Results for "Yuan Feng"
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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 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 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 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. 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 Finding eta_c' and h_c at HERA-BMay 31 2000Oct 09 2000The production of Charmonium states $\etacp$ and $\hc$ at fixed-target experiment of $pN$ collisions at HERA-$B$ is considered. It is found that the HERA-$B$ at DESY is one of the best machines in further confirming and detecting these two kinds of Charmonia ... More Transverse Spin Structure of the NucleonOct 22 2015We review the current status and future perspectives of theory and experiments of transverse spin phenomena in high-energy scattering processes off nucleon targets and related issues in nucleon structure and QCD. Systematic exploration of transverse spin ... 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 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 Quarkonium production in SM Higgs decaysMay 22 1998We investigate the SM Higgs decays into heavy quarkonia J/\psi and \Upsilon in both color-singlet and color-octet mechanisms. It is found that in J/\psi production the contribution through color-octet processes overwhelm that in color-singlet processes ... More Decomposition of Quantum Markov Chains and Zero-error CapacityAug 22 2016Markov chains have been widely applied in information theory and various areas of its applications. Quantum Markov chains are a natural quantum extension of Markov chains. This paper studies irreducibility and periodicity of (discrete time) quantum Markov ... 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 Steady state solution of warped accretion discsMay 25 2009We consider a thin accretion disc warped due to the Bardeen-Petterson effect, presenting both analytical and numerical solutions for the situation that the two viscosity coefficients vary with radius as power law, with the two power law indices not necessarily ... More Counting Rule for Hadronic Light-Cone Wave FunctionsJan 17 2003We introduce a systematic way to write down the Fock components of a hadronic light-cone wave function with $n$ partons and orbital angular momentum projection $l_z$. We show that the wave function amplitude $\psi_n(x_i,k_{i\perp},l_{zi})$ has a leading ... More Testing RIAF model for Sgr A* using the size measurementsMar 24 2006Recent radio observations by the VLBA at 7 and 3.5 mm produced the high-resolution images of the compact radio source located at the center of our Galaxy--Sgr A*, and detected its wavelength-dependent intrinsic sizes at the two wavelengths. This provides ... 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 Single Transverse-Spin Asymmetry in Hadronic Dijet ProductionJun 08 2007We study the single transverse-spin asymmetry for dijet production in hadronic collisions in both the collinear QCD factorization approach and the Brodsky-Hwang-Schmidt model. We show that a nonvanishing asymmetry is generated by both initial-state and ... 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 Prompt J/psi production at e^+e^- collidersMar 27 1997In this paper, we discuss the prompt j/psi production at e^+e^- colliders via color-singlet and color-octet production mechanisms. The color-singlet production processes include 1) e^+e^- to J/\psi gg; 2) e^+e^- to J/\psi c\bar{c}; 3) e^+e^- to q \bar ... More Optimal dense coding with arbitrary pure entangled statesApr 20 2006Aug 17 2006We examine dense coding with an arbitrary pure entangled state sharing between the sender and the receiver. Upper bounds on the average success probability in approximate dense coding and on the probability of conclusive results in unambiguous dense coding ... More Local cloning of two product statesJan 17 2005Mar 23 2005Local quantum operations and classical communication (LOCC) put considerable constraints on many quantum information processing tasks such as cloning and discrimination. Surprisingly however, discrimination of any two pure states survives such constraints ... More An Ensemble EM Algorithm for Bayesian Variable SelectionMar 14 2016We study the Bayesian approach to variable selection in the context of linear regression. Motivated by a recent work by Rockova and George (2014), we propose an EM algorithm that returns the MAP estimate of the set of relevant variables. Due to its particular ... More Model checking quantum Markov chainsMay 10 2012Nov 14 2013Although the security of quantum cryptography is provable based on the principles of quantum mechanics, it can be compromised by the flaws in the design of quantum protocols and the noise in their physical implementations. So, it is indispensable to develop ... More Local Distinguishability of Multipartite Unitary OperationsMay 10 2007We show that any two different unitary operations acting on an arbitrary multipartite quantum system can be perfectly distinguishable by local operations and classical communication when a finite number of runs is allowed. We then directly extend this ... More Catalyst-assisted Probabilistic Entanglement TransformationApr 27 2004Mar 04 2005We are concerned with catalyst-assisted probabilistic entanglement transformations. A necessary and sufficient condition is presented under which there exist partial catalysts that can increase the maximal transforming probability of a given entanglement ... More Factorization of Large-x Quark Distributions in a HadronNov 30 2004We present a factorization formula for valence quark distributions in a hadron in x-->1 limit. For the example of pion, we arrive at the form of factorization by analyzing momentum flow in the leading and high-order Feynman diagrams. The result confirms ... 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 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 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 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 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 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 Thick Accretion Disk Model for Ultraluminous Supersoft SourcesJan 18 2016We propose a geometrically thick, super-Eddington accretion disk model, where an optically thick wind is not necessary, to understand ultraluminous supersoft sources (ULSs). For high mass accretion rates $\dot M \ga 30\dot M_{\rm Edd}$ and not small inclination ... More Black Hole Shadow Image and Visibility Analysis of Sagittarius A*Mar 12 2007Mar 13 2007The compact dark objects with very large masses residing at the centres of galaxies are believed to be black holes. Due to the gravitational lensing effect, they would cast a shadow larger than their horizon size over the background, whose shape and size ... More Identification and Distance Measures of Measurement ApparatusJan 13 2006Apr 05 2006We propose simple schemes that can perfectly identify projective measurement apparatus secretly chosen from a finite set. Entanglements are used in these schemes both to make possible the perfect identification and to improve the efficiency significantly. ... More A Magnetohydrodynamic Model for the Formation of Episodic JetsNov 18 2008Feb 24 2009Episodic ejection of plasma blobs have been observed in many black hole systems. While steady, continuous jets are believed to be associated with large-scale open magnetic fields, what causes the episodic ejection of blobs remains unclear. Here by analogy ... More Magneto-thermal Disk Wind from Protoplanetary DisksNov 20 2015Global evolution and dispersal of protoplanetary disks (PPDs) is governed by disk angular momentum transport and mass-loss processes. Recent numerical studies suggest that angular momentum transport in the inner region of PPDs is largely driven by magnetized ... More Model Checking Applied to Quantum PhysicsFeb 08 2019Model checking has been successfully applied to verification of computer hardware and software, communication systems and even biological systems. In this paper, we further push the boundary of its applications and show that it can be adapted for applications ... More Modeling Attention Flow on GraphsNov 01 2018Jan 08 2019Real-world scenarios demand reasoning about process, more than final outcome prediction, to discover latent causal chains and better understand complex systems. It requires the learning algorithms to offer both accurate predictions and clear interpretations. ... More