Results for "T. Hung"

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Beyond Worst-Case Analysis for Joins with MinesweeperFeb 05 2013Mar 28 2014We describe a new algorithm, Minesweeper, that is able to satisfy stronger runtime guarantees than previous join algorithms (colloquially, `beyond worst-case guarantees') for data in indexed search trees. Our first contribution is developing a framework ... More
Non-reciprocal mu-near-zero mode in PT-symmetric magnetic domainsDec 18 2014Apr 29 2015We find that a new type of non-reciprocal modes exist at an interface between two \emph{parity-time} ($\mathcal{PT}$) symmetric magnetic domains (MDs) near the frequency of zero effective permeability. The new mode is non-propagating and purely magnetic ... More
Optimal rates of convergence of matrices with applicationsJul 02 2014We present a systematic study on the linear convergence rates of the powers of (real or complex) matrices. We derive a characterization when the optimal convergence rate is attained. This characterization is given in terms of semi-simpleness of all eigenvalues ... More
Topological Edge Plasmon Modes between Diatomic Chains of NanoparticlesJan 29 2014May 08 2015We study the topological edge plasmon modes between two "diatomic" chains of identical plasmonic nanoparticles. Zak phase for longitudinal plasmon modes in each chain is calculated analytically by solutions of macroscopic Maxwell's equations for particles ... More
Photon Emission Rate Engineering using Graphene Nanodisc CavitiesSep 09 2013Mar 04 2014In this work, we present a systematic study of the plasmon modes in a system of vertically stacked pair of graphene discs. Quasistatic approximation is used to model the eigenmodes of the system. Eigen-response theory is employed to explain the spatial ... More
Topological interface modes in local resonant acoustic systemsDec 12 2017Topological phononic crystals (PCs) are periodic artificial structures which can support nontrivial acoustic topological bands, and their topological properties are linked to the existence of topological edge modes. Most previous studies focused on the ... More
Direct Observation of Valley Coupled Topological Current in MoS$_2$May 15 2018The valley degree of freedom of electrons in two-dimensional transition metal dichalcogenides has been extensively studied by theory, optical and optoelectronic experiments. However, generation and detection of pure valley current without relying on optical ... More
A PTAS for subset TSP in minor-free graphsApr 04 2018We give the first polynomial time approximation scheme for the subset Traveling Salesperson Problem (subset TSP) in $H$-minor-free graphs. Our main technical contribution is a polynomial time algorithm that, given an edge-weighted $H$-minor-free graph ... More
The Gauss map of a free boundary minimal surfaceNov 15 2017In this paper, we study the Gauss map of a free boundary minimal surface. The main theorem asserts that if components of the Gauss map are eigenfunctions of the Jacobi-Steklov operator, then the surface must be rotationally symmetric.
Local well-posedness for the Zakharov system on the background of a line solitonMay 12 2016Mar 21 2018We prove that the Cauchy problem for the two-dimensional Zakharov system is locally well-posed for initial data which are localized perturbations of a line solitary wave. Furthermore, for this Zakharov system, we prove weak convergence to a nonlinear ... More
On Closed Manifolds with Harmonic Weyl CurvatureFeb 03 2016Nov 14 2017We derive point-wise and integral rigidity/gap results for a closed manifold with harmonic Weyl curvature in any dimension. In particular, there is a generalization of Tachibana's theorem for non-negative curvature operator. The key ingredients are new ... More
Melting of Rare-Gas Crystals: Monte Carlo Simulation versus ExperimentsOct 04 2012We study the melting transition in crystals of rare gas Ar, Xe, and Kr by the use of extensive Monte Carlo simulations with the Lennard-Jones potential. The parameters of this potential have been deduced by Bernardes in 1958 from experiments of rare gas ... More
Monte Carlo Simulation of Melting and Lattice Relaxation of the (111) Surface of SilverJan 15 2013It is experimentally observed and theoretically proved that the distance between topmost layers of a metal surface has a contraction. However, well-known potentials such as Lennard-Jones and Morse potentials lead to an expansion of the surface inter-layer ... More
An optimal algorithm for the weighted backup 2-center problem on a treeAug 30 2014Jul 08 2015In this paper, we are concerned with the weighted backup 2-center problem on a tree. The backup 2-center problem is a kind of center facility location problem, in which one is asked to deploy two facilities, with a given probability to fail, in a network. ... More
Global estimates for quasilinear parabolic equations on Reifenberg flat domains and its applications to Riccati type parabolic equations with distributional dataOct 22 2015In this paper, we prove global weighted Lorentz and Lorentz-Morrey estimates for gradients of solutions to the quasilinear parabolic equations: $$u_t-\operatorname{div}(A(x,t,\nabla u))=\operatorname{div}(F),$$ in a bounded domain $\Omega\times (0,T)\subset\mathbb{R}^{N+1}$, ... More
Potential estimates and quasilinear parabolic equations with measure dataMay 11 2014Oct 21 2015In this paper, we study the existence and regularity of the quasilinear parabolic equations: $$u_t-\text{div}(A(x,t,\nabla u))=B(u,\nabla u)+\mu$$ in $\mathbb{R}^{N+1}$, $\mathbb{R}^N\times(0,\infty)$ and a bounded domain $\Omega\times (0,T)\subset\mathbb{R}^{N+1}$. ... More
Linear Convergence of the Douglas-Rachford Method for Two Closed SetsJan 25 2014Feb 19 2015In this paper, we investigate the Douglas-Rachford method for two closed (possibly nonconvex) sets in Euclidean spaces. We show that under certain regularity conditions, the Douglas-Rachford method converges locally with R-linear rate. In convex settings, ... More
Tight closure of parameter ideals in local rings $F$-rational on the punctured spectrumApr 03 2017May 10 2017Let $(R, \mathfrak{m}, k)$ be an excellent equidimensional local ring of characteristic $p>0$. The aim of this paper is to show that $\ell_R(\mathfrak{q}^*/\mathfrak{q})$ does not depend on the choice of parameter ideal $\mathfrak{q}$ provided $R$ is ... More
Rokhlin dimension of Z^m actions on simple C*-algebrasAug 03 2016Nov 15 2017We study Rokhlin dimension of Z^m-actions on simple separable stably finite nuclear C*-algebras. We prove that under suitable assumptions, a strongly outer Z^m-action has finite Rokhlin dimension. This extends the known result for automorphisms. As an ... More
Finite groups whose prime graphs are regularJul 05 2013Aug 23 2013Let G be a finite group and let Irr(G) be the set of all irreducible complex characters of G. Let cd(G) be the set of all character degrees of G and denote by \rho(G) the set of primes which divide some character degrees of G. The prime graph \Delta(G) ... More
Complete manifolds with bounded curvature and spectral gapsOct 16 2015Nov 14 2017We study the spectrum of complete noncompact manifolds with bounded curvature and positive injectivity radius. We give general conditions which imply that their essential spectrum has an arbitrarily large finite number of gaps. In particular, for any ... More
Groups whose prime graphs have no trianglesMar 14 2013Let G be a finite group and let cd(G) be the set of all complex irreducible character degrees of G Let \rho(G) be the set of all primes which divide some character degree of G. The prime graph \Delta(G) attached to G is a graph whose vertex set is \rho(G) ... More
Einstein four-manifolds of pinched sectional curvatureDec 19 2016In this paper, we obtain classification of four-dimensional Einstein manifolds with positive Ricci curvature and pinched sectional curvature. In particular, the first result concerns with an upper bound of sectional curvature, improving a theorem of E. ... More
Gradient estimates for singular quasilinear elliptic equations with measure dataMay 21 2017May 25 2017In this paper, we prove $L^q$-estimates for gradients of solutions to singular quasilinear elliptic equations with measure data $$-\operatorname{div}(A(x,\nabla u))=\mu,$$ in a bounded domain $\Omega\subset\mathbb{R}^{N}$, where $A(x,\nabla u)\nabla u ... More
Gradient weighted norm inequalities for very weak solutions of linear parabolic equations with BMO coefficientsMay 21 2017In this paper, we prove the Lorentz space $L^{q,p}$-estimates for gradients of very weak solutions to the linear parabolic equations with $\mathbf{A}_q$-weights $$u_t-\operatorname{div}(A(x,t)\nabla u)=\operatorname{div}(F),$$ in a bounded domain $\Omega\times ... More
k-Mixing Properties of Multidimensional Cellular AutomataOct 08 2014Aug 03 2015This paper investigates the $k$-mixing property of a multidimensional cellular automaton. Suppose $F$ is a cellular automaton with the local rule $f$ defined on a $d$-dimensional convex hull $\mathcal{C}$ which is generated by an apex set $C$. Then $F$ ... More
Four-manifolds of Pinched Sectional CurvatureSep 13 2018In this paper, we study closed four-dimensional manifolds. In particular, we show that under various new pinching curvature conditions (for example, the sectional curvature is no more than 5/6 of the smallest Ricci eigenvalue) then the manifold is definite. ... More
Some results on local cohomology of polynomial and formal power series rings: the one dimensional caseJul 09 2015Aug 03 2016In this paper, we prove several results on the finiteness of local cohomology of polynomial and formal power series rings. In particular, we give a partial affirmative answer for a question of L. N\'{u}\~{n}ez-Betancourt in [J. Algebra 399 (2014), 770--781]. ... More
When Sets Are Not Sum-dominantMar 08 2019Given a set $A$ of nonnegative integers, define the sum set $A+A = \{a_i+a_j|a_i,a_j\in A\}$ and the difference set $A-A = \{a_i-a_j|a_i,a_j\in A\}$. The set $A$ is said to be sum-dominant if $|A+A|>|A-A|$. In answering a question by Nathanson, Hegarty ... More
An upper bound on the fractional chromatic number of triangle-free subcubic graphsNov 18 2012May 16 2014An $(a:b)$-coloring of a graph $G$ is a function $f$ which maps the vertices of $G$ into $b$-element subsets of some set of size $a$ in such a way that $f(u)$ is disjoint from $f(v)$ for every two adjacent vertices $u$ and $v$ in $G$. The fractional chromatic ... More
Rokhlin dimension of Z^m actions on simple C*-algebrasAug 03 2016We study Rokhlin dimension of Z^m-actions on simple separable stably finite nuclear C*-algebras. We prove that under suitable assumptions, a strongly outer Z^m-action has finite Rokhlin dimension. This extends the known result for automorphisms. As an ... More
On $r$-Equitable Coloring of Complete Multipartite GraphsNov 19 2012Aug 07 2013Let $r \geqslant 0$ and $k \geqslant 1$ be integers. We say that a graph $G$ has an $r$-equitable $k$-coloring if there exists a proper $k$-coloring of $G$ such that the sizes of any two color classes differ by at most $r$. The least $k$ such that a graph ... More
Copula Variational Bayes inference via information geometryMar 29 2018Variational Bayes (VB), also known as independent mean-field approximation, has become a popular method for Bayesian network inference in recent years. Its application is vast, e.g. in neural network, compressed sensing, clustering, etc. to name just ... More
Uniform bounds for rational points on complete intersections of two quadric surfacesMar 19 2017We give uniform upper bounds for the number of rational points of height at most $B$ on non-singular complete intersections of two quadrics in $\mathbb{P}^3$ defined over $\mathbb{Q}$. To do this, we combine determinant methods with descent arguments. ... More
Mean Value Inequalities and Conditions to Extend Ricci FlowMar 19 2013This paper concerns conditions related to the first finite singularity time of a Ricci flow solution on a closed manifold. In particular, we provide a systematic approach to the mean value inequality method, suggested by N. Le and F. He. We also display ... More
Persistence versus extinction under a climate change in mixed environmentsDec 02 2014Sep 23 2015This paper is devoted to the study of the persistence versus extinction of species in the reaction-diffusion equation: \begin{equation} u_t-\Delta u=f(t,x_1-ct,y,u) \quad\quad t>0,\ x\in\Omega,\nonumber \end{equation} where $\Omega$ is of cylindrical ... More
The Weyl Tensor of Gradient Ricci SolitonsNov 04 2013This paper derives new identities for the Weyl tensor on a gradient Ricci soliton, particularly in dimension four. First, we prove a Bochner-Weitzenb\"ock type formula for the norm of the self-dual Weyl tensor and discuss its applications, including connections ... More
Analytical study of the plasmonic modes of metal nanoparticle circular arrayDec 28 2007We analyze the plasmonic modes of a metal nanoparticle circular array. Closed form solutions to the eigenmode problem are given. For each polarization, the plasmonic mode with the highest quality is found to be an antiphase mode. We found that the significant ... More
Optical response of metal nanoparticle chainsMay 02 2006We study the optical responses of metal nanoparticle chains. Multiple scattering calculations are used to study the extinction cross sections of silver nanosphere chains of finite length embedded in a glass matrix. The transmission and reflection coefficients ... More
Designing ferromagnetism in vanadium-oxide based superlatticesMar 16 2013Jun 02 2013Motivated by recent reports (Phys. Rev. B\textbf{80}, 241102) of room-temperature ferromagnetism in vanadium-oxide based superlattices, a single-site dynamical mean field study of the dependence of the paramagnetic-ferromagnetic phase boundary on superlattice ... More
Plasmonic modes in periodic metal nanoparticle chains: A direct dynamic eigenmode analysisOct 30 2006We demonstrate an efficient eigen-decomposition method for analyzing the guided modes in metal nanoparticle chains. The proposed method has the advantage of showing the dispersion relation and mode quality simultaneously. It can also separate the material ... More
Phase Transition in Dimer LiquidsSep 05 2013We study the phase transition in a system composed of dimers interacting with each other via a nearest-neighbor (NN) exchange $J$ and competing interactions taken from a truncated dipolar coupling. Each dimer occupies a link between two nearest sites ... More
A Model of Low-lying States in Strongly Interacting Electroweak Symmetry-Breaking SectorDec 01 1994Apr 19 1996It is proposed that, in a strongly-interacting electroweak sector, besides the Goldstone bosons, the coexistence of a scalar state ($H$) and vector resonances such as $A_1$ [$I^G(J^P)=1^-(1^+$)], $V$ [$1^+(1^-)$] and $\omega_H^{}$ [$0^-(1^-)$] is required ... More
Theory of ferromagnetism in vanadium-oxide based perovskitesFeb 13 2013May 02 2013The conditions under which ferromagnetism may occur in transition metal oxides with partially filled $t_{2g}$ shells such as vanadium-based perovskites are studied using a combination of density functional and single-site dynamical mean field methods. ... More
Lepton acceleration in the vicinity of the event horizon: High-energy and Very-high-energy emissions from rotating black holes with various massesOct 25 2016We investigate the electrostatic acceleration of electrons and positrons in the vicinity of the event horizon, applying the pulsar outer-gap model to black hole magnetospheres. During a low accretion phase, the radiatively inefficient accretion flow (RIAF) ... More
Searching for High Energy, Horizon-scale Emissions from Galactic Black Hole Transients during QuiescenceJul 27 2017We search for the gamma-ray counterparts of stellar-mass black holes using long-term Fermi archive to investigate the electrostatic acceleration of electrons and positrons in the vicinity of the event horizon, by applying the pulsar outer-gap model to ... More
A Two-Stage Dimension Reduction Method for Induced Responses and Its ApplicationsMar 16 2012Researchers in the biological sciences nowadays often encounter the curse of high-dimensionality, which many previously developed statistical models fail to overcome. To tackle this problem, sufficient dimension reduction aims to estimate the central ... More
Sphaleron transition rate at high temperature in the 1+1 D abelian Higgs modelDec 02 1994New results for the rate are presented using the canonical ensemble in the classical approximation on a spatial lattice. We find that the rate at high temperatures is proportional to $T^2$, and strongly dependent on the lattice spacing $a$. We conclude ... More
Inverse Mean Curvature Flow with SingularitiesNov 11 2018Feb 26 2019This paper concerns the inverse mean curvature flow of convex hypersurfaces which are Lipschitz in general. After defining a weak solution, we study the evolution of the singularity by looking at the blow-up tangent cone around each singular point. We ... More
3-dimensional Griess algebras and Miyamoto involutionsApr 15 2016We consider a series of VOAs generated by 3-dimensional Griess algebras. We will show that these VOAs can be characterized by their 3-dimensional Griess algebras and their structures are uniquely determined. As an application, we will determine the groups ... More
On the structure of framed vertex operator algebras and their pointwise frame stabilizersMay 07 2006Feb 09 2010In this paper, we study the structure of a general framed vertex operator algebra. We show that the structure codes (C,D) of a framed VOA V satisfy certain duality conditions. As a consequence, we prove that every framed VOA is a simple current extension ... More
Hopf algebras of prime dimension in positive characteristicSep 30 2018Feb 19 2019We prove that a Hopf algebra of prime dimension $p$ over an algebraically closed field, whose characteristic is equal to $p$, is either a group algebra or a restricted universal enveloping algebra. Moreover, we show that any Hopf algebra of prime dimension ... More
Robust mislabel logistic regression without modeling mislabel probabilitiesAug 16 2016Logistic regression is among the most widely used statistical methods for linear discriminant analysis. In many applications, we only observe possibly mislabeled responses. Fitting a conventional logistic regression can then lead to biased estimation. ... More
Ground State Degeneracy of Topological Phases on Open SurfacesJul 31 2014Feb 22 2015We relate the ground state degeneracy (GSD) of a non-Abelian topological phase on a surface with boundaries to the anyon condensates that break the topological phase to a trivial phase. Specifically, we propose that gapped boundary conditions of the surface ... More
Linear colorings of subcubic graphsJun 23 2012Feb 23 2013A linear coloring of a graph is a proper coloring of the vertices of the graph so that each pair of color classes induce a union of disjoint paths. In this paper, we prove that for every connected graph with maximum degree at most three and every assignment ... More
Variations of Landau's theorem for p-regular and p-singular conjugacy classesAug 04 2013Mar 26 2015The well-known Landau's theorem states that, for any positive integer $k$, there are finitely many isomorphism classes of finite groups with exactly $k$ (conjugacy) classes. We study variations of this theorem for $p$-regular classes as well as $p$-singular ... More
The Conway-Miyamoto correspondences for the Fischer 3-transposition groupsApr 18 2016In this paper, we present a general construction of 3-transposition groups as automorphism groups of vertex operator algebras. Applying to the moonshine vertex operator algebra, we establish the Conway-Miyamoto correspondences between Fischer 3-transposition ... More
Gauge invariants from the powers of antipodesSep 04 2016We prove that the trace of the $n$th power of the antipode of a Hopf algebra with the Chevalley property is a gauge invariant, for each integer $n$. As a consequence, the order of the antipode, and its square, are invariant under Drinfeld twists. The ... More
Reversibility Problem of Multidimensional Finite Cellular AutomataSep 30 2016Apr 05 2017While the reversibility of multidimensional cellular automata is undecidable and there exists a criterion for determining if a multidimensional linear cellular automaton is reversible, there are only a few results about the reversibility problem of multidimensional ... More
Generalized Twisted Quantum Doubles of a Finite Group and Rational OrbifoldsMar 19 2017In previous work the authors introduced a new class of modular quasi-Hopf algebras $D^{\omega}(G, A)$ associated to a finite group $G$, a central subgroup $A$, and a $3$-cocycle $\omega\in Z^3(G, C^x)$. In the present paper we propose a description of ... More
Generalized ADE Classification of Gapped Domain WallsFeb 06 2015Feb 22 2015In this paper we would like to demonstrate how the known rules of anyon condensation motivated physically proposed by Bais \textit{et al} can be recovered by the mathematics of twist-free commutative separable Frobenius algebra (CSFA). In some simple ... More
String-Net Models with $Z_N$ Fusion AlgebraJul 26 2012Dec 19 2012We study the Levin-Wen string-net model with a $Z_N$ type fusion algebra. Solutions of the local constraints of this model correspond to $Z_N$ gauge theory and double Chern-simons theories with quantum groups. For the first time, we explicitly construct ... More
On the exit distribution of partially reflected Brownian motion in planar domainsJul 08 2010We show that the dimension of the exit distribution of planar partially reflected Brownian motion can be arbitrarily close to 2.
On 1-loop diagrams in AdS space and the random disorder problemJul 15 2010Sep 22 2010We study the complex scalar loop corrections to the boundary-boundary gauge two point function in pure AdS space in Poincare coordinates, in the presence of a boundary quadratic perturbation to the scalar. These perturbations correspond to double trace ... More
Reconstructing the energy landscape of a distribution from Monte Carlo samplesJan 26 2009Defining the energy function as the negative logarithm of the density, we explore the energy landscape of a distribution via the tree of sublevel sets of its energy. This tree represents the hierarchy among the connected components of the sublevel sets. ... More
Equation of State, Radial Flow and Freeze-out in High Energy Heavy Ion CollisionsSep 05 1997We have shown that recent experimental data on radial flow, both from AGS and SPS energies, are in agreement with the Equation of State (EOS) including the QCD phase transition. New hydro-kinetic model (HKM) is developed, which incorporates hydrodynamical ... More
Low Rank Matrix Recovery for Joint Array Self-Calibration and Sparse Model DoA EstimationDec 16 2017In this work, combined calibration and DoA estimation is approached as an extension of the formulation for the Single Measurement Vector (SMV) model of self-calibration to the Multiple Measurement Model (MMV) case. By taking advantage of multiple snapshots, ... More
In situ imaging of atomic quantum gasesDec 02 2013May 07 2014One exciting progress in recent cold atom experiments is the development of high resolution, in situ imaging techniques for atomic quantum gases [1-3]. These new powerful tools provide detailed information on the distribution of atoms in a trap with resolution ... More
Critically fast pick-and-place with suction cupsSep 10 2018Mar 03 2019Fast robotics pick-and-place with suction cups is a crucial component in the current development of automation in logistics (factory lines, e-commerce, etc.). By "critically fast" we mean the fastest possible movement for transporting an object such that ... More
A New Approach to Time-Optimal Path Parameterization based on Reachability AnalysisJul 23 2017Nov 22 2017Time-Optimal Path Parameterization (TOPP) is a well-studied problem in robotics and has a wide range of applications. There are two main families of methods to address TOPP: Numerical Integration (NI) and Convex Optimization (CO). NI-based methods are ... More
Zeros of quadratic Dirichlet $L$-functions in the hyperelliptic ensembleMay 23 2016We study the $1$-level density and the pair correlation of zeros of quadratic Dirichlet $L$-functions in function fields, as we average over the ensemble $\mathcal{H}_{2g+1}$ of monic, square-free polynomials with coefficients in $\mathbb{F}_q[x]$. In ... More
On uniqueness sets of additive eigenvalue problems and applicationsJan 16 2018In this paper, we provide a simple way to find uniqueness sets for additive eigenvalue problems of first and second order Hamilton--Jacobi equations by using a PDE approach. An application in finding the limiting profiles for large time behaviors of first ... More
Stop-and-Stare: Optimal Sampling Algorithms for Viral Marketing in Billion-scale NetworksMay 25 2016Sep 07 2016Influence Maximization (IM), that seeks a small set of key users who spread the influence widely into the network, is a core problem in multiple domains. It finds applications in viral marketing, epidemic control, and assessing cascading failures within ... More
Charge-induced electrochemical actuation of armchair carbon nanotube bundlesDec 06 2016The effects of charge doping on the structural deformation and on the electronic structure of armchair single wall carbon nanotube (SWNT) bundles are investigated through first-principles calculations. In particular, we select a (6; 6) SWNT as an example ... More
Stop-and-Stare: Optimal Sampling Algorithms for Viral Marketing in Billion-scale NetworksMay 25 2016Feb 22 2017Influence Maximization (IM), that seeks a small set of key users who spread the influence widely into the network, is a core problem in multiple domains. It finds applications in viral marketing, epidemic control, and assessing cascading failures within ... More
Insulator, semiclassical oscillations and quantum Hall liquids at low magnetic fieldsSep 13 2012Magneto-transport measurements are performed on two-dimensional GaAs electron systems to probe the quantum Hall (QH) effect at low magnetic fields. Oscillations following the Shubnikov-de Haas (SdH) formula are observed in the transition from the insulator ... More
One loop contributions to neutral Higgs decay h-->mu tauMay 23 2016In calculating one-loop contributions to amplitudes of the lepton flavor violating decays of the neutral Higgses (LFVHD) to different flavor charged leptons, the analytic expressions can be written in term of Passarino-Veltman (PV) functions. Then, they ... More
One loop contributions to neutral Higgs decay h-->mu tauMay 23 2016Oct 27 2016In calculating one-loop contributions to amplitudes of the lepton-flavor violating decays of the neutral Higgses (LFVHD) to different flavor charged leptons, the analytic expressions can be written in term of Passarino-Veltman functions. Then, they can ... More
Probing temperature-driven flow lines in a gated two-dimensional electron gas with tunable spin-splittingSep 05 2012We study the temperature flow of conductivities in a gated GaAs two-dimensional electron gas (2DEG) containing self-assembled InAs dots and compare the results with recent theoretical predictions. By changing the gate voltage, we are able to tune the ... More
Probing onset of strong localization and electron-electron interactions with the presence of direct insulator-quantum Hall transitionApr 29 2010We have performed low-temperature transport measurements on a disordered two-dimensional electron system (2DES). Features of the strong localization leading to the quantum Hall effect are observed after the 2DES undergoes a direct insulator-quantum Hall ... More
General formula for symmetry factors of Feynman diagramsNov 18 2010Mar 23 2012General formula for symmetry factors (S-factor) of Feynman diagrams containing fields with high spins is derived. We prove that symmetry factors of Feynman diagrams of well-known theories do not depend on spins of fields. In contributions to S-factors, ... More
3-3-1-1 model for dark matterMay 02 2013May 21 2013We show that the SU(3)_C X SU(3)_L X U(1)_X (3-3-1) model of strong and electroweak interactions can naturally accommodate an extra U(1)_N symmetry behaving as a gauge symmetry. Resulting theory based on SU(3)_C X SU(3)_L X U(1)_X X U(1)_N (3-3-1-1) gauge ... 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
Comparison of various image fusion methods for impervious surface classification from VNREDSat-1Mar 06 2018May 04 2018Impervious surface is an important indicator for urban development monitoring. Accurate urban impervious surfaces mapping with VNREDSat-1 remains challenging due to their spectral diversity not captured by individual PAN image. In this artical, five multi-resolution ... More
Improved treatment of blocking effect at finite temperatureAug 11 2016Sep 01 2016The blocking effect caused by the odd particle on the pairing properties of systems with odd number of fermions at finite temperature interacting via the monopole pairing force is studied within several approximations. The results are compared with the ... More
Higher Order City Voronoi DiagramsApr 19 2012We investigate higher-order Voronoi diagrams in the city metric. This metric is induced by quickest paths in the L1 metric in the presence of an accelerating transportation network of axis-parallel line segments. For the structural complexity of kth-order ... More
A weighted combination similarity measure for mobility patterns in wireless networksJun 07 2012The similarity between trajectory patterns in clustering has played an important role in discovering movement behaviour of different groups of mobile objects. Several approaches have been proposed to measure the similarity between sequences in trajectory ... More
Collective plasmonic modes of metal nano-particles in two-dimensional periodic regular arraysJan 07 2008We investigate the collective plasmonic modes of metal nano-particles in periodic two-dimensional (2D) arrays within a point-dipole description. As an open system, the full-dynamic dispersion relations of the 2D arrays are obtained through an efficient ... More
Negative group velocity in layer-by-layer chiral photonic crystalsNov 10 2008We study the group velocity of light in layer-by-layer chiral photonic crystals composed of dielectrics and metals. Through studying the band structures with an extended-zone scheme that is given by a Fourier analysis, we show the existence of negative ... More
Sequential tunneling and shot noise in ferromagnet/normal-metal/ferromagnet double tunnel junctionsJan 06 2007The tunneling through a ferromagnet/normal metal/ferromagnet double junction in the Coulomb blockade regime is studied, assuming that the spin relaxation time of electron in the central metallic island is sufficiently large. Using the master equation, ... More
Towards Optimal Strategy for Adaptive Probing in Incomplete NetworksFeb 05 2017We investigate a graph probing problem in which an agent has only an incomplete view $G' \subsetneq G$ of the network and wishes to explore the network with least effort. In each step, the agent selects a node $u$ in $G'$ to probe. After probing $u$, ... More
Blocking Self-avoiding Walks Stops Cyber-epidemics: A Scalable GPU-based ApproachFeb 20 2017Feb 21 2017Cyber-epidemics, the widespread of fake news or propaganda through social media, can cause devastating economic and political consequences. A common countermeasure against cyber-epidemics is to disable a small subset of suspected social connections or ... More
Meson-exchange $πN$ Models in Three-Dimensional Bethe-Salpeter FormulationDec 31 2000Jan 28 2001The pion-nucleon scattering is investigated by using several three-dimensional reduction schemes of the Bethe-Salpeter equation for a model Lagrangian involving $\pi$, $N$, $\Delta$, $\rho$, and $\sigma$ fields. It is found that all of the resulting meson-exchange ... More
"Cultural additivity" and how the values and norms of Confucianism, Buddhism, and Taoism co-exist, interact, and influence Vietnamese society: A Bayesian analysis of long-standing folktales, using R and StanMar 05 2018Every year, the Vietnamese people reportedly burned about 50,000 tons of joss papers, which took the form of not only bank notes, but iPhones, cars, clothes, even housekeepers, in hope of pleasing the dead. The practice was mistakenly attributed to traditional ... More
Theory of charged impurities in correlated electron materials: Application to muon spectroscopy of high-Tc superconductorsApr 29 2010Jun 23 2010Single-site and cluster dynamical mean-field methods are used to estimate the response of a doped Mott insulator to a charged impurity. The effect of correlations on the Thomas-Fermi screening properties is determined. The charge density, the on-site ... More
Complex band structure and plasmon lattice Green's function of a periodic metal-nanoparticle chainJan 07 2009Jan 09 2009When the surface plasmon resonance in a metal-nanoparticle chain is excited at one point, the response signal will generally decay down the chain due to absorption and radiation losses. The decay length is a key parameter in such plasmonic systems. By ... More
Magnetic Properties of Two-dimensional Nanodots: Ground State and Phase TransitionSep 29 2013We study the effect of perpendicular single-ion anisotropy, $-As_{\text{z}}^2$, on the ground-state structure and finite-temperature properties of a two-dimensional magnetic nanodot in presence of a dipolar interaction of strength $D$. By a simulated ... More
Ferromagnetism and correlation strength in cubic barium ruthenate in comparison to strontium and calcium ruthenate: a dynamical mean field studyDec 22 2015We present density functional plus dynamical mean field studies of cubic BaRuO$_3$ using interaction parameters previously found to be appropriate for the related materials CaRuO$_3$ and SrRuO$_3$. The calculated variation in transition temperature between ... More
Time Monitoring of Radio Jets and Magnetospheres in the Nearby Young Stellar Cluster R Coronae AustralisNov 19 2013We report JVLA 8-10 GHz ($\lambda$=3.0-3.7 cm) monitoring observations toward the YSO cluster R Coronae Australis (R\,CrA), taken in 2012, from March 15 to September 12. These observations were planned to measure the radio flux variabilities in timescales ... More
Probing Landau quantisation with the presence of insulator-quantum Hall transition in a GaAs two-dimensional electron systemFeb 11 2008Magneto-transport measurements are performed on the two-dimensional electron system (2DES) in an AlGaAs/GaAs heterostructure. By increasing the magnetic field perpendicular to the 2DES, magnetoresistivity oscillations due to Landau quantisation can be ... More