Results for "Xing Lu"

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High-order Phase Transition in Random HypergrpahsSep 03 2014In this paper, we study the high-order phase transition in random $r$-uniform hypergraphs. For a positive integer $n$ and a real $p\in [0,1]$, let $H:=H^r(n,p)$ be the random $r$-uniform hypergraph on the vertex set $[n]$, where each $r$-set is an edge ... More
Monochromatic 4-term arithmetic progressions in 2-colorings of $\mathbb Z_n$Jul 14 2011This paper is motivated by a recent result of Wolf \cite{wolf} on the minimum number of monochromatic 4-term arithmetic progressions(4-APs, for short) in $\Z_p$, where $p$ is a prime number. Wolf proved that there is a 2-coloring of $\Z_p$ with 0.000386% ... More
The Fractional Chromatic Number of Triangle-free Graphs with $Δ\leq 3$Nov 10 2010Jul 25 2012Let $G$ be any triangle-free graph with maximum degree $\Delta\leq 3$. Staton proved that the independence number of $G$ is at least 5/14n. Heckman and Thomas conjectured that Staton's result can be strengthened into a bound on the fractional chromatic ... More
Spectra of edge-independent random graphsApr 27 2012Let $G$ be a random graph on the vertex set $\{1,2,..., n\}$ such that edges in $G$ are determined by independent random indicator variables, while the probability $p_{ij}$ for $\{i,j\}$ being an edge in $G$ is not assumed to be equal. Spectra of the ... More
High-order Phase Transition in Random HypergrpahsSep 03 2014Aug 02 2018In this paper, we study the high-order phase transition in random $r$-uniform hypergraphs. For a positive integer $n$ and a real $p\in [0,1]$, let $H:=H^r(n,p)$ be the random $r$-uniform hypergraph with vertex set $[n]$, where each $r$-set is selected ... More
The Correlation Potential of a Test Ion Near a Strongly Charged PlateNov 01 2013Mar 15 2014We analytically calculate the correlation potential of a test ion near a \emph{strongly} charged plate inside a dilute $m:-n$ electrolyte. We do this by calculating the electrostatic Green's function in the presence of a nonlinear background potential, ... More
$b$-invariant edges in essentially 4-edge-connected near-bipartite cubic bricksMay 17 2019Aug 10 2019A {\em brick} is a non-bipartite matching covered graph without non-trivial tight cuts. Bricks are building blocks of matching covered graphs. We say that an edge $e$ in a brick $G$ is {\em $b$-invariant} if $G-e$ is matching covered and it contains exactly ... More
Scalar Hairy Black Holes in General DimensionsDec 18 2013Jan 13 2014We obtain a class of asymptotic flat or (A)dS hairy black holes in D-dimensional Einstein gravity coupled to a scalar with certain scalar potential. For a given mass, the theory admits both the Schwarzschild-Tangherlini and the hairy black holes with ... More
Charged Plate in Asymmetric Electrolytes: One-loop Renormalization of Surface Charge Density and Debye Length due to Ionic CorrelationsFeb 12 2016The self-consistent field theory (SCFT) is used to study the mean potential near a charged plate inside a $m:-n$ electrolyte. A perturbation series is developed in terms of $g = 4 \pi b/\ell_{\rm {\scriptscriptstyle DB}}$, where $b, \ell_{\rm{\scriptscriptstyle ... More
Bounce Universe and Black Holes from Critical Einsteinian Cubic GravityJul 19 2017We show that there exists a critical point for the coupling constants in Einsteinian cubic gravity where the linearized equations on the maximally-symmetric vacuum vanish identically. We construct an exact isotropic bounce universe in the critical theory ... More
Time Machines and AdS Solitons with Negative MassDec 30 2016We show that in D=2n+1 dimensions, when mass is negative and all angular momenta are non-vanishing, Kerr and Kerr-AdS metrics describe smooth time machines, with no curvature singularity. Turning off the angular momenta appropriately can lead to static ... More
Listwise View Ranking for Image CroppingMay 14 2019Rank-based Learning with deep neural network has been widely used for image cropping. However, the performance of ranking-based methods is often poor and this is mainly due to two reasons: 1) image cropping is a listwise ranking task rather than pairwise ... More
Efficient Graph Edit Distance Computation and Verification via Anchor-aware Lower Bound EstimationSep 20 2017Oct 01 2017Graph edit distance (GED) is an important similarity measure adopted in a similarity-based analysis between two graphs, and computing GED is a primitive operator in graph database analysis. Partially due to the NP-hardness, the existing techniques for ... More
Distributed interaction between computer virus and patch: A modeling studyMay 13 2017The decentralized patch distribution mechanism holds significant promise as an alternative to its centralized counterpart. For the purpose of accurately evaluating the performance of the decentralized patch distribution mechanism and based on the exact ... More
Generalized Deam-Edwards Approach to the Statistical Mechanics of Randomly Crosslinked SystemsMay 03 2013We address the statistical mechanics of randomly and permanently crosslinked networks. We develop a theoretical framework (vulcanization theory) which can be used to systematically analyze the correlation between the statistical properties of random networks ... More
Statistical physics of isotropic-genesis nematic elastomers: I. Structure and correlations at high temperaturesApr 14 2013Isotropic-genesis nematic elastomers (IGNEs) are liquid crystalline polymers (LCPs) that have been randomly, permanently cross-linked in the high-temperature state so as to form an equilibrium random solid. Thus, instead of being free to diffuse throughout ... More
Fragmentation of Molecular Clumps and Formation of ProtoclusterMar 10 2015Sufficiently massive clumps of molecular gas collapse under self-gravity and fragment to spawn a cluster of stars that have a range of masses. We investigate observationally the early stages of formation of a stellar cluster in a massive filamentary infrared ... More
A Feasibility Study on Deep Learning-Based Radiotherapy Dose CalculationAug 08 2019Purpose: Various dose calculation algorithms are available for radiation therapy for cancer patients. However, these algorithms are faced with the tradeoff between efficiency and accuracy. The fast algorithms are generally less accurate, while the accurate ... More
Improving Deep Pancreas Segmentation in CT and MRI Images via Recurrent Neural Contextual Learning and Direct Loss FunctionJul 16 2017Jul 18 2017Deep neural networks have demonstrated very promising performance on accurate segmentation of challenging organs (e.g., pancreas) in abdominal CT and MRI scans. The current deep learning approaches conduct pancreas segmentation by processing sequences ... More
A Novel Rate and Channel Control Scheme Based on Data Extraction Rate for LoRa NetworksFeb 12 2019Long Range (LoRa) has become one of the most popular Low Power Wide Area (LPWA) technologies, which provides a desirable trade-off among communication range, battery life, and deployment cost. In LoRa networks, several transmission parameters can be allocated ... More
Multifractal cross wavelet analysisOct 29 2016Feb 25 2018Complex systems are composed of mutually interacting components and the output values of these components are usually long-range cross-correlated. We propose a method to characterize the joint multifractal nature of such long-range cross correlations ... More
Topological thermal Hall effect driven by fluctuation of spin chirality in frustrated antiferromagnetsNov 18 2018Nov 22 2018By revealing an underlying relation between the Dzyaloshinskii-Moriya interaction (DMI) and the scalar spin chirality, we develop the theory of magnon thermal Hall effects in antiferromagnetic systems. The dynamic fluctuation of the scalar chirality is ... More
Modeling and Performance Analysis of Pull-Based Live Streaming Schemes in Peer-to-Peer NetworkFeb 17 2013Recent years mesh-based Peer-to-Peer live streaming has become a promising way for service providers to offer high-quality live video streaming service to Internet users. In this paper, we make a detailed study on modeling and performance analysis of ... More
Initial Fragmentation in the Infrared Dark Cloud G28.53-0.25Mar 30 2015To study the fragmentation and gravitational collapse of dense cores in infrared dark clouds (IRDCs), we have obtained submillimeter continuum and spectral line data as well as multiple inversion transitions of NH3 and H2O maser data of four massive clumps ... More
Anisotropic deformation of Rydberg blockade sphere in few-atom systemsSep 02 2013Rydberg blockade sphere persists an intriguing picture by which a number of collective many-body effects caused by the strong Rydberg-Rydberg interactions can be clearly understood and profoundly investigated. In the present work, we develop a new definition ... More
Extended Equal Service and Differentiated Service Models for Peer-to-Peer File SharingMar 30 2012Peer-to-Peer (P2P) systems have proved to be the most effective and popular file sharing applications in recent years. Previous studies mainly focus on the equal service and the differentiated service strategies when peers have no initial data before ... More
GLStyleNet: Higher Quality Style Transfer Combining Global and Local Pyramid FeaturesNov 18 2018Recent studies using deep neural networks have shown remarkable success in style transfer especially for artistic and photo-realistic images. However, the approaches using global feature correlations fail to capture small, intricate textures and maintain ... More
Pancreas Segmentation in CT and MRI Images via Domain Specific Network Designing and Recurrent Neural Contextual LearningMar 30 2018Automatic pancreas segmentation in radiology images, eg., computed tomography (CT) and magnetic resonance imaging (MRI), is frequently required by computer-aided screening, diagnosis, and quantitative assessment. Yet pancreas is a challenging abdominal ... More
Godel Universe from String TheoryDec 06 2016Dec 12 2016G\"odel universe is a direct product of a line and a three-dimensional spacetime we call G$_\alpha$. In this paper, we show that the G\"odel metrics can arise as exact solutions in Einstein-Maxwell-Axion, Einstein-Proca-Axion, or Freedman-Schwarz gauged ... More
Design and Implementation of Open LoRa for IoTDec 21 2018Jul 23 2019Long Range (LoRa) network is emerging as one of the most promising Low Power Wide Area (LPWA) networks, since it enables the energy-constraint devices distributed over wide areas to establish affordable connectivity. However, how to implement a cost-effective ... More
A Unified Mechanism for Hydrogen Trapping at Metal VacanciesNov 05 2013Interaction between hydrogen (H) and metals is central to many materials problems of scientific and technological importance. Chief among them is the development of H storage and H-resistant materials. H segregation or trapping at lattice defects, including ... More
Multifractal characteristics and return predictability in the Chinese stock marketsJun 20 2018By adopting Multifractal detrended fluctuation (MF-DFA) analysis methods, the multifractal nature is revealed in the high-frequency data of two typical indexes, the Shanghai Stock Exchange Composite 180 Index (SH180) and the Shenzhen Stock Exchange Composite ... More
Ultrasensitive, high-dynamic-range and broadband strain sensing by time-of-flight detection with femtosecond-laser frequency combsJun 21 2017Ultrahigh-resolution optical strain sensors provide powerful tools in various scientific and engineering fields, ranging from long-baseline interferometers to civil and aerospace industries. Here we demonstrate an ultrahigh-resolution fibre strain sensing ... More
Simulating Z_2 topological insulators via a one-dimensional cavity optomechanical cells arrayNov 15 2018We propose a novel scheme to simulate Z_2 topological insulators via one-dimensional (1D) cavity optomechanical cells array. The direct mapping between 1D cavity optomechanical cells array and 2D quantum spin Hall (QSH) system can be achieved by using ... More
A note on periodicity of long-term variations of optical continuum in active galactic nucleiApr 03 2016Graham et al. found a sample of active galactic nuclei (AGNs) and quasars from the Catalina Real-time Transient Survey (CRTS) that have long-term periodic variations in optical continuum, the nature of the periodicity remains uncertain. We investigate ... More
PTrix: Efficient Hardware-Assisted Fuzzing for COTS BinaryMay 25 2019Despite its effectiveness in uncovering software defects, American Fuzzy Lop (AFL), one of the best grey-box fuzzers, is inefficient when fuzz-testing source-unavailable programs. AFL's binary-only fuzzing mode, QEMU-AFL, is typically 2-5X slower than ... More
Cavity-induced switching between localized and extended states in a non-interacting Bose-Einstein condensateAug 24 2011Oct 08 2011We study an ultracold atom-cavity coupling system, which had been implemented in experiment to display weak light nonlinearity [S. Gupta \textit{et al}., Phys. Rev. Lett. \textbf{99}, 213601 (2007)]. The model is described by a non-interacting Bose-Einstein ... More
High-pressure phases of Weyl semimetals NbP, NbAs, TaP and TaAsAug 14 2017The high pressure phase diagrams of TaAs family (NbP, NbAs, TaP and TaAs) are explored systematically using crystal structure search together with first-principles calculations. Our calculations show that NbAs and TaAs have similar phase diagrams and ... More
Localizing Discriminative Visual Landmarks for Place RecognitionApr 14 2019We address the problem of visual place recognition with perceptual changes. The fundamental problem of visual place recognition is generating robust image representations which are not only insensitive to environmental changes but also distinguishable ... More
Defend against advanced persistent threats: An optimal control approachSep 09 2017Dec 28 2017The new cyber attack pattern of advanced persistent threat (APT) has posed a serious threat to modern society. This paper addresses the APT defense problem, i.e., the problem of how to effectively defend against an APT campaign. Based on a novel APT attack-defense ... More
A cost-effective rumor-containing strategySep 08 2017Dec 28 2017This paper addresses the issue of suppressing a rumor using the truth in a cost-effective way. First, an individual-level dynamical model capturing the rumor-truth mixed spreading processes is proposed. On this basis, the cost-effective rumor-containing ... More
Maximizing the overall profit of a word-of-mouth marketing campaign: A modeling studyApr 23 2017As compared to the traditional advertising, the word-of-mouth (WOM) communications have striking advantages such as significantly lower cost and rapid delivery; this is especially the case with the popularity of online social networks. This paper addresses ... More
Study of $B \to K_0^*(1430)K^{(*)}$ decays in QCD Factorization ApproachJan 16 2015Within the QCD factorization approach, we calculate the branching fractions and $CP$ asymmetry parameters of 12 $B \to K_0^*(1430)K^{(*)}$ decay modes under the assumption that the scalar meson $K_0^*(1430)$ is the first excited state or the lowest lying ... More
A discount strategy in word-of-mouth marketing and its assessmentApr 23 2017This paper addresses the discount pricing in word-of-mouth (WOM) marketing. A new discount strategy known as the Infection-Based Discount (IBD) strategy is proposed. The basic idea of the IBD strategy lies in that each customer enjoys a discount that ... More
Analysis of the effectiveness of the truth-spreading strategy for inhibiting rumorsMay 17 2017Spreading truths is recognized as a feasible strategy for inhibiting rumors. This paper is devoted to assessing the effectiveness of the truth-spreading strategy. An individual-level rumor-truth spreading model (the generic URTU model) is derived. Under ... More
High-ordered Random Walks and Generalized Laplacians on HypergraphsFeb 22 2011Despite of the extreme success of the spectral graph theory, there are relatively few papers applying spectral analysis to hypergraphs. Chung first introduced Laplacians for regular hypergraphs and showed some useful applications. Other researchers treated ... More
Loose Laplacian spectra of random hypergraphsSep 15 2011Dec 05 2011Let $H=(V,E)$ be an $r$-uniform hypergraph with the vertex set $V$ and the edge set $E$. For $1\leq s \leq r/2$, we define a weighted graph $G^{(s)}$ on the vertex set ${V\choose s}$ as follows. Every pair of $s$-sets $I$ and $J$ is associated with a ... More
An Open Source Modeling Framework for Interdependent Energy-Transportation- Communication Infrastructure in Smart and Connected CommunitiesApr 07 2019Infrastructure in future smart and connected communities is envisioned as an aggregate of public services, including the energy, transportation and communication systems, all intertwined with each other. The intrinsic interdependency among these systems ... More
The damage inflicted by a computer virus: A new estimation methodJun 07 2017This paper addressed the issue of estimating the damage caused by a computer virus. First, an individual-level delayed SIR model capturing the spreading process of a digital virus is derived. Second, the damage inflicted by the virus is modeled as the ... More
On the effectiveness of the truth-spreading/rumor-blocking strategy for restraining rumorsMay 28 2017Spreading truths and blocking rumors are two typical strategies for inhibiting rumors. In practice, a tradeoff between the two strategies, which is known as the TSRB strategy, may achieve a better cost-effectiveness. This paper is devoted to assessing ... More
The large unsaturated magnetoresistance of Weyl semimetalsSep 14 2015Sep 15 2015The Weyl semimetal (WSM) is a novel topological gapless state with promises exotic transport due to chiral anomaly. Recently, a family of nonmagnetic WSM candidates including TaAs, NbAs, NbP etc is confirmed by first principle calculation and experiments. ... More
On Compression of Unsupervised Neural Nets by Pruning Weak ConnectionsJan 21 2019Jan 23 2019Unsupervised neural nets such as Restricted Boltzmann Machines(RBMs) and Deep Belif Networks(DBNs), are powerful in automatic feature extraction,unsupervised weight initialization and density estimation. In this paper,we demonstrate that the parameters ... More
Cooperative three- and four- player quantum gamesAug 12 2002A cooperative multi-player quantum game played by 3 and 4 players has been studied. Quantum superposed operator is introduced in this work which solves the non-zero sum difficulty in previous treatment. The role of quantum entanglement of the initial ... More
Single Magnetic Impurity in Tilted Dirac Surface StatesNov 02 2017Dec 29 2017We utilize variational method to investigate the Kondo screening of a spin-1/2 magnetic impurity in tilted Dirac surface states with the Dirac cone tilted along the $k_y$-axis. We mainly study about the effect of the tilting term on the binding energy ... More
Predictive Deployment of UAV Base Stations in Wireless Networks: Machine Learning Meets Contract TheoryNov 03 2018Aug 19 2019In this paper, a novel framework is proposed to enable a predictive deployment of unmanned aerial vehicles (UAVs) as temporary flying base stations (BSs) to complement ground cellular systems in face of downlink traffic overload. First, a novel learning ... More
VLA observations of ammonia in high-mass star formation regionsMay 30 2014We report systematic mapping observations of the NH$_{3}$ (1,1) and (2,2) inversion lines towards 62 high-mass star-forming regions using VLA in its D and DnC array configurations. The VLA images cover a spatial dynamic range from 40$"$ to 3$"$, allowing ... More
Security evaluation of cyber networks under advanced persistent threatsJul 12 2017This paper is devoted to measuring the security of cyber networks under advanced persistent threats (APTs). First, an APT-based cyber attack-defense process is modeled as an individual-level dynamical system. Second, the dynamic model is shown to exhibit ... More
The $Λ_c(2595)$ resonance as a dynamically generated state: the compositeness condition and the large $N_c$ evolutionMar 17 2016Recent studies have shown that the well established $\Lambda_c(2595)$ resonance contains a large meson-baryon component, which can vary depending on the specific formalism. In this work, we examine such a picture by utilizing the compositeness condition ... More
A Massive Prestellar Clump Hosting no High-Mass CoresApr 26 2017The Infrared Dark Cloud (IRDC) G028.23-00.19 hosts a massive (1,500 Msun), cold (12 K), and 3.6-70 um IR dark clump (MM1) that has the potential to form high-mass stars. We observed this prestellar clump candidate with the SMA (~3.5" resolution) and JVLA ... More
The Galactic Center Molecular Cloud Survey. I. A Steep Linewidth-Size Relation & Suppression of Star FormationOct 11 2016Nov 04 2016The Central Molecular Zone (CMZ; inner $\sim{}200~\rm{}pc$) of the Milky Way is a star formation (SF) environment with very extreme physical properties. Exploration of SF in this region is important because (i) this region allows us to test models of ... More
The Galactic Center Molecular Cloud Survey. I. A Steep Linewidth-Size Relation & Suppression of Star FormationOct 11 2016The Central Molecular Zone (CMZ; inner $\sim{}200~\rm{}pc$) of the Milky Way is a star formation (SF) environment with very extreme physical properties. Exploration of SF in this region is important because (i) this region allows us to test models of ... More
Higher-Derivative Gravity with Non-minimally Coupled Maxwell FieldDec 30 2015We construct higher-derivative gravities with a non-minimally coupled Maxwell field. The Lagrangian consists of polynomial invariants built from the Riemann tensor and the Maxwell field strength in such a way that the equations of motion are second order ... More
Deeply Embedded Protostellar Population in the Central Molecular Zone Suggested by H$_2$O Masers and Dense CoresSep 27 2016The Central Molecular Zone (CMZ), usually referring to the inner 500 pc of the Galaxy, contains a dozen of massive ($\sim10^5$ $M_\odot$) molecular clouds. Are these clouds going to actively form stars like Sgr B2? How are they affected by the extreme ... More
Observation of eight-photon entanglementMay 31 2011Using ultra-bright sources of pure-state entangled photons from parametric down conversion, an eight-photon interferometer and post-selection detection, we demonstrate the ability to experimentally manipulate eight individual photons and report the creation ... More
Experimental measurement-based quantum computing beyond the cluster-state modelApr 23 2010Jun 14 2012The paradigm of measurement-based quantum computation opens new experimental avenues to realize a quantum computer and deepens our understanding of quantum physics. Measurement-based quantum computation starts from a highly entangled universal resource ... More
Dielectric Screening in Atomically Thin Boron Nitride NanosheetsMar 02 2015Two-dimensional (2D) hexagonal boron nitride (BN) nanosheets are excellent dielectric substrate for graphene, molybdenum disulfide and many other 2D nanomaterials based electronic and photonic devices. To optimize the performance of these 2D devices, ... More
Deeply Embedded Protostellar Population in the 20 km s-1 Cloud of the Central Molecular ZoneOct 16 2015We report the discovery of a population of deeply embedded protostellar candidates in the 20 km s$^{-1}$ cloud, one of the massive molecular clouds in the Central Molecular Zone (CMZ) of the Milky Way, using interferometric submillimeter continuum and ... More
SMA Observations of Extended $\rm{CO}\,(J=2-1)$ Emission in Interacting Galaxy NGC 3627Aug 22 2018We present moderate (${\sim}5^{\prime\prime}$) and high angular resolution (${\sim}1^{\prime\prime}$) observations of $^{12}\rm{CO\,}(J=2-1)$ emission toward nearby, interacting galaxy NGC 3627 taken with the Submillimeter Array (SMA). These SMA mosaic ... More
Diagnosing the magnetic field-tuned symmetry nature of the topological electrons by conductance fluctuations in bulk-insulating BiSbTeSe2 devicesDec 10 2017We extract the quantum conductance fluctuations and study its magnetic field dependence in the gate-dependent transport of the topological electrons in bulk-insulating BiSbTeSe2 devices. While increasing the magnetic field from 0 to 12 Tesla, the fluctuation ... More
Implementation of a Measurement-Device-Independent Entanglement WitnessApr 16 2014Entanglement, the essential resource in quantum information processing, should be witnessed in many tasks such as quantum computing and quantum communication. The conventional entanglement witness method, relying on an idealized implementation of measurements, ... More
Spatial anisotropy of Kondo screening cloud in a type-II Weyl semimetalApr 10 2019We theoretically study the Kondo screening of a spin-1/2 magnetic impurity in the bulk of a type-II Weyl semimetal (WSM) by use of the variational wave function method. We consider a type-II WSM model with two Weyl nodes located on the $k_z$-axis, and ... More
SMA Observations of the Hot Molecular Core IRAS 18566+0408Aug 24 2017We present Submillimeter Array (SMA) observations toward the high-mass star-forming region IRAS 18566+0408. Observations at 1.3 mm continuum and in several molecular line transitions were performed in the compact (2."4 angular resolution) and very-extended ... More
The Galactic Center Molecular Cloud Survey. II. A Lack of Dense Gas & Cloud Evolution along Galactic Center OrbitsOct 11 2016Jun 08 2017We present the first systematic study of the density structure of clouds found in a complete sample covering all major molecular clouds in the Central Molecular Zone (CMZ; inner $\sim{}200~\rm{}pc$) of the Milky Way. This is made possible by using data ... More
Butterfly Velocity Bound and Reverse Isoperimetric InequalityJan 18 2017Jan 24 2017We study the butterfly effect of the AdS planar black holes in the framework of Einstein's general relativity. We find that the butterfly velocities can be expressed by a universal formula $v_{\rm B}^2 = TS/(2V_{\rm th} P)$. In doing so, we come upon ... More
Direct experimental verification of quantum commutation relations for Pauli operatorsFeb 08 2010We propose and demonstrate scheme for direct experimental testing of quantum commutation relations for Pauli operators. The implemented device is an advanced quantum processor that involves two programmable quantum gates. Depending on a state of two-qubit ... More
Supermassive black holes with high accretion rates in active galactic nuclei: II. the most luminous standard candles in the UniverseAug 11 2014This is the second in a series of papers reporting on a large reverberation mapping (RM) campaign to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). The goal is to identify super-Eddington accreting massive black holes ... More
Gap Anisotropy in Iron-Based Superconductors: A Point-Contact Andreev Reflection Study of BaFe$_{2-x}$Ni$_{x}$As$_2$ Single CrystalsJun 15 2011Nov 11 2011We report a systematic investigation on c-axis point-contact Andreev reflection (PCAR) in BaFe$_{2-x}$Ni$_x$As$_2$ superconducting single crystals from underdoped to overdoped regions (0.075 $\leq x\leq 0.15$). At optimal doping ($x=0.1$) the PCAR spectrum ... More
Band-selective shaped pulse for high fidelity quantum control in diamondApr 09 2014Apr 10 2014High fidelity quantum control over qubits is of crucial importance for realistic quantum computing, and it turns to be more challenging when there are inevitable interactions among qubits. By employing a bandselective shaped pulse, we demonstrate a high ... More
Origin of the superconductivity of WTe2 under pressureDec 02 2015Apr 13 2016Tungsten ditelluride (WTe2) has attracted significant attention due to its interesting electronic properties, such as the unsaturated magnetoresistance and superconductivity. Recently, it has been proposed to be a new type of Weyl semimetal, which is ... More
Complexity and Two Identities of Action GrowthNov 07 2016The recently proposed complexity-action conjecture allows one to calculate how fast one can produce a quantum state from a reference state in terms of the on-shell action of the dual AdS black hole at the Wheeler-DeWitt patch. We show that the action ... More
Cooperative Multi-Agent Policy Gradients with Sub-optimal DemonstrationDec 05 2018Many reality tasks such as robot coordination can be naturally modelled as multi-agent cooperative system where the rewards are sparse. This paper focuses on learning decentralized policies for such tasks using sub-optimal demonstration. To learn the ... More
Pressure-induced metallization and superconducting phase in ReS2Feb 14 2017Among the family of TMDs, ReS2 takes a special position, which crystalizes in a unique distorted low-symmetry structure at ambient conditions. The interlayer interaction in ReS2 is rather weak, thus its bulk properties are similar to that of monolayer. ... More
Equivalent classes in matching covered graphsFeb 25 2019Let $G$ be a matching covered graph. Two edges $ e_1$ and $e_2$ of $G$ are {\it equivalent} if $\{e_1,e_2\}\subseteq M$ or $\{e_1,e_2\}\cap M=\emptyset$ for every perfect matching $M$ of $G$. An {\it equivalent class} of $G$ is an edge set $S$ of $G$ ... More
Holographic Complexity and Two Identities of Action GrowthNov 07 2016Nov 23 2016The recently proposed complexity-action conjecture allows one to calculate how fast one can produce a quantum state from a reference state in terms of the on-shell action of the dual AdS black hole at the Wheeler-DeWitt patch. We show that the action ... More
$b$-invariant edges in cubic near-bipartite brickMay 17 2019A brick is a non-bipartite graph without non-trivial tight cuts. Bricks are building blocks of matching covered graphs. We say that an edge $e$ in a brick $G$ is $b$-invariant if $G-e$ is matching covered and it contains exactly one brick. Kothari, Carvalho, ... More
$b$-invariant edges in cubic near-bipartite bricksMay 17 2019May 20 2019A brick is a non-bipartite graph without non-trivial tight cuts. Bricks are building blocks of matching covered graphs. We say that an edge $e$ in a brick $G$ is $b$-invariant if $G-e$ is matching covered and it contains exactly one brick. Kothari, Carvalho, ... More
Recovery of Saturated $γ$ Signal Waveforms by Artificial Neural NetworksOct 18 2018Particle may sometimes have energy outside the range of radiation detection hardware so that the signal is saturated and useful information is lost. We have therefore investigated the possibility of using an Artificial Neural Network (ANN) to restore ... More
Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. III. Detection of Fe II Reverberation in Nine Narrow-Line Seyfert 1 GalaxiesMar 12 2015This is the third in a series of papers reporting on a large reverberation-mapping campaign aimed to study the properties of active galactic nuclei (AGNs) with high accretion rates. We present new results on the variability of the optical Fe II emission ... More
A Fractional Analogue of Brooks' TheoremMar 17 2011Nov 13 2011Let $\Delta(G)$ be the maximum degree of a graph $G$. Brooks' theorem states that the only connected graphs with chromatic number $\chi(G)=\Delta(G)+1$ are complete graphs and odd cycles. We prove a fractional analogue of Brooks' theorem in this paper. ... More
Oscillating planar Hall response from the surface electrons in bulk crystal Sn doped Bi1.1Sb0.9Te2SApr 12 2018We report the low-temperature magneto-transport in the bulk-insulating single crystal of topological insulator Sn doped Bi1.1Sb0.9Te2S. The Shubnikov-de Haas oscillations appear with their reciprocal frequency proportional to cos/theta , demonstrating ... More
Extraordinarily bound quasi-one-dimensional trions in two-dimensional phosphorene atomic semiconductorsNov 22 2014The anisotropic nature of the new two-dimensional (2D) material phosphorene, in contrast to other 2D materials such as graphene and transition metal dichalcogenide (TMD) semiconductors, allows excitons to be confined in a quasi-one-dimensional (1D) space ... More
Palladium Diselenide Long-Wavelength Infrared Photodetector with High Sensitivity and StabilityFeb 06 2019A long-wavelength infrared (IR) photodetector based on two-dimensional materials working at room temperature would have wide applications in many aspects in remote sensing, thermal imaging, biomedical optics, and medical imaging. However, sub-bandgap ... More
On-Demand Single Photons with High Extraction Efficiency and Near-Unity Indistinguishability from a Resonantly Driven Quantum Dot in a MicropillarJan 03 2016May 13 2016Scalable photonic quantum technologies require on-demand single-photon sources with simultaneously high levels of purity, indistinguishability, and efficiency. These key features, however, have only been demonstrated separately in previous experiments. ... More
A new topological semimetal with iso-energetic Weyl fermions in TaAs under high pressureSep 24 2015Nov 11 2015TaAs as one of the experimentally discovered topological Weyl semimetal has attracted intense interests recently. The ambient TaAs has two types of Weyl nodes which are not on the same energy level. As an effective way to tune lattice parameters and electronic ... More
Filamentary Fragmentation and Accretion in High-Mass Star-Forming Molecular CloudsJan 18 2018Filamentary structures are ubiquitous in high-mass star-forming molecular clouds. Their relation with high-mass star formation is still to be understood. Here we report interferometric observations toward 8 filamentary high-mass star-forming clouds. A ... More
Star Formation Rates of Massive Molecular Clouds in the Central Molecular ZoneJan 23 2019Feb 21 2019We investigate star formation at very early evolutionary phases in five massive clouds in the inner 500 pc of the Galaxy, the Central Molecular Zone. Using interferometer observations of H$_2$O masers and ultra-compact H II regions, we find evidence of ... More
Experimental Test of Bell inequalities with Six-Qubit Graph StatesJun 18 2009Jan 04 2011We report on the experimental realization of two different Bell inequality tests based on six-qubit linear-type and Y-shape graph states. For each of these states, the Bell inequalities tested are optimal in the sense that they provide the maximum violation ... More
Experimental Realization of a Controlled-NOT Gate with Four-Photon Six-Qubit Cluster StatesMay 13 2009Mar 30 2010We experimentally demonstrate an optical controlled-NOT (CNOT) gate with arbitrary single inputs based on a 4-photon 6-qubit cluster state entangled both in polarization and spatial modes. We first generate the 6-qubit state, and then by performing single-qubit ... More
Experimental demonstration of a hyper-entangled ten-qubit Schrödinger cat stateSep 24 2008Coherent manipulation of an increasing number of qubits for the generation of entangled states has been an important goal and benchmark in the emerging field of quantum information science. The multiparticle entangled states serve as physical resources ... More
Magnetic effect on dynamical tide in rapidly rotating astronomical objectsJan 17 2018Jan 19 2018By numerically solving the equations of rotating magnetohydrodynamics (MHD), the magnetic effect on dynamical tide is studied. It is found that magnetic field has a significant impact not only on the flow structure, i.e. the internal shear layers in rotating ... More