circles in the 3-sphereJun 08 2013Mar 18 2019We classify the singular loci of surfaces in the 3-sphere that are the pointwise Euclidean sum or Hamiltonian product of circles. Such surfaces are the union of circles in at least two ways. As an application we classify surfaces that are covered by both ... More
Cohomology of G-sheaves in positive characteristicDec 19 2002Apr 13 2003Let X be a noetherian scheme defined over an algebraically closed field of positive characteristic p, and G be a finite group, of order divisible by p, acting on X. We introduce a refinement of the equivariant K-theory of X to take into account the information ... More
Embeddings of homogeneous spaces in prime characteristicsFeb 16 1995Let $G$ be a reductive linear algebraic group. The simplest example of a projective homogeneous $G$-variety in characteristic $p$, not isomorphic to a flag variety, is the divisor $x_0 y_0^p+x_1 y_1^p+x_2 y_2^p=0$ in $P^2\times P^2$, which is $SL_3$ modulo ... More