Results for "Yuan Feng"
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Accretion and ejection in Sgr A*Feb 16 2010We review our current understanding to the accretion and ejection processes in Sgr A*. Roughly speaking, they correspond to the quiescent and flare states of the source respectively. The high-resolution {\it Chandra} observations to the gas at the Bondi ... More Sivers Function in the MIT Bag ModelAug 14 2003The Sivers function, an asymmetric transverse-momentum distribution of the quarks in a transversely polarized nucleon, is calculated in the MIT bag model. The bag quark wave functions contain both $S$-wave and $P$-wave components, and their interference ... More Luminous hot accretion disksSep 13 2000Dec 05 2000We find a new two-temperature hot branch of equilibrium solutions for stationary accretion disks around black holes. In units of Eddington accretion rate defined as $10L_{\rm Edd}/c^2$, the accretion rates to which these solutions correspond are within ... More Accretion flows: the Role of the Outer Boundary ConditionJul 23 1999We investigate the influences of the outer boundary conditions(OBCs) on the structure of an optically thin accretion flow. We find that OBC plays an important role in determining the topological structure and the profiles of the surface density and temperature ... More Generalized Parton Distributions at x->1Nov 22 2003Generalized parton distributions at large $x$ are studied in perturbative QCD approach. As $x\to 1$ and at finite $t$, there is no $t$ dependence for the GPDs which means that the active quark is at the center of the transverse space. We also obtain the ... More Studying High Energy Final State Interactions by N/D MethodSep 07 1998Jan 26 1999We discuss the final state interaction effects at high energies via a multi-channel N/D method. We find that the 2 by 2 charge--exchange final state interactions typically contribute an enhancement factor of a few times $10^{-2}$ in the $B$ meson decay ... More Observational evidence for AGNs feedback at parsec scaleMay 24 2011In a hot accretion flow, the radiation from the innermost region of the flow propagates outward and heats the electrons at large radii via Compton scattering. It has been shown in previous works that if the radiation is strong enough, $L\ga 2%L_{\rm Edd}$, ... More Characterizing locally distinguishable orthogonal product statesJul 24 2007Bennett et al. \cite{BDF+99} identified a set of orthogonal {\em product} states in the $3\otimes 3$ Hilbert space such that reliably distinguishing those states requires non-local quantum operations. While more examples have been found for this counter-intuitive ... More Acute Triangulations of the Cuboctahedral SurfaceSep 20 2012In this paper we prove that the surface of the cuboctahedron can be triangulated into 8 non-obtuse triangles and 12 acute triangles. Furthermore, we show that both bounds are the best possible. On hybrid models of quantum finite automataJun 11 2012Mar 27 2014In the literature, there exist several quantum finite automata (QFA) models with both quantum and classical states. These models are of particular interest,as they show praiseworthy advantages over the fully quantum models in some nontrivial aspects. ... More Model Checking Quantum Systems --- A SurveyJul 25 2018This article discusses the essential difficulties in developing model-checking techniques for quantum systems that are never present in model checking classical systems. It further reviews some early researches on checking quantum communication protocols ... More Energy Evolution for the Sivers Asymmetries in Hard ProcessesApr 18 2013Aug 12 2013We investigate the energy evolution of the azimuthal spin asymmetries in semi-inclusive hadron production in deep inelastic scattering (SIDIS) and Drell-Yan lepton pair production in pp collisions. The scale dependence is evaluated by applying an approximate ... More Open Bisimulation for Quantum ProcessesJan 02 2012Quantum processes describe concurrent communicating systems that may involve quantum information. We propose a notion of open bisimulation for quantum processes and show that it provides both a sound and complete proof methodology for a natural extensional ... More Superconductivity in doped two-leg ladder cupratesMar 22 2006May 20 2006Within the t-J ladder model, superconductivity with a modified d-wave symmetry in doped two-leg ladder cuprates is investigated based on the kinetic energy driven superconducting mechanism. It is shown that the spin-liquid ground-state at the half-filling ... More NLO QCD Corrections to $B_c$-to-Charmonium Form FactorsMar 10 2011Apr 15 2012The $B_c(^1S_0)$ meson to S-wave Charmonia transition form factors are calculated in next-to-leading order(NLO) accuracy of Quantum Chromodynamics(QCD). Our results indicate that the higher order corrections to these form factors are remarkable, and hence ... More On The Waiting Time for A M/M/1 Queue with ImpatienceApr 06 2017This paper focuses on the problem of modeling the correspondence pattern for ordinary people. Suppose that letters arrive at a rate $\lambda$ and are answered at a rate $\mu$. Furthermore, we assume that, for a constant $T$, a letter is disregarded when ... More The Radiative Efficiency of Hot Accretion FlowsJul 12 2012Sep 03 2012Two significant progresses have been made in the past years on our understanding of hot accretion flows. One is that only a small fraction of accretion flow available at the outer boundary can finally falls onto the black hole while most of them is lost ... More Single Transverse-Spin Asymmetries at Large-xOct 18 2006The large-$x$ behavior of the transverse-momentum dependent quark distributions is analyzed in the factorization-inspired perturbative QCD framework, particularly for the naive time-reversal-odd quark Sivers function which is responsible for the single ... More Proton Spin Structure from Measurable Parton DistributionsFeb 13 2012Oct 17 2012We present a systematic study of the proton spin structure in terms of measurable parton distributions. For a transversely-polarizedproton, we derive a polarization sum rule from the leading generalized parton distributions appearing in hard exclusive ... More Energy Harvesting for Secure OFDMA SystemsSep 12 2014Energy harvesting and physical-layer security in wireless networks are of great significance. In this paper, we study the simultaneous wireless information and power transfer (SWIPT) in downlink orthogonal frequency-division multiple access (OFDMA) systems, ... More Intrinsic Ferromagnetism in ElectrenesApr 10 2019We report intrinsic ferromagnetism in monolayer electrides or electrenes, in which excess electrons act as anions. Our first-principles calculations demonstrate that magnetism in such electron-rich two-dimensional (2D) materials originates from the anionic ... More Quantum Privacy-Preserving PerceptronJul 31 2017With the extensive applications of machine learning, the issue of private or sensitive data in the training examples becomes more and more serious: during the training process, personal information or habits may be disclosed to unexpected persons or organisations, ... More Quantum Privacy-Preserving Data AnalyticsFeb 14 2017Data analytics (such as association rule mining and decision tree mining) can discover useful statistical knowledge from a big data set. But protecting the privacy of the data provider and the data user in the process of analytics is a serious issue. ... More The Perfect Distinguishability of Quantum OperationsAug 03 2009We provide a feasible necessary and sufficient condition for when an unknown quantum operation (quantum device) secretely selected from a set of known quantum operations can be identified perfectly within a finite number of queries, and thus complete ... More Transverse Polarization of the Nucleon in Parton PictureSep 14 2012The proton's transverse polarization structure is examined in terms of the Lorentz-covariant Pauli-Lubanski vector in QCD. We find that there are contributions from leading, subleading, and next-to-subleading partonic contributions in the light-front ... More Charge transport in underdoped bilayer cupratesMay 13 2003Within the t-J model, we study the charge transport in underdoped bilayer cuprates by considering the bilayer interaction. Although the bilayer interaction leads to the band splitting in the electronic structure, the qualitative behavior of the charge ... More Modeling the hard states of three black hole candidatesMay 24 2010Jun 05 2010Simultaneous multiwavelength observations were recently performed for three black hole candidates --- SWIFT J1753.5-0127, GRO J1655-40 and XTE J1720-318. In this paper we test the accretion-jet model originally proposed to XTE J1118+480 by investigating ... More Outflow from Hot Accretion FlowsOct 23 2012Numerical simulations of hot accretion flows have shown that the mass accretion rate decreases with decreasing radius. Two models have been proposed to explain this result. In the adiabatic inflow-outflow solution (ADIOS), it is thought to be due to the ... More Ergodicity for Neutral Type SDEs with Infinite Length of MemoryMay 09 2018May 22 2018In this paper, the weak Harris theorem developed in \cite{HMS11} is illustrated by using a straightforward Wasserstein coupling, which implies the exponential ergodicity of the functional solutions to a range of neutral type SDEs with infinite length ... More Condition and capability of quantum state separationJun 02 2005Jul 18 2005The linearity of quantum operations puts many fundamental constraints on the information processing tasks we can achieve on a quantum system whose state is not exactly known, just as we observe in quantum cloning and quantum discrimination. In this paper ... More Partial Recovery of Quantum EntanglementApr 07 2004Feb 09 2007Suppose Alice and Bob try to transform an entangled state shared between them into another one by local operations and classical communications. Then in general a certain amount of entanglement contained in the initial state will decrease in the process ... More Unambiguous discrimination between quantum mixed statesMar 20 2004Apr 07 2005We prove that the states secretly chosen from a mixed state set can be perfectly discriminated if and only if these states are orthogonal. The sufficient and necessary condition when nonorthogonal quantum mixed states can be unambiguously discriminated ... More On the origin of X-ray emission in some FR Is: ADAF or jet?Jun 28 2007We investigate the X-ray origin in FR Is using the radio, submillimetre, optical, and {\em Chandra} X-ray data of a small sample consisting of eight FR I sources. These sources are very dim, with X-ray luminosities $L_{\rm X}/L_{\rm Edd} \sim 10^{-4}-10^{-8}$ ... More X-ray Spectral Variability of TeV Blazars during Rapid FlaresApr 25 2006May 08 2006The spectral energy distribution (SED) of TeV blazars peaks both at keV and TeV energies. The X-ray emission is generally believed to originate in the synchrotron emission from relativistic electrons (and positrons) in the jet of these sources, while ... More Panoptic Edge DetectionJun 03 2019Pursuing more complete and coherent scene understanding towards realistic vision applications drives edge detection from category-agnostic to category-aware semantic level. However, finer delineation of instance-level boundaries still remains unexcavated. ... More QCD Evolution of the Transverse Momentum Dependent CorrelationsDec 24 2008We study the QCD evolution for the twist-three quark-gluon correlation functions associated with the transverse momentum odd quark distributions. Different from that for the leading twist quark distributions, these evolution equations involve more general ... More Limit Theorems for Additive Functionals of Path-Dependent SDEsApr 05 2019By using limit theorems of uniform mixing Markov processes and martingale difference sequences, the strong law of large numbers, central limit theorem, and the law of iterated logarithm are established for additive functionals of path-dependent stochastic ... More Best polynomial approximation on the triangleNov 13 2017Let $E_n(f)_{\alpha,\beta,\gamma}$ denote the error of best approximation by polynomials of degree at most $n$ in the space $L^2(\varpi_{\alpha,\beta,\gamma})$ on the triangle $\{(x,y): x, y \ge 0, x+y \le 1\}$, where $\varpi_{\alpha,\beta,\gamma}(x,y) ... More Semi-inclusive Deep Inelastic Scattering at small xJun 08 2009Oct 30 2009We study the semi-inclusive hadron production in deep inelastic scattering at small $x$. A transverse momentum dependent factorization is found consistent with the results calculated in the small-$x$ approaches, such as the color-dipole framework and ... More Asymmetric Di-jet Production in Polarized Hadronic CollisionsApr 09 2007Using the collinear QCD factorization approach, we study the single-transverse-spin dependent cross section Delta sigma(S_perp) for the hadronic production of two jets of momenta P_1=P+q/2 and P_2=-P+q/2. We consider the kinematic region where the transverse ... More Scale Dependence of Hadronic Wave Functions and Parton DensitiesMay 23 2002May 28 2002We study how the components of hadronic wave functions in light-cone quantization depend on the ultraviolet cut-off by relating them in a systematic way to the matrix elements of a class of quark-gluon operators between the QCD vacuum and the hadrons. ... More