Still searching Arxiv, refresh for possibly better results.

Results for "M. Gu"

total 207161took 0.13s
New Benchmark of X-ray Line Emission Models of Fe XVIIMay 05 2009We review the accuracy of existing \ion{Fe}{17} X-ray line emission models by comparing them with an extensive analysis of \textit{Chandra} high energy transmission grating (HETG) observations of stellar coronae. We find significant discrepancies between ... More
Connectivity, toughness, spanning trees of bounded degree, and the spectrum of regular graphsFeb 18 2016In this paper, we present some new results describing connections between the spectrum of a regular graph and its generalized connectivity, toughness, and the existence of spanning trees with bounded degree.
Absence of finite-temperature ballistic charge transport in the 1D half-filled Hubbard modelSep 06 2012Jun 26 2013Finite-temperature T>0 transport properties of integrable and nonintegrable one-dimensional (1D) many-particle quantum systems are rather different, showing in the metallic phases ballistic and diffusive behavior, respectively. The repulsive 1D Hubbard ... More
Collapsing and Separating Completeness Notions under Average-Case and Worst-Case HypothesesJan 04 2010Feb 03 2010This paper presents the following results on sets that are complete for NP. 1. If there is a problem in NP that requires exponential time at almost all lengths, then every many-one NP-complete set is complete under length-increasing reductions that are ... More
A reduced complexity numerical method for optimal gate synthesisNov 28 2010Although quantum computers have the potential to efficiently solve certain problems considered difficult by known classical approaches, the design of a quantum circuit remains computationally difficult. It is known that the optimal gate design problem ... More
Inner-shell Absorption Lines of Fe~VI-- Fe~XVI: A Many-body Perturbation Theory ApproachDec 15 2005We provide improved atomic calculation of wavelengths, oscillator strengths, and autoionization rates relevant to the $2\to 3$ inner-shell transitions of Fe~VI--XVI, the so-called Fe~M-shell unresolved transition array (UTA). A second order many-body ... More
Robust charge and magnetic order under electric field and current in the multiferroic LuFe(2)O(4)Jan 20 2010Apr 20 2010We performed elastic neutron scattering measurements on the charge- and magnetically-ordered multiferroic material LuFe(2)O(4). An external electric field along the [001] direction with strength up to 20 kV/cm applied at low temperature (~100 K) does ... More
SymFET: A Proposed Symmetric Graphene Tunneling Field Effect TransistorJan 04 2013In this work, an analytical model to calculate the channel potential and current-voltage characteristics in a Symmetric tunneling Field-Effect-Transistor (SymFET) is presented. The current in a SymFET flows by tunneling from an n-type graphene layer to ... More
The morphology and temperature dependent tensile properties of diamond nanothreadsMar 17 2018The ultrathin one-dimensional sp3 diamond nanothreads (NTHs), as successfully synthesised recently, have greatly augmented the interests from the carbon community. In principle, there can exist different stable NTH structures. In this work, we studied ... More
Numerical and Monte Carlo Bethe ansatz method: 1D Heisenberg modelOct 22 2002In this paper we present two new numerical methods for studying thermodynamic quantities of integrable models. As an example of the effectiveness of these two approaches, results from numerical solutions of all sets of Bethe ansatz equations, for small ... More
High-energy magnetic excitations from dynamic stripes in LBCO (x=1/8)Feb 01 2007We use inelastic neutron scattering to study the temperature dependence of magnetic excitations (for energies up to 100 meV) in the cuprate La$_{1.875}$Ba$_{0.125}$CuO$_4$. This compound exhibits stripe order below a temperature of ~50 K; previous measurements ... More
A strongly inhomogeneous superfluid in an iron-based superconductorJan 01 2019Among the mysteries surrounding unconventional, strongly correlated superconductors is the possibility of spatial variations in their superfluid density. We use atomic-resolution Josephson scanning tunneling microscopy to reveal a strongly inhomogeneous ... More
Density diagnostics of ionized outflows in active galactic nuclei: X-ray and UV absorption lines from metastable levels in Be-like to C-like ionsJul 29 2017Aug 15 2017Ionized outflows in Active Galactic Nuclei (AGN) are thought to influence their nuclear and local galactic environment. However, the distance of the outflows with respect to the central engine is poorly constrained, which limits our understanding of their ... More
Integrable systems from the classical reflection equationMay 21 2014Jun 08 2015We construct integrable Hamiltonian systems on $G/K$, where $G$ is a quasitriangular Poisson Lie group and $K$ is a Lie subgroup arising as the fixed point set of a group automorphism $\sigma$ of $G$ satisfying the classical reflection equation. In the ... More
The evolution of dusty torus covering factor in quasarsJul 04 2013Jul 15 2013We have assembled a large sample of 5996 quasars at redshift 2.0=< z <= 2.4 (high-z) or 0.7=< z <= 1.1 (low-z) from SDSS data release nine and seven quasar catalogs. The spectral energy distribution (SED) of quasars were constructed by collecting WISE, ... More
A Study of Weakly Discontinuous Solutions for Hyperbolic Differential Equations Based on Wavelet Transform MethodsNov 03 2013Dec 04 2013A new approach to prove the one-dimensional Cauchy problem's weakly discontinuous solutions for hyperbolic PDEs are on the characteristics is discussed in this paper. To do so, I use wavelet singularity detection methods or WTMM [1] based on two-dimensional ... More
On algebraic surfaces of general type with negative c2Nov 30 2014Dec 08 2014We prove that for any prime number $p\ge 3$, there exists a positive number $\kappa_p$ such that $\chi(\mathcal{O}_X)\ge \kappa_pc_1^2$ holds true for all algebraic surfaces $X$ of general type in characteristic $p$. In particular, $\chi(\mathcal{O}_X)>0$. ... More
Some torsion classes in the Chow ring and cohomology of $BPGL_n$Jan 29 2019Apr 22 2019In the integral cohomology ring of the classifying space of the projective linear group $PGL_n$ (over $\mathbb{C}$), we find a collection of $p$-torsions $y_{p,k}$ of degree $2(p^{k+1}+1)$ for any odd prime divisor $p$ of $n$, and $k\geq 0$. If in addition, ... More
On Topological Brauer Classes over $8$-Complexes with Periods Divisible by $4$Mar 14 2018We determine the index of the topological Brauer class $\beta_n$, the canonical generator of $H^3(X;\mathbb{Z})$, where $X$ is the $8$th skeleton of the Eilenberg-Mac Lane space $K(\mathbb{Z}/n,2)$, and $4|n$. This makes an important complement to a theorem ... More
Regularity criteria for suitable weak solutions to the four dimensional incompressible magneto-hydrodynamic equations near boundaryMay 19 2014In this paper, we consider suitable weak solutions of the four dimensional incompressible magneto-hydrodynamic equations. We give two different kind $\varepsilon$-regularity criteria. One only requires the smallness of scaling $L^{p,q}$ norm of $u$, another ... More
On a measure of distance for quantum strategiesAug 27 2010Mar 14 2012The present paper studies an operator norm that captures the distinguishability of quantum strategies in the same sense that the trace norm captures the distinguishability of quantum states or the diamond norm captures the distinguishability of quantum ... More
Spanning rigid subgraph packing and sparse subgraph coveringMay 01 2014Jun 12 2018Rigidity, arising in discrete geometry, is the property of a structure that does not flex. Laman provides a combinatorial characterization of rigid graphs in the Euclidean plane, and thus rigid graphs in the Euclidean plane have applications in graph ... More
A note on dimensions of polynomial size circuitsApr 22 2004Apr 22 2004In this paper, we use resource-bounded dimension theory to investigate polynomial size circuits. We show that for every $i\geq 0$, $\Ppoly$ has $i$th order scaled $\pthree$-strong dimension 0. We also show that $\Ppoly^\io$ has $\pthree$-dimension 1/2, ... More
Gaussian fluctuations of the 2D KPZ equationDec 18 2018We prove the 2D KPZ equation with a logarithmically tuned nonlinearity and a small coupling constant, scales to the Edwards-Wilkinson equation with an effective variance.
Anderson orthogonality catastrophe in $2+1$-D topological systemsMay 01 2019In the thermodynamic limit, a many-body ground state has zero overlap with another state which is a slightly perturbed state of the original one, known as the Anderson orthogonality catastrophe (AOC). The amplitude of the overlap for two generic ground ... More
Contractible open manifolds which embed in no compact, locally connected and locally 1-connected metric spaceSep 07 2018This paper pays a visit to a famous contractible open 3-manifold $W^3$ proposed by R. H. Bing in 1950's. By the finiteness theorem \cite{Hak68}, Haken proved that $W^3$ can embed in no compact 3-manifold. However, until now, the question about whether ... More
Quantum Action Principle with Generalized Uncertainty PrincipleNov 01 2013One of the common features in all promising candidates of quantum gravity is the existence of a minimal length scale, which naturally emerges with a generalized uncertainty principle, or equivalently a modified commutation relation. Schwinger's quantum ... More
Non-Fermi Liquid Behavior in 3+1 Dimensions with PT Invariant Gauge Field: An Renormalization Group ApproachNov 29 1994We introduce a Hamiltonian coupled between a normal Fermi surface and a polarized Maxwell type gauge field.We adopt a {\it calibrated scaling } approach in order to be consistent with the results obtained at $2+1$ dimensions as well as the Weinberg's ... More
Well-posedness of axially symmetric incompressible ideal magnetohydrodynamic equations with vacuum under the non-collinearity conditionNov 23 2017We consider a free boundary problem for the axially symmetric incompressible ideal magnetohydrodynamic equations that describes the motion of the plasma in vacuum. Both the plasma magnetic field and vacuum magnetic field are tangent along the plasma-vacuum ... More
Well-posedness of axially symmetric incompressible ideal magnetohydrodynamic equations with vacuum under the Rayleigh-Taylor sign conditionDec 06 2017We consider a free boundary problem for the axially symmetric incompressible ideal magnetohydrodynamic equations that describes the motion of the plasma in vacuum. Both the plasma magnetic field and vacuum magnetic field are tangent along the plasma-vacuum ... More
Quantum Strategies and Local OperationsFeb 26 2010Mar 14 2012This thesis is divided into two parts. In Part I we introduce a new formalism for quantum strategies, which specify the actions of one party in any multi-party interaction involving the exchange of multiple quantum messages among the parties. This formalism ... More
Short Quantum GamesNov 03 2005In this thesis we introduce quantum refereed games, which are quantum interactive proof systems with two competing provers. We focus on a restriction of this model that we call "short quantum games" and we prove an upper bound and a lower bound on the ... More
A partition of connected graphsMay 09 2005We define an algorithm k which takes a connected graph G on a totally ordered vertex set and returns an increasing tree R (which is not necessarily a subtree of G). We characterize the set of graphs G such that k(G)=R. Because this set has a simple structure ... More
The Topological Period-Index Problem over 8-ComplexesSep 04 2017We study the Postnikov tower of the classifying space of a compact Lie group P(n,mn), which gives obstructions to lifting a topological Brauer class of period $n$ to a PU_{mn}-torsor, where the base space is a CW complex of dimension 8. Combined with ... More
On the Cohomology of the Classifying Spaces of Projective Unitary GroupsDec 01 2016Jan 29 2019Let $\mathbf{B}PU_{n}$ be the classifying space of $PU_n$, the projective unitary group of order $n$, for $n>1$. We use the Serre spectral sequence associated to a fiber sequence $\mathbf{B}U_n\rightarrow\mathbf{B}PU_n\rightarrow K(\mathbb{Z},3)$ to determine ... More
A remark on descent for Coxeter groupsJul 04 2017Jul 06 2017Let $\Gamma$ be a finite Coxeter group with reflection representation $R$. We show that a $\Gamma$-equivariant quasicoherent sheaf on $R$ descends to the quotient space $R//\Gamma$ if it descends to the quotient space $R//\langle s_i\rangle$ for every ... More
Evidence of Chiral Order in the Charge-Ordered Phase of Superconducting La1.875Ba0.125Cuo4 Single Crystals Using Polar Kerr-Effect MeasurementsAug 22 2013Feb 25 2014High resolution polar Kerr effect (PKE) measurements were performed on La1.875Ba0.125Cuo4 single crystals revealing that a finite Kerr signal is measured below an onset temperature-T_K that coincides with charge ordering transition temperature T_{CO}. ... More
Field-enhanced diamagnetism in intense magnetic field in the pseudogap state of the cuprate $\rm Bi_2Sr_2CaCu_2O_{8+δ}Mar 08 2005Oct 20 2005In hole-doped cuprates, Nernst experiments imply that the superconducting state is destroyed by spontaneous creation of vortices which destroy phase coherence. Using torque magnetometry on $\rm Bi_2Sr_2CaCu_2O_{8+\delta}$, we uncover a field-enhanced ... More
Overarching framework between Gaussian quantum discord and Gaussian quantum illuminationNov 30 2016Feb 28 2017We cast the problem of illuminating an object in a noisy environment into a communication protocol. A probe is sent into the environment, and the presence or absence of the object constitutes a signal encoded on the probe. The probe is then measured to ... More
FeTe$_{0.55}$Se$_{0.45}$: a multiband superconductor in the clean and dirty limitFeb 26 2015Apr 09 2015The detailed optical properties of the multiband iron-chalcogenide superconductor FeTe$_{0.55}$Se$_{0.45}$ have been reexamined for a large number of temperatures above and below the critical temperature $T_c=14$ K for light polarized in the a-b planes. ... More
Antiferromagnetism and chiral d-wave superconductivity from an effective $t-J-D$ model for twisted bilayer grapheneJan 31 2019Starting from the strong-coupling limit of an extended Hubbard model, we develop a spin-fermion theory to study the insulating phase and pairing symmetry of the superconducting phase in twisted bilayer graphene. Assuming that the insulating phase is an ... More
On the apparent permeability of porous media in rarefied gas flowsApr 12 2017The apparent gas permeability of the porous medium is an important parameter in the prediction of unconventional gas production, which was first investigated systematically by Klinkenberg in 1941 and found to increase with the reciprocal mean gas pressure ... More
On the interplay of paramagnetism and topology in the Fe-based High Tc SuperconductorsMar 25 2019The high Tc superconductor FeTe0.55Se0.45 has recently been shown to support a surface state with topological character. Here we use low-energy laser-based ARPES with variable light polarization, including both linear and circular polarization, to re-examine ... More
Interplay between magnetism and superconductivity in iron-chalcogenide superconductors: crystal growth and characterizationsApr 04 2011Jul 09 2011In this review, we present a summary of the results on single crystal growth of two types of iron-chalcogenide superconductors, Fe(1+y)Te(1-x)Se(x) (11), and A(x)Fe(2-y)Se(2) (A= K, Rb, Cs, Tl, Tl/K, Tl/Rb), using Bridgman, zone-melting, vapor self-transport, ... More
The Hard X-ray emission of the blazar PKS 2155--304Oct 23 2017The synchrotron peak of the X-ray bright High Energy Peaked Blazar (HBL) PKS 2155$-$304 occurs in the UV-EUV region and hence its X-ray emission (0.6--10 keV) lies mostly in the falling part of the synchrotron hump. We aim to study the X-ray emission ... More
Deionization Shock Driven by Electroconvection in a Circular ChannelJan 30 2019In a circular channel passing over-limiting current (faster than diffusion), transient vortices of bulk electroconvection are observed in salt-depleted region within the horizontal plane. The spatiotemporal evolution of the salt concentration is directly ... More
Magnetic field induced enhancement of spin-order peak intensity in La(1.875)Ba(0.125)CuO(4)Oct 22 2008Dec 18 2008We report on neutron-scattering results on the impact of a magnetic field on stripe order in the cuprate La$_{1.875}$Ba$_{0.125}$CuO$_4$. It is found that a 7 T magnetic field applied along the {\it c} axis causes a small but finite enhancement of the ... More
Evidence for local moment magnetism in superconducting FeTe0.35Se0.65Dec 10 2010The nature of the magnetic correlations in Fe-based superconductors remains a matter of controversy. To address this issue, we use inelastic neutron scattering to characterize the strength and temperature dependence of low-energy spin fluctuations in ... More
Strong Suppression of the Spin Hall Effect in the Spin Glass StateOct 03 2015Nov 09 2015We have measured spin Hall effects in spin glass metals, CuMnBi alloys, with the spin absorption method in the lateral spin valve structure. Far above the spin glass temperature Tg where the magnetic moments of Mn impurities are randomly frozen, the spin ... More
The AFLOW Library of Crystallographic PrototypesJul 08 2016Dec 07 2016An easily available resource of common crystal structures is essential for researchers, teachers, and students. For many years this was provided by the U.S. Naval Research Laboratory's $Crystal\ Lattice\ Structures$ web page, which contained nearly 300 ... More
The Energy Landscape Underpinning Module Dynamics in the Human Brain ConnectomeSep 05 2016Human brain dynamics can be profitably viewed through the lens of statistical mechanics, where neurophysiological activity evolves around and between local attractors representing preferred mental states. Many physically-inspired models of these dynamics ... More
Neutrino masses, leptogenesis and dark matter in hybrid seesawNov 06 2008We suggest a hybrid seesaw model where relatively ``light''right-handed neutrinos give no contribution to the neutrino mass matrix due to a special symmetry. This allows their Yukawa couplings to the standard model particles to be relatively strong, so ... More
Thermal conductivity of a new carbon nanotube analogue: the diamond nanothreadNov 05 2015Based on the non-equilibrium molecular dynamics simulations, we have studied the thermal conductivities of a novel ultra-thin one-dimensional carbon nanomaterial - diamond nanothread (DNT). Unlike single-wall carbon nanotube (CNT), the existence of the ... More
Baryon content and dynamic state of galaxy clusters: XMM-Newton observations of A1095 and A1926Mar 11 2016We have initiated a program to study the baryon content and dynamic state of galaxy clusters. Here we present results primarily from XMM-Newton observations of two optically-selected galaxy clusters, A1095 ($z \simeq 0.210$) and A1926 ($z \simeq 0.136$). ... More
Operational resource theory of continuous-variable nonclassicalityApr 26 2018Dec 10 2018Genuinely quantum states of a harmonic oscillator may be distinguished from their classical counterparts by the Glauber-Sudarshan P-representation -- a state lacking a positive P-function is said to be nonclassical. In this paper, we propose a general ... More
Magnetic field control of charge structures in the magnetically disordered phase of the multiferroic LuFe$_2$O$_4$Apr 09 2009Apr 10 2009Using neutron diffraction, we have studied the magnetic field effect on charge structures in the charge-ordered multiferroic material LuFe$_2$O$_4$. An external magnetic field is able to change the magnitude and correlation lengths of the charge valence ... More
Experimental investigation of linear-optics-based quantum target detectionApr 12 2019The development of new techniques to improve measurements is crucial for all sciences. By employing quantum systems as sensors to probe some physical property of interest allows the application of quantum resources, such as coherent superpositions and ... More
Enhanced charge stripe order of superconducting La(2-x)Ba(x)CuO(4) in a magnetic fieldDec 14 2012The effect of a magnetic field on the charge stripe order in La(2-x)Ba(x)CuO(4) has been studied by means of high energy (100 keV) x-ray diffraction for charge carrier concentrations ranging from strongly underdoped to optimally doped. We find that charge ... More
Determination of the optical properties of La{2-x}Ba{x}CuO{4} for several dopings, including the anomalous x=1/8 phaseOct 10 2011Apr 11 2012The optical properties the high-temperature superconductor La{2-x}Ba{x}CuO{4} have been measured over a wide frequency and temperature range for light polarized in the a-b planes and along the c axis. Three different Ba concentrations have been examined, ... More
Large Bi-2212 single crystal growth by the floating-zone techniqueMay 29 2008Effects of the growth velocity on the crystal growth behavior of Bi_2Sr_2Ca_1Cu_2O_x (Bi-2212) have been studied by floating zone technique. The results show that a necessary condition for obtaining large single crystals along the c-axis is that the solid-liquid ... More
Universal magnetic excitation spectrum in cupratesNov 03 2004We have recently used inelastic neutron scattering to measure the magnetic excitation spectrum of La(1.875)Ba(0.125)CuO(4) up to 200 meV. This particular cuprate is of interest because it exhibits static charge and spin stripe order. The observed spectrum ... More
Neutron scattering study on La1.9Ca1.1Cu2O6+delta and La1.85Sr0.15CaCu2O6+deltaAug 13 2004We present neutron scattering data on two single crystals of the high temperature superconductor La2-x(Ca,Sr)xCaCu2O6+delta. The Ca0.1-doped crystal exhibits a long-range antiferromagnetically ordered ground state. In contrast, the Sr0.15-doped crystal ... More
Quantum Magnetic Excitations from Stripes in Copper-Oxide SuperconductorsJan 30 2004Apr 09 2004In the copper-oxide parent compounds of the high-transition-temperature superconductors, the valence electrons are localized, one per copper site, due to strong intraatomic Coulomb repulsion. A symptom of the localization is antiferromagnetism, where ... More
Nano-engineering of electron correlation in oxide superlatticesMar 14 2019Oxide heterostructures and superlattices have attracted a great deal of attention in recent years owing to the rich exotic properties encountered at their interfaces. We focus on the potential of tunable correlated oxides by investigating the spectral ... More
Strong pinning in the hole-doped pnictide superconductor La$_{0.34}$Na$_{0.66}$Fe$_2$As$_2$Mar 10 2019We present magnetization studies as a function of time, temperature and magnetic field for $H$ $\parallel$ c-axis, in a hole-doped pnictide superconductor, La$_{0.34}$Na$_{0.66}$Fe$_2$As$_2$, with, $T_c$ $\approx$ 27 K. The obtained vortex phase-diagram ... More
Optimization of Surface Registrations using Beltrami Holomorphic FlowMay 14 2010In shape analysis, finding an optimal 1-1 correspondence between surfaces within a large class of admissible bijective mappings is of great importance. Such process is called surface registration. The difficulty lies in the fact that the space of all ... More
Testing the itinerancy of spin dynamics in superconducting Bi2212Feb 16 2009May 27 2009Much of what we know about the electronic states of high-temperature superconductors is due to photoemission and scanning tunneling spectroscopy studies of the compound Bi2212. The demonstration of well-defined quasiparticles in the superconducting state ... More
Quantitative Raman measurements of the evolution of the Cooper-pairs density with doping in Bi2Sr2CaCu2O8+d superconductorsJan 17 2009Sep 21 2009We report Raman measurements on Bi2Sr2CaCu2O8+d single crystals which allow us to quantitavely evaluate the doping dependence of the density of Cooper pairs in the superconducting state. We show that the drastic loss of Cooper pairs in the antinodal region ... More
Comparison of charge modulations in La$_{1.875}$Ba$_{0.125}$CuO$_4$ and YBa$_2$Cu$_3$O$_{6.6}$May 23 2013A charge modulation has recently been reported in (Y,Nd)Ba$_2$Cu$_3$O$_{6+x}$ [Ghiringhelli {\em et al.} Science 337, 821 (2013)]. Here we report Cu $L_3$ edge soft x-ray scattering studies comparing the lattice modulation associated with the charge modulation ... More
Diagonal charge stripes giving a suppression of spectral weight at selected spots on the Fermi surfaceNov 06 1998Here we report an asymmetric suppresion of spectral weight at the Fermi surface around the M points using angle resolved photoemission spectroscopy. The results provide direct evidence for diagonal stripes in the Bi2212 superconductors.
Universal condition for critical percolation thresholds of kagome-like latticesDec 01 2008Jan 13 2009Lattices that can be represented in a kagome-like form are shown to satisfy a universal percolation criticality condition, expressed as a relation between P_3, the probability that all three vertices in the triangle connect, and P_0, the probability that ... More
Simplicial Ricci Flow: An Example of a Neck Pinch Singularity in 3DAug 19 2013Apr 28 2014We examine a Type-1 neck pinch singularity in simplicial Ricci flow (SRF) for an axisymmetric piecewise flat 3-dimensional geometry with 3-sphere topology. SRF was recently introduced as an unstructured mesh formulation of Hamilton's Ricci flow (RF). ... More
Low energy magnetic excitations from the Fe$_{1+y-z}$(Ni/Cu)$_{z}$Te$_{1-x}$Se$_{x}$ systemApr 04 2014We report neutron scattering measurements on low energy ($\hbar\omega \sim 5$~meV) magnetic excitations from a series of Fe$_{1+y-z}$(Ni/Cu)$_{z}$Te$_{1-x}$Se$_{x}$ samples which belong to the "11" Fe-chalcogenide family. Our results suggest a strong ... More
Electronic Raman Scattering in copper oxide Superconductors: Understanding the Phase DiagramMar 29 2011Apr 30 2011Electronic Raman scattering measurements have been performed on hole doped copper oxide superconductors as a function of temperature and doping level. In the superconducting state coherent Bogoliubov quasiparticles develop preferentially over the nodal ... More
Influences of Si sheet doping densities on the morphological, conductive and optical characteristics of InAs/GaAs quantum dotsJun 10 2011The influences of Si sheet doping levels on the properties of InAs/GaAs quantum dots (QDs) are investigated by atomic force microscopy (AFM) and photoluminescence (PL). AFM measurements reveal that Si sheet doping doesn't change the morphology of InAs ... More
On exterior calculus and curvature in piecewise-flat manifoldsDec 05 2012Simplicial, piecewise-flat discretizations of manifolds provide a clear path towards curvature analysis on discrete geometries and for solutions of PDE's on manifolds of complex topologies. In this manuscript we review and expand on discrete exterior ... More
Is anisotropic flow really acoustic?Jan 02 2013Aug 18 2013The flow harmonics for charged hadrons ($v_{n}$) and their ratios $(v_n/v_2)_{n\geq 3}$, are studied for a broad range of transverse momenta ($p_T$) and centrality ($\text{cent}$) in Pb+Pb collisions at $\sqrt{s_{NN}}= 2.76$ TeV. They indicate characteristic ... More
Does quark number scaling breakdown in Pb+Pb collisions at Root_s = 2.76 TeV?Jul 08 2012Jul 14 2012The anisotropy coefficient $v_2$, for unidentified and identified charged hadrons [pions ($\pi$), kaons ($K$) and protons ($p$)] measured in Au+Au collisions at $\sqrt{s_{NN}}= 0.20$ TeV (RHIC) and Pb+Pb collisions at $\sqrt{s_{NN}}= 2.76$ TeV (LHC), ... More
Crossing on hyperbolic latticesNov 23 2011Jun 05 2012We divide the circular boundary of a hyperbolic lattice into four equal intervals, and study the probability of a percolation crossing between an opposite pair, as a function of the bond occupation probability p. We consider the {7,3} (heptagonal), enhanced ... More
Large magnetoresistance in La2/3Ca1/3MnO3 thin films induced by metal masked ion damage techniqueMar 09 2006e have developed a simple process to obtain large magnetoresistance (MR) in perovskite manganite thin films by a combination of focused ion beam (FIB) milling and 120 keV H$_{2}^{+}$ ion implantation. Metal slits about 70 nm in width were printed by 30 ... More
Science with hot astrophysical plasmasJul 05 2017We present some recent highlights and prospects for the study of hot astrophysical plasmas. Hot plasmas can be studied primarily through their X-ray emission and absorption. Most astrophysical objects, from solar system objects to the largest scale structures ... More
Digital Fourier transform spectroscopy: a high-performance, scalable technology for on-chip spectrum analysisFeb 15 2018Mar 16 2018Optical spectrum analysis is the cornerstone of spectroscopic sensing, optical network performance monitoring, and hyperspectral imaging. While conventional high-performance spectrometers used to perform such analysis are often large benchtop instruments, ... More
Probing the dynamical state, baryon content, and multiphase nature of galaxy clusters with bright background QSOsOct 09 2018We have initiated a programme to study the physical/dynamical state of gas in galaxy clusters and the impact of the cluster environment on gaseous halos of individual galaxies using X-ray imaging and UV absorption line spectroscopy of background QSOs. ... More
Effect of magnetic field on the spin resonance in FeTe(0.5)Se(0.5) as seen via inelastic neutron scatteringSep 30 2009Mar 26 2010Inelastic neutron scattering and susceptibility measurements have been performed on the optimally-doped Fe-based superconductor FeTe(0.5)Se(0.5), which has a critical temperature, Tc of 14 K. The magnetic scattering at the stripe antiferromagnetic wave-vector ... More
Short-range incommensurate magnetic order near the superconducting phase boundary in Fe(1+d)Te(1-x)Se(x)Jun 20 2009Sep 11 2009We performed elastic neutron scattering and magnetization measurements on Fe(1.07)Te(0.75)Se(0.25) and FeTe(0.7)Se(0.3). Short-range incommensurate magnetic order is observed in both samples. In the former sample with higher Fe content, a broad magnetic ... More
Computing Quasiconformal Maps on Riemann surfaces using Discrete Curvature FlowMay 25 2010Dec 01 2010Surface mapping plays an important role in geometric processing. They induce both area and angular distortions. If the angular distortion is bounded, the mapping is called a {\it quasi-conformal} map. Many surface maps in our physical world are quasi-conformal. ... More
Electron-phonon coupling reflecting dynamic charge inhomogeneity in copper-oxide superconductorsDec 03 2005Feb 28 2006The attempt to understand cuprate superconductors is complicated by the presence of multiple strong interactions. While many believe that antiferromagnetism is important for the superconductivity, there has been revived interest in the role of electron-lattice ... More
Quantum oscillations and Dirac dispersion in the BaZnBi2 semimetal guaranteed by local Zn vacancy orderJan 23 2018Mar 27 2018We have synthesized single crystals of Dirac semimetal candidates AZnBi2 with A=Ba and Sr. In contrast to A=Sr, the Ba material displays a novel local Zn vacancy ordering, which makes the observation of quantum oscillations in out-of-plane magnetic fields ... More
Low Energy Phonons in $Bi_2Sr_2CaCu_2O_{8+δ}$ and their Possible Interaction with Electrons Measured by Inelastic Neutron ScatteringFeb 14 2017Angle-resolved photoemission (ARPES) experiments on copper oxide superconductors revealed enigmatic kinks in electronic dispersions near 10 meV presumably due to phonons or impuritites. We used inelastic neutron scattering to measure phonon branches below ... More
Morphology of Graphene on SiC(000-1) SurfacesJul 30 2009Aug 13 2009Graphene is formed on SiC(000-1) surfaces (the so-called C-face of the crystal) by annealing in vacuum, with the resulting films characterized by atomic force microscopy, Auger electron spectroscopy, scanning Auger microscopy and Raman spectroscopy. Morphology ... More
XMM-Newton Reflection Grating Spectrometer Observations of Discrete Soft-X-ray Emission Features from NGC 1068Mar 19 2002Apr 11 2002We present the first high-resolution, soft-X-ray spectrum of the prototypical Seyfert 2 galaxy, NGC 1068. This spectrum was obtained with the XMM-Newton Reflection Grating Spectrometer. Emission lines from H-like and He-like low-Z ions (from C to Si) ... More
3-extra connectivity of 3-ary n-cube networksSep 19 2013Let G be a connected graph and S be a set of vertices. The h-extra connectivity of G is the cardinality of a minimum set S such that G-S is disconnected and each component of G-S has at least h+1 vertices. The h-extra connectivity is an important parameter ... More
New p- and n-type ferromagnetic semiconductors: Cr-doped BaZn2As2Oct 12 2016We find new ferromagnetic semiconductors, Cr-doped BaZn2As2, by employing a combined method of the density functional theory and the quantum Monte Carlo simulation. Due to a narrow band gap of 0.2 eV in host BaZn2As2 and the different hybridization of ... More
Diluted magnetic semiconductors with narrow band gapsJan 20 2016Oct 11 2016We propose a method to realize diluted magnetic semiconductors (DMS) with p- and n-type carriers by choosing host semiconductors with a narrow band gap. By employing a combination of the density function theory and quantum Monte Carlo simulation, we demonstrate ... More
Periodic homogenization of Green's functions for Stokes systemsOct 15 2017Dec 05 2017This paper is devoted to establishing the uniform estimates and asymptotic behaviors of the Green's functions $(G_\varepsilon,\Pi_\varepsilon)$ (and fundamental solutions $(\Gamma_\varepsilon, Q_\varepsilon)$) for the Stokes system with periodically oscillating ... More
Microreversibility, fluctuations, and nonlinear transport in transistorsDec 21 2018We present a stochastic approach for charge transport in transistors. In this approach, the electron and hole densities are governed by diffusion-reaction stochastic differential equations satisfying local detailed balance and the electric field is determined ... More
The equivariant Euler characteristic of real Coxeter toric varietiesJun 04 2008Oct 21 2008Let $W$ be a Weyl group, and let $\CT_W$ be the complex toric variety attached to the fan of cones corresponding to the reflecting hyperplanes of $W$, and its weight lattice. The real locus $\CT_W(\R)$ is a smooth, connected, compact manifold with a $W$-action. ... More
On the construction of solutions to the free-surface incompressible ideal magnetohydrodynamic equationsSep 22 2016We consider a free boundary problem for the incompressible ideal magnetohydrodynamic equations that describes the motion of the plasma in vacuum. The magnetic field is tangent and the total pressure vanishes along the plasma-vacuum interface. Under the ... More
Partial Regularity of solutions to the Four-Dimensional Navier-Stokes EquationsFeb 06 2013In this paper, we consider suitable weak solutions of incompressible Navier--Stokes equations in four spatial dimensions. We prove that the two-dimensional time-space Hausdorff measure of the set of singular points is equal to zero.
Max-Pooling Dropout for Regularization of Convolutional Neural NetworksDec 04 2015Recently, dropout has seen increasing use in deep learning. For deep convolutional neural networks, dropout is known to work well in fully-connected layers. However, its effect in pooling layers is still not clear. This paper demonstrates that max-pooling ... More