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Results for "G. Chen"

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Motion Segmentation by SCC on the Hopkins 155 DatabaseSep 09 2009We apply the Spectral Curvature Clustering (SCC) algorithm to a benchmark database of 155 motion sequences, and show that it outperforms all other state-of-the-art methods. The average misclassification rate by SCC is 1.41% for sequences having two motions ... More
The Tricomi EquationNov 13 2013Jul 25 2015The Tricomi equation is a second-order partial differential equation of mixed elliptic-hyperbolic type. It was first analyzed in the work by Francesco Giacomo Tricomi (1923) on the well-posedness of a boundary value problem. The Tricomi equation can be ... More
Supersonic Flow onto Solid Wedges, Multidimensional Shock Waves and Free Boundary ProblemsMar 11 2017May 08 2017When an upstream steady uniform supersonic flow impinges onto a symmetric straight-sided wedge, governed by the Euler equations, there are two possible steady oblique shock configurations if the wedge angle is less than the detachment angle -- the steady ... More
Anomalous Dimension in the Solution of the Barenblatt's EquationFeb 28 2001A new method is presented to obtain the anomalous dimension in the solution of the Barenblatt's equation. The result is the same as that in the renormalization group (RG) approach. It gives us insight on the perturbative solution of the Barenblatt's equation ... More
Weak Continuity and Compactness for Nonlinear Partial Differential EquationsAug 08 2014Jul 24 2015We present several examples of fundamental problems involving weak continuity and compactness for nonlinear partial differential equations, in which compensated compactness and related ideas have played a significant role. We first focus on the compactness ... More
Gibbsian Hypothesis in TurbulenceMay 14 2002Mar 23 2003We show that Kolmogorov multipliers in turbulence cannot be statistically independent of others at adjacent scales (or even a finite range apart) by numerical simulation of a shell model and by theory. As the simplest generalization of independent distributions, ... More
The puzzling abundance pattern of HD134439 and HD134440Jul 13 2006Abundances of 18 elements are determined for the common proper-motion pair, HD134439 and HD134440, which shows high [Mn/Fe] and low [\alpha/Fe] ratios as compared to normal halo stars. Moreover, puzzling abundances are indicated from elements whose origins ... More
A Discrete Proof of The General Jordan-Schoenflies TheoremApr 20 2015Mar 11 2019In the early 1960s, Brown and Mazur proved the general Jordan-Schoenflies theorem. This fundamental theorem states: If we embed an $(n-1)$ sphere $S^{(n-1)}$ locally flatly in an $n$ sphere $S^{n}$, then it decomposes $S^{n}$ into two components. In addition, ... More
Stochastic Flow Models with Delays and Applications to Multi-Intersection Traffic Light ControlMar 17 2017Nov 07 2017We extend Stochastic Flow Models (SFMs), used for a large class of discrete event and hybrid systems, by including the delays which typically arise in flow movement. We apply this framework to the multi-intersection traffic light control problem by including ... More
Invariant Einstein metrics on generalized Wallach spacesNov 09 2015Aug 04 2017Invariant Einstein metrics on generalized Wallach spaces have been classified except $SO(k+l+m)/SO(k)\times SO(l)\times SO(m)$. In this paper, we give a survey on the study of invariant Einstein metrics on generalized Wallach spaces, and prove that there ... More
Kernel Spectral Curvature Clustering (KSCC)Sep 09 2009Multi-manifold modeling is increasingly used in segmentation and data representation tasks in computer vision and related fields. While the general problem, modeling data by mixtures of manifolds, is very challenging, several approaches exist for modeling ... More
A Discrete Proof of The General Jordan-Schoenflies TheoremApr 20 2015Feb 23 2016In this paper we give a discrete proof of the general Jordan-Schoenflies Theorem. This theorem states: Embedding an $(n-1)$-sphere $S^{(n-1)}$ local flatly in an $n$-sphere $S^{n}$, it decomposes $S^{n}$ into two components. In addition, the embedded ... More
R CrA SMM1A: Fragmentation in A Prestellar CoreAug 09 2010We report the discovery of multiple condensations in the prestellar core candidate SMM1A in the R~CrA cloud, which may represent the earliest phase of core fragmentation observed thus far. The separation between the condensations is between 1000 and 2100 ... More
Optimization of Ride Sharing Systems Using Event-driven Receding Horizon ControlJan 07 2019Jan 08 2019We develop an event-driven Receding Horizon Control (RHC) scheme for a Ride Sharing System (RSS) in a transportation network where vehicles are shared to pick up and drop off passengers so as to minimize a weighted sum of passenger waiting and traveling ... More
A Comparative Study on Lithium Abundances in Solar--Type Stars With and Without PlanetsJul 13 2006We have investigated the abundance anomalies of lithium for stars with planets in the temperature range of 5600--5900 K reported by Israelian and coworkers, as compared to 20 normal stars at the same temperature and metallicity ranges. Our result indicates ... More
Invariant Einstein metrics on generalized Wallach spacesNov 09 2015Invariant Einstein metrics on generalized Wallach spaces have been classified except $SO(k+l+m)/SO(k)\times SO(l)\times SO(m)$. In this paper, we give a survey on the study of invariant Einstein metrics on generalized Wallach spaces, and prove that there ... More
Geodesic orbit Riemannian spaces with two isotropy summands. IApr 06 2017The paper is devoted to the study of geodesic orbit Riemannian spaces that could be characterize by the property that any geodesic is an orbit of a 1-parameter group of isometries. The main result is the classification of compact simply connected geodesic ... More
Ricci flow on Kähler-Einstein manifoldsAug 27 2001Feb 15 2003In our previous paper math.DG/0010008, we develop some new techniques in attacking the convergence problems for the K\"ahler Ricci flow. The one of main ideas is to find a set of new functionals on curvature tensors such that the Ricci flow is the gradient ... More
Numerical Method for Solving Obstacle Scattering Problems by an Algorithm Based on the Modified Rayleigh ConjectureAug 14 2004A numerical algorithm is presented for solving the direct scattering problems by the Modified Rayleigh Conjecture Method (MRC) introduced by A.G.Ramm. Some numerical examples are given. They show that the method is numerically efficient.
Constraint from Lamb Shift and Anomalous Magnetic Moment on Radiatively Induced Lorentz and CPT Violation in Quantum ElectrodynamicsFeb 29 2000Jul 16 2000We investigate the precisely measured anomalous magnetic moment and Lamb shift as tests for the possible existence of the radiatively induced Lorentz and CPT violation effects in quantum electrodynamics. To this end we calculate the one-loop vacuum polarization ... More
Geometry of Kähler Metrics and Foliations by Holomorphic DiscsJul 07 2005The purpose of this paper is to establish a completely new partial regularity theory on certain homogeneous complex Monge-Ampere equations. Our partial regularity theory will be obtained by studying foliations by holomorphic curves and and their relations ... More
A data-driven linear-programming methodology for optimal transportOct 09 2017A data-driven formulation of the optimal transport problem is presented and solved using adaptively refined meshes to decompose the problem into a sequence of finite linear programming problems. Both the marginal distributions and their unknown optimal ... More
Raman spectra in epitaxial thin films $La_{1-x}Ca_xMnO_3$ (x = 0.33, 0.5) grown on different substratesAug 04 2004Raman spectra of LCMO films grown on LAO (001), STO (001), and MgO (001) substrates were studied at different temperatures. The effect of temperature, doping level and strain on Raman spectra are discussed in detail. With decreasing temperature, the changes ... More
Evidence for Electron Landau Damping in Space Plasma TurbulenceFeb 15 2019How turbulent energy is dissipated in weakly collisional space and astrophysical plasmas is a major open question. Here, we present the application of a field-particle correlation technique to directly measure the transfer of energy between the turbulent ... More
Non-Markovian band-edge effect and entanglement generation of quantum dot excitons coupled to nanowire surface plasmonsJun 09 2008Jun 12 2008The radiative decay of quantum dot (QD) excitons into surface plasmons in a cylindrical nanowire is investigated theoretically. Maxwell's equations with appropriate boundary conditions are solved numerically to obtain the dispersion relations of surface ... More
Morphology of Galactic Open ClustersAug 02 2004We analyzed the shapes of Galactic open clusters by the star counting technique with the 2MASS star catalog database. Morphological parameters such as the ellipticity and size have been derived via stellar density distribution, weighed by clustering probability. ... More
Resonant Interactions in Rotating Homogeneous Three-dimensional TurbulenceApr 29 2004Direct numerical simulations of three-dimensional (3D) homogeneous turbulence under rapid rigid rotation are conducted to examine the predictions of resonant wave theory for both small Rossby number and large Reynolds number. The simulation results reveal ... More
Stability and Asymptotic Behavior of Transonic Flows Past Wedges for the Full Euler EquationsDec 30 2016Jan 08 2018The existence, uniqueness, and asymptotic behavior of steady transonic flows past a curved wedge, involving transonic shocks, governed by the two-dimensional full Euler equations are established. The stability of both weak and strong transonic shocks ... More
A Note on Community Trees in NetworksOct 11 2017We introduce the concept of community trees that summarizes topological structures within a network. A community tree is a tree structure representing clique communities from the clique percolation method (CPM). The community tree also generates a persistent ... More
Aharonov-Bohm Effect in Concentric Quantum Double RingsNov 06 2006We propose a theoretical model to study the single-electron spectra of the concentric quantum double ring fabricated lately by self-assembled technique. Exact diagonalization method is employed to examine the Aharonov-Bohm effect in the concentric double ... More
Formation of Singularities and Existence of Global Continuous Solutions for the Compressible Euler EquationsMay 19 2019We are concerned with the formation of singularities and the existence of global continuous solutions of the Cauchy problem for the one-dimensional non-isentropic Euler equations for compressible fluids. For the isentropic Euler equations, we pinpoint ... More
Partial Resampling to Approximate Covering Integer ProgramsJul 27 2015May 26 2016We consider column-sparse positive covering integer programs, which generalize set cover and which have attracted a long line of research developing (randomized) approximation algorithms. We develop a new rounding scheme based on the Partial Resampling ... More
Compensated Compactness in Banach Spaces and Weak Rigidity of Isometric Immersions of ManifoldsOct 01 2016Feb 11 2018We present a compensated compactness theorem in Banach spaces established recently, whose formulation is originally motivated by the weak rigidity problem for isometric immersions of manifolds with lower regularity. As a corollary, a geometrically intrinsic ... More
High-Order-Mode Soliton Structures in Two-Dimensional Lattices with Defocusing NonlinearityOct 27 2006While fundamental-mode discrete solitons have been demonstrated with both self-focusing and defocusing nonlinearity, high-order-mode localized states in waveguide lattices have been studied thus far only for the self-focusing case. In this paper, the ... More
A Constraint Network Based Approach to Memory Layout OptimizationOct 25 2007While loop restructuring based code optimization for array intensive applications has been successful in the past, it has several problems such as the requirement of checking dependences (legality issues) and transformation of all of the array references ... More
Compensated Compactness in Banach Spaces and Weak Rigidity of Isometric Immersions of ManifoldsOct 01 2016We present a compensated compactness theorem in Banach spaces established recently, whose formulation is originally motivated by the weak rigidity problem for isometric immersions of manifolds with lower regularity. As a corollary, a geometrically intrinsic ... More
Phase Retrieval by Linear AlgebraJul 25 2016The null vector method, based on a simple linear algebraic concept, is proposed as a solution to the phase retrieval problem. In the case with complex Gaussian random measurement matrices, a non-asymptotic error bound is derived, yielding an asymptotic ... More
Tripartite entangled plaquette state in a cluster magnetApr 11 2017Using large-scale quantum Monte Carlo simulations we show that a spin-$1/2$ XXZ model on a two-dimensional anisotropic Kagome lattice exhibits a tripartite entangled plaquette state that preserves all of the Hamiltonian symmetries. It is connected via ... More
Kolmogorov-Type Theory of Compressible Turbulence and Inviscid Limit of the Navier-Stokes Equations in $R^3$Sep 23 2018We are concerned with the inviscid limit of the Navier-Stokes equations to the Euler equations for isentropic compressible fluids in $R^3$. Motivated by the Kolmogorov hypothesis (1941) for incompressible flow, we introduce a Kolmogorov-type hypothesis ... More
Long term aging of Selenide glasses: Evidence of sub-Tg endotherms and pre-Tg exothermsJul 18 2009Jan 12 2010Long term aging is studied on several families of chalcogenide glasses including the Ge-Se, As-Se, Ge-P-Se and Ge-As-Se systems. Special attention is given to the As-Se binary, a system that displays a rich variety of aging behavior intimately tied to ... More
Asymptotic Bayesian Theory of Quickest Change Detection for Hidden Markov ModelsJul 03 2016In the 1960s, Shiryaev developed a Bayesian theory of change-point detection in the i.i.d. case, which was generalized in the beginning of the 2000s by Tartakovsky and Veeravalli for general stochastic models assuming a certain stability of the log-likelihood ... More
On the weak Kähler-Ricci flowFeb 06 2008In this note, we define and study K\"ahler-Ricci flow with initial data not being smooth with some natural applications.
Systematically improvable optimized atomic basis sets for {\it ab inito} calculationsMay 24 2010We propose a unique scheme to construct fully optimized atomic basis sets for density-functional calculations. The shapes of the radial functions are optimized by minimizing the {\it spillage} of the wave functions between the atomic orbital calculations ... More
Magnetically Multiplexed Heating of Single Domain NanoparticlesMar 06 2014Selective hysteretic heating of multiple collocated sets of single domain magnetic nanoparticles (SDMNPs) by alternating magnetic fields (AMFs) may offer a useful tool for biomedical applications. The possibility of magnetothermal multiplexing has not ... More
Local Uniqueness of Steady Spherical Transonic Shock-fronts for the Three-Dimensional Full Euler EquationsDec 08 2011We establish the local uniqueness of steady transonic shock solutions with spherical symmetry for the three-dimensional full Euler equations. These transonic shock-fronts are important for understanding transonic shock phenomena in divergent nozzles. ... More
Gauss-Green theorem for weakly differentiable vector fields, sets of finite perimeter, and balance lawsSep 24 2007We analyze a class of weakly differentiable vector fields (\FF \colon \rn \to \rn) with the property that (\FF\in L^{\infty}) and (\div \FF) is a Radon measure. The primary focus of our investigation is to introduce a suitable notion of the normal trace ... More
When Is the Achievable Rate Region Convex in Two-User Massive MIMO Systems?Jun 19 2018This letter investigates the achievable rate region in Massive multiple-input-multiple-output (MIMO) systems with two users, with focus on the i.i.d.~Rayleigh fading and line-of-sight (LoS) scenarios. If the rate region is convex, spatial multiplexing ... More
Discovering and Removing Exogenous State Variables and Rewards for Reinforcement LearningJun 05 2018Exogenous state variables and rewards can slow down reinforcement learning by injecting uncontrolled variation into the reward signal. We formalize exogenous state variables and rewards and identify conditions under which an MDP with exogenous state can ... More
Kolmogorov-Type Theory of Compressible Turbulence and Inviscid Limit of the Navier-Stokes Equations in $\mathbb{R}^3$Sep 23 2018Jun 08 2019We are concerned with the inviscid limit of the Navier-Stokes equations to the Euler equations for compressible fluids in $\mathbb{R}^3$. Motivated by the Kolmogorov hypothesis (1941) for incompressible flow, we introduce a Kolmogorov-type hypothesis ... More
Injectivity Radius of Lorentzian ManifoldsDec 29 2006Motivated by the application to spacetimes of general relativity we investigate the geometry and regularity of Lorentzian manifolds under certain curvature and volume bounds. We establish several injectivity radius estimates at a point or on the past ... More
Are there the VP couplings in the psi(3770) non-charmed decays hidden behind the current experiment measurements?Aug 01 2008Jan 14 2010A global analysis of the full amplitudes for $e^+e^- \to$ VP (Vector and Pseudoscalar) channels at $\sqrt{s}$ =3.773 GeV and 3.670 GeV, which were measured by the CLEO-c Collaboration, shows that those measurements are essentially nontrivial for searching ... More
Review of Experimental Studies of $ψ(3770)$ non-$D\bar D$ DecaysMar 18 2010We review the progress on experimental studies of the non-$D\bar D$ decays of the $\psi(3770)$ resonance. With the world average of the observed cross sections for $D\bar D$ production measured at 3.773 GeV by the MARK-I, MARK-II, BES and CLEO Collaborations, ... More
A fully implicit, conservative, non-linear, electromagnetic hybrid particle-ion/fluid-electron algorithmMar 19 2018The quasi-neutral hybrid model with kinetic ions and fluid electrons is a promising approach for bridging the inherent multi-scale nature of many problems in space and laboratory plasmas. Here, a novel, implicit, particle-in-cell based scheme for the ... More
Local foliations and optimal regularity of Einstein spacetimesDec 30 2008We investigate the local regularity of pointed spacetimes, that is, time-oriented Lorentzian manifolds in which a point and a future-oriented, unit timelike vector (an observer) are selected. Our main result covers the class of Einstein vacuum spacetimes. ... More
Shock Reflection-Diffraction, von Neumann's Conjectures and Nonlinear Equations of Mixed TypeNov 21 2013Shock waves are fundamental in nature. One of the most fundamental problems in fluid mechanics is shock reflection-diffraction by wedges. The complexity of reflection-diffraction configurations was first reported by Ernst Mach in 1878. The problems remained ... More
Stability of Steady Multi-Wave Configurations for the Full Euler Equations of Compressible Fluid FlowJul 17 2018We are concerned with the stability of steady multi-wave configurations for the full Euler equations of compressible fluid flow. In this paper, we focus on the stability of steady four-wave configurations that are the solutions of the Riemann problem ... More
$L^1$-Stability of Vortex Sheets and Entropy Waves in Steady Compressible Supersonic Euler Flows over Lipschitz WallsMay 20 2012Aug 26 2012We establish the well-posedness of compressible vortex sheets and entropy waves in two-dimensional steady supersonic Euler flows over Lipschitz walls under a $BV$ boundary perturbation. In particular, when the total variation of the incoming flow perturbation ... More
Weak Continuity of the Cartan Structural System on Semi-Riemannian Manifolds with Lower RegularityMay 07 2019We are concerned with the global weak continuity of the Cartan structural system - or equivalently, the Gauss-Codazzi-Ricci system - on semi-Riemannian manifolds. We prove the $W^{2,p}$ weak continuity of the Cartan structural system for $p>2$: For a ... More
Effect of Mo doping for the Mn site in the ferromagnetic manganite La0.7Ca0.3MnO3May 22 2007The structure, electronic, and magnetic properties of the Mo-doped perovskite La0.7Ca0.3Mn1-xMoxO3 (x < 0.1) have been studied. A significant increase in resistivity and lattice parameters were observed with Mo doping. A marginal decrease in the Curie ... More
Magnetic orders, excitations, and phase transitions in Fe_1+yTeJun 20 2013Jun 21 2013We study the magnetic properties of Fe_1+y Te, a parent compound of the iron-based high-temperature superconductors. Motivated by recent neutron scattering experiments, we show that a spin-1 exchange model, supplemented by a single-ion spin anisotropy, ... More
Simulation of the Burgers equation by NMR quantum information processingOct 25 2004We report on the implementation of Burgers equation as a type-II quantum computation on an NMR quantum information processor. Since the flow field evolving under the Burgers equation develops sharp features over time, this is a better test of liquid state ... More
Decoherence of a Single Qubit from Quantum AnomalyJul 13 2007Sep 21 2007We show via an explicit example that quantum anomalies can lead to decoherence of a single quantum qubit through phase relaxation. The anomaly causes the Hamiltonian to develop a non-self-adjoint piece due to the non-invariance of the domain of the Hamiltonian ... More
Frequency dependence of pulse width for 150 radio normal pulsarsJun 23 2014Nov 23 2014The frequency dependence of pulse width is studied for 150 normal pulsars, mostly selected from the European Pulsar Network, for which the 10\% multifrequency pulse widths can be well fit with the Thorsett relationship W_{10}=A\nu^{\mu}+W_{\rm 10, min}. ... More
From Centralized to Decentralized Coded CachingJan 23 2018We consider the problem of designing decentralized schemes for coded caching. In this problem there are $K$ users each caching $M$ files out of a library of $N$ total files. The question is to minimize $R$, the number of broadcast transmissions to satisfy ... More
Entropy and Convexity for Nonlinear Partial Differential Equations: IntroductionOct 29 2013Nov 06 2013Partial differential equations are ubiquitous in almost all applications of mathematics, where they provide a natural mathematical description of many phenomena involving change in physical, chemical, biological, and social processes. The concept of entropy ... More
Production of X(3872) at PANDAFeb 21 2008Mar 17 2008The recently discovered $X$(3872) has many possible interpretations. We study the production of $X$(3872) with PANDA at GSI for the antiproton-proton collision with two possible interpretations of X(3872). One is as a loosely-bound molecule of $D$-mesons, ... More
The quark axial vector coupling and heavy meson decaysFeb 28 1995Form factors and decay widths for $D^{\ast}\rightarrow D \gamma$ and $D^{\ast}\rightarrow D \pi$ decays are estimated in a relativistic constituent quark model. Relativistic corrections due to light quarks are found to be substantial and to suppress the ... More
Dynamic Scheduling and Power Control in Uplink Massive MIMO with Random Data ArrivalsApr 09 2019In this paper, we study the joint power control and scheduling in uplink massive multiple-input multiple-output (MIMO) systems with random data arrivals. The data is generated at each user according to an individual stochastic process. Using Lyapunov ... More
Partial resampling to approximate covering integer programsJul 27 2015Sep 20 2018We consider column-sparse covering integer programs, a generalization of set cover, which have attracted a long line of research developing (randomized) approximation algorithms. We develop a new rounding scheme based on the Partial Resampling variant ... More
On the Role of Mobility for Multi-message GossipApr 13 2012Feb 07 2013We consider information dissemination in a large $n$-user wireless network in which $k$ users wish to share a unique message with all other users. Each of the $n$ users only has knowledge of its own contents and state information; this corresponds to ... More
Periodic billiard orbits of self-similar Sierpinski carpetsMar 17 2013We identify a collection of periodic billiard orbits in a self-similar Sierpinski carpet billiard table. Based on a refinement of the result of Durand-Cartagena and Tyson regarding nontrivial line segments in a self-similar Sierpinski carpet, we construct ... More
Local Moments Coupled to a Strongly Correlated Electron ChainNov 14 1995A 1D model hamiltonian that is motivated by the recent discovery of the heavy-fermion behavior in the cuprates of the $Nd_2CuO_4$ type is studied. It consists of $t-J$ interacting conduction electrons coupled to a lattice of localized spins through a ... More
Effect of H^\pm on B^\pm\to τ^\pmν_τand D^\pm_s\to μ^\pmν_μ,τ^\pmν_τJan 10 2007Apr 13 2007The recent observation of the purely leptonic decay B^\pm\to \tau^\pm\nu_\tau at the B factories permits a sizeable contribution from a charged Higgs boson (H^\pm). Such a H^\pm would also contribute to the decays D^\pm_s\to \mu^\pm\nu_\mu and D^\pm_s\to ... More
Global Weak Rigidity of the Gauss-Codazzi-Ricci Equations and Isometric Immersions of Riemannian Manifolds with Lower RegularityJul 22 2016We are concerned with the global weak rigidity of the Gauss-Codazzi-Ricci (GCR) equations on Riemannian manifolds and the corresponding isometric immersions of Riemannian manifolds into the Euclidean spaces. We develop a unified intrinsic approach to ... More
Electronic structure interpolation via atomic orbitalsDec 22 2010We present an efficient scheme for accurate electronic structure interpolations based on the systematically improvable optimized atomic orbitals. The atomic orbitals are generated by minimizing the spillage value between the atomic basis calculations ... More
$N\bar N$ Scattering at NLO Order in An Effective TheoryJan 21 2011May 25 2011We have proposed to use an effective theory to describe interactions of an $N\bar N$-system. The effective theory can be constructed in analogy to the existing effective theory for an $NN$-system. In this work we study the next-to-leading order correction ... More
$L^p$ regularity of the Bergman Projection on domains covered by the polydiskMar 25 2019If a bounded domain can be covered by the polydisk through a rational proper holomorphic map, then the Bergman projection is $L^p$-bounded for $p$ in a certain range depending on the ramified rational covering. This result can be applied to the symmetrized ... More
Speech Denoising with Deep Feature LossesJun 27 2018Sep 14 2018We present an end-to-end deep learning approach to denoising speech signals by processing the raw waveform directly. Given input audio containing speech corrupted by an additive background signal, the system aims to produce a processed signal that contains ... More
Vanishing Viscosity Solutions of the Compressible Euler Equations with Spherical Symmetry and Large Initial DataSep 27 2014We are concerned with spherically symmetric solutions of the Euler equations for multidimensional compressible fluids, which are motivated by many important physical situations. Various evidences indicate that spherically symmetric solutions of the compressible ... More
Convergence of the largest eigenvalue of normalized sample covariance matrices when p and n both tend to infinity with their ratio converging to zeroNov 23 2012Let $\mathbf{X}_p=(\mathbf{s}_1,...,\mathbf{s}_n)=(X_{ij})_{p \times n}$ where $X_{ij}$'s are independent and identically distributed (i.i.d.) random variables with $EX_{11}=0,EX_{11}^2=1$ and $EX_{11}^4<\infty$. It is showed that the largest eigenvalue ... More
Global Weak Rigidity of the Gauss-Codazzi-Ricci Equations and Isometric Immersions of Riemannian Manifolds with Lower RegularityJul 22 2016Aug 26 2017We are concerned with the global weak rigidity of the Gauss-Codazzi-Ricci (GCR) equations on Riemannian manifolds and the corresponding isometric immersions of Riemannian manifolds into the Euclidean spaces. We develop a unified intrinsic approach to ... More
Free Boundary Problems in Shock Reflection/Diffraction and Related Transonic Flow ProblemsDec 03 2014Shock waves are steep wave fronts that are fundamental in nature, especially in high-speed fluid flows. When a shock hits an obstacle, or a flying body meets a shock, shock reflection/diffraction phenomena occur. In this paper, we show how several longstanding ... More
The GTC exoplanet transit spectroscopy survey X. Stellar spots versus Rayleigh scattering: the case of HAT-P-11bDec 25 2018Rayleigh scattering in a hydrogen-dominated exoplanet atmosphere can be detected from ground or space based telescopes, however, stellar activity in the form of spots can mimic Rayleigh scattering in the observed transmission spectrum. Quantifying this ... More
A Universal Phase Diagram for PMN-xPT and PZN-xPTApr 11 2003The phase diagram of the Pb(Mg1/3Nb2/3)O3 and PbTiO3 solid solution (PMN-xPT) indicates a rhombohedral ground state for x < 0.32. X-ray powder measurements by Dkhil et al. show a rhombohedrally split (222) Bragg peak for PMN-10%PT at 80 K. Remarkably, ... More
Laboratory photo-chemistry of pyrene clusters: an efficient way to form large PAHsSep 26 2018In this work, we study the photodissociation processes of small PAH clusters (e.g., pyrene clusters). The experiments are carried out using a quadrupole ion trap in combination with time-of-flight (QIT-TOF) mass spectrometry. The results show that pyrene ... More
Equation-free dynamic renormalization in a glassy compaction modelDec 31 2004Jan 07 2005Combining dynamic renormalization with equation-free computational tools, we study the apparently self-similar evolution of void distribution dynamics in the diffusion-deposition problem proposed by Stinchcombe and Depken [Phys. Rev. Lett. 88, 125701 ... More
Constraints on the quark matter equation of state from astrophysical observationsJan 17 2013We calculate the structure of neutron star interiors comprising both the hadronic and the quark phases. For the hadronic sector we employ a microscopic equation of state involving nucleons and hyperons derived within the Brueckner-Hartree-Fock many-body ... More
Bosonization study of quantum phase transitions in the one-dimensional asymmetric Hubbard modelMay 11 2007The quantum phase transitions in the one-dimensional asymmetric Hubbard model are investigated with the bosonization approach. The conditions for the phase transition from density wave to phase separation, the correlation functions and their exponents ... More
Modulations to molecular high order harmonic generation by electron de Broglie waveJan 29 2008We present a new theory that the molecular high order harmonic generation in an intense laser field is determined by molecular internal symmetry and momentum distribution of the tunneling-ionized electron. The molecular internal symmetry determines the ... More
Coulomb-induced ionization time lag after electrons tunnel out of a barrierMay 31 2019After electrons tunnel out of a laser-Coulomb-formed barrier, %formed by the strong laser field and the atomic Coulomb potential, the movement of the tunneling electron can be affected by the Coulomb tail. We show that this Coulomb effect induces a large ... More
Transport properties and magnetic field induced localization in the misfit cobaltite [Bi$_2$Ba$_{1.3}$K$_{0.6}$Co$_{0.1}$]$^{RS}$[CoO$_2$]$_{1.97}$ single crystalSep 11 2007Resistivity under magnetic field, thermopower and Hall coefficient are systematically studied for [Bi$_2$Ba$_{1.3}$K$_{0.6}$Co$_{0.1}$]$^{RS}$[CoO$_2$]$_{1.97}$ single crystal. In-plane resistivity ($\rho_{ab}$(T)) shows metallic behavior down to 2 K ... More
High energy pseudogap and its evolution with doping in Fe-based superconductors as revealed by optical spectroscopyMay 19 2011We report optical spectroscopic measurements on electron- and hole-doped BaFe2As2. We show that the compounds in the normal state are not simple metals. The optical conductivity spectra contain, in addition to the free carrier response at low frequency, ... More
Novel dynamical effects and glassy response in strongly correlated electronic systemMar 25 2007We find an unconventional nucleation of low temperature paramagnetic metal (PMM) phase with monoclinic structure from the matrix of high-temperature antiferromagnetic insulator (AFI) phase with tetragonal structure in strongly correlated electronic system ... More
Effect of iron-doping on spin-state transition and ferromagnetism in Pr$_{0.5}$Ca$_{0.5}$CoO$_{3-δ}$ cobalt oxidesSep 21 2005Resistivity and dc magnetization measurements were performed for the polycrystalline Pr$_{0.5}$Ca$_{0.5}$Co$_{1-x}$Fe$_{x}$O$_{3-\delta}$ ($x$ = 0, 0.05, 0.10 and 0.15) samples. The as-fabricated samples exhibit ferromagnetic (FM) transition and the transition ... More
Maximal Acceleration Corrections to the Lamb Shift of Muonic HydrogenAug 28 1998The maximal acceleration corrections to the Lamb shift of muonic hydrogen are calculated by using the relativistic Dirac wave functions. The correction for the $2S-2P$ transition is $\sim 0.38$ meV and is higher than the accuracy of present QED calculations ... More
Giant isotope effect and spin state transition induced by oxygen isotope exchange in ($Pr_{1-x}Sm_x)_{0.7}Ca_{0.3}CoO_3$Mar 28 2006Apr 30 2006We systematically investigate effect of oxygen isotope in $(Pr_{1-x}Sm_x)_{0.7}Ca_{0.3}CoO_3$ which shows a crossover with x from ferromagnetic metal to the insulator with spin-state transition. A striking feature is that effect of oxygen isotope on the ... More
Shape Selection and Multi-stability in Helical RibbonsDec 12 2013Helical structures, almost ubiquitous in biological systems, have inspired the design and manufacturing of helical devices with applications in nanoelecromechanical systems (NEMS), morphing structures, optoelectronics, micro-robotics and drug delivery ... More
Towards exotic hidden-charm pentaquarks in QCDJul 14 2015Sep 27 2015Inspired by $P_c(4380)$ and $P_c(4450)$ recently observed by LHCb, a QCD sum rule investigation is performed, by which they can be identified as exotic hidden-charm pentaquarks composed of an anti-charmed meson and a charmed baryon. Our results suggest ... More
Hunting for exotic doubly hidden-charm/bottom tetraquark statesMay 05 2016Sep 07 2017We develop a moment QCD sum rule method augmented by fundamental inequalities to study the existence of exotic doubly hidden-charm/bottom tetraquark states made of four heavy quarks. Using the compact diquark-antidiquark configuration, we calculate the ... More
$a_1(1420)$ resonance as a tetraquark state and its isospin partnerMar 09 2015May 21 2015We systematically construct tetraquark currents of $I^GJ^{PC}=1^-1^{++}$ and classify them into types $\mathbf{A}$ (antisymmetric), $\mathbf{S}$ (symmetric) and $\mathbf{M}$ (mixed), based on flavor symmetries of diquarks and antidiquarks composing the ... More