Results for "X. Shi"

total 18787took 0.13s
Star Formation Rate Indicators in WISE/SDSSDec 06 2013With the goal of investigating the degree to which the total infrared luminosity ($L_{\rm TIR}$) traces the star formation rate (SFR), we analyze the $L_{\rm TIR}$ from the dust in a sample of $\sim$ 6000 star-forming galaxies, based on the 3.4, 4.6, ... More
Radiation-Induced "Zero-Resistance State" and the Photon Assisted TransportFeb 19 2003Mar 13 2003We demonstrate that the radiation induced "zero-resistance state" observed in a two-dimensional electron gas is a result of the non-trivial structure of the density of states of the systems and the photon assisted transport. A toy model of a structureless ... More
Quantum gates by periodic drivingMay 19 2015Sep 12 2015Topological quantum computation has been extensively studied due to its robustness against decoherence. A conventional way to realize it is by adiabatic operations---it requires relatively long time to accomplish so that the speed of quantum computation ... More
Dephasing and Metal-Insulator TransitionDec 07 2000The metal-insulator transition (MIT) observed in two-dimensional (2D) systems is apparently contradictory to the well known scaling theory of localization. By investigating the conductance of disordered one-dimensional systems with a finite phase coherence ... More
Can the age discrepancies of neutron stars be circumvented by an accretion-assisted torque?Jul 07 2003Aug 23 2003It is found that 1E 1207.4-5209 could be a low-mass bare strange star if its small radius or low altitude cyclotron formation can be identified. The age problems of five sources could be solved by a fossil-disk-assisted torque. The magnetic dipole radiation ... More
Reply to Comment on: "Radiation-Induced 'Zero-Resistance State' and the Photon Assisted Transport"Mar 07 2003We show that the comment by A.F. Volkov ignores a delicate issue in the conductance measurement for a hall bar system. In such system, $\rho _{xx}\approx \rho_{xy}^{2}\sigma_{xx}$ while $\sigma_{xy}\gg \sigma_{xx}$, as correctly pointed out in Ref.3. ... More
The Droplet State and the Compressibility Anomaly in Dilute 2D Electron SystemsMar 26 2001We investigate the space distribution of carrier density and the compressibility of two-dimensional (2D) electron systems by using the local density approximation. The strong correlation is simulated by the local exchange and correlation energies. A slowly ... More
Robust state transfer with high fidelity in spin-1/2 chains by Lyapunov controlMay 19 2015Based on the Lyapunov control, we present a scheme to realize state transfer with high fidelity by only modulating the boundary spins in a quantum spin-1/2 chain. Recall that the conventional transmission protocols aim at nonstationary state (or information) ... More
Preparation of topological modes by Lyapunov controlNov 20 2014Sep 14 2015By Lyapunov control, we present a proposal to drive quasi-particles into a topological mode in quantum systems described by a quadratic Hamiltonian. The merit of this control is the individual manipulations on the boundary sites. We take the Kitaev's ... More
Couplings between Majorana bound states mediated by topologically-trivial chainsJul 13 2015Oct 02 2015We examine the couplings between two Majorana bound states mediated by topologically-trivial chains. Four types of chain are considered, e.g., the Kitaev chain with/without pairing couplings to the Majorana fermion, the Kitaev chain with next nearest-neighbor ... More
Dephasing Effect in Photon-Assisted Resonant Tunneling through Quantum DotsMar 26 2001We analyze dephasing in single and double quantum dot systems. The decoherence is introduced by the B\"{u}ttiker model with current conserving fictitious voltage leads connected to the dots. By using the non-equilibrium Green function method, we investigate ... More
Meta-Percolation and Metal-Insulator Transition in Two DimensionsApr 27 1999According to the scaling theory of localization, all quantum electronic states are localized in two-dimensional (2D) systems. One consequence of the theory is that there is no quantum percolation transition in 2D. However, in a real system at a finite ... More
Population transfer driven by far-off-resonant fieldsApr 20 2016Sep 16 2016For a two-level system, it is believed that a far-off-resonant driving can not help coherent population transfer between the states. In this work, we propose a scheme to implement the coherent transfer with far-off-resonant driving. The scheme works well ... More
Oxygen abundance in the Sloan Digital Sky SurveyMar 10 2006We present two samples of $\hii$ galaxies from the Sloan Digital Sky Survey (SDSS) spectroscopic observations data release 3. The electron temperatures($T_e$) of 225 galaxies are calculated with the photoionized $\hii$ model and $T_e$ of 3997 galaxies ... More
Bispectrum covariance in the flat-sky limitJul 16 2009Feb 03 2010To probe cosmological fields beyond the Gaussian level, three-point statistics can be used, all of which are related to the bispectrum. Hence, measurements of CMB anisotropies, galaxy clustering, and weak gravitational lensing alike have to rely upon ... More
Wax and wane of the cross-sectional momentum and contrarian effects: Evidence from the Chinese stock marketsJul 18 2017This paper investigates the time-varying risk-premium relation of the Chinese stock markets within the framework of cross-sectional momentum and contrarian effects by adopting the Capital Asset Pricing Model and the French-Fama three factor model. The ... More
A Droplet State in an Interacting Two-Dimensional Electron SystemSep 30 1999It is well known that the dielectric constant of two-dimensional (2D) electron system goes negative at low electron densities. A consequence of the negative dielectric constant could be the formation of the droplet state. The droplet state is a two-phase ... More
Floquet theorem for open systems and its applicationsDec 17 2015For a closed system with periodic driving, Floquet theorem tells that the time evolution operator can be written as $ U(t,0)\equiv P(t)e^{\frac{-i}{\hbar}H_F t}$ with $P(t+T)=P(t)$, and $H_F$ is Hermitian and time-independent called Floquet Hamiltonian. ... More
The influence of localization transition on dynamical properties for an extended Aubry-André-Harper modelApr 07 2017Jun 27 2017We show the localization transition and its effect on two dynamical processes for an extended Aubry-Andr\'e-Harper model with incommensurate on-site and hopping potentials. After specifying an extended Aubry-Andr\'e-Harper model, we check the localization ... More
Edge state preparation in one dimensional lattice by quantum Lyapunov controlDec 10 2016Quantum Lyapunov control uses a feedback control methodology to determine control fields which are applied to control quantum systems in an open-loop way. In this work, we adopt two Lyapunov control schemes to prepare an edge state for a fermionic chain ... More
Effect of loss on the topological features of dimer chain described by the extended Aubry-André-Harper modelJan 10 2017By introducing loss to one sublattice of a dimer chain described by the extended Aubry-Andr\'e or Harper (AAH) model, we study the topological features including the edge states, spectrum and winding number of the chain. We find that the parameter region ... More
Optical Schrödinger Cat States in One Mode and two Coupled-Modes Subject to EnvironmentsNov 24 2016Jun 19 2017Taking the decoherence into account, we investigate nonclassical features of the optical Schr\"odinger cat states in one mode and two coupled-modes systems with two-photon driving. In the one mode system, the relationship between the Schr\"odinger cat ... More
Quantum computation with surface-state electrons by rapid population passagesSep 15 2012Quantum computation requires coherently controlling the evolutions of qubits. Usually, these manipulations are implemented by precisely designing the durations (such as the $\pi$-pulses) of the Rabi oscillations and tunable interbit coupling. Relaxing ... More
Am I a Baller? Basketball Performance Assessment from First-Person VideosNov 16 2016Aug 02 2017This paper presents a method to assess a basketball player's performance from his/her first-person video. A key challenge lies in the fact that the evaluation metric is highly subjective and specific to a particular evaluator. We leverage the first-person ... More
First Person Action-Object Detection with EgoNetMar 15 2016Jun 10 2017Unlike traditional third-person cameras mounted on robots, a first-person camera, captures a person's visual sensorimotor object interactions from up close. In this paper, we study the tight interplay between our momentary visual attention and motor action ... More
Learning Non-Lambertian Object Intrinsics across ShapeNet CategoriesDec 27 2016We consider the non-Lambertian object intrinsic problem of recovering diffuse albedo, shading, and specular highlights from a single image of an object. We build a large-scale object intrinsics database based on existing 3D models in the ShapeNet database. ... More
Constraints on Neutrino Oscillations from Big Bang NucleosynethesisJul 16 1993We discuss in detail the effect of neutrino oscillations in Big Bang nucleosynthesis, between active and sterile neutrinos, as well as between active and active neutrinos. We calculate the constraints on mixings between active and sterile neutrinos from ... More
Broadening the bandwidth of entangled photons: a step towards the generation of extremely short biphotonsJul 25 2008We demonstrate a technique that allows to fully control the bandwidth of entangled photons independently of the frequency band of interest and of the nonlinear crystal. We show that this technique allows to generate nearly transform-limited biphotons ... More
Approximating Cross-validatory Predictive Evaluation in Bayesian Latent Variables Models with Integrated IS and WAICApr 10 2014Jan 15 2015A natural method for approximating out-of-sample predictive evaluation is leave-one-out cross-validation (LOOCV) --- we alternately hold out each case from a full data set and then train a Bayesian model using Markov chain Monte Carlo (MCMC) without the ... More
Saturation of the magnetorotational instability in the unstratified shearing box with zero net flux: convergence in taller boxesDec 03 2015Previous studies of the nonlinear regime of the magnetorotational instability in one particular type of shearing box model -- unstratified with no net magnetic flux -- find that without explicit dissipation (viscosity and resistivity) the saturation amplitude ... More
Stark-chirped rapid adiabatic passage in the presence of dissipation for quantum computationApr 16 2013Nov 25 2014Stark-chirped rapid adiabatic passage (SCRAP) is an important technique used for coherent quantum controls. In this paper we investigate how the practically-existing dissipation of the system influences on the efficiency of the passage, and thus the fidelities ... More
Unsupervised Learning of Important Objects from First-Person VideosNov 16 2016Aug 02 2017A first-person camera, placed at a person's head, captures, which objects are important to the camera wearer. Most prior methods for this task learn to detect such important objects from the manually labeled first-person data in a supervised fashion. ... More
Convolutional Random Walk Networks for Semantic Image SegmentationMay 24 2016May 08 2017Most current semantic segmentation methods rely on fully convolutional networks (FCNs). However, their use of large receptive fields and many pooling layers cause low spatial resolution inside the deep layers. This leads to predictions with poor localization ... More
Enhancement of Transition Temperature in FexSe0.5Te0.5 Film via Iron VacanciesJul 07 2014The effects of iron deficiency in FexSe0.5Te0.5 thin films (0.8<x<1) on superconductivity and electronic properties have been studied. A significant enhancement of the superconducting transition temperature (TC) up to 21K was observed in the most Fe deficient ... More
Temporal Variation of the Hemispheric Solar RotationDec 07 2011The daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from January 1, 1945 to December 31, 2010 are used to investigate the temporal variation of the rotational cycle length through the continuous wavelet transformation ... More
Anti-Resonance and the 0.7 Anomaly in Conductance through a Quantum Point ContactMar 03 2004We investigate the transmission of electrons through a quantum point contact by using a quasi-one-dimensional model with a local bound state below the band bottom. While the complete transmission in lower channels gives rise to plateaus of conductance ... More
Preparation of edge states by shaking boundariesOct 28 2014Jul 14 2016Preparing topological states of quantum matter, such as edge states, is one of the most important directions in condensed matter physics. In this work, we present a proposal to prepare edge states in Aubry-Andr$\acute{\textrm{e}}$-Harper (AAH) model with ... More
An integrated device with high performance multi-function generators and Time-to-digital convertorsJan 12 2017A highly integrated, high performance, and re-configurable device, which is designed for the Nitrogen-Vacancy center based quantum applications, is reported. The digital compartment of the device is fully implemented in a Field-Programmable-Gate- Array. ... More
Effects of the sintering atmosphere on the superconductivity of SmFeAsO1-xFx compoundsFeb 28 2011A series of SmFeAsO1-xFx samples were sintered in quartz tubes filled with air of different pressures. The effects of the sintering atmosphere on the superconductivity were systematically investigated. The SmFeAsO1-xFx system maintains a transition temperature ... More
Superconductivity, charge ordering and structural properties of alpha and beta-NaxCoO2.y(H2O, D2O)Aug 21 2005Two series of &#61537;alpha and beta-NaxCoO2 materials have been prepared by means of Na deintercalation from the parent &#61537;alpha-NaCoO2 and &#61538;beta-Na0.6CoO2 phases, respectively. The &#61537;alpha-NaxCoO2 materials undergo a clear phase transition ... More
Low-temperature thermal conductivity of antiferromagnetic S = 1/2 chain material CuCl_2$\cdot$2((CH_3)_2SO)Oct 14 2013We study the heat transport of S = 1/2 chain compound CuCl_2$\cdot$2((CH_3)_2SO) along the b axis (vertical to the chain direction) at very low temperatures. The zero-field thermal conductivity (\kappa) shows a distinct kink at about 0.9 K, which is related ... More
Anomalous carrier density independent superconductivity in iron pnictidesApr 11 2016Dome-shape superconductivity phase diagram can commonly be observed in cuprate and iron-based systems via tuning parameters such as charge carrier doping, pressure, bond angle, and etc. We report doping electrons from transition-metal elements (TM = Co, ... More
Thermal noise limited higher-order mode locking of a reference cavityJan 12 2018Higher-order mode locking has been proposed to reduce the thermal noise limit of reference cavities. By locking a laser to the HG02 mode of a 10-cm long all ULE cavity, and measure its performance with the three-cornered-hat method among three independently ... More
Possible Phase Separation and Transport Properties in Large Superconducting Ca0.77La0.18Fe0.90As2 CrystalsDec 30 2013Mar 17 2016We synthesized large superconducting single crystal Ca0.77La0.18Fe0.90As2 ('112' type) of 2 millimeter size. Scanning electron microscopy (SEM) measurements revealed that bright and dark stripes alternately spread on the surface of crystals, indicating ... More
Anomalous magneto-optical Kerr effect in perpendicularly magnetized Co/Pt films on two-dimensional colloidal crystalsMar 02 2009Mar 04 2009We have studied the magneto-optical Kerr effect and optical reflectance of perpendicular magnetized Co/Pt films on self-assembly two-dimensional polystyrene spheres. It is shown that the magneto-optical and the reflectance spectra are correlated to each ... More
Accurate evaluation of the Green's function of disordered graphenesMay 20 2010An accurate simulation of Green's function and self-energy function of non-interacting electrons in disordered graphenes are performed. Fundamental physical quantities such as the elastic relaxation time {\tau}e, the phase velocity vp, and the group velocity ... More
Anomalous Tail Effect on Resistivity Transition and Weak-link Behavior of Iron Based SuperconductorMay 09 2011Temperature dependent resistivity of the iron-based superconductor NdFeAsO0.88F0.12 was measured under different applied fields and excitation currents. Arrhenius plot shows an anomalous tail effect, which contains obvious two resistivity dropping stages. ... More
Possible existence of a band of extended states induced by inter-Landau-band mixing in quantum Hall systemDec 16 2005The mixing of states with {\it opposite chirality} in quantum Hall system is shown to have delocalization effect. It is possible that extended states may form bands because of this mixing, as is shown through a numerical calculation on a two-channel network ... More
The radio spectrum and magnetic field structure of SNR HB3Jun 10 2008Jul 30 2008Evidence for a spectral flattening of the supernova remnant (SNR) HB3 (G132.7+1.3) was recently claimed in literature based on previously published total flux density data, and the flattening was further interpreted as the discovery of thermal bremsstrahlung ... More
Synthesis, characterization and physical properties of layered bismuthide PtBi$_2$May 29 2016Jun 02 2016We report details of single crystal growth of stoichiometric bismuthide PtBi$_2$ whose structure consists of alternate stacking of Pt layer sandwiched by Bi bilayer along the $c$-axis. The compound crystallizes in space group P-3 with a hexagonal unit ... More
Influence of magnetism on the superconducting properties of iron-based superconductor NdFeAsO0.88F0.12Mar 30 2010Mar 31 2010Both DC and AC magnetization measurements were performed on the NdFeAsO0.88F0.12 superconductor to investigate the influence of magnetism on the superconducting properties of this system. The crossover of the ZFC and FC magnetic susceptibility curves ... More
Phase diagram of the NdFe1-xRhxAsO superconductorFeb 04 2010Polycrystalline samples with a nominal composition of NdFe1-xRhxAsO (0 <= x <= 0.25) were synthesized using a solid state reaction method. Bulk superconductivity with a maximum Tc = 13 K is observed in the x = 0.1 sample. A temperature-composition phase ... More
Reply to Valla's Comment on "Multiple Bosonic Mode Coupling in Electron Self-Energy of (La_{2-x}Sr_x)CuO_4"Feb 01 2005From consistency among different measurements, new measurements with better energy resolution, as well as simulations, we show that the fine structure we have identified in the electron self-enery of LSCO is intrinsic, not due to random noise as Valla ... More
The effect of inter-Landau-band mixing on extended states in quantum Hall systemMay 01 2003The effect of inter-Landau-band mixing on electron localization in an integer quantum Hall system is studied. We find that mixing of localized states with {\it opposite chirality} tends to delocalize the states. This delocalization effect survives the ... More
Theoretical study of the thermoelectric properties of SiGe nanotubesJun 23 2014The thermoelectric properties of two typical SiGe nanotubes are investigated using a combination of density functional theory, Boltzmann transport theory, and molecular dynamics simulations. Unlike carbon nanotubes, these SiGe nanotubes tend to have gear-like ... More
The sino-german 6cm polarization survey of the galactic plane: A summaryFeb 09 2012We have finished the 6cm polarization survey of the Galactic plane using the Urumqi 25m radio telescope. It covers 10deg<l<230deg in Galactic longitude and |b| <5deg in Galactic latitude. The new polarization maps not only reveal new properties of the ... More
Vacancy Induced Splitting of Dirac Nodal Point in GrapheneSep 16 2011We investigate the vacancy effects on quasiparticle band structure of graphene near the Dirac point. It is found that each Dirac nodal point splits into two new nodal points due to the coherent scattering among vacancies. The splitting energy between ... More
Effects of Mn and Ti doping on superconductivity and charge ordering in NaxCoO2 systemJan 04 2005The superconductivity in Na0.3Co1-xMxO2.1.3H2O and the charge ordering in Na0.5Co1-xMxO2 have been investigated for M = Mn and Ti substituting for Co. We have first successfully synthesized the single-phase Na0.7Co1-xMxO2(M= Mn and Ti) materials with ... More
Non-monotonic variation of anomalous Hall effect with spin orbit coupling strengthApr 05 2010Apr 27 2010For L1(0) FePt films, the anomalous Hall resistivity is found to be proportional to spontaneous magnetization $M_{\mathrm{S}}$. After the $M_{\mathrm{S}}$ temperature effect is eliminated, $\rho_{\mathrm{xyo}}$ can be fitted by $\rho_{\mathrm{xyo}}=a_{\mathrm{o}}\rho_{\mathrm{xx}}+ ... More
Spin 3/2 PentaquarksMar 17 2005Jun 06 2005We investigate the possible existence of the spin 3/2 pentaquark states using interpolating currents with K-N color-octet structure in the framework of QCD finite energy sum rule (FESR). We pay special attention to the convergence of the operator product ... More
The SHER-HIAF Ring Lattice DesignMay 22 2013Super Heavy Experimental Ring (SHER) is one of the rings of the next accelerator complex High Intensity Heavy Ion Accelerator Facility (HIAF) at IMP[4]. Here, present ideas of the lattice design for the operation of the large acceptance ring are presented. ... More
Cerenkov Line-like Radiation, The Extended and Improved Formulae SystemSep 07 2000You & Cheng (1980) argued that, for relativistic electrons moving through a dense gas, the Cerenkov effect will produce peculiar atomic and/or molecular emission lines--Cerenkov lines. They presented a series of formulae to describe the new line-mechanism. ... More
The CP violating phase $γ$ from global fit of rare charmless hadronic B decaysNov 28 2000Mar 28 2001We study constraints on the CP violating phase $\gamma$ in the Kobayashi-Maskawa model using available experimental data. We first follow the conventional method to up date the constraint on $\gamma$ by performing a $\chi^2$ analysis using data from $|\epsilon_K|$, ... More
SU(3) Predictions of $B\to PP$ Decays in the Standard ModelOct 17 2002With SU(3) symmetry one only needs 13 hadronic parameters to describe $B\to PP$ decays in the Standard Model. When annihilation contributions are neglected, only 7 hadronic parameters are needed. These parameters can be determined from existing experimental ... More
Giant Peak Effect Observed in Ultrapure YBCO CrystalNov 01 1999A giant peak in the temperature dependence of the screening current is observed in the ac magnetic response of an ultra-pure YBa$_2$Cu$_3$O$_{6.993}$ crystal in a magnetic field. At H = 2.0 T ({\bf $H$}$||${\bf c}), the screening current density $J_c(T)$ ... More
The shape of disorder broadened Landau subbands in grapheneOct 24 2008Density of states (DOS) of graphene under a high uniform magnetic field and white-noise random potential is numerically calculated. The disorder broadened zero-energy Landau band has a Gaussian shape whose width is proportional to the random potential ... More
Adversarial Structure Matching Loss for Image SegmentationMay 18 2018The per-pixel cross-entropy loss (CEL) has been widely used in structured output prediction tasks as a spatial extension of generic image classification. However, its i.i.d. assumption neglects the structural regularity present in natural images. Various ... More
Density effect on critical current density and flux pinning properties of polycrystalline SmFeAsO1-xFx superconductorOct 20 2011Oct 29 2011A series of polycrystalline SmFeAs1-xOx bulks was prepared to systematically investigate the influence of sample density on flux pinning properties. Different sample densities were achieved by controlling the pelletizing pressure. The superconducting ... More
Peak Effect of Flux Pinning in Sc5Ir4Si10 SuperconductorsOct 15 2010Magnetic hysteresis loops (MHLs) have been comparatively measured on both textured and single crystalline Sc5Ir4Si10 superconductors. Critical current densities and flux pinning forces are calculated from MHLs by Bean model. Three kinds of peaks of the ... More
Electronic Behavior of Superconducting SmFeAsO0.75Feb 28 2011High-quality polycrystalline SmFeAsO0.75 was synthesized with a superconducting transition width less than 1 K, and the electronic behavior was systematically studied by transport and specific heat measurements. An obvious superconducting jump was witnessed, ... More
The role of major gas-rich mergers on the evolution of galaxies from the blue cloud to the red sequenceApr 25 2016With the aim of exploring the fast evolutionary path from the blue cloud of star-forming galaxies to the red sequence of quiescent galaxies in the local universe, we select a local advanced merging infrared luminous and ultraluminous galaxy (adv-merger ... More
Topological quantum matter with cold atomsOct 22 2018Oct 29 2018This is an introductory review of the physics of topological quantum matter with cold atoms. Topological quantum phases, originally discovered and investigated in condensed matter physics, have recently been explored in a range of different systems, which ... More
Precision Dijet Acoplanarity Tomography of the Chromo Structure of Perfect QCD FluidsAug 09 2018Aug 29 2018Dijet acoplanarity is dominated by vacuum (Sudakov) pQCD radiation even in Pb+Pb collisions, but future higher precision measurements of the tails of the acoplanarity distributions can help to resolve {\em separately} the medium opacity, $\chi=L/\lambda$, ... More
Surface Phase Transitions Induced by Electron Mediated Adatom-Adatom InteractionMar 20 2003We propose that the indirect adatom-adatom interaction mediated by the conduction electrons of a metallic surface is responsible for the $\sqrt{3}\times \sqrt{3}\Leftrightarrow 3\times 3$ structural phase transitions observed in Sn/Ge (111) and Pb/Ge ... More
Annealing Effect on Microstructure and Superconductivity of KxFeySe2 Synthesized by an Easy One-step MethodJan 27 2014High-quality superconducting KxFeySe2 single crystals were synthesized using an easy one-step method. Detailed annealing studies were performed to make clear the phase formation process in KxFeySe2. Compatible observations were found in temperature-dependent ... More
Pentaquark Magnetic Moments In Different ModelsDec 04 2003Feb 27 2004We calculate the magnetic moments of the pentaquark states from different models and compare our results with predictions of other groups.
Network Coding as a WiMAX Link Reliability MechanismAug 23 2012Aug 01 2013We design and implement a network-coding-enabled reliability architecture for next generation wireless networks. Our network coding (NC) architecture uses a flexible thread-based design, with each encoder-decoder instance applying systematic intra-session ... More
Possible Systematic Decreases in the Age of Globular ClustersMar 29 1994The ages of globular clusters inferred from observations depends sensitively on assumptions like the initial helium abundance and the mass loss rate. A high helium abundance (e.g., $Y\approx$0.28) or a mass loss rate of $\sim$10$^{-11}M_\odot$ yr$^{-1}$ ... More
A microfabricated surface ion trap on a high-finesse optical mirrorNov 23 2010Jul 05 2011A novel approach to optics integration in ion traps is demonstrated based on a surface electrode ion trap that is microfabricated on top of a dielectric mirror. Additional optical losses due to fabrication are found to be as low as 80 ppm for light at ... More
Topological Transition of Graphene from Quantum Hall Metal to Quantum Hall Insulator at $ν=0$Jun 03 2010The puzzle of recently observed insulating phase of graphene at filling factor $\nu=0$ in high magnetic field quantum Hall (QH) experiments is investigated. We show that the magnetic field driven Peierls-type lattice distortion (due to the Landau level ... More
Spin-orbit torque in MgO/CoFeB/Ta/CoFeB/MgO symmetric structure with interlayer antiferromagnetic couplingFeb 17 2017Spin current generated by spin Hall effect in the heavy metal would diffuse up and down to adjacent ferromagnetic layers and exert torque on their magnetization, called spin-orbit torque. Antiferromagnetically coupled trilayers, namely the so-called synthetic ... More
Thermal conductivity of the diamond-chain compound Cu_3(CO_3)_2(OH)_2Dec 17 2015Thermal conductivity (\kappa) of a distorted spin diamond-chain system, Cu_3(CO_3)_2(OH)_2, is studied at low temperatures down to 0.3 K and in magnetic fields up to 14 T. In zero field, the \kappa(T) curve with heat current along the chain direction ... More
Interface Ferromagnetism in (110)-Oriented La0.7Sr0.3MnO3/SrTiO3 Ultrathin SuperlatticesOct 07 2008Apr 23 2009We explore manganite interface magnetism in epitaxially grown La0.7Sr0.3MnO3(LSMO)/SrTiO3 ultrathin superlattices (SL) along (110) orientation. we show that robust ferromagnetism persists down to four monolayers LSMO(MLs) (~1.1 nm in thickness), of which ... More
Universal scheme to generate metal-insulator transition in disordered systemsNov 24 2012We propose a scheme to generate metal-insulator transition in random binary layer (RBL) model, which is constructed by randomly assigning two types of layers. Based on a tight-binding Hamiltonian, the localization length is calculated for a variety of ... More
MoS2 nanoribbons as promising thermoelectric materialsMay 23 2014May 30 2014The thermoelectric properties of MoS2 armchair nanoribbons with different width are studied by using first-principles calculations and Boltzmann transport theory, where the relaxation time is predicted from deformation potential theory. Due to the dangling ... More
DAC-SDC Low Power Object Detection Challenge for UAV ApplicationsSep 01 2018The 55th Design Automation Conference (DAC) held its first System Design Contest (SDC) in 2018. SDC'18 features a lower power object detection challenge (LPODC) on designing and implementing novel algorithms based object detection in images taken from ... More
Electron energy loss spectra of Na0.33CoO2.yH2O (y = 0, 0.6 and 1.3)Dec 30 2004Electron energy loss (EEL) spectra have been obtained on materials with the nominal compositions of Na0.33CoO2_yH2O (y = 0, 0.6 and 1.3). Spectral analyses revealed systematic changes in the low-loss energy region (< 10eV) and the core losses(O-K, Co-L3,2) ... More
Niobium based intermetallics as a source of high-current/high-magnetic field superconductorsSep 05 2001The article is focused on low temperature intermetallic A15 superconducting wires development for Nuclear Magnetic Resonance, NMR, and Nuclear Magnetic Imaging, MRI, magnets and also on cryogen-free magnets. There are many other applications which would ... More
3D analysis of spatial resolution of MIRO/Rosetta measurements at 67P/CGMar 04 2019The MIRO instrument's remote sensing capability is integral in constraining water density, temperature and velocity fields in the coma of 67P/Churyumov-Gersimenko. Our aim is to quantify the contribution to the water density from all facets inside and ... More
Observation of strong-coupling pairing with weakened Fermi-surface nesting at optimal hole doping in Ca$_{0.33}$Na$_{0.67}$Fe$_2$As$_2$Feb 24 2014We report an angle-resolved photoemission investigation of optimally-doped Ca$_{0.33}$Na$_{0.67}$Fe$_2$As$_2$. The Fermi surface topology of this compound is similar to that of the well-studied Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ material, except for larger ... More
Experimental investigation of the electronic structure of Ca$_{0.83}$La$_{0.17}$Fe$_2$As$_2$Oct 27 2012Jan 05 2013We performed a combined angle-resolved photoemission spectroscopy and scanning tunneling microscopy study of the electronic structure of electron-doped Ca$_{0.83}$La$_{0.17}$Fe$_2$As$_2$. A surface reconstruction associated with the dimerization of As ... More
Entanglement between Lowly and Highly Lying Atomic Spin WavesDec 09 2015Jan 20 2017Establishing a quantum interface between different physical systems is of special importance for developing the practical versatile quantum networks. Entanglement between low- and high-lying atomic spin waves is essential for building up Rydberg-based ... More
Observation of momentum-confined in-gap impurity state in Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$: evidence for anti-phase $s_{\pm}$ pairingDec 26 2013May 13 2014We report the observation by angle-resolved photoemission spectroscopy of an impurity state located inside the superconducting gap of Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$ and vanishing above the superconducting critical temperature, for which the spectral ... More
Observation of topological transition in high-T$_{c}$ superconductor FeTe$_{1-x}$Se$_{x}$/SrTiO$_{3}$(001) monolayersMar 14 2019Superconductors with topological surface or edge states have been intensively explored for the prospect of realizing Majorana bound states, which obey non-Abelian statistics and are crucial for topological quantum computation. The traditional routes for ... More
Ferroelectricity of structural origin in spin-chain compounds Ca$_3$Co$_{2-x}$Mn$_x$O$_6$Aug 09 2017We report a systematic study of the structure, electric and magnetic properties of Ca$_3$Co$_{2-x}$Mn$_x$O$_6$ single crystals with $x =$ 0.72 and 0.26. The DC and AC magnetic susceptibilities display anomalies with characteristic of the spin freezing. ... More
Three new barium dwarfs with WD companions: BD+68 1027, RE J0702+129 and BD+80 670Oct 30 2017We report three new barium (Ba) dwarfs lying in Sirius-like systems, which provides direct evidence that Ba dwarfs are companions to white dwarfs (WDs). Atmospheric parameters, stellar masses, and chemical abundances of 25 elements, including light, $\alpha$, ... More
Observation of strong electron pairing on bands without Fermi surfaces in LiFe1-xCoxAsJun 04 2014Jun 05 2014In conventional BCS superconductors, the quantum condensation of superconducting electron pairs is understood as a Fermi surface (FS) instability, in which the low-energy electrons are paired by attractive interactions. Whether this explanation is still ... More
Radio polarization observations of large supernova remnants at 6cmApr 07 2013May 31 2014We have observed 79 supernova remnants (SNRs) with the Urumqi 25m telescope at 6cm during the Sino-German 6cm polarization survey of the Galactic plane. We measured flux densities of SNRs at 6cm, some of which are the first ever measured or the measurements ... More
Observation of a nodal chain with Dirac surface states in TiB2May 12 2018Topological nodal-line semimetals (TNLSMs) are characterized by symmetry-protected band crossings extending along one-dimensional lines in momentum space. The nodal lines exhibit a variety of possible configurations, such as nodal ring, nodal link, nodal ... More
Enhanced superconductivity accompanying a Lifshitz transition in electron-doped FeSe monolayerJun 05 2016The origin of enhanced superconductivity over 50 K in the recently discovered FeSe monolayer films grown on SrTiO$_{3}$ (STO), as compared to 8 K in bulk FeSe, is intensely debated. As with the ferrochalcogenides A$_{x}$Fe$_{2-y}$Se$_{2}$ and potassium ... More