Results for "Y. Feng"

total 47778took 0.12s
Sudden death and birth of entanglement beyond the Markovian approximationMar 25 2009Apr 19 2009We investigate the entanglement dynamics of two initially entangled qubits interacting independently with two uncorrelated reservoirs beyond the Markovian approximation. Quite different from the Markovian reservoirs [C. E. Lopez et al., Phys. Rev. Lett. ... More
Discovery of Two Types of X-ray Dips in Cyg X-1Dec 06 2001We observed Cyg X-1 with {\em RXTE} contiguously over its 5.6-day binary orbit. The source was found to be in the hard state throughout the observation. Many intensity dips were detected in the X-ray light curves. We found that the dips fell into two ... More
Entanglement preservation for multilevel systems under non-ideal pulse controlMay 18 2010We investigate how to effectively preserve the entanglement between two noninteracting multilevel oscillators coupled to a common reservoir under non-ideal pulse control. A universal characterization using fidelity is developed for the behavior of the ... More
Next-To-Leading Order Differential Cross-Sections for $J/ψ$, $ψ(2S)$ and $Υ$ Production in Proton-Proton Collisions at a Fixed-Target Experiment using the LHC Beams (AFTER@LHC)Oct 18 2015Using nonrelativistic QCD (NRQCD) factorization, we calculate the yields for $J/\psi$, $\psi(2S)$ and $\Upsilon(1S)$ hadroproduction at $\sqrt{s}=$ 72 GeV and 115 GeV including the next-to-leading order QCD corrections. Both these center-of-mass energies ... More
Group divisible (K_4-e)-packings with any minimum leaveMay 24 2017A decomposition of $K_{n(g)}\setminus L$, the complete n-partite equipartite graph with a subgraph L (called the leave) removed, into edge disjoint copies of a graph G is called a maximum group divisible packing of $K_{n(g)}$ with G if L contains as few ... More
A Resolution of the Paradox of EnrichmentApr 21 2011Mar 11 2013The paradox of enrichment was observed by M. Rosenzweig in a class of predator-prey models. Two of the parameters in the models are crucial for the paradox. These two parameters are the prey's carrying capacity and prey's half-saturation for predation. ... More
On the Chaotic Flux Dynamics in a Long Josephson JunctionJul 16 2009Flux dynamics in an annular long Josephson junction is studied. Three main topics are covered. The first is chaotic flux dynamics and its prediction via Melnikov integrals. It turns out that DC current bias cannot induce chaotic flux dynamics, while AC ... More
Multiferroic phases of the frustrated quantum spin-chain compound linariteSep 20 2016Dec 09 2016The dielectric properties of the prototypical frustrated ferromagnetic spin-chain compound PbCuSO$_4$(OH)$_2$ known as linarite, are studied across its strongly anisotropic magnetic phase diagram in single crystal samples. The ferroelectric character ... More
Impact of Baryonic Physics on Intrinsic AlignmentsJul 25 2016We explore the effects of specific assumptions in the subgrid models of star formation and stellar and AGN feedback on intrinsic alignments of galaxies in cosmological simulations of "MassiveBlack-II" family. Using smaller volume simulations, we explored ... More
Multiple Reggeon Exchange from Summing QCD Feynman DiagramsJun 17 1996Multiple reggeon exchange supplies subleading logs that may be used to restore unitarity to the Low-Nussinov Pomeron, provided it can be proven that the sum of Feynman diagrams to all orders gives rise to such multiple regge exchanges. This question cannot ... More
On the Structure of the Bose-Einstein Condensate Ground StateMay 07 1999We construct a macroscopic wave function that describes the Bose-Einstein condensate and weakly excited states, using the su(1,1) structure of the mean-field hamiltonian, and compare this state with the experimental values of second and third order correlation ... More
DIAGRAMMATIC ANALYSIS OF QCD GAUGE TRANSFORMATIONS AND GAUGE CANCELLATIONSMar 13 1995Diagrammatic techniques are invented to implement QCD gauge transformations. These techniques can be used to discover how gauge-dependent terms are cancelled among diagrams to yield gauge-invariant results in the sum. In this way a multiloop pinching ... More
Short term unpredictability of high Reynolds number turbulence --- rough dependence on initial dataFeb 09 2017Jun 26 2019Short term unpredictability is discovered numerically for high Reynolds number fluid flows under periodic boundary conditions. Furthermore, the abundance of the short term unpredictability is also discovered. These discoveries support our theory that ... More
Evaluation of Multiloop Diagrams via Lightcone IntegrationJul 18 1997May 03 1998We present a systematic method to determine the dominant regions of internal momenta contributing to any two-body high-energy near-forward scattering diagram. Such a knowledge is used to evaluate leading high-energy dependences of loop diagrams. It also ... More
Gauge Cancellation for Electroweak Processes and the Gervais-Neveu GaugeAug 02 1996A graphical method is developed to study the total or partial cancellation of gauge-dependent (divergence) terms in electroweak theory. The method is used to work out rules in the Gervais-Neveu gauge, whose triple-gauge vertex contains three terms rather ... More
String Organization of Field Theories: Duality and Gauge InvarianceSep 14 1994String theories should reduce to ordinary four-dimensional field theories at low energies. Yet the formulation of the two are so different that such a connection, if it exists, is not immediately obvious. With the Schwinger proper-time representation, ... More
Short term unpredictability of high Reynolds number turbulence --- rough dependence on initial dataFeb 09 2017Short term unpredictability is discovered numerically for high Reynolds number fluid flows under periodic boundary conditions. Furthermore, the abundance of the short term unpredictability is also discovered. These discoveries support our theory that ... More
Poincaré Inequality for Dirichlet Distributions and Infinite-Dimensional GeneralizationsApr 11 2015Sep 04 2015For any $N\ge 2$ and $\aa:=(\aa_1,\cdots, \aa_{N+1})\in (0,\infty)^{N+1}$, let $\mu^{(N)}_{\aa}$ be the corresponding Dirichlet distribution on $\DD:= \big\{ x=(x_i)_{1\le i\le N}\in [0,1]^N:\ \sum_{1\le i\le N} x_i\le 1\big\}.$ We prove the Poincar\'e ... More
Activating Mg acceptors in AlN by oxygen: first principles calculationsSep 17 2007First principles calculations based on density functional theory (DFT) are performed to study the electronic properties of Mg acceptors in AlN at the presence of oxygen. It is found that Mg and O tend to form complexes like Mg-O, Mg$_2$-O, Mg$_3$-O and ... More
Magnetic phase diagram of the strongly frustrated quantum spin chain system PbCuSO$_4$(OH)$_2$ in tilted magnetic fieldsApr 06 2018Aug 17 2018We report the $\mathbf{H}-T$ phase diagram of $S=1/2$ strongly frustrated anisotropic spin chain material linarite PbCuSO$_4$(OH)$_2$ in tilted magnetic fields up to 10 T and temperatures down to 0.2 K. By means of torque magnetometry we investigate the ... More
Graphitic-BN Based Metal-free Molecular Magnets From A First Principle StudyMar 02 2005We perform a first principle calculation on the electronic properties of carbon doped graphitic boron nitride graphitic BN. It was found that carbon substitution for either boron or nitrogen atom in graphitic BN can induce spontaneous magnetization. Calculations ... More
Generalized Background-Field MethodJun 04 1997The graphical method discussed previously can be used to create new gauges not reachable by the path-integral formalism. By this means a new gauge is designed for more efficient two-loop QCD calculations. It is related to but simpler than the ordinary ... More
An isoperimetric inequality for eigenvalues of the bi-harmonic operatorJan 27 2011} In this article, we put forward a Neumann eigenvalue problem for the bi-harmonic operator $\Delta^2$ on a bounded smooth domain $\Om$ in the Euclidean $n$-space ${\bf R}^n$ ($n\ge2$) and then prove that the corresponding first non-zero eigenvalue $\Upsilon_1(\Om)$ ... More
On the Nevanlinna characteristic of f(z+η) and difference equations in the complex planeSep 12 2006May 09 2008We investigate the growth of the Nevanlinna Characteristic of f(z+\eta) for a fixed \eta in this paper. In particular, we obtain a precise asymptotic relation between T(r,f(z+\eta) and T(r,f), which is only true for finite order meromorphic functions. ... More
Multiband Fitting to Three Long GRBs with Fermi/LAT Data: Structured Ejecta Sweeping up a Density-Jump MediumNov 13 2010Jun 04 2011We present broadband (radio, optical, X-ray and GeV) fits to the afterglow light curves and spectra of three long-duration gamma-ray bursts (GRBs 080916C, 090902B, and 090926A) detected by the Gamma-Ray Burst Monitor (GBM) and Large Area Telescope (LAT) ... More
Graphene on metal surface: gap opening and n-dopingDec 25 2007Graphene grown on metal surface, Cu(111), with a boron nitride(BN) buffer layer is studied for the first time. Our first-principles calculations reveal that charge is transferred from the copper substrate to graphene through the BN buffer layer which ... More
Dissipative dynamics of quantum discord under quantum chaotic environmentOct 19 2010We investigate the dissipative dynamics of quantum discord in a decoherence model with two initially entangled qubits in addition to a quantum kicked top. The two qubits are uncoupled during the period of our study and one of them interacts with the quantum ... More
Nuclear spin qubits in a trapped-ion quantum computerApr 26 2009Physical systems must fulfill a number of conditions to qualify as useful quantum bits (qubits) for quantum information processing, including ease of manipulation, long decoherence times, and high fidelity readout operations. Since these conditions are ... More
Converse flexoelectricity around ferroelastic domain wallsMay 21 2019Domain walls (DWs) are ubiquitous in ferroelectric materials. Ferroelastic DWs refer to those who separate two domains with unparalleled polarizations (or two different ferroelastic variants). It is long believed that the structures of ferroelastic DWs ... More
Observation of two-level critical state in the superconducting FeTe thin filmsJun 22 2019FeTe, a non-superconducting parent compound in the iron-chalcogenide family, becomes superconducting after annealing in oxygen. Under the presence of magnetism, spin-orbit coupling, inhomogeneity and lattice distortion, the nature of its superconductivity ... More
Lepton flavor violation two-body decays of quarkoniumsDec 15 2002In this paper we firstly study various model-independent bounds on lepton flavor violation (LFV) in processes of $J/\Psi$, $\Psi'$ and $\Upsilon$ two-body decays, then calculate their branch ratios % By using the constraints from other ways, we obtain ... More
Event-Driven Implicit Authentication for Mobile Access ControlJul 27 2016In order to protect user privacy on mobile devices, an event-driven implicit authentication scheme is proposed in this paper. Several methods of utilizing the scheme for recognizing legitimate user behavior are investigated. The investigated methods compute ... More
Quantum-memory-assisted entropic uncertainty principle under noiseMar 15 2012The measurement outcomes of two incompatible observables on a particle can be precisely predicted when it is maximally entangled with a quantum memory, as quantified recently [Nature Phys. 6, 659 (2010)]. We explore the behavior of the uncertainty relation ... More
Applicability of coupling strength estimation for linear chains of restricted accessMar 10 2019The characterization of an unknown quantum system requires the Hamiltonian identification. The full access to the system, however, is usually restricted, hindering the direct retrieval of relevant parameters, and a reliable indirect estimation is usually ... More
Magnetism in BN nanotubes induced by Carbon SubstitutionJan 06 2005We performed ab initio calculation on the pristine and carbon-doped (5,5) and (9,0) BN nanotubes. It was found that Carbon substitution for either boron or nitrogen in BN nanotubes can induce spontaneous magnetization. Calculations based on density functional ... More
Cut Diagrams for High Energy ScatteringsApr 29 1996A new approach is introduced to study QCD amplitudes at high energy and comparatively small momentum transfer. Novel cut diagrams, representing resummation of Feynman diagrams, are used to simplify calculation and to avoid delicate cancellations encountered ... More
Preparation of 18-filament Cu/NbZr/MgB2 tape with high transport critical current densityJun 05 2001Cu-stabilized 18-filament MgB2 tapes with NbZr buffer have been fabricated by using powder-in-tube technique. The phase composition and microstructure were examined by X-ray diffraction and optical microscopy. Transport critical current measurements were ... More
Continuous Implicit Authentication for Mobile Devices based on Adaptive Neuro-Fuzzy Inference SystemMay 18 2017As mobile devices have become indispensable in modern life, mobile security is becoming much more important. Traditional password or PIN-like point-of-entry security measures score low on usability and are vulnerable to brute force and other types of ... More
Universal quantum computation with quantum-dot cellular automata in dephasing-free subspaceJan 30 2008Aug 22 2008We investigate the possibility to have electron-pairs in dephasing-free subspace (DFS), by means of the quantum-dot cellular automata (QCA) and single-spin rotations, to carry out a high-fidelity and deterministic universal quantum computation. We show ... More
Proposed method for direct measurement of non-Markovian character of the qubits coupled to bosonic reservoirsDec 15 2009Mar 24 2010The non-Markovianity is a recently proposed characterization of the non-Markovian behavior in an open quantum system, based on which we first present a practical idea for directly measuring the non-Markovian character of a single qubit coupled to a zero-temperature ... More
Implementation of three-qubit Grover search in cavity QEDJul 03 2007Using resonant interaction of three Rydberg atoms with a single-mode microwave cavity, we consider a realization of three-qubit Grover search algorithm in the presence of weak cavity decay, based on a previous idea for three-qubit quantum gate [Phys. ... More
Dimerized Decomposition of Quantum Evolution on an Arbitrary GraphJan 12 2017May 26 2017The study of quantum evolution on graphs for diversified topologies is beneficial to modeling various realistic systems. A systematic method, the dimerized decomposition, is proposed to analyze the dynamics on an arbitrary network. By introducing global ... More
X-ray Shots of Cyg X-1Oct 08 1998X-ray shots of Cyg X-1 in different energy bands and spectral states have been studied with PCA/RXTE observations. The detailed shot structure is obtained by superposing many shots with one millisecond time bin through aligning their peaks with an improved ... More
Pressure-induced Spin-Peierls to Incommensurate Charge-Density-Wave Transition in the Ground State of TiOClAug 04 2009The ground state of the spin-Peierls system TiOCl was probed using synchrotron x-ray diffraction on a single-crystal sample at T = 6 K. We tracked the evolution of the structural superlattice peaks associated with the dimerized ground state as a function ... More
Multi-waveband polarimetric observations of NRAO 530 on parsec-scaleJun 16 2010We report on multi-bands VLBA polarimetric observations of NRAO 530 in February 1997. Total intensity, EVPA distributions at all these frequencies are presented. Model fitting has been performed, from which the fitted southmost component A is confirmed ... More
Remote-control spin filtering through a $T$-type structureOct 05 2006Mar 01 2007We propose a spin filter scheme using a $T$-stub waveguide. By applying a moderate magnetic field at the tip of the sidearm, this device can produce both large electric and spin current. The direction, polarization of the output spin current can be further ... More
Probing the Inflow/Out-flow and Accretion Disk of Cyg X-1 in the High State with HETG/ChandraAug 14 2003Cyg X-1 was observed in the high state at the conjunction orbital phase (0) with HETG/Chandra. Strong and asymmetric absorption lines of highly ionized species were detected, such as Fe XXV, Fe XXIV, Fe XXIII, Si XIV, S XVI, Ne X, and etc. In the high ... More
Temporal and Spectral Correlations of Cyg X-1Mar 15 1999Mar 16 1999Temporal and spectral properties of X-ray rapid variability of Cyg X-1 are studied by an approach of correlation analysis in the time domain on different time scales. The correlation coefficients between the total intensity in 2-60 keV and the hardness ... More
Metal Insulator transition at B=0 in p-SiGeAug 15 1997Aug 16 1997Observations are reported of a metal-insulator transition in a 2D hole gas in asymmetrically doped strained SiGe quantum wells. The metallic phase, which appears at low temperatures in these high mobility samples, is characterised by a resistivity that ... More
Bilinear R-parity Violation and $τ^{\mp} \tildeκ^{\pm}$ mixing production in e^+ e^- collidersJun 27 1998Nov 23 1998A R-parity breaking SUSY model characterized by an effective bilinear violation with only $\tau$-lepton number breaking in the superpotential is outlined. The CP-odd Higgs boson masses and those of charged Higgs bosons are discussed. In the model, several ... More
Upgrade of the SDL Control SystemNov 28 2001Feb 06 2002The Source Development Lab (SDL) at BNL consists of a 230 MeV electron linac and a 10 m long wiggler for short wavelength Free Electronic Laser (FEL) development. The original control system [1] was based on the one in use at the National Synchrotron ... More
Nodal Manifolds Bounded by Exceptional Points on Non-Hermitian Honeycomb Lattices and Electrical-Circuit RealizationsOct 22 2018Topological semimetals feature a diversity of nodal manifolds including nodal points, various nodal lines and surfaces, and recently novel quantum states in non-Hermitian systems have been arousing widespread research interests. In contrast to Hermitian ... More
Fuzzy Logic-based Implicit Authentication for Mobile Access ControlSep 12 2016In order to address the increasing compromise of user privacy on mobile devices, a Fuzzy Logic based implicit authentication scheme is proposed in this paper. The proposed scheme computes an aggregate score based on selected features and a threshold in ... More
Q-Factor Measurement of Nonlinear Superconducting ResonatorsJan 21 2000A novel method, which combined a multi-bandwidth measurement and an extrapolation procedure, is proposed for extracting the loaded Q-factor (Q_{L}) with improved accuracy from non-Lorentzian resonances of nonlinear superconducting resonators.
Analysis and Visualization of Deep Neural Networks in Device-Free Wi-Fi Indoor LocalizationApr 23 2019May 22 2019Device-free Wi-Fi indoor localization has received significant attention as a key enabling technology for many Internet of Things (IoT) applications. Machine learning-based location estimators, such as the deep neural network (DNN), carry proven potential ... More
Quantum anomalous Hall effect with field-tunable Chern number near Z2 topological critical pointJan 05 2016We study the practicability of achieving quantum anomalous Hall (QAH) effect with field-tunable Chern number in a magnetically doped, topologically trivial insulating thin film. Specifically in a candidate material, TlBi(S$_{1-\delta}$Se$_{\delta}$)$_2$, ... More
3D nano-bridge-based SQUID susceptometers for scanning magnetic imaging of quantum materialsMar 27 2019We designed and fabricated a new type of superconducting quantum interference device (SQUID) susceptometers for magnetic imaging of quantum materials. The 2-junction SQUID sensors employ 3D Nb nano-bridges fabricated using electron beam lithography. The ... More
Sealing off a carbon nanotube with a self-assembled aqueous valve for the storage of hydrogen in GPa pressureJun 29 2012The end section of a carbon nanotube, cut by acid treatment, contains hydrophillic oxygen groups. Water molecules can self-assemble around these groups to seal off a carbon nanotube and form an "aqueous valve". Molecular dynamics simulations on single-wall ... More
Morphological evolution of a 3D CME cloud reconstructed from three viewpointsMar 15 2012The propagation properties of coronal mass ejections (CMEs) are crucial to predict its geomagnetic effect. A newly developed three dimensional (3D) mask fitting reconstruction method using coronagraph images from three viewpoints has been described and ... More
Perfect spin-fillter and spin-valve in carbon atomic chainsNov 01 2009We report ab initio calculations of spin-dependent transport in single atomic carbon chains bridging two zigzag graphene nanoribbon electrodes. Our calculations show that carbon atomic chains coupled to graphene electrodes are perfect spin-filters with ... More
A New Method to Use Chandra Data to Resolve the X-Ray Halos Around Point Sources and Its Application to Cygnus X-1Mar 06 2003Jul 22 2003With excellent angular resolution, good energy resolution and broad energy band, the Chandra ACIS is the best instrument for studying the X-ray halos around some galactic X-ray point sources caused by the dust scattering of X-rays in the interstellar ... More
New prototype scintillator detector for the Tibet AS$γ$ ExperimentDec 18 2017The hybrid Tibet AS array was successfully constructed in 2014. It has 4500 m$^{2}$ underground water Cherenkov pools used as the muon detector (MD) and 789 scintillator detectors covering 36900 m$^{2}$ as the surface array. At 100 TeV, cosmic-ray background ... More
Deterministically entangling distant nitrogen-vacancy centers by a nanomechanical cantileverJul 31 2009Aug 27 2009We present a practical scheme by global addressing to deterministically entangle negatively charged nitrogen-vacancy (N-V) centers in distant diamonds using a nano-mechanical cantilever with the magnetic tips strongly coupled to the N-V electron spins. ... More
A Cold Atomic Beam InterferometerFeb 16 2014Nov 08 2014We demonstrate an atom interferometer that uses a laser-cooled continuous beam of $^{87}$Rb atoms having velocities of 10--20 m/s. With spatially separated Raman beams to coherently manipulate the atomic wave packets, Mach--Zehnder interference fringes ... More
Franck-Condon Physics in A Single Trapped IonSep 08 2010Mar 23 2011We propose how to explore the Franck-Condon (FC) physics via a single ion confined in a spin-dependent potential, formed by the combination of a Paul trap and a magnetic field gradient. The correlation between electronic and vibrational degrees of freedom, ... More
Purification of Single Photons from Room-Temperature Quantum DotsOct 04 2017Single photon emitters are indispensable to photonic quantum technologies. Here we demonstrate waveform-controlled high-purity single photons from room-temperature colloidal quantum dots. The purity of the single photons does not vary with the excitation ... More
Streamer Wave Events Observed in Solar Cycle 23May 22 2011In this paper we conduct a data survey searching for well-defined streamer wave events observed by the Large Angle and Spectrometric Coronagraph (LASCO) on-board the Solar and Heliospheric Observatory (SOHO) throughout Solar Cycle 23. As a result, 8 candidate ... More
Radio signatures of CME-streamer interaction and source diagnostics of type II radio burstApr 25 2012It has been suggested that type II radio bursts are due to energetic electrons accelerated at coronal shocks. Radio observations, however, have poor or no spatial resolutions to pinpoint the exact acceleration locations of these electrons. In this paper, ... More
Diagnostics on the source properties of type II radio burst with spectral bumpsMar 06 2013In recent studies (Feng et al., 2012; Kong et al., 2012), we proposed that source properties of type II radio bursts can be inferred through a causal relationship between the special shape of the type II dynamic spectrum (e.g., bump or break) and simultaneous ... More
Discovery of Weyl nodal lines in a single-layer ferromagnetJan 05 2019Two-dimensional (2D) materials have attracted great attention and spurred rapid development in both fundamental research and device applications. The search for exotic physical properties, such as magnetic and topological order, in 2D materials could ... More
Tunable Fe-vacancy disorder-order transition in FeSe thin filmsNov 17 2015Various Fe-vacancy orders have been reported in tetragonal Fe1-xSe single crystals and nanowires/nanosheets, which are similar to those found in alkali metal intercalated A1-xFe2-ySe2 superconductors. Here we report the in-situ angle-resolved photoemission ... More
Observation of Dirac Cone Band Dispersion in FeSe Thin Films by Photoemission SpectroscopyAug 29 2015The electronic structure of FeSe thin films grown on SrTiO3 substrate is studied by angle-resolved photoemission spectroscopy (ARPES). We reveal the existence of Dirac cone band dispersions in FeSe thin films thicker than 1 Unit Cell below the nematic ... More
Study on a prototype of the large dimensional refractive lens for the future large field-of-view IACTSep 06 2015In gamma ray astronomy, the energy range from sub-100GeV to TeV is crucial due to where there is a gap between space experiments and ground-based ones. In addition, observations in this energy range are expected to provide more details about the high ... More
Insulator-metal transition shift related to magnetic polarons in La0.67-xYxCa0.33MnO3Jan 16 2003The magnetic transport properties have been measured for La0.67-xYxCa0.33MnO3 (0 <= x <= 0.14) system. It was found that the transition temperature Tp almost linearly moves to higher temperature as H increases. Electron spin resonance confirms that above ... More
Carbon-doped ZnO: A New Class of Room Temperature Dilute Magnetic SemiconductorOct 31 2006We report magnetism in carbon doped ZnO. Our first-principles calculations based on density functional theory predicted that carbon substitution for oxygen in ZnO results in a magnetic moment of 1.78 $\mu_B$ per carbon. The theoretical prediction was ... More
Direct Experimental Observation of the Gas Filamentation Effect using a Two-bunch X-ray FEL BeamMay 28 2017We report the experimental observation of the filamentation effect in gas devices designed for X-ray Free-electron Lasers. The measurements were carried out at the Linac Coherent Light Source on the X-ray Correlation Spectroscopy (XCS) instrument using ... More
X-ray flares: late internal and late external shocksDec 22 2005We analyze several recently detected gamma-ray bursts (GRBs) with late X-ray flares in the context of late internal shock and late external shock models. We find that the X-ray flares in GRB 050421 and GRB 050502B originate from late internal shocks, ... More
Strain-stress study of AlxGa1-xN/AlN heterostructures on c-plane sapphire and related optical propertiesMay 10 2019This work presents a systematic study of stress and strain of AlxGa1-xN/AlN with composition ranging from GaN to AlN, grown on a c-plane sapphire by metal-organic chemical vapor deposition, using synchrotron radiation high-resolution X-ray diffraction ... More
Intense source of cold cesium atoms based on a two-dimensional magneto-optical trap with independent axial cooling and pushingSep 24 2015We report our studies on an intense source of cold cesium atoms based on a two-dimensional magneto-optical trap with independent axial cooling and pushing. The new-designed source, proposed as 2D-HP MOT, uses hollow laser beams for axial cooling and a ... More
Fermi liquid breakdown and evidence for superconductivity in YFe$_2$Ge$_2$Nov 01 2013Sep 26 2014In the d-electron system YFe$_2$Ge$_2$, an unusually high and temperature dependent Sommerfeld ratio of the specific heat capacity $C/T \sim 100~\mathrm{mJ/(molK^2)}$ and an anomalous power law temperature dependence of the electrical resistivity $\rho ... More
Micropipette aspiration method for characterizing biological materials with surface energyJan 11 2018Many soft biological tissues possess a considerable surface stress, which plays a significant role in their biophysical functions, but most previous methods for characterizing their mechanical properties have neglected the effects of surface stress. In ... More
The effect of electron holes on cyclotron maser emission driven by horseshoe distributionsNov 07 2016This Brief Communication presents a quantitative investigation for the effect of electron holes on electron-cyclotron maser (ECM) driven by horseshoe distributions. The investigation is based on an integrated distribution function for the horseshoe distributions ... More
Dynamical Evolution of Gamma-Ray Burst Remnants with Evolving Radiative EfficiencyOct 30 2002In previous works, a generic dynamical model has been suggested by Huang et al., which is shown to be correct for both adiabatic and radiative blastwaves, and in both ultra-relativistic and non-relativistic phases. In deriving their equations, Huang et ... More
Electron Transport Properties of Atomic Carbon Nanowires between Graphene ElectrodesOct 21 2009Oct 31 2009Long, stable and free-standing linear atomic carbon wires have been carved out from graphene recently [Meyer et al: Nature (London) 2008, 454, 319; Jin et al: Phys: Rev: Lett: 2009, 102, 205501]. They can be considered as the extremely narrow graphene ... More
Universal Behaviour of Metal-Insulator Transitions in the p-SiGe SystemJun 17 1999Magnetoresistance measurements are presented for a strained p-SiGe quantum well sample where the density is varied through the B=0 metal-insulator transition. The close relationship between this transition, the high field Hall insulator transition and ... More
Fractal Conductance Fluctuations in a Soft Wall Stadium and a Sinai BilliardSep 08 1997Dec 19 1997Conductance fluctuations have been studied in a soft wall stadium and a Sinai billiard defined by electrostatic gates on a high mobility semiconductor heterojunction. These reproducible magnetoconductance fluctuations are found to be fractal confirming ... More
Quasi-Periodic Releases of Streamer Blobs and Velocity Variability of the Slow Solar Wind near the SunJul 05 2009We search for persistent and quasi-periodic release events of streamer blobs during 2007 with the Large Angle Spectrometric Coronagraph on the \textit{Solar and Heliospheric Observatory} and assess the velocity of the slow solar wind along the plasma ... More
Breaking the energy-symmetry blockade in magneto-optical rotationApr 20 2018The magneto-optical polarization rotation effect has prolific applications in various research areas spanning the scientific spectrum including space and interstellar research, nano-technology and material science, biomedical imaging, and sub-atomic particle ... More
Nanotesla-level, shield-less, field-compensation-free, wave-mixing-enhanced body-temperature atomic magnetometry for biomagnetismApr 22 2018We report an optical inelastic-wave-mixing-enhanced atomic magnetometry technique that results in nT-level magnetic field detection at temperatures compatible with the human body without magnetic shielding, zero-field compensation, or high-frequency modulated ... More
Burst behavior due to quasimode excited by stimulated Brillouin scattering in high-intensity laser-plasma interactionJun 24 2019The strong-coupling mode, called quasimode, will be excited by stimulated Brillouin scattering (SBS) in high-intensity laser-plasma interaction. And SBS of quasimode will compete with SBS of fast mode (or slow mode) in multi-ion species plasmas, thus ... More
Magnetic properties and spin structure of MnO single crystal and powderFeb 13 2017Zero field cooled (ZFC)/Field Cooled (FC) magnetization curves of a bulk MnO single crystal show a peculiar peak at low temperatures (~40K) similar to the low temperature peak observed in MnO nanoparticles. In order to investigate the origin of this peak, ... More
Time-dependent occurrence rate of electromagnetic cyclotron waves in the solar wind: evidence for effect of alpha particles?Sep 04 2017Previous studies revealed that electromagnetic cyclotron waves (ECWs) near the proton cyclotron frequency exist widely in the solar wind, and the majority of ECWs are left-handed (LH) polarized waves. Using the magnetic field data from the STEREO mission, ... More
Decoupling of magnetism and electric transport in single-crystal (Sr1-xAx)2IrO4 (A = Ca or Ba)Dec 15 2017May 03 2018We report a systematical structural, transport and magnetic study of Ca or Ba doped Sr2IrO4single crystals. Isoelectronically substituting Ca2+ (up to 15%) or Ba2+ (up to 4%) ion for the Sr2+ ion provides no additional charge carriers but effectively ... More
$Pb_{0.4}Bi_{1.6}Sr_{2}Ca_{1}Cu_{2}O_{8+x}$ and Oxygen Stoichiometry: Structure, Resistivity, Fermi Surface Topology and Normal State PropertiesOct 19 1994$Pb_{0.4}Bi_{1.6}Sr_2CaCu_2O_{8+x}$ ($Bi(Pb)-$2212) single crystal samples were studied using transmission electron microscopy (TEM), $ab-$plane ($\rho_{ab}$) and $c-$axis ($\rho_c$) resistivity, and high resolution angle-resolved ultraviolet photoemission ... More
Possible Nodeless Superconducting Gaps in Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ and YBa$_2$Cu$_3$O$_{7-x}$ Revealed by Cross-Sectional Scanning Tunneling SpectroscopyNov 14 2016Pairing in the cuprate high-temperature superconductors and its origin remain among the most enduring mysteries in condensed matter physics. With cross-sectional scanning tunneling microscopy/ spectroscopy, we clearly reveal the spatial-dependence or ... More
Adaptation in multivariate log-concave density estimationDec 30 2018We study the adaptation properties of the multivariate log-concave maximum likelihood estimator over two subclasses of log-concave densities. The first consists of densities with polyhedral support whose logarithms are piecewise affine. The complexity ... More
Angle-resolved photoemission spectroscopy study on iron-based superconductorsJul 22 2013Aug 13 2013Angle-resolved photoemission spectroscopy (ARPES) has played an important role in determining the band structure and the superconducting gap structure of iron-based superconductors. Here from the ARPES perspective, we briefly review the main results from ... More
Evolution of Iron K$_α$ Line Emission in the Black Hole Candidate GX 339-4Jan 25 2001GX 339-4 was regularly monitored with RXTE during a period (in 1999) when its X-ray flux decreased significantly (from 4.2$\times 10^{-10}$ erg cm$^{-2} s^{-1}$ to 7.6$\times 10^{-12}$ erg cm$^{-2}$s$^{-1}$ in the 3--20 keV band), as the source settled ... More
Strongly-coupled quantum critical point in an all-in-all-out antiferromagnetMay 04 2018Dimensionality and symmetry play deterministic roles in the laws of Nature. They are important tools to characterize and understand quantum phase transitions, especially in the limit of strong correlations between spin, orbit, charge, and structural degrees ... More
An imaging study of a complex solar coronal radio eruptionJul 30 2016Solar coronal radio bursts are enhanced radio emission excited by energetic electrons accelerated during solar eruptions, studies on which are important for investigating the origin and physical mechanism of energetic particles and further diagnosing ... More