Results for "D. Sun"

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One-dimensional spin-1/2 Heisenberg antiferromagnet in a weak external magnetic fieldFeb 07 2000The one dimensional spin-1/2 Heisenberg antiferromagnet in a weak magnetic field h is studied using the bosonization method. We derive a set of renormalization group equations. The fixed point is reached when the field is scaled to the value at which ... More
A unified framework for heat and mass transport at the atomic scaleJan 17 2018Feb 07 2018We present a unified framework to simulate heat and mass transport in systems of particles. The proposed framework is based on kinematic mean field theory and uses a phenomenological master equation to compute effective transport rates between particles ... More
Local Coarse-grained Approximation to Path Integral Monte Carlo Integration for Fermion SystemsAug 18 2008May 08 2009An approximate treatment of exchange in finite-temperature path integral Monte Carlo simulations for fermions has been proposed. In this method, some of the fine details of density matrix due to permutations have been smoothed over or averaged out by ... More
Geometric phase of a quantum dot system in nonunitary evolutionDec 29 2009Practical implementations of quantum computing are always done in the presence of decoherence. Geometric phase is useful in the context of quantum computing as a tool to achieve fault tolerance. Recent experimental progresses on coherent control of single ... More
Effect of the equilibrium pair separation on cluster structuresJan 17 2008Jul 16 2008A simple pair potential, which equilibrium pair separation can be varied under a fixed interaction range, has been proposed. The new potential can make both face-centered-cubic(fcc) and body-centered-cubic(bcc) structure stable by simply changing one ... More
Electronic Properties, Screening and Efficient Carrier Transport in NaSbS2Jan 22 2017NaSbS2 is a semiconductor that was recently shown to have remarkable efficacy as a solar absorber indicating efficient charge collection even in defected material. We report first principles calculations of properties that show (1) an indirect gap only ... More
Generating entangled photon pairs from a cavity-QED systemSep 22 2005Nov 20 2007We propose a scheme for the controlled generation of Einstein-Podosky-Rosen (EPR) entangled photon pairs from an atom coupled to a high Q optical cavity, extending the prototype system as a source for deterministic single photons. A thorough theoretical ... More
A small X-ray corona of the narrow-angle tail radio galaxy NGC 1265 soaring through the Perseus clusterJan 24 2005Jul 14 2005A deep Chandra observation of NGC 1265 (3C 83.1B), the prototype for the narrow-angled-tailed (NAT) radio galaxy, reveals a small cool X-ray thermal corona (~ 0.6 keV) embedded in the hot ICM of the Perseus cluster (~ 6.7 keV). The corona is asymmetric ... More
The constant-pressure molecular dynamics for finite systems and its applicationsFeb 01 2008Recently we proposed a new constant-pressure molecular dynamics method for finite systems. In this paper, we discuss the current understanding of this method and its technique details. We also review the recent theoretical advances of nano-system under ... More
A unified formulation of Gaussian vs. sparse stochastic processes - Part I: Continuous-domain theoryAug 31 2011Oct 05 2012We introduce a general distributional framework that results in a unifying description and characterization of a rich variety of continuous-time stochastic processes. The cornerstone of our approach is an innovation model that is driven by some generalized ... More
AOSO-LogitBoost: Adaptive One-Vs-One LogitBoost for Multi-Class ProblemOct 18 2011Jul 04 2012This paper presents an improvement to model learning when using multi-class LogitBoost for classification. Motivated by the statistical view, LogitBoost can be seen as additive tree regression. Two important factors in this setting are: 1) coupled classifier ... More
Analytic approach to the one-dimensional spin-Peierls system in the entire frequency rangeOct 31 2000We use the two cut-off renormalization group (RG) method to study the spin-Peierls model in one-dimension for the entire phonon frequency range. We integrate out the phonon and solve the effective Fermion system via mean field and RG methods. We make ... More
Time-Independent Measurements of D0-D0bar Mixing and Relative Strong Phases Using Quantum CorrelationsJul 20 2005Dec 14 2007Due to quantum correlations in the C=-1 and C=+1 D0 D0bar pairs produced in the reactions e+ e- --> D0 D0bar (n pi0) and e+ e- --> D0 D0bar gamma (n pi0), respectively, the time-integrated D0 D0bar decay rates are sensitive to interference between amplitudes ... More
A new constant-pressure molecular dynamics method for finite systemFeb 10 2001In this letter, by writing the volume as a function of coordinates of atoms, we present a new constant-pressure molecular dynamics method with parameters free. This method is specially appropriate for the finite system in which the periodic boundary condition ... More
A lossy transmission line as a quantum open system in the standard quantum limitJun 30 2004We systematically investigate how to quantize a transmission line resonator (TLR) in a mesoscopic electrical circuits in the presence of the resistance and the conductance of the dielectric media. Developed from the quantum bath based effective Hamiltonian ... More
Second order quantum decoherence in the boson systemApr 09 2001Apr 22 2001The second order quantum decoherence (SOQDC)is proposed as a novel description for the loss of quantum coherence only reflected by second order quantum correlations. By calculating the two-time correlation function, the phenomenon of SOQDC is studied ... More
Tracking continuous gravitational waves from a neutron star at once and twice the spin frequency with a hidden Markov modelMar 09 2019Searches for continuous gravitational waves from rapidly spinning neutron stars normally assume that the star rotates about one of its principal axes of moment of inertia, and hence the gravitational radiation emits only at twice the spin frequency of ... More
The Half-Integer Charged Particles of the Orbifold ModelsJan 08 2008In this paper, we consider half-integer charged particles predicted by models of orbifold compactification of the $E_8\times E_8$ heterotic string theory. We find that it is possible for half-integer charged particles to exist in our universe, and the ... More
Conjecture on the Avoidance of the Big CrunchJun 26 2005KKLT give a mechanism to generate de Sitter vacua in string theory. And recently, the scenario, {\em landscape}, is suggested to explain the problem of the cosmological constant. In this scenario, the cosmological constant is a de Sitter vacuum. The vacuum ... More
Non Gaussianity of General Multiple-Field Inflationary ModelsOct 25 2005Apr 13 2006Using the "$\delta N$-formalism", We obtain the expression of the non-Gaussianity of multiple-field inflationary models with the nontrivial field-space metric. Further, we rewritten the result by using the slow-rolling approximation.
Quantum decoherence effect and neutrino oscillationAug 15 1998In the view of the quantum dynamic theory of measurement developed from the Hepp-Colemen (HC) model (K. Hepp, Hev.Phys.Acta, {\bf 45}, 237 (1972)), the quantum decoherence in neutrino flavor oscillation caused by an environment surrounding neutrinos is ... More
Entanglement between two fermionic atoms inside a cylindrical harmonic trapJan 18 2007We investigate quantum entanglement between two (spin-1/2) fermions inside a cylindrical harmonic trap, making use of the von Neumann entropy for the reduced single particle density matrix as the pure state entanglement measure. We explore the dependence ... More
Operator fidelity susceptibility: an indicator of quantum criticalityMar 20 2008Mar 28 2008We introduce the operator fidelity and propose to use its susceptibility for characterizing the sensitivity of quantum systems to perturbations. Two typical models are addressed: one is the transverse Ising model exhibiting a quantum phase transition, ... More
Branches of the LandscapeJan 27 2005Jan 30 2005With respect to the question of supersymmetry breaking, there are three branches of the flux landscape. On one of these, if one requires small cosmological constant, supersymmetry breaking is predominantly at the fundamental scale; on another, the distribution ... More
Optical and Electronic Properties of Doped $p$-type CuI: Explanation of Transparent Conductivity from First PrinciplesMar 13 2018We report properties of the reported transparent conductor CuI, including the effect of heavy $p$-type doping. The results, based on first principles calculations, include analysis of the electronic structure and calculations of optical and dielectric ... More
Holonomic Quantum Computation Using Rf-SQUIDs Coupled Through A Microwave CavityJul 09 2004Oct 23 2004We propose a new scheme to realize holonomic quantum computation with rf-SQUID qubits in a microwave cavity. In this scheme associated with the non-Abelian holonomies, the single-qubit gates and a two-qubit control-Phase gate as well as a control-NOT ... More
Quantum storage and information transfer with superconducting qubitsJun 17 2005We design theoretically a new device to realize the general quantum storage based on dcSQUID charge qubits. The distinct advantages of our scheme are analyzed in comparison with existing storage scenarios. More arrestingly, the controllable XY-model spin ... More
Graphite under uniaxial compression along c-axis: a new parameter relates out-of-plane strain to in-plane phonon frequencyFeb 15 2015Aug 27 2015Stacking graphene sheets forms graphite. Two in-plane vibrational modes of graphite, E1u and E2g(2), are derived from graphene E2g mode, the shifts of which under compression are all considered as results of in-plane bond shortening. Values of Gruneisen ... More
Anisotropic spin fluctuations and multiple superconducting gaps in hole-doped Ba_0.7K_0.3Fe_2As_2: NMR in a single crystalMar 29 2009Aug 18 2009We report the first ^{75}As-NMR study on a single crystal of the hole-doped iron-pnictide superconductor Ba_{0.7}K_{0.3}Fe_2As_{2} (T_c = 31.5 K). We find that the Fe antiferromagnetic spin fluctuations are anisotropic and are weaker compared to underdoped ... More
Exact post-selection inference, with application to the lassoNov 25 2013May 03 2016We develop a general approach to valid inference after model selection. At the core of our framework is a result that characterizes the distribution of a post-selection estimator conditioned on the selection event. We specialize the approach to model ... More
Phonon anomalies in pure and underdoped R{1-x}K{x}Fe{2}As{2} (R = Ba, Sr) investigated by Raman light scatteringJul 03 2009Aug 18 2009We present a detailed temperature dependent Raman light scattering study of optical phonons in Ba{1-x}K{x}Fe{2}As{2} (x ~ 0.28, superconducting Tc ~ 29 K), Sr{1-x}K{x}Fe{2}As{2} (x ~ 0.15, Tc ~ 29 K) and non-superconducting BaFe{2}As{2} single crystals. ... More
On a hierarchical control strategy for multi-agent formation without reflectionAug 01 2018This paper considers a formation shape control problem for point agents in a two-dimensional ambient space, where the control is distributed, is based on achieving desired distances between nominated agent pairs, and avoids the possibility of reflection ... More
Quantum heat engine with continuum working mediumJul 18 2006We introduce a new quantum heat engine, in which the working medium is a quantum system with a discrete level and a continuum. Net work done by this engine is calculated and discussed. The results show that this quantum heat engine behaves like the two-level ... More
Non-singular boundary integral methods for fluid mechanics applicationsFeb 09 2019A formulation of the boundary integral method for solving partial differential equations has been developed whereby the usual weakly singular integral and the Cauchy principal value integral can be removed analytically. The broad applicability of the ... More
Fractional quantum Hall effect in the absence of Landau levelsFeb 14 2011It has been well-known that topological phenomena with fractional excitations, i.e., the fractional quantum Hall effect (FQHE) \cite{Tsui1982} will emerge when electrons move in Landau levels. In this letter, we report the discovery of the FQHE in the ... More
Density-Dependent Synthetic Gauge Fields Using Periodically Modulated InteractionsNov 13 2013Nov 19 2014We show that density-dependent synthetic gauge fields may be engineered by combining periodically modu- lated interactions and Raman-assisted hopping in spin-dependent optical lattices. These fields lead to a density- dependent shift of the momentum distribution, ... More
The structure of Lennard-Jones nanowires encapsulated by carbon nanotubesSep 18 2012Oct 06 2012Molecular dynamics simulations have been used to investigate the structures of Lennard-Jones (LJ) nanowires (NWs) encapsulated by carbon nanotubes (CNTs). We found that, when the radius of CNTs is small, the structures of NWs are quite simple, {\it i.e,} ... More
Differential emission measure Analysis of a limb solar flare on 2012 July 19Mar 25 2014Mar 27 2014We perform Differential Emission Measure (DEM) analysis of an M7.7 flare that occurred on 2012 July 19 and was well observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamic Observatory. Using the observational data with unprecedented ... More
Theory of Optically-Driven Sideband Cooling for Atomic Collective Excitations and Its GeneralizationJun 04 2009We explore how to cool atomic collective excitations in an optically-driven three-level atomic ensemble, which may be described by a model of coupled two harmonic oscillators (HOs) with a time-dependent coupling. Moreover, the coupled two-HO model is ... More
Coherent excitation transferring via dark state in light-harvesting processFeb 04 2011Feb 15 2011We study the light absorption and energy transferring in a donor-acceptor system with a bionic structure. In the optimal case with uniform couplings, it is found that the quantum dynamics of this seemingly complicated system is reduced as a three-level ... More
Supervised Deep Sparse Coding NetworksJan 29 2017May 23 2017In this paper, we describe the deep sparse coding network (SCN), a novel deep network that encodes intermediate representations with nonnegative sparse coding. The SCN is built upon a number of cascading bottleneck modules, where each module consists ... More
Kernel Approximation on Manifolds II: The $L_{\infty}$-norm of the $L_2$-projectorMay 13 2010Dec 16 2010This article addresses two topics of significant mathematical and practical interest in the theory of kernel approximation: the existence of local and stable bases and the L_p--boundedness of the least squares operator. The latter is an analogue of the ... More
Ferromagnetic resonance study of polycrystalline Fe_{1-x}V_x alloy thin filmsOct 15 2007Oct 17 2007Ferromagnetic resonance has been used to study the magnetic properties and magnetization dynamics of polycrystalline Fe$_{1-x}$V$_{x}$ alloy films with $0\leq x < 0.7$. Films were produced by co-sputtering from separate Fe and V targets, leading to a ... More
Communication-efficient sparse regression: a one-shot approachMar 14 2015Aug 11 2015We devise a one-shot approach to distributed sparse regression in the high-dimensional setting. The key idea is to average "debiased" or "desparsified" lasso estimators. We show the approach converges at the same rate as the lasso as long as the dataset ... More
A dimension-breaking phenomenon for water waves with weak surface tensionNov 10 2014Sep 08 2016It is well known that the water-wave problem with weak surface tension has small-amplitude line solitary-wave solutions which to leading order are described by the nonlinear Schr\"odinger equation. The present paper contains an existence theory for three-dimensional ... More
A robust and accurate formulation of molecular and colloidal electrostaticsFeb 08 2019This paper presents a re-formulation of the boundary integral method (BIM) for the Debye-Huckel model of molecular and colloidal electrostatics that removes the mathematical singularities that have been accepted as an intrinsic part of the conventional ... More
Trace-back Along Capsules and Its Application on Semantic SegmentationJan 09 2019In this paper, we propose a capsule-based neural network model to solve the semantic segmentation problem. By taking advantage of the extractable part-whole dependencies available in capsule layers, we derive the probabilities of the class labels for ... More
Quantum computation based on d-level cluster statesApr 08 2003Jul 08 2003The concept of qudit (a d-level system) cluster state is proposed by generalizing the qubit cluster state (Phys. Rev. Lett. \textbf{86}, 910 (2001)) according to the finite dimensional representations of quantum plane algebra. We demonstrate their quantum ... More
Collective effects of multi-scatterer on coherent propagation of photon in a two dimensional networkDec 22 2012Jul 22 2013We study the collective phenomenon in the scattering of a single-photon by one or two layers of two-level atoms. By modeling the photon dispersion with a two-dimensional (2D) coupled cavity array, we analytically derive the scattering probability of a ... More
Probing Quantum Phase Transition in Macroscopic Qubit Array via circuit QED architectureMar 02 2006Jun 06 2006We demonstrate a universal physical mechanism to probe the macroscopic quantum phase transition based on circuit QED architecture. We found that, with certain parameters, the Josephson junction qubit array behaves as an antiferromagnetic Ising model in ... More
Quantum teleportation using cluster statesApr 25 2003A protocol of quantum communication is proposed in terms of the multi-qubit quantum teleportation through cluster states (Phys. Rev. Lett. \textbf{86}, 910 (2001)). Extending the cluster state based quantum teleportation on the basic unit of three qubits ... More
Sparse Coding with Fast Image Alignment via Large Displacement Optical FlowDec 21 2015Sparse representation-based classifiers have shown outstanding accuracy and robustness in image classification tasks even with the presence of intense noise and occlusion. However, it has been discovered that the performance degrades significantly either ... More
Task-Driven Dictionary Learning for Hyperspectral Image Classification with Structured Sparsity ConstraintsFeb 03 2015Sparse representation models a signal as a linear combination of a small number of dictionary atoms. As a generative model, it requires the dictionary to be highly redundant in order to ensure both a stable high sparsity level and a low reconstruction ... More
Courteous Autonomous CarsAug 08 2018Aug 16 2018Typically, autonomous cars optimize for a combination of safety, efficiency, and driving quality. But as we get better at this optimization, we start seeing behavior go from too conservative to too aggressive. The car's behavior exposes the incentives ... More
Planar tunneling spectroscopy of the topological Kondo insulator SmB$_6$Jun 26 2017Several technical issues and challenges are identified and investigated for the planar tunneling spectroscopy of the topological Kondo insulator SmB$_6$. Contrasting behaviors of the tunnel junctions prepared in two different ways are analyzed and explained ... More
Magnetization DynamicsOct 10 2018Magnetism primarily describes the physics and materials science of systems presenting a magnetization -- a macroscopic order parameter characterizing electron angular momentum. The order parameter is associated with the electronic exchange interactions, ... More
An inexact subsampled proximal Newton-type method for large-scale machine learningAug 28 2017We propose a fast proximal Newton-type algorithm for minimizing regularized finite sums that returns an $\epsilon$-suboptimal point in $\tilde{\mathcal{O}}(d(n + \sqrt{\kappa d})\log(\frac{1}{\epsilon}))$ FLOPS, where $n$ is number of samples, $d$ is ... More
The Thermal Composite Supernova Remnant Kes 27 as Viewed by CHANDRA: Shock Reflection from a Cavity WallNov 04 2007Feb 13 2008We present a spatially resolved spectroscopic study of the thermal composite supernova remnant Kes 27 with Chandra. The X-ray spectrum of Kes 27 is characterized by K lines from Mg, Si, S, Ar, and Ca. The X-ray emitting gas is found to be enriched in ... More
Superradiant quantum phase transition in a circuit QED system: a revisit from a fully microscopic point of viewApr 12 2012In order to examine whether or not the quantum phase transition of Dicke type exists in realistic systems, we revisit the model setup of the superconducting circuit QED from a microscopic many-body perspective based on the BCS theory with pseudo-spin ... More
Mosaic spin models with topological orderAug 06 2007Nov 02 2007We study a class of two-dimensional spin models with the Kitaev-type couplings in mosaic structure lattices to implement topological orders. We show that they are exactly solvable by reducing them to some free Majorana fermion models with gauge symmetries. ... More
Quantum theory for spatial motion of polaritons in inhomogeneous fieldsJun 23 2007Feb 18 2008Polaritons are the collective excitations of many atoms dressed by resonant photons, which can be used to explain the slow light propagation with the mechanism of electromagnetically induced transparency. As quasi-particles, these collective excitations ... More
Quantum Critical Dynamics of A Qubit Coupled to An Isotropic Lipkin-Meshkov-Glick BathFeb 28 2007We explore a dynamic signature of quantum phase transition (QPT) in an isotropic Lipkin-Meshkov-Glick (LMG) model by studying the time evolution of a central qubit coupled to it. We evaluate exactly the time-dependent purity, which can be used to measure ... More
Quantum criticality in a generalized Dicke modelApr 13 2006Oct 01 2007We employ a generalized Dicke model to study theoretically the quantum criticality of an extended two-level atomic ensemble interacting with a single-mode quantized light field. Effective Hamiltonians are derived and diagonalized to investigate numerically ... More
Two-Qubits Entanglement Induced by a Faster Data BusJan 11 2004We propose a theoretical protocol to create the entanglement of two qubits via the Born-Oppenheimer (BO) approximation. In our scheme, each qubit is coupled to a faster data bus whose frequency is much larger than the energy spacing of the qubits and ... More
Idealization Second Quantization of Composite ParticlesDec 16 2000A practical method is developed to deal with the second quantization of the many-body system containing the composite particles. In our treatment, the modes associated with composite particles are regarded approximately as independent ones compared with ... More
Quantum Maxwell's Demon in Thermodynamic CyclesSep 14 2010We study the physical mechanism of Maxwell's Demon (MD) helping to do extra work in thermodynamic cycles, by describing measurement of position, insertion of wall and information erasing of MD in a quantum mechanical fashion. The heat engine is exemplified ... More
Stellar rotation and the extended main sequence turnoff in the open cluster NGC 5822Apr 06 2019The origin of extended main sequence turnoffs (eMSTOs) in intermediate-age (1-3 Gyr) clusters is one of the most intriguing questions in current star cluster research. Unlike the split main sequences found in some globular clusters. which are caused by ... More
On some determinants involving Jacobi symbolsDec 19 2018Jan 27 2019In this paper we study some conjectures on determinants with Jacobi symbol entries posed by Z.-W. Sun. For any positive integer $n\equiv3\pmod4$, we show that $$(6,1)_n=[6,1]_n=(3,2)_n=[3,2]_n=0$$ and $$(4,2)_n=(8,8)_n=(3,3)_n=(21,112)_n=0$$ as conjectured ... More
Higher order Voronoi based mobile coverage controlOct 07 2014Most current results on coverage control using mobile sensors require that one partitioned cell is the sole responsibility of one sensor. In this paper, we consider a class of generalized Voronoi coverage control problems by using higher order Voronoi ... More
Spin injection efficiency from two adjoining ferromagnetic metals into a two-dimensional electron gasDec 17 2002In order to enhance spin injection efficiency from ferromagnetic (FM) metal into a two-dimensional electron gas (2DEG), we introduce another FM metal and two tunnel barriers (I) between them to investigate the current polarization in such ballistic FM/I/FM/I/2DEG ... More
Decoherence-Based Quantum Zeno Effect in a Cavity-QED SystemJul 27 2010We present a decoherence-based interpretation for the quantum Zeno effect (QZE) where measurements are dynamically treated as dispersive couplings of the measured system to the apparatus, rather than the von Neumann's projections. It is found that the ... More
Dimerization-assisted energy transport in light-harvesting complexesFeb 02 2010Jun 24 2010We study the role of the dimer structure of light-harvesting complex II (LH2) in excitation transfer from the LH2 (without a reaction center (RC)) to the LH1 (surrounding the RC), or from the LH2 to another LH2. The excited and un-excited states of a ... More
Spin wave based quantum storage of electronic spin with a ring array of nuclear spinsSep 18 2004Apr 14 2006We propose a solid state based protocol to implement the universal quantum storage for electronic spin qubit. The quantum memory in this scheme is the spin wave excitation in the ring array of nuclei in a quantum dot. We show that the quantum information ... More
Understanding destruction of nth-order quantum coherence in terms of multi-path interferenceMar 18 2002The classic example of the destruction of interference fringes in a ``which-way'' experiment, caused by an environmental interaction, may be viewed as the destruction of first-order coherence as defined by Glauber many years ago (Glauber). However, the ... More
Engineering Progressive Decoherence with Quantum Jumps in Charge QubitDec 14 2002Dec 27 2002For the Josephson junction charge qubits with macroscopically quantum natures, we propose a theoretical scheme to observe the loss of quantum coherence through coupling such qubit system to an engineered reservoir, the harmonic oscillator mode in the ... More
High order quantum decoherence via multi-particle amplitude for boson systemMay 24 2001In this paper we depict the high order quantum coherence of a boson system by using the multi-particle wave amplitude, whose norm square is just the high order correlation function. This multi-time amplitude can be shown to be a superposition of several ... More
Decoherence in a single trapped ion due to engineered reservoirApr 18 2000The decoherence in trapped ion induced by coupling the ion to the engineered reservoir is studied in this paper. The engineered reservoir is simulated by random variations in the trap frequency, and the trapped ion is treated as a two-level system driven ... More
Transformable topological mechanical metamaterialsOct 21 2015Mechanical metamaterials are engineered materials that gain their remarkable mechanical properties, such as negative Poisson's ratios, negative compressibility, phononic bandgaps, and topological phonon modes, from their structure rather than composition. ... More
Sequence-specific polyampholyte phase separation in membraneless organellesMay 29 2016Sep 21 2016Liquid-liquid phase separation of charge/aromatic-enriched intrinsically disordered proteins (IDPs) is critical in the biological function of membraneless organelles. Much of the physics of this recent discovery remains to be elucidated. Here we present ... More
Periodic solitons for the elliptic-elliptic focussing Davey-Stewartson equationsApr 07 2015Sep 09 2016We consider the elliptic-elliptic, focussing Davey-Stewartson equations, which have an explicit bright line soliton solution. The existence of a family of periodic solitons, which have the profile of the line soliton in the longitudinal spatial direction ... More
Higher order mobile coverage control with application to localizationMar 07 2017Feb 08 2018Most current results on coverage control using mobile sensors require that one partitioned cell is associated with precisely one sensor. In this paper, we consider a class of coverage control problems involving higher order Voronoi partitions, motivated ... More
Should unfolded histograms be used to test hypotheses?Jul 24 2016In many analyses in high energy physics, attempts are made to remove the effects of detector smearing in data by techniques referred to as "unfolding" histograms, thus obtaining estimates of the true values of histogram bin contents. Such unfolded histograms ... More
Adding One Neuron Can Eliminate All Bad Local MinimaMay 22 2018One of the main difficulties in analyzing neural networks is the non-convexity of the loss function which may have many bad local minima. In this paper, we study the landscape of neural networks for binary classification tasks. Under mild assumptions, ... More
Existence and conditional energetic stability of three-dimensional fully localised solitary gravity-capillary water wavesAug 09 2011In this paper we show that the hydrodynamic problem for three-dimensional water waves with strong surface-tension effects admits a fully localised solitary wave which decays to the undisturbed state of the water in every horizontal direction. The proof ... More
Inside a kettleOct 13 2012This fluid dynamics video images the different heat transport mechanisms at play when a liquid confined in a vertical Hele-Shaw cell is heated from below. The two-dimensional time resolved temperature field inside the cell is measured by a quantitative ... More
Cooling of Nanomechanical Resonator Based on Periodical Coupling to Cooper Pair BoxOct 20 2004Oct 31 2005We propose and study an active cooling mechanism for the nanomechanical resonator (NAMR) based on periodical coupling to a Cooper pair box (CPB), which is implemented by a designed series of magnetic flux pluses threading through the CPB. When the initial ... More
Second Quantization of Cini Model for High Order Quantum Decoherence in Quantum MeasurementJun 02 2001By making the second quantization for the Cini Model of quantum measurement without wave function collapse [M. Cini, Nuovo Cimento, B73 27(1983)], the second order quantum decoherence (SOQD) is studied with a two mode boson system interacting with an ... More
A nonlinear mechanism of charge qubit decoherence in a lossy cavity: the quasi normal mode approachSep 09 2004Dec 21 2004In the viewpoint of quasi normal modes, we describe a novel decoherence mechanism of charge qubit of Josephson Junctions (JJ) in a lossy micro-cavity, which can appear in the realistic experiment for quantum computation based on JJ qubit. We show that ... More
The evolution of the physical state of the IGMJan 14 2002Using a new, increased dataset of 7 QSOs from VLT/UVES observations combined with one QSO from the literature, the minimum Doppler parameters as a function of neutral hydrogen column density N(HI), b_c(N), of the Lyman-alpha forest has been derived at ... More
The Lyman-Alpha Forest at 1.5 < z < 4Dec 30 2000May 02 2001Using high resolution (R ~ 45000), high S/N (20-50) VLT/UVES observations covering the Lyman-alpha forest at 1.5 < z < 2.4 combined with similar observations at z > 2.4 from the literature, we have presented the redshift evolution of the Lyman-alpha forest ... More
Structured Priors for Sparse-Representation-Based Hyperspectral Image ClassificationJan 16 2014Pixel-wise classification, where each pixel is assigned to a predefined class, is one of the most important procedures in hyperspectral image (HSI) analysis. By representing a test pixel as a linear combination of a small subset of labeled pixels, a sparse ... More
On bubble clustering and energy spectra in pseudo-turbulenceDec 08 20093D-Particle Tracking (3D-PTV) and Phase Sensitive Constant Temperature Anemometry in pseudo-turbulence--i.e., flow solely driven by rising bubbles-- were performed to investigate bubble clustering and to obtain the mean bubble rise velocity, distributions ... More
Non-filamentary memristive switching in Pt/CuOx/Si/Pt systemsApr 15 2013We report a memristive switching effect in the Pt/CuOx/Si/Pt devices prepared by rf sputtering technique at room temperature. Different from other Cu-based switching systems, the devices show a non-filamentary switching effect. A gradual electroforming ... More
Transport properties and the anisotropy of Ba_{1-x}K_xFe_2As_2 single crystals in normal and superconducting statesJul 15 2009The transport and superconducting properties of Ba_{1-x}K_xFe_2As_2 single crystals with T_c = 31 K were studied. Both in-plane and out-of plane resistivity was measured by modified Montgomery method. The in-plane resistivity for all studied samples, ... More
Self-energy effects and electron-phonon coupling in Fe-As superconductorsAug 29 2009We report on Raman scattering experiments of the undoped SrFe2As2 and superconducting Sr0.85K0.15Fe2As2 (Tc=28K) and Ba0.72K0.28Fe2As2 (Tc=32K) single crystals. The frequency and linewidth of the B1g mode at 210 cm-1 exhibits an appreciable temperature ... More
Discrete time symmetry breaking in quantum circuits: exact solutions and tunnelingApr 10 2019We discuss general properties of discrete time quantum symmetry breaking in superconducting quantum circuits. Recent experiments in superconducting quantum circuit with Josephson junction nonlinearities give rise to new properties of strong parametric ... More
Modeling Magnetic Field Structure of a Solar Active Region Corona using Nonlinear Force-Free Fields in Spherical GeometryOct 03 2012We test a nonlinear force-free field (NLFFF) optimization code in spherical geometry using an analytical solution from Low and Lou. Several tests are run, ranging from idealized cases where exact vector field data are provided on all boundaries, to cases ... More
Investigating Two Successive Flux Rope Eruptions In A Solar Active RegionApr 28 2013We investigate two successive flux rope (FR1 and FR2) eruptions resulting in two coronal mass ejections (CMEs) on 2012 January 23. Both FRs appeared as an EUV channel structure in the images of high temperature passbands of the Atmospheric Imaging Assembly ... More
Persistence of an Energy Scale in Over-Doped High-Tc SuperconductorsMar 30 2004May 26 2004Citing the disappearance of a sharp peak in the electron self-energy, extracted from optics and angle-resolved photoemission spectroscopy (ARPES) experiments in deeply over-doped copper-oxide superconductors with Tc of 55-60K, Hwang, Timusk et al. argue ... More
Fast entanglement of two charge-phase qubits through nonadiabatic coupling to a large junctionJul 02 2003Jan 06 2004We propose a theoretical protocol for quantum logic gates between two Josephson junction charge-phase qubits through the control of their coupling to a large junction. In the low excitation limit of the large junction when $E_{J}\gg E_{c}$, it behaves ... More