Results for "T. Hung"

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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
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
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
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
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
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
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
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
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
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
The $(1|1)_R$-Centroid Problem on the PlaneAug 12 2016In 1982, Drezner proposed the (1|1)-centroid problem on the plane, in which two players, called the leader and the follower, open facilities to provide service to customers in a competitive manner. The leader opens the first facility, and then the follower ... More
Negative Group Velocity from Quadrupole Resonance of Plasmonic SpheresDec 15 2008We study the dispersions of plasmonic bands that arise from the coupling of electric quadrupole resonances in three dimensional photonic crystals (PCs) consisting of plasmonic spheres. Through analytical derivation, we show that two branches of quadrupole ... More
New two-dimensional phase of tin chalcogenides: candidates for high-performance thermoelectric materialsJan 02 2019Tin-chalcogenides SnX (X = Te, Se and S) have been arousing research interest due to their thermoelectric physical properties. The two-dimensional (2D) counterparts, which are expected to enhance the property, nevertheless, have not been fully explored ... More
Density functional plus dynamical mean field theory of the metal-insulator transition in early transition metal oxidesJul 24 2014Sep 24 2014The combination of density functional theory and single-site dynamical mean-field theory, using both Hartree and full continuous-time quantum Monte Carlo impurity solvers, is used to study the metal-insulator phase diagram of perovskite transition-metal ... More
A correlated Anderson insulator on the honeycomb latticeOct 31 2016We study the effect of disorder on the semimetal -- Mott insulator transition in the half-filled repulsive Hubbard model on a honeycomb lattice, a system that features vanishing density of states at the Fermi level. Using the determinant quantum Monte ... More
Localization characteristics of two-dimensional quasicrystals consisting of metal nanoparticlesFeb 27 2009Sep 03 2009Using the eigen-decomposition method, we investigated the plasmonic modes in a two-dimensional quasicrystalline array of metal nanoparticles. Various properties of the plasmonic modes, such as their symmetry, radiation loss and spatial localization are ... More
Current-Driven Magnetic Memory with Tunable Magnetization SwitchingMay 15 2001Co(x nm, x=10nm or 40nm)/Cu(5nm)/Co(2.5nm) layers were deposited between copper electrodes in SiO2 vias. Magnetic states, and the corresponding resistance states, of these devices were switched by electric currents perpendicular to the layers. The I-V ... More
Outward Influence and Cascade Size Estimation in Billion-scale NetworksApr 16 2017Estimating cascade size and nodes' influence is a fundamental task in social, technological, and biological networks. Yet this task is extremely challenging due to the sheer size and the structural heterogeneity of networks. We investigate a new influence ... 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
Mott transition in the triangular lattice Hubbard model: a dynamical cluster approximation studyNov 27 2014Apr 02 2015Based on dynamical cluster approximation (DCA) quantum Monte Carlo simulations, we study the interaction-driven Mott metal-insulator transition (MIT) in the half-filled Hubbard model on the anisotropic two-dimensional triangular lattice, where the degree ... 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
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
Transitivity Demolition and the Falls of Social NetworksFeb 05 2017In this paper, we study crucial elements of a complex network, namely its nodes and connections, which play a key role in maintaining the network's structure and function under unexpected structural perturbations of nodes and edges removal. Specifically, ... More
Harnack Estimates for Ricci Flow on a Warped ProductNov 27 2012In this paper, we study the Ricci flow on closed manifolds equipped with warped product metric $(N\times F,g_{N}+f^2 g_{F})$ with $(F,g_{F})$ Ricci flat. Using the framework of monotone formulas, we derive several estimates for the adapted heat conjugate ... More
Elliptic equations with transmission and Wentzell boundary conditions and an application to steady water waves in the presence of windJun 12 2017Jan 23 2018In this paper, we present results about the existence and uniqueness of solutions of elliptic equations with transmission and Wentzell boundary conditions. We provide Schauder estimates and existence results in H\"older spaces. As an application, we develop ... More
A better bound on the largest induced forests in triangle-free planar graphsNov 14 2016Jan 26 2017It is well-known that there exists a triangle-free planar graph of $n$ verticess such that the largest induced forest has size at most $\frac{5n}{8}$. Salavatipour proved that there is a forest of size at least $\frac{5n}{9.41}$ in any triangle-free planar ... 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.
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
On the existence and instability of solitary water waves with a finite dipoleDec 08 2018This paper considers the existence and stability properties of two-dimensional solitary waves traversing an infinitely deep body of water. We assume that above the water is vacuum, and that the waves are acted upon by gravity with surface tension effects ... More
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
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
Chiral microstructures (spirals) fabrication by holographic lithographyAug 02 2005Sep 06 2005We present an optical interference model to create chiral microstructures (spirals) and its realization in photoresist using holographic lithography. The model is based on the interference of six equally-spaced circumpolar linear polarized side beams ... 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
Quantitative estimates for regular Lagrangian flows with $BV$ vector fieldsMay 03 2018In this paper, we solve a main open problem mentioned in \cite{AmbCrip}. Specifically, we prove the well posedness of regular Lagrangian flows to vector fields $\mathbf{B}=(\mathbf{B}^1,...,\mathbf{B}^d)\in L^1((0,T);L^1\cap L^\infty(\mathbb{R}^d))$ satisfying ... 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
Characters of p'-degree and Thompson's character degree theoremJun 22 2015A classical theorem of John Thompson on character degrees asserts that if the degree of every ordinary irreducible character of a finite group $G$ is 1 or divisible by a prime $p$, then $G$ has a normal $p$-complement. We obtain a significant improvement ... More
Normal restriction in finite groupsDec 04 2009In this paper, we will prove some sufficient conditions for the solvability of groups.
Improving Temporal Interpolation of Head and Body Pose using Gaussian Process Regression in a Matrix Completion SettingAug 06 2018This paper presents a model for head and body pose estimation (HBPE) when labelled samples are highly sparse. The current state-of-the-art multimodal approach to HBPE utilizes the matrix completion method in a transductive setting to predict pose labels ... More
Uncountable families of prime z-ideals in C_0(R)Jan 01 2008Denote by $\continuum=2^{\aleph_0}$ the cardinal of continuum. We construct an intriguing family $(P_\alpha: \alpha\in\continuum)$ of prime $z$-ideals in $\C_0(\reals)$ with the following properties: If $f\in P_{i_0}$ for some $i_0\in\continuum$, then ... More
Approximating the minimum directed tree coverApr 21 2010Sep 02 2010Given a directed graph $G$ with non negative cost on the arcs, a directed tree cover of $G$ is a rooted directed tree such that either head or tail (or both of them) of every arc in $G$ is touched by $T$. The minimum directed tree cover problem (DTCP) ... More
Truly Optimal Euclidean SpannersApr 26 2019Euclidean spanners are important geometric structures, having found numerous applications over the years. Cornerstone results in this area from the late 80s and early 90s state that for any $d$-dimensional $n$-point Euclidean space, there exists a $(1+\epsilon)$-spanner ... 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
Hopf Algebras of Dimension $pq$Apr 12 2003May 07 2003Let $H$ be a non-semisimple Hopf algebra with antipode $S$ of dimension $pq$ over an algebraically closed field of characteristic 0 where $p \le q$ are odd primes. We prove that $\Tr(S^{2p})=p^2d$ where $d \equiv pq \pmod{4}$. As a consequence, if $p,q$ ... 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
Counting rational points on smooth cubic curvesMay 25 2016Feb 10 2017We use a global version of Heath-Brown's $p-$adic determinant method developed by Salberger to give upper bounds for the number of rational points of height at most $B$ on non-singular cubic curves defined over $\mathbb{Q}$. The bounds are uniform in ... More
Light Spanner and Monotone TreeJul 16 2012In approximation algorithm design, light spanners has applications in graph-metric problems such as metric TSP (the traveling salesman problem). We have developed an efficient algorithm for light spanners in bounded pathwidth graphs, based on an intermediate ... More
Some Constructions of the Golden Ratio in an Arbitrary TriangleApr 02 2019We establish some new constructions of the golden ratio in an arbitrary triangle using symmedians and nine-point circle.
Long Time Existence of the Cross Curvature Flow in 3-Manifolds with Negative Sectional CurvatureAug 23 2016Sep 09 2016Given a closed 3-manifold with an initial Riemannian metric of negative sec- tional curvature, we consider the cross curvature flow an evolution equation of metric on M3. We prove long-time existence of a solution to the cross curvature flow via the maximum ... 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
Rank 3 permutation characters and maximal subgroupsDec 04 2009Feb 23 2011In this paper we classify all maximal subgroups M of a nearly simple primitive rank 3 group G of type L=Omega_{2m+1}(3), m > 3; acting on an L-orbit E of non-singular points of the natural module for L such that 1_P^G <=1_M^G where P is a stabilizer of ... More
Brauer characters and normal Sylow $p$-subgroupsFeb 03 2018Mar 13 2018In this paper, we study some variations of the well-known It\^{o}-Michler theorem for $p$-Brauer characters using various inequalities involving the $p$-Brauer character degrees of finite groups. Several new criteria for the existence of a normal Sylow ... More
Light spanners for bounded treewidth graphs imply light spanners for $H$-minor-free graphsMar 30 2017Grigni and Hung~\cite{GH12} conjectured that H-minor-free graphs have $(1+\epsilon)$-spanners that are light, that is, of weight $g(|H|,\epsilon)$ times the weight of the minimum spanning tree for some function $g$. This conjecture implies the {\em efficient} ... More
Local Search is a PTAS for Feedback Vertex Set in Minor-free GraphsApr 17 2018Given an undirected graph, the Feedback Vertex Set (FVS) problem asks for a minimum set of vertices that hits all the cycles of the graph. Fomin, Lokshtanov, Rauman and Saurabh gave a PTAS for the FVS problem in $H$-minor-free graphs. Their algorithm ... More
Fuzzy Logic in Narrow Sense with HedgesAug 29 2016Classical logic has a serious limitation in that it cannot cope with the issues of vagueness and uncertainty into which fall most modes of human reasoning. In order to provide a foundation for human knowledge representation and reasoning in the presence ... More
An Elementary Approach to a Curious Identity from RamanujanApr 19 2019In his notebooks, Ramanujan wrote the following identity: \begin{equation} \sqrt{2 \left(1 - \frac{1}{3^2}\right) \left(1 - \frac{1}{7^2}\right) \left(1 - \frac{1}{11^2}\right) \left(1 - \frac{1}{19^2}\right)} \ = \ \left(1 + \frac{1}{7}\right) \left(1 ... More
Rank Verification for Exponential FamiliesOct 13 2016Jul 03 2017Many statistical experiments involve comparing multiple population groups. For example, a public opinion poll may ask which of several political candidates commands the most support; a social scientific survey may report the most common of several responses ... 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
On the uniform bound of Frobenius test exponentsApr 02 2018Oct 16 2018In this paper we prove the existence of a uniform bound for Frobenius test exponents for parameter ideals of a local ring $(R, \frak m)$ of prime characteristic in the following cases: (1) $R$ is generalized Cohen-Macaulay. Our proof is much more simpler ... 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
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
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
2-Parts of real class sizesApr 25 2018Aug 16 2018We investigate the structure of finite groups whose non-central real class sizes have the same $2$-part. In particular, we prove that such groups are solvable and have $2$-length one. As a consequence, we show that a finite group is solvable if it has ... More
Real class sizesMar 01 2018In this paper, we study the structures of finite groups using some arithmetic conditions on the sizes of real conjugacy classes. We prove that a finite group is solvable if the prime graph on the real class sizes of the group is disconnected. Moreover, ... 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
Groups with some arithmetic conditions on real class sizesJun 26 2013Let G be a finite group. An element x in G is a real element if x is conjugate to its inverse in G. For x in G, the conjugacy class x^G is said to be a real conjugacy class if every element of x^G is real. We show that if 4 divides no real conjugacy class ... 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
Quasisimple classical groups and their complex group algebrasAug 14 2011Let $H$ be a finite quasisimple classical group, i.e. $H$ is perfect and $S:=H/Z(H)$ is a finite simple classical group. We prove in this paper that, excluding the cases when the simple group $S$ has a very exceptional Schur multiplier such as $\PSL_3(4)$ ... More
Orbifold vertex operator algebras associated with coinvariant lattices of Leech latticeMay 28 2018We prove that the orbifold vertex operator algebra $V_{L_g}^{\hat{g}}$ associated with the coinvariant lattice of a unimodular lattice $L$ and an isometry $g\in O(L)$ has group-like fusion. We also determine their fusion rings and the corresponding quadratic ... 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
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
The kernel and continuity ideals of homomorphisms from C_0(Ω)Jan 01 2008We give a description of the continuity ideals and the kernels of homomorphisms from the algebras of continuous functions on locally compact spaces into Banach algebras.
Optimal dynamic program for r-domination problems over tree decompositionsFeb 03 2015There has been recent progress in showing that the exponential dependence on treewidth in dynamic programming algorithms for solving NP-hard problems are optimal under the Strong Exponential Time Hypothesis (SETH). We extend this work to $r$-domination ... More
On the uniform bound of the index of reducibility of parameter ideals of a module whose polynomial type is at most oneNov 05 2013Let $(R, \frak m)$ be a Noetherian local ring, $M$ a finitely generated $R$-module. The aim of this paper is to prove a uniform formula for the index of reducibility of paprameter ideals of $M$ provided the polynomial type of $M$ is at most one.
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
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
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
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
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
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
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: Very-high-energy emissions from super-massive black holesJun 09 2017Around a rapidly rotating black hole (BH), when the plasma accretion rate is much less than the Eddington rate, the radiatively inefficient accretion flow (RIAF) cannot supply enough MeV photons that are capable of materializing as pairs. In such a charge-starved ... 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
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
The GROWTH Marshal: A Dynamic Science Portal for Time-Domain AstronomyFeb 05 2019We describe a dynamic science portal called the GROWTH Marshal that allows time-domain astronomers to define science programs, program filters to save sources from different discovery streams, co-ordinate follow-up with various robotic or classical telescopes, ... 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
Mapping Unparalleled Clinical Professional and Consumer Languages with Embedding AlignmentJun 25 2018Mapping and translating professional but arcane clinical jargons to consumer language is essential to improve the patient-clinician communication. Researchers have used the existing biomedical ontologies and consumer health vocabulary dictionary to translate ... More
Duality for spherical representations in exceptional theta correspondencesMay 19 2017We study the exceptional theta correspondence for real groups obtained by restricting the minimal representation of the split exceptional group of the type E_n, to a split dual pair where one member is the exceptional group of the type G_2. We prove that ... More
Localization at countably infinitely many prime ideals and applicationsJul 13 2014Mar 06 2015In this paper we present a technical lemma about localization at countable infinitely many prime ideals. We apply this lemma to get many results about the finiteness of associated prime ideals of local cohomology modules.
Rational forms of exceptional dual pairsDec 10 2012Nov 12 2014We show that every exceptional Lie algebra over a number field can be obtained by Tits' construction from an octonion algebra O and a cubic Jordan algebra J. In particular, the exceptional Lie algebra contains a dual pair which is the direct sum of the ... More
On the average character degree of finite groupsSep 01 2013Dec 05 2013We prove that if the average of the degrees of the irreducible characters of a finite group $G$ is less than 16/5, then $G$ is solvable. This solves a conjecture of I.M. Isaacs, M. Loukaki, and the first author. We discuss related questions.
A rigidity result for effective Hamiltonians with $3$-mode periodic potentialsJul 06 2017We continue studying an inverse problem in the theory of periodic homogenization of Hamilton-Jacobi equations proposed in [14]. Let $V_1, V_2 \in C(\mathbb{R}^n)$ be two given potentials which are $\mathbb{Z}^n$-periodic, and $\overline{H}_1, \overline{H}_2$ ... More
The Hamilton-Waterloo Problem for Triangle-Factors and Heptagon-FactorsApr 21 2015Given 2-factors $R$ and $S$ of order $n$, let $r$ and $s$ be nonnegative integers with $r+s=\lfloor \frac{n-1}{2}\rfloor$, the Hamilton-Waterloo problem asks for a 2-factorization of $K_n$ if $n$ is odd, or of $K_n-I$ if $n$ is even, in which $r$ of its ... 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
On the Bernoulli Automorphism of Reversible Linear Cellular AutomataMar 20 2015Sep 22 2015This investigation studies the ergodic properties of reversible linear cellular automata over $\mathbb{Z}_m$ for $m \in \mathbb{N}$. We show that a reversible linear cellular automaton is either a Bernoulli automorphism or non-ergodic. This gives an affirmative ... More
A dynamical approach to the large-time behavior of solutions to weakly coupled systems of Hamilton--Jacobi equationsAug 30 2012Mar 12 2013We investigate the large-time behavior of the value functions of the optimal control problems on the $n$-dimensional torus which appear in the dynamic programming for the system whose states are governed by random changes. From the point of view of the ... More
Idempotents of small normOct 13 2015Let $\Gamma$ be a locally compact group. We answer two questions left open in [7] and [9]: i) For abelian $\Gamma$, we prove that if $\chi_S \in B(\Gamma)$ is an idempotent with norm $\left\|\chi_S \right\| < \frac{4}{3}$, then $S$ is the union of two ... More