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Results for "Haijun Yu"

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On Efficient Second Order Stabilized Semi-Implicit Schemes for the Cahn-Hilliard Phase-Field EquationAug 31 2017May 22 2018Efficient and energy stable high order time marching schemes are very important but not easy to construct for the study of nonlinear phase dynamics. In this paper, we propose and study two linearly stabilized second order semi-implicit schemes for the ... More
Energy Stable Second Order Linear Schemes for the Allen-Cahn Phase-Field EquationJul 06 2018Oct 31 2018Phase-field model is a powerful mathematical tool to study the dynamics of interface and morphology changes in fluid mechanics and material sciences. However, numerically solving a phase field model for a real problem is a challenge task due to the non-convexity ... More
An improved pure source transfer domain decomposition method for Helmholtz equations in unbounded domainMay 22 2015Dec 11 2016We propose an improved pure source transfer domain decomposition method (PSTDDM) for solving the truncated perfectly matched layer (PML) approximation in bounded domain of Helmholtz scattering problem. The method is based on the the source transfer domain ... More
Convergence analysis of a finite element approximation of minimum action methodsOct 10 2017Mar 20 2018In this work, we address the convergence of a finite element approximation of the minimizer of the Freidlin-Wentzell (F-W) action functional for non-gradient dynamical systems perturbed by small noise. The F-W theory of large deviations is a rigorous ... More
An improved pure source transfer domain decomposition method for Helmholtz equations in unbounded domainMay 22 2015Jun 15 2015We propose an improved pure source transfer domain decomposition method (pSTDDM) for solving the truncated perfectly matched layer (PML) approximation in bounded domain of Helmholtz scattering problem. The method is based on the the source transfer domain ... More
Numerical Approximations for a Phase-Field Moving Contact Line Model with Variable Densities and ViscositiesJan 17 2017We consider the numerical approximations of a two-phase hydrodynamics coupled phase-field model that incorporates the variable densities, viscosities and moving contact line boundary conditions. The model is a nonlinear, coupled system that consists of ... More
Preasymptotic error analysis of higher order FEM and CIP-FEM for Helmholtz equation with high wave numberJan 17 2014A preasymptotic error analysis of the finite element method (FEM) and some continuous interior penalty finite element method (CIP-FEM) for Helmholtz equation in two and three dimensions is proposed. $H^1$- and $L^2$- error estimates with explicit dependence ... More
Numerical approximation of elliptic problems with log-normal random coefficientsOct 11 2018In this work, we consider a non-standard preconditioning strategy for the numerical approximation of the classical elliptic equations with log-normal random coefficients. In \cite{Wan_model}, a Wick-type elliptic model was proposed by modeling the random ... More
Application of Bounded Total Variation Denoising in Urban Traffic AnalysisAug 04 2018Feb 25 2019While it is believed that denoising is not always necessary in many big data applications, we show in this paper that denoising is helpful in urban traffic analysis by applying the method of bounded total variation denoising to the urban road traffic ... More
Linear, Second order and Unconditionally Energy Stable schemes for a phase-field moving contact line ModelMar 03 2017In this paper, we consider the numerical approximations for solving a hydrodynamics coupled phase field model consisting of incompressible Navier-Stokes equations with generalized Navier boundary conditions, and the Cahn-Hilliard equation with dynamic ... More
Convergence Analysis of an Unconditionally Energy Stable Linear Crank-Nicolson Scheme for the Cahn-Hilliard EquationOct 09 2017Efficient and unconditionally stable high order time marching schemes are very important but not easy to construct for nonlinear phase dynamics. In this paper, we propose and analysis an efficient stabilized linear Crank-Nicolson scheme for the Cahn-Hilliard ... More
Numerical approximation of elliptic problems with log-normal random coefficientsOct 11 2018Feb 25 2019In this work, we consider a non-standard preconditioning strategy for the numerical approximation of the classical elliptic equations with log-normal random coefficients. In \cite{Wan_model}, a Wick-type elliptic model was proposed by modeling the random ... More
Irreducible modules over Witt algebras $\mathcal{W}_n$ and over $\mathfrak{sl}_{n+1}(\mathbb{C})$Dec 19 2013In this paper, by using the "twisting technique" we obtain a class of new modules $A_b$ over the Witt algebras $\mathcal{W}_n$ from modules $A$ over the Weyl algebras $\mathcal{K}_n$ (of Laurent polynomials) for any $b\in\mathbb{C}$. We give the necessary ... More
Ground-State Entropy of the Random Vertex-Cover ProblemOct 03 2008Mar 17 2009Counting the number of ground states for a spin-glass or NP-complete combinatorial optimization problem is even more difficult than the already hard task of finding a single ground state. In this paper the entropy of minimum vertex-covers of random graphs ... More
Observation of Coulomb gap in the quantum spin Hall candidate single-layer 1T'-WTe$_2$Nov 20 2017The two-dimensional topological insulators (2DTI) host a full gap in the bulk band, induced by spin-orbit coupling (SOC) effect, together with the topologically protected gapless edge states. However, the SOC-induced gap is usually small, and it is challenging ... More
A kind of infinite-dimensional Novikov algebras and its realizationJun 02 2011In this paper, we construct a kind of infinite-dimensional Novikov algebras and give its realization by hyperbolic sine functions and hyperbolic cosine functions.
Better Approximations of High Dimensional Smooth Functions by Deep Neural Networks with Rectified Power UnitsMar 14 2019Deep neural networks with rectified linear units (ReLU) get very popular recently due to its universal representation power and successful applications. In this paper, we show that deep networks with rectified power units (RePU) can give better approximations ... More
Quasi-potential Calculation and Minimum Action Method for Limit CycleJun 11 2018We study the noise-induced escape from a stable limit cycle of a non-gradient dynamical system driven by a small additive noise. The fact that the optimal transition path in this case is infinitely long imposes a severe numerical challenge to resolve ... More
On energy dissipation theory and numerical stability for time-fractional phase field equationsAug 04 2018For the time-fractional phase field models, the corresponding energy dissipation law has not been settled on both the continuous level and the discrete level. In this work, we shall address this open issue. More precisely, we prove for the first time ... More
Superconvergence analysis of linear FEM based on the polynomial preserving recovery and Richardson extrapolation for Helmholtz equation with high wave numberMar 01 2017We study superconvergence property of the linear finite element method with the polynomial preserving recovery (PPR) and Richardson extrapolation for the two dimensional Helmholtz equation. The $H^1$-error estimate with explicit dependence on the wave ... More
A novel linear complementarity approach for analysis of sliding cable with frictionsSep 15 2018Sliding cable system with frictions is encountered in many engineering applications. Such system is typically characterized by existences of complex and varied motion states of different sliding nodes (pulleys), which leads to significant difficulties ... More
Core percolation on complex networksJun 12 2012Jun 15 2012As a fundamental structural transition in complex networks, core percolation is related to a wide range of important problems. Yet, previous theoretical studies of core percolation have been focusing on the classical Erd\H{o}s-R\'enyi random networks ... More
On the high energy spin excitations in the high temperature superconductors: an RVB theoryMay 21 2013The high energy spin excitation in the high T$_{c}$ cuprates is studied in the single mode approximation for the $t-t'-J$ model. An exact form for the mode dispersion is derived. When the Gutzwiller projected BCS state is used as the variational ground ... More
Finite-orbit-width effects on the geodesic acoustic mode in the toroidally rotating tokamak plasmaNov 16 2016The Landau damping of geodesic acoustic mode (GAM) in a torodial rotating tokamak plasma is analytically investigated by taking into account the finite-orbit-width (FOW) resonance effect to the 3rd order. The analytical result is shown to agree well with ... More
Temporal Action Detection by Joint Identification-VerificationOct 19 2018Temporal action detection aims at not only recognizing action category but also detecting start time and end time for each action instance in an untrimmed video. The key challenge of this task is to accurately classify the action and determine the temporal ... More
Boltzmann distribution of free energies in a finite-connectivity spin-glass system and the cavity approachOct 06 2007At sufficiently low temperatures, the configurational phase space of a large spin-glass system breaks into many separated domains, each of which is referred to as a macroscopic state. The system is able to visit all spin configurations of the same macroscopic ... More
Temperature- and Force-Induced beta-Sheet Unfolding in an Exactly Solvable ModelDec 06 2001Mar 18 2002The stability of a $\beta$-sheeted conformation and its transition into a random coil are studied with a 2D lattice biopolymer model. At low temperature and low external force, the polymer folds back and forth on itself and forms a $\beta$-sheet. Our ... More
Pattern formation in vortex matter with pinning and frustrated inter-vortex interactionsApr 01 2017We investigate the effects related to vortex core deformations when vortices approach each other. As a result of these vortex core deformations, the vortex-vortex interaction effectively acquires an attractive component leading to a variety of vortex ... More
Downlink Energy Efficiency of Power Allocation and Wireless Backhaul Bandwidth Allocation in Heterogeneous Small Cell NetworksOct 09 2017The widespread application of wireless services and dense devices access have triggered huge energy consumption. Because of the environmental and financial considerations, energy-efficient design in wireless networks becomes an inevitable trend. To the ... More
Solution space heterogeneity of the random K-satisfiability problem: Theory and simulationsJan 18 2010Jul 02 2010The random K-satisfiability (K-SAT) problem is an important problem for studying typical-case complexity of NP-complete combinatorial satisfaction; it is also a representative model of finite-connectivity spin-glasses. In this paper we review our recent ... More
Network Landscape from a Brownian Particle's PerspectiveFeb 11 2003Given a complex biological or social network, how many clusters should it be decomposed into? We define the distance $d_{i,j}$ from node $i$ to node $j$ as the average number of steps a Brownian particle takes to reach $j$ from $i$. Node $j$ is a global ... More
Scaling exponents and clustering coefficients of a growing random networkMar 26 2003The statistical property of a growing scale-free network is studied based on an earlier model proposed by Krapivsky, Rodgers, and Redner [Phys. Rev. Lett. 86, 5401 (2001)], with the additional constraints of forbidden of self-connection and multiple links ... More
Long Range Frustrations in a Spin Glass Model of the Vertex Cover ProblemNov 03 2004Nov 06 2012In a spin glass system on a random graph, some vertices have their spins changing among different configurations of a ground--state domain. Long range frustrations may exist among these unfrozen vertices in the sense that certain combinations of spin ... More
Fog Radio Access Networks: Mobility Management, Interference Mitigation and Resource OptimizationJul 20 2017In order to make Internet connections ubiquitous and autonomous in our daily lives, maximizing the utilization of radio resources and social information is one of the major research topics in future mobile communication technologies. Fog radio access ... More
Geodesic Acoustic Mode in Toroidally Rotating Anisotropic TokamaksMar 04 2015Effects of anisotropy on the geodesic acoustic mode (GAM) is analyzed by using gyro-kinetic equations applicable to low-frequency microinstabilities in a toroidally rotating tokamak plasma. Dispersion relation in the presence of arbitrary Mach number ... More
Criticality and Heterogeneity in the Solution Space of Random Constraint Satisfaction ProblemsNov 23 2009Jul 02 2010Random constraint satisfaction problems are interesting model systems for spin-glasses and glassy dynamics studies. As the constraint density of such a system reaches certain threshold value, its solution space may split into extremely many clusters. ... More
Long range frustration in finite connectivity spin glasses: A mean field theory and its application to the random $K$-satisfiability problemNov 03 2004May 19 2005Shortened abstract: A mean field theory of long range frustration is constructed for spin glass systems with quenched randomness of vertex--vertex connections and of spin--spin coupling strengths. This theory is applied to a spin glass model of the random ... More
Vertex cover problem studied by cavity method: Analytics and population dynamicsFeb 14 2003We study the vertex cover problem on finite connectivity random graphs by zero-temperature cavity method. The minimum vertex cover corresponds to the ground state(s) of a proposed Ising spin model. When the connectivity c>e=2.718282, there is no state ... More
$T \to 0$ mean-field population dynamics approach for the random 3-satisfiability problemDec 31 2007Sep 25 2008During the past decade, phase-transition phenomena in the random 3-satisfiability (3-SAT) problem has been intensively studied by statistical physics methods. In this work, we study the random 3-SAT problem by the mean-field first-step replica-symmetry-broken ... More
Continuous Interior Penalty Finite Element Methods for the Helmholtz Equation with Large Wave NumberJun 21 2011This paper develops and analyzes some continuous interior penalty finite element methods (CIP-FEMs) using piecewise linear polynomials for the Helmholtz equation with the first order absorbing boundary condition in two and three dimensions. The novelty ... More
Adsorption of Externally Stretched Two-Dimensional Flexible and Semi-flexible Polymers near an Attractive WallJun 30 2009We study analytically a model of a two dimensional, partially directed, flexible or semiflexible polymer, attached to an attractive wall which is perpendicular to the preferred direction. In addition, the polymer is stretched by an externally applied ... More
Cooperative Interference Mitigation and Handover Management for Heterogeneous Cloud Small Cell NetworksApr 30 2015May 01 2015Heterogeneous small cell network has attracted much attention to satisfy users' explosive data traffic requirements. Heterogeneous cloud small cell network (HCSNet), which combines cloud computing and heterogeneous small cell network, will likely play ... More
PCN: Part and Context Information for Pedestrian Detection with CNNsApr 12 2018Pedestrian detection has achieved great improvements in recent years, while complex occlusion handling is still one of the most important problems. To take advantage of the body parts and context information for pedestrian detection, we propose the part ... More
Operator Tail Dependence of CopulasNov 18 2016A notion of tail dependence based on operator regular variation is introduced for copulas, and the standard tail dependence used in the copula literature is included as a special case. The non-standard tail dependence with marginal power scaling functions ... More
Effects of Circulating Energetic Ions on Geodesic Acoustic Modes with Finite Wave NumbersDec 16 2013May 06 2014Effects of circulating energetic particles on the geodesic acoustic modes (GAMs) with finite wave numbers are analyzed by using the hybrid kinetic-fluid model. The dispersion relation is derived by adopting the slowing beam ions distribution function ... More
Distance, dissimilarity index, and network community structureFeb 11 2003We address the question of finding the community structure of a complex network. In an earlier effort [H. Zhou, {\em Phys. Rev. E} (2003)], the concept of network random walking is introduced and a distance measure defined. Here we calculate, based on ... More
Glassy Behavior and Jamming of a Random Walk Process for Sequentially Satisfying a Constraint Satisfaction FormulaJul 02 2009Dec 20 2009Random $K$-satisfiability ($K$-SAT) is a model system for studying typical-case complexity of combinatorial optimization. Recent theoretical and simulation work revealed that the solution space of a random $K$-SAT formula has very rich structures, including ... More
Force-Induced Melting and Thermal Melting of a Double-Stranded BiopolymerJul 03 2000Aug 09 2000As a prototype of systems bearing a localization-delocalization transition, the strand-separation (melting) process in a double-stranded biopolymer is studied by a mapping to a quantum-mechanical problem with short-ranged potentials. Both the bounded ... More
Partition Function Expansion on Region-Graphs and Message-Passing EquationsOct 05 2011Nov 21 2011Disordered and frustrated graphical systems are ubiquitous in physics, biology, and information science. For models on complete graphs or random graphs, deep understanding has been achieved through the mean-field replica and cavity methods. But finite-dimensional ... More
Phenomenological Analysis of B->PP Decays with QCD FactorizationAug 17 2001Jan 31 2002In this paper, we study nonleptonic charmless B decays to two light pseudoscalar mesons within the frame of QCD factorization, including the contributions from the chirally enhanced power corrections and weak annihilation. Predictions for the CP-averaged ... More
Phenomenological Analysis of Charmless Decays B-->PV with QCD FactorizationJan 28 2002May 13 2002We study the hadronic charmless two-body B decays to final states involving pseudoscalar and vector mesons with QCD factorization approach, including the contributions from the chirally enhanced power corrections and weak annihilations. The CP-averaged ... More
Observation of anomalous π modes in photonic Floquet engineeringApr 13 2018Aug 20 2018Recent progresses on Floquet topological phases have shed new light on time-dependant quantum systems, among which one-dimensional (1D) Floquet systems have been under extensive theoretical research. However, an unambiguous experimental observation of ... More
$\W_n^+$- and $W_n$-module structures on $U(h)$Jan 06 2014Jun 04 2014Let $\h_n$ be the Cartan subalgebra of the Witt algebras $\W_n^+=\text{Der}\C[t_1, t_2, ..., t_n]$ and $\W_n=\text{Der}\C[t_1^{\pm 1},t_2^{\pm 1},\cdots,t_n^{\pm1}]$ where $1\le n\le \infty$. In this paper, we classify the modules over $\W_n^+$ and over ... More
Landau Damping of Geodesic Acoustic Mode in Toroidally Rotating TokamaksJan 08 2015Jan 16 2015Geodesic acoustic mode (GAM) is analyzed by using modified gyro-kinetic (MGK) equation applicable to low-frequency microinstabilities in a rotating axisymmetric plasma. Dispersion relation of GAM in the presence of arbitrary Mach number is analytically ... More
$hp$-discontinuous Galerkin Methods for the Helmholtz Equation with Large Wave NumberJul 20 2009This paper develops some interior penalty $hp$-discontinuous Galerkin ($hp$-DG) methods for the Helmholtz equation in two and three dimensions. The proposed $hp$-DG methods are defined using a sesquilinear form which is not only mesh-dependent but also ... More
FEM and CIP-FEM for Helmholtz Equation with High Wave Number and PML truncationJun 25 2018The Helmholtz scattering problem with high wave number is truncated by the perfectly matched layer (PML) technique and then discretized by the linear continuous interior penalty finite element method (CIP-FEM). It is proved that the truncated PML problem ... More
A combined finite element and multiscale finite element method for the multiscale elliptic problemsNov 13 2012The oversampling multiscale finite element method (MsFEM) is one of the most popular methods for simulating composite materials and flows in porous media which may have many scales. But the method may be inapplicable or inefficient in some portions of ... More
Tail Densities of Skew-Elliptical DistributionsJan 18 2019Skew-elliptical distributions constitute a large class of multivariate distributions that account for both skewness and a variety of tail properties. This class has simpler representations in terms of densities rather than cumulative distribution functions, ... More
Combined local search strategy for learning in networks of binary synapsesMay 09 2011Jul 11 2011Learning in networks of binary synapses is known to be an NP-complete problem. A combined stochastic local search strategy in the synaptic weight space is constructed to further improve the learning performance of a single random walker. We apply two ... More
Learning by random walks in the weight space of the Ising perceptronMar 04 2010May 30 2010Several variants of a stochastic local search process for constructing the synaptic weights of an Ising perceptron are studied. In this process, binary patterns are sequentially presented to the Ising perceptron and are then learned as the synaptic weight ... More
Communities of solutions in single solution clusters of a random K-Satisfiability formulaMar 17 2009Sep 24 2009The solution space of a K-satisfiability (K-SAT) formula is a collection of solution clusters, each of which contains all the solutions that are mutually reachable through a sequence of single-spin flips. Knowledge of the statistical property of solution ... More
Seesaw mechanism in three flavorsMar 14 2001Sep 08 2001We advance a method used to analyse the neutrino properties (masses and mixing) in the seesaw mechanism. Assuming the hierarchical Dirac and light neutrino masses we establish rather simple relations between the light and the heavy neutrino parameters ... More
Activity patterns on random scale-free networks: Global dynamics arising from local majority rulesJan 18 2007Activity or spin patterns on random scale-free network are studied by mean field analysis and computer simulations. These activity patterns evolve in time according to local majority-rule dynamics which is implemented using (i) parallel or synchronous ... More
Message passing for vertex coversMay 08 2006Sep 08 2006Constructing a minimal vertex cover of a graph can be seen as a prototype for a combinatorial optimization problem under hard constraints. In this paper, we develop and analyze message passing techniques, namely warning and survey propagation, which serve ... More
Ground-state configuration space heterogeneity of random finite-connectivity spin glasses and random constraint satisfaction problemsAug 25 2010We demonstrate through two case studies, one on the p-spin interaction model and the other on the random K-satisfiability problem, that a heterogeneity transition occurs to the ground-state configuration space of a random finite-connectivity spin glass ... More
Pre-asymptotic Error Analysis of CIP-FEM and FEM for Helmholtz Equation with High Wave Number. Part II: $hp$ versionApr 23 2012In this paper, which is part II in a series of two, the pre-asymptotic error analysis of the continuous interior penalty finite element method (CIP-FEM) and the FEM for the Helmholtz equation in two and three dimensions is continued. While part I contained ... More
An absolutely stable discontinuous Galerkin method for the indefinite time-harmonic Maxwell equations with large wave numberOct 22 2012Dec 09 2012This paper develops and analyzes an interior penalty discontinuous Galerkin (IPDG) method using piecewise linear polynomials for the indefinite time harmonic Maxwell equations with the impedance boundary condition in the three dimensional space. The main ... More
Variational study of the quantum phase transition in bilayer Heisenberg model with Bosonic RVB wave functionFeb 09 2011We study the ground state phase diagram of the bilayer Heisenberg model on square lattice with a Bosonic RVB wave function. The wave function has the form of a Gutzwiller projected Schwinger Boson mean field ground state and involves two variational parameters. ... More
Hierarchical Chain Model of Spider Capture Silk ElasticityDec 20 2004Jan 24 2005Spider capture silk is a biomaterial with both high strength and high elasticity, but the structural design principle underlying these remarkable properties is still unknown. It was revealed recently by atomic force microscopy that, an exponential force--extension ... More
A posteriori error estimates for finite element approximations of the Cahn-Hilliard equation and the Hele-Shaw flowAug 15 2007This paper develops a posteriori error estimates of residual type for conforming and mixed finite element approximations of the fourth order Cahn-Hilliard equation $u_t+\De\bigl(\eps \De u-\eps^{-1} f(u)\bigr)=0$. It is shown that the {\it a posteriori} ... More
An unfitted $hp$-interface penalty finite element method for elliptic interface problemsJul 17 2010An $hp$ version of interface penalty finite element method ($hp$-IPFEM) is proposed for elliptic interface problems in two and three dimensions on unfitted meshes. Error estimates in broken $H^1$ norm, which are optimal with respect to $h$ and suboptimal ... More
Phenomenological analysis of properties of the RH Majorana neutrino in the seesaw mechanismApr 18 2001As an extension of our previous work in the seesaw mechanism, we analyze the influence of $U_{e3}$ on the properties (masses and mixing) of the RH Majorana neutrinos in three flavors. The quasidegenerate light neutrinos case is also considered. Assuming ... More
Resonance in the seesaw mechanismApr 18 2001We study the RH neutrino properties from the low energy neutrino data in the seesaw mechanism. Reonance behavior is found for the right-handed (RH) mixing angle as a function of light neutrino mass ratios in two favored region of the solar neutrino problem ... More
Dynamics-Driven Evolution to Structural Heterogeneity in Complex NetworksApr 20 2008Mar 17 2009The mutual influence of dynamics and structure is a central issue in complex systems. In this paper we study by simulation slow evolution of network under the feedback of a local-majority-rule opinion process. If performance-enhancing local mutations ... More
Distribution of equilibrium free energies in a thermodynamic system with broken ergodicityOct 06 2007At low temperatures the configurational phase space of a macroscopic complex system (e.g., a spin-glass) of $N\sim 10^{23}$ interacting particles may split into an exponential number $\Omega_s \sim \exp({\rm const} \times N)$ of ergodic sub-spaces (thermodynamic ... More
Pulling hairpinned polynucleotide chains: Does base-pair stacking interaction matter?Jan 18 2001Force-induced structural transitions both in relatively random and in designed single-stranded DNA (ssDNA) chains are studied theoretically. At high salt conditions, ssDNA forms compacted hairpin patterns stabilized by base-pairing and base-pair stacking ... More
Fronthauling for 5G LTE-U Ultra Dense Cloud Small Cell NetworksJul 24 2016Ultra dense cloud small cell network (UDCSNet), which combines cloud computing and massive deployment of small cells, is a promising technology for the fifth-generation (5G) LTE-U mobile communications because it can accommodate the anticipated explosive ... More
Energy-Efficient Resource Allocation in NOMA Heterogeneous NetworksJan 14 2018Non-orthogonal multiple access (NOMA) has attracted much recent attention owing to its capability for improving the system spectral efficiency in wireless communications. Deploying NOMA in heterogeneous network can satisfy users' explosive data traffic ... More
Irreducible Virasoro modules from tensor productsJan 10 2013In this paper, we obtain a class of irreducible Virasoro modules by taking tensor products of the irreducible Virasoro modules $\Omega(\lambda,b)$ defined in [LZ], with irreducible highest weight modules $V(\theta,h)$ or with irreducible Virasoro modules ... More
Counting solutions from finite samplingsNov 18 2011Feb 01 2012We formulate the solution counting problem within the framework of inverse Ising problem and use fast belief propagation equations to estimate the entropy whose value provides an estimate on the true one. We test this idea on both diluted models (random ... More
Approaching the ground states of the random maximum two-satisfiability problem by a greedy single-spin flipping processApr 14 2011In this brief report we explore the energy landscapes of two spin glass models using a greedy single-spin flipping process, {\tt Gmax}. The ground-state energy density of the random maximum two-satisfiability problem is efficiently approached by {\tt ... More
Cavity approach to the Sourlas code systemMay 18 2009Aug 13 2009The statistical physics properties of regular and irregular Sourlas codes are investigated in this paper by the cavity method. At finite temperatures, the free energy density of these coding systems is derived and compared with the result obtained by ... More
Region graph partition function expansion and approximate free energy landscapes: Theory and some numerical resultsApr 09 2012Jul 31 2012Graphical models for finite-dimensional spin glasses and real-world combinatorial optimization and satisfaction problems usually have an abundant number of short loops. The cluster variation method and its extension, the region graph method, are theoretical ... More
Discontinuous Galerkin Methods for the Helmholtz Equation with Large Wave NumberOct 08 2008This paper develops and analyzes some interior penalty discontinuous Galerkin methods using piecewise linear polynomials for the Helmholtz equation with the first order absorbing boundary condition in the two and three dimensions. It is proved that the ... More
Topological axion states in magnetic insulator MnBi$_2$Te$_4$ with the quantized magnetoelectric effectAug 24 2018Nov 06 2018Topological states of quantum matter have attracted great attention in condensed matter physics and materials science. The study of time-reversal-invariant (TRI) topological states in quantum materials has made tremendous progress in both theories and ... More
Helicity dependent photocurrent in electrically gated (Bi,Sb)_2Te_3 thin filmsJun 14 2017Circularly polarized photons are known to generate a directional helicity-dependent photocurrent in three-dimensional topological insulators at room temperature. Surprisingly, the phenomenon is readily observed at photon energies that excite electrons ... More
Partition function loop series for a general graphical model: free energy corrections and message-passing equationsApr 19 2011Sep 13 2011A loop series expansion for the partition function of a general statistical model on a graph is carried out. If the auxiliary probability distributions of the expansion are chosen to be a fixed point of the belief-propagation equation, the first term ... More
Films with the discrete nano-DLC-particles as the field emission cascadeAug 31 2010The films with the discrete diamond-like-carbon nanoparticles were prepared by the deposition of the carbon nanoparticle beam. Their morphologies were imaged by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The nanoparticles were ... More
The first result on 76Ge neutrinoless double beta decay from CDEX-1 experimentMar 06 2017We report the first result on Ge-76 neutrinoless double beta decay from CDEX-1 experiment at China Jinping Underground Laboratory. A mass of 994 g p-type point-contact high purity germanium detector has been installed to search the neutrinoless double ... More
Pressure induced metallization with absence of structural transition in layered MoSe2Apr 30 2015Layered transition-metal dichalcogenides have emerged as exciting material systems with atomically thin geometries and unique electronic properties. Pressure is a powerful tool for continuously tuning their crystal and electronic structures away from ... More
Can pulling cause right- to left-handed structural transitions in negatively supercoiled DNA double-helix?Aug 09 1999Sep 29 1999The folding angle distribution of stretched and negatively supercoiled DNA double-helix is investigated based on a theoretical model we proposed earlier [H. Zhou et al., Phys. Rev. Lett. 82, 4560 (1999)]. It is shown that pulling can transit a negatively ... More
From one solution of a 3-satisfiability formula to a solution cluster: Frozen variables and entropySep 25 2008Mar 17 2009A solution to a 3-satisfiability (3-SAT) formula can be expanded into a cluster, all other solutions of which are reachable from this one through a sequence of single-spin flips. Some variables in the solution cluster are frozen to the same spin values ... More
High-precision realization of robust quantum anomalous Hall state in a hard ferromagnetic topological insulatorDec 11 2014Jan 17 2015The discovery of the quantum Hall (QH) effect led to the realization of a topological electronic state with dissipationless currents circulating in one direction along the edge of a two dimensional electron layer under a strong magnetic field. The quantum ... More
Analysis of D_s-> phi pi beyond naive factorizationSep 12 2001We analyze the decay $D_s\to \phi \pi$ with QCD factorization in the heavy quark limit. The nonfactorizable contributions, including hard spectator contribution are discussed and numerical results are presented. Our predictions on the branching ratio ... More
Monte Carlo implementation of supercoiled double-stranded DNANov 29 1999Metropolis Monte Carlo simulation is used to investigate the elasticity of torsionally stressed double-stranded DNA, in which twist and supercoiling are incorporated as a natural result of base-stacking interaction and backbone bending constrained by ... More
Long-range frustration in T=0 first-step replica-symmetry-broken solutions of finite-connectivity spin glassesJun 02 2007In a finite-connectivity spin-glass at the zero-temperature limit, long-range correlations exist among the unfrozen vertices (whose spin values being non-fixed). Such long-range frustrations are partially removed through the first-step replica-symmetry-broken ... More
Spontaneous curvature-induced dynamical instability of Kirchhoff filaments: Application to DNA kink deformationsOct 05 1998The Kirchhoff elastic theory of thin filaments with spontaneous curvature is employed in the understanding of the onset of the kink transitions observed in short DNA rings. Dynamical analysis shows that when its actual curvature is less than some threshold ... More
Effects of Circulating Energetic Ions on Geodesic Acoustic Modes with Toroidal RotationNov 12 2013May 06 2014Effects of circulating energetic ions (CEIs) on the geodesic acoustic modes (GAMs) in toroidally rotating tokamaks are theoretically analyzed utilizing the hybrid kinetic-fluid model. The frequencies of GAMs in the presence of toroidal rotation and CEIs ... More
Gapless quantum spin liquid ground state in the two-dimensional spin-1/2 triangular antiferromagnet YbMgGaO$_4$Jun 23 2015Jun 24 2015Quantum spin liquid (QSL) is a novel state of matter which refuses the conventional spin freezing even at 0 K. Experimentally searching for the structurally perfect candidates is a big challenge in condensed matter physics. Here we report the successful ... More
Multilevel Preconditioner with Stable Coarse Grid Corrections for the Helmholtz EquationApr 25 2013In this paper we consider a class of robust multilevel precontioners for the Helmholtz equation with high wave number. The key idea in this work is to use the continuous interior penalty finite element methods (CIP-FEM) studied in \cite{Wu12,Wu12-hp} ... More