Results for "M. -H. Chou"

total 255463took 0.14s
Electronic and Magnetic Properties of Sr and Ca Doped Lanthanum Manganites from First-PrinciplesApr 14 2006The complicated electronic, magnetic, and colossal magnetoresistant (CMR) properties of Sr and Ca doped lanthanum manganites can be understood by spin-polarized first-principles calculations. The electronic properties can be attributed to a detailed balancing ... More
Dressed-atom multiphoton analysis of anomalous electromagnetically induced absorptionJul 15 2010A method to interpret probe spectra of driven degenerate atomic systems is discussed. The dressed-atom multiphoton spectroscopy (DAMS) is based on a dressing of the atomic system with the strong coupling field, followed by a perturbative treatment of ... More
Temperature-Dependent Anomalies in the Structure of the (001) Surface of LiCu2O2Apr 05 2010Surface corrugation functions, derived from elastic helium atom scattering (HAS) diffraction patterns at different temperatures, reveal that the Cu2+ rows in the (001) surface of LiCu2O2 undergo an outward displacement of about 0.15 {\AA} as the surface ... More
Extremely large non-saturating magnetoresistance and ultrahigh mobility due to topological surface states in metallic Bi2Te3 topological insulatorApr 02 2017Apr 08 2017Weak antilocalization (WAL) effects in Bi2Te3 single crystals have been investigated at high and low bulk charge carrier concentrations. At low charge carrier density the WAL curves scale with the normal component of the magnetic field, demonstrating ... More
Diluted magnetism in Mn doped SrZnO2 single crystalsOct 14 2014We have investigated the magnetic properties of Mn and Cu substituted SrZnO2 single crystals (SrZn0.99Mn0.01O2 and SrZn0.99Cu0.01O2). We observed signatures of weak ferromagnetism as a sharp increase of magnetic susceptibility below 5 K even in the low ... More
Investigation of the Structural and Dynamical Properties of the (001) Surface of LiCu2O2Oct 03 2009We report on studies of the structure and dynamics of the (001)surface of single crystal LiCu2O2, investigated by He beam scattering at room temperature, and with lattice dynamical models. The best fit surface corrugation to measured diffraction patterns ... More
Topological semi-metals with line nodes and drumhead surface statesOct 09 2015Oct 27 2015In an ordinary three-dimensional metal the Fermi surface forms a two-dimensional closed sheet separating the filled from the empty states. Topological semimetals, on the other hand, can exhibit protected one-dimensional Fermi lines or zero-dimensional ... More
Coarsening and accelerated equilibration in mass-conserving heterogeneous nucleationOct 09 2011We propose a model of mass-conserving heterogeneous nucleation to describe the dynamics of ligand-receptor binding in closed cellular compartments. When the ligand dissociation rate is small, competition among receptors for free ligands gives rise to ... More
Lattice Vibrational Modes and their Frequency Shifts in Semiconductor NanowiresAug 28 2011We have performed first-principles calculations to study the lattice vibrational modes and their Raman activities in silicon nanowires (SiNWs). Two types of characteristic vibrational modes are examined: high-frequency optical modes and low-frequency ... More
Theoretical study of hydrogen-covered diamond (100) surfaces: A chemical potential analysisJul 01 1996The bare and hydrogen-covered diamond (100) surfaces were investigated through pseudopotential density-functional calculations within the local-density approximation. Different coverages, ranging from one to two, were considered. These corresponded to ... More
Characterization of hexagonal boron nitride layers on nickel surfaces by low-energy electron microscopyNov 15 2016The thickness and interfacial geometry of hexagonal boron nitride (hBN) films grown by chemical vapor deposition on polycrystalline nickel foils is studied using low-energy electron microscopy (LEEM). The reflectivity of the electrons, measured over an ... More
Characterization of hexagonal boron nitride layers on nickel surfaces by low-energy electron microscopyNov 15 2016Feb 04 2017The thickness and interfacial geometry of hexagonal boron nitride (hBN) films grown by chemical vapor deposition on polycrystalline nickel foils is studied using low-energy electron microscopy (LEEM). The reflectivity of the electrons, measured over an ... More
Neutron scattering study of the effects of dopant disorder on the superconductivity and magnetic order in stage-4 La_2CuO_{4+y}Sep 12 2003We report neutron scattering measurements of the structure and magnetism of stage-4 La_2CuO_{4+y} with T_c ~42 K. Our diffraction results on a single crystal sample demonstrate that the excess oxygen dopants form a three-dimensional ordered superlattice ... More
Plasmons dispersion and nonvertical interband transitions in single-crystal Bi2Se3 investigated by electron energy loss spectroscopyJan 03 2013Plasmons dispersion and nonvertical interband transitions in Bi2Se3 single crystals were investigated by electron energy-loss spectroscopy in conjunction with (scanning) transmission electron microscopy, (S)TEM-EELS. Both volume plasmons ({\pi} plasmon ... More
Generation of Nonclassical Photon Pairs for Scalable Quantum Communication with Atomic EnsemblesMay 27 2003Quantum information science attempts to exploit capabilities from the quantum realm to accomplish tasks that are otherwise impossible in the classical domain [1]. Although sufficient conditions have been formulated for the physical resources required ... More
Possible spin-orbit driven spin-liquid ground state in the double perovskite phase of Ba3YIr2O9Oct 16 2012Oct 25 2013We report the structural transformation of hexagonal Ba3YIr2O9 to a cubic double perovskite form (stable in ambient conditions) under an applied pressure of 8GPa at 1273K. While the ambient pressure (AP) synthesized sample undergoes long-range magnetic ... More
Beyond the local approximation to exchange and correlation: the role of the Laplacian of the density in the energy density of SiJun 18 2005We model the exchange-correlation (XC) energy density of the Si crystal and atom as calculated by variational Monte Carlo (VMC) methods with a gradient analysis beyond the local density approximation (LDA). We find the Laplacian of the density to be an ... More
A Faraway Quasar in the Direction of the Highest Energy Auger EventJan 06 2010Aug 05 2010The highest energy cosmic ray event reported by the Auger Observatory has an energy of 148 EeV. It does not correlate with any nearby (z$<$0.024) object capable of originating such a high energy event. Intrigued by the fact that the highest energy event ... More
X-ray imaging of the dynamic magnetic vortex core deformationNov 09 2008Jan 14 2009Magnetic platelets with a vortex configuration are attracting considerable attention. The discovery that excitation with small in-plane magnetic fields or spin polarised currents can switch the polarisation of the vortex core did not only open the possibility ... More
Li non-stoichiometry and crystal growth of untwinned 1D quantum spin system Lix Cu2 O2Nov 04 2008Floating-zone growth of untwinned single crystal of Li_xCu_2O_2 with high Li content of x ~ 0.99 is reported. Li content of Li_xCu_2O_2 has been determined accurately through combined iodometric titration and thermogravimetric methods, which also ruled ... More
Nonmagnetic impurity perturbation to the quasi-two-dimensional quantum helimagnet LiCu2O2Jun 28 2010A complete phase diagram of Zn substituted quantum quasi-two-dimensional helimagnet LiCu2O2 has been presented. Helical ordering transition temperature (T_h) of the original LiCu2O2 follows finite size scaling for less than ~ 5.5% Zn substitution, which ... More
Nonstoichiometric doping and Bi antisite defect in single crystal Bi2Se3Aug 08 2012We studied the defects of Bi2Se3 generated from Bridgman growth of stoichiometric and nonstoichiometric self-fluxes. Growth habit, lattice size, and transport properties are strongly affected by the types of defect generated. Major defect types of Bi_Se ... More
On-demand quantum state transfer and entanglement between remote microwave cavity memoriesDec 15 2017Modular quantum computing architectures require fast and efficient distribution of quantum information through propagating signals. Here we report rapid, on-demand quantum state transfer between two remote superconducting cavity quantum memories through ... More
Optimal Correlation Estimators for Quantized SignalsOct 26 2012Using a maximum-likelihood criterion, we derive optimal correlation strategies for signals with and without digitization. We assume that the signals are drawn from zero-mean Gaussian distributions, as is expected in radio-astronomical applications, and ... More
Designing dark energy afterglow experimentsApr 24 2012Chameleon fields, which are scalar field dark energy candidates, can evade fifth force constraints by becoming massive in high-density regions. However, this property allows chameleon particles to be trapped inside a vacuum chamber with dense walls. Afterglow ... More
New Detectors to Explore the Lifetime FrontierJun 20 2016Jan 13 2017Long-lived particles (LLPs) are a common feature in many beyond the Standard Model theories, including supersymmetry, and are generically produced in exotic Higgs decays. Unfortunately, no existing or proposed search strategy will be able to observe the ... More
Sodium vacancy ordering and the co-existence of localized spins and itinerant charges in NaxCoO2Sep 02 2007The sodium cobaltate family (NaxCoO2) is unique among transition metal oxides because the Co sits on a triangular lattice and its valence can be tuned over a wide range by varying the Na concentration x. Up to now detailed modeling of the rich phenomenology ... More
Emergence of Anchored Flux Tubes Through the Convection ZoneMay 02 2010May 28 2015We model the evolution of buoyant magnetic flux tubes in the Sun's convection zone. A flux tube is assumed to lie initially near the top of the stably stratified radiative core below the convection zone, but a segment of it is perturbed into the convection ... More
Effect of a magnetic field on long-range magnetic order in stage-4 and stage-6 superconducting La2CuO(4+y)Sep 27 2002Feb 06 2003We have measured the enhancement of the static incommensurate spin-density wave (SDW) order by an applied magnetic field in stage-4 and stage-6 samples of superconducting La2CuO(4+y). We show that the stage-6 La2CuO(4+y) (Tc=32 K) forms static long-range ... More
Deterministic teleportation of a quantum gate between two logical qubitsJan 16 2018A quantum computer has the potential to effciently solve problems that are intractable for classical computers. Constructing a large-scale quantum processor, however, is challenging due to errors and noise inherent in real-world quantum systems. One approach ... More
Characterisation of SCUBA-2 450um and 850um-selected Galaxies in the COSMOS FieldFeb 11 2013Sep 04 2013We present deep 450um and 850um observations of a large, uniformly covered 394arcmin^2 area in the COSMOS field obtained with the SCUBA-2 instrument on the James Clerk Maxwell Telescope (JCMT). We achieve root-mean-square noise values of 4.13mJy at 450um ... More
Sodium ion ordering of Na0.77CoO2 under competing multi-vacancy cluster, superlattice and domain formationSep 28 2009Hexagonal superlattice formed by sodium multi-vacancy cluster ordering in Na$_{0.77}$CoO$_2$ has been proposed based on synchrotron X-ray Laue diffraction study on electrochemically fine-tuned single crystals. The title compound sits closely to the proposed ... More
Entangling Bosonic Modes via an Engineered Exchange InteractionJun 19 2018The realization of robust universal quantum computation with any platform ultimately requires both the coherent storage of quantum information and (at least) one entangling operation between individual elements. The use of continuous-variable bosonic ... More
Magnetic susceptibility study of hydrated and non-hydrated NaxCoO2-yH2O single crystalsApr 02 2004Jun 01 2004We have measured the magnetic susceptibility of single crystal samples of non-hydrated NaxCoO2 (x ~ 0.75, 0.67, 0.5, and 0.3) and hydrated Na0.3CoO2-yH2O (y ~ 0, 0.6, 1.3). Our measurements reveal considerable anisotropy between the susceptibilities with ... More
Macroscopic Quantum Phenomena from the Correlation, Coupling and Criticality PerspectivesJul 15 2011In this sequel paper we explore how macroscopic quantum phenomena can be measured or understood from the behavior of quantum correlations which exist in a quantum system of many particles or components and how the interaction strengths change with energy ... More
A Bayesian Finite Mixture Model with Variable Selection for Data with Mixed-type VariablesMay 09 2019Finite mixture model is an important branch of clustering methods and can be applied on data sets with mixed types of variables. However, challenges exist in its applications. First, it typically relies on the EM algorithm which could be sensitive to ... More
Hybrid Density- and Partition-based Clustering Algorithm for Data with Mixed-type VariablesMay 06 2019Clustering is an essential technique for discovering patterns in data. The steady increase in amount and complexity of data over the years led to improvements and development of new clustering algorithms. However, algorithms that can cluster data with ... More
Tensor form factors of $B \to K_1$ transition from QCD light cone sum rulesNov 21 2010Apr 30 2011The tensor form factors of $B$ into p--wave axial vector meson transition are calculated within light cone QCD sum rules method. The parametrizations of the tensor form factors based on the series expansion are presented.
Magnetic correlations in spin ice Ho2-xYxTi2O7 as revealed by neutron polarization analysisMar 24 2010Nov 10 2010We present single-crystal neutron-diffuse-scattering measurements with polarization analysis on the spin ice Ho2-xYxTi2O7 (x = 0, 0.3, and 1). At 2 K, the spin flip scattering patterns are typical of a nearest-neighbor spin ice and the effects of Y doping ... More
Quantum-spin-Hall insulator with a large gap: single-layer 1T' WSe$_2$May 21 2018Two-dimensional (2D) topological insulators (TIs) are promising platforms for low-dissipation spintronic devices based on the quantum spin Hall (QSH) effect, but experimental realization of such systems with a large band gap suitable for room-temperature ... More
Electronic phase diagram of LixCoO2 revisited with potentiostatically de-intercalated single crystalsJan 11 2012Electronic phase diagram of LixCoO2 has been re-examined using potentiostatically de-intercalated single crystal samples. Stable phases of x ~ 0.87, 0.72, 0.53, 0.50, 0.43, and 0.33 were found and isolated for physical property studies. A-type and chain-type ... More
Unique gap structure and symmetry of the charge density wave in single-layer VSe$_2$Nov 14 2018Single layers of transition metal dichalcogenides (TMDCs) are excellent candidates for electronic applications beyond the graphene platform; many of them exhibit novel properties including charge density waves (CDWs) and magnetic ordering. CDWs in these ... More
Study of structure and lattice dynamics of the Sr$_2$CuO$_2$Cl$_2$(001) surface by helium-atom scatteringMar 29 2005Structure and lattice dynamics of the (001) surface of Sr$_2$CuO$_2$Cl$_2$ have been studied by helium atom scattering (HAS). Analysis of diffraction patterns obtained by elastic HAS revealed a surface periodicity consistent with bulk termination, and ... More
New Detectors to Explore the Lifetime FrontierJun 20 2016Sep 17 2016Long-lived particles (LLPs) are a common feature in many beyond the Standard Model theories, including supersymmetry, and are generically produced in exotic Higgs decays. Unfortunately, no existing or proposed search strategy will be able to observe the ... More
Capillary Wave Scattering from a Surfactant DomainJan 14 1995The study of capillary wave scattering by a circular region with different interfacial properties from the rest of an otherwise homogeneous interface is motivated by experiments on wave attenuation at a monolayer covered air-water interface where domains ... More
Macroscopic Quantum Phenomena from the Coupling Pattern and Entanglement Structure PerspectiveAug 20 2013We explore in this paper ways to qualify and quantify the quantum entanglement $E(M)$ between two macroscopic objects by way of model studies. Knowing that a macroscopic object is a composite, how does one determine $E(M)$ in terms of the entanglements ... More
Exploring Halo Substructure with Giant Stars: The Velocity Dispersion Profiles of the Ursa Minor and Draco Dwarf Spheroidals At Large Angular SeparationsApr 01 2005Nov 17 2005We analyze velocity dispersion profiles for the Draco and Ursa Minor (UMi) dwarf spheroidal (dSph) galaxies based on published and new Keck HIRES spectra for stars in the outer UMi field. Washington+DDO51 filter photometric catalogs provide additional ... More
Momentum Distribution for Bosons with Positive Scattering Length in a TrapMay 09 1996The coordinate-momentum double distribution function $\rho ({\bf r}, {\bf p}) d^{3}rd^{3}p$ is calculated in the local density approximation for bosons with positive scattering length $a$ in a trap. The calculation is valid to the first order of $a$. ... More
Bose-Einstein Condensation of Atoms in a TrapFeb 28 1996We point out that the local density approximation (LDA) of Oliva is an adaptation of the Thomas-Fermi method, and is a good approximation when $\varepsilon = \hbar\omega/kT <<1$. For the case of scattering length $a > 0$, the LDA leads to a quantitative ... More
Macroscopic quantum phenomena from the large N perspectiveJun 03 2011Macroscopic quantum phenomena (MQP) is a relatively new research venue, with exciting ongoing experiments and bright prospects, yet with surprisingly little theoretical activity. What makes MQP intellectually stimulating is because it is counterpoised ... More
New Production Mechanism of Neutral Higgs Bosons with Right scalar tau neutrino as the LSPJun 28 2000Jul 04 2000Motived by the neutrino oscillation data, we consider the lightest tau sneutrino $\tilde \nu_{\tau_1}$ (which is mostly the right tau sneutrino) to be the lightest supersymmetric particle (LSP) in the framework of the minimal supersymmetric Standard Model. ... More
Secret Key Generation from Sparse Wireless Channels: Ergodic Capacity and Secrecy OutageAug 18 2012This paper investigates generation of a secret key from a reciprocal wireless channel. In particular we consider wireless channels that exhibit sparse structure in the wideband regime and the impact of the sparsity on the secret key capacity. We explore ... More
Arrival Times in a Zero-Range Process with Injection and DecayFeb 16 2010Explicit expressions for arrival times of particles moving in a one-dimensional Zero-Range Process (ZRP) are computed. Particles are fed into the ZRP from an injection site and can also evaporate from anywhere in the interior of the ZRP. Two dynamics ... More
Key Generation Using External Source Excitation: Capacity, Reliability, and Secrecy ExponentOct 28 2011We study the fundamental limits to secret key generation from an excited distributed source (EDS). In an EDS a pair of terminals observe dependent sources of randomness excited by a pre-arranged signal. We first determine the secret key capacity for such ... More
Gapless insulating edges of dirty interacting topological insulatorsOct 11 2017Aug 22 2018We demonstrate that a combination of disorder and interactions in a two-dimensional bulk topological insulator can generically drive its helical edge insulating. We establish this within the framework of helical Luttinger liquid theory and exact Emery-Luther ... More
Constraints on the Mass and Radius of the Neutron Star XTE J1807-294Jun 16 2011Nov 21 2011The accreting millisecond pulsar XTE J1807-294 is studied through a pulse shape modeling analysis. The model includes blackbody and Comptonized emission from the one visible hot spot and makes use of the Oblate Schwarzschild approximation for ray-tracing. ... More
Enhanced Optical Conductivity Induced by Surface States in ABC-stacked Few-Layer GrapheneJun 03 2011The surface states of ABC-stacked few-layer graphene (FLG) are studied based on density-functional theory. These states form flat bands near the Fermi level, with the k-space range increasing with the layer number. Based on a tight-binding model, the ... More
Structural and Electronic Properties of Oxidized GrapheneAug 21 2009We have systematically investigated the effect of oxidation on the structural and electronic properties of graphene based on first-principles calculations. Energetically favorable atomic configurations and building blocks are identified, which contain ... More
Stochastic self-assembly of incommensurate clustersNov 20 2011We examine the classic problem of homogeneous nucleation and growth by deriving and analyzing a fully discrete stochastic master equation. Upon comparison with results obtained from the corresponding mean-field Becker-D\"{o}ring equations we find striking ... More
Electronic and Vibrational Properties of gamma-AlH3Jul 31 2007Aluminum hydride (alane) AlH_3 is an important material in hydrogen storage applications. It is known that AlH_3 exists in multiply forms of polymorphs, where $\alpha$-AlH_3 is found to be the most stable with a hexagonal structure. Recent experimental ... More
Charge transport through graphene junctions with wetting metal leadsOct 06 2013Graphene is believed to be an excellent candidate material for next-generation electronic devices. However, one needs to take into account the nontrivial effect of metal contacts in order to precisely control the charge injection and extraction processes. ... More
Swarming in viscous fluids: three-dimensional patterns in swimmer- and force-induced flowsMar 07 2016We derive from first principles a three-dimensional theory of self-propelled particle swarming in a viscous fluid environment. Our model predicts emergent collective behavior that depends critically on fluid opacity, mechanism of self-propulsion, and ... More
Light-Cone Distribution Amplitudes of Light $J^{PC}=2^{--}$ Tensor Mesons in QCDJun 15 2017Dec 30 2017We present a study for two-quark light-cone distribution amplitudes for the $1^3D_2$ light tensor meson states with quantum number $J^{PC}=2^{--}$. Because of the G-parity, the chiral-even two-quark light-cone distribution amplitudes of this tensor meson ... More
Optimal H2 order-one reduction by solving eigenproblems for polynomial equationsJun 13 2007A method is given for solving an optimal H2 approximation problem for SISO linear time-invariant stable systems. The method, based on constructive algebra, guarantees that the global optimum is found; it does not involve any gradient-based search, and ... More
A Schrodinger Cat Living in Two BoxesJan 21 2016Quantum superpositions of distinct coherent states in a single-mode harmonic oscillator, known as "cat states", have been an elegant demonstration of Schrodinger's famous cat paradox. Here, we realize a two-mode cat state of electromagnetic fields in ... More
Localized surfaces of three dimensional topological insulatorsJan 16 2019We study the surface of a three-dimensional spin chiral $\mathrm{Z}_2$ topological insulator (class CII), demonstrating the possibility of its localization. This arises through an interplay of interaction and statistically-symmetric disorder, that confines ... More
Localized surfaces of three dimensional topological insulatorsJan 16 2019Apr 08 2019We study the surface of a three-dimensional spin chiral $\mathrm{Z}_2$ topological insulator (class CII), demonstrating the possibility of its localization. This arises through an interplay of interaction and statistically-symmetric disorder, that confines ... More
Mott glass from localization and confinementMar 12 2018May 21 2018We study a system of fermions in one spatial dimension with linearly confining interactions and short-range disorder. We focus on the zero temperature properties of this system, which we characterize using bosonization and the Gaussian variational method. ... More
Finite-size effect of antiferromagnetic transition and electronic structure in LiFePO4Oct 26 2012The finite-size effect on the antiferromagnetic (AF) transition and electronic configuration of iron has been observed in LiFePO4. Determination of the scaling behavior of the AF transition temperature (TN) versus the particle-size dimension (L) in the ... More
Electron-Phonon Interactions for Optical Phonon Modes in Few-Layer GrapheneJan 20 2009We present a first-principles study of the electron-phonon (e-ph) interactions and their contributions to the linewidths for the optical phonon modes at $\Gamma$ and K in one to three-layer graphene. It is found that due to the interlayer coupling and ... More
Anomalous behavior in the phonon dispersion of the (001) surface of Bi$_2$Te$_3$ determined from helium atom-surface scattering measurementsMay 07 2013We employ inelastic helium atom-surface scattering to measure the low energy phonon dispersion along high-symmetry directions on the surface of the topological insulator Bi$_2$Te$_3$. Results indicate that one particular low-frequency branch experiences ... More
Testing the Blazar Paradigm: ASCA Observations of FSRQs with Steep Soft X-ray SpectraDec 14 1999We present the first observations at medium-hard X-rays with ASCA in 1998 August--November of four Flat Spectrum Radio Quasars (FSRQs), characterized by unusually steep soft X-ray spectra (photon index, \Gamma_{0.2-2.4 keV} \sim 2-2.5), as previously ... More
Comparative study of density functional theories of the exchange-correlation hole and energy in siliconJan 24 2001May 17 2001We present a detailed study of the exchange-correlation hole and exchange-correlation energy per particle in the Si crystal as calculated by the Variational Monte Carlo method and predicted by various density functional models. Nonlocal density averaging ... More
Optical Phonon Anomaly in Bilayer Graphene with Ultrahigh Carrier DensitiesApr 07 2012Electron-phonon coupling (EPC) in bilayer graphene (BLG) at different doping levels is studied by first-principles calculations. The phonons considered are long-wavelength high-energy symmetric (S) and antisymmetric (AS) optical modes. Both are shown ... More
A mathematical model of the effects of aging on naive T-cell population and diversityJan 02 2019The human adaptive immune response is known to weaken in advanced age, resulting in increased severity of pathogen-born illness, poor vaccine efficacy, and a higher prevalence of cancer in the elderly. Age-related erosion of the T-cell compartment has ... More
Phonon dispersions and vibrational properties of monolayer, bilayer, and trilayer grapheneJan 20 2009The phonon dispersions of monolayer and few-layer graphene (AB bilayer, ABA and ABC trilayers) are investigated using the density-functional perturbation theory (DFPT). Compared with the monolayer, the optical phonon $E_{2g}$ mode at $\Gamma$ splits into ... More
Implementing and characterizing precise multi-qubit measurementsJun 02 2016Jun 07 2016There are two general requirements to harness the computational power of quantum mechanics: the ability to manipulate the evolution of an isolated system and the ability to faithfully extract information from it. Quantum error correction and simulation ... More
Observation of a topological 3D Dirac semimetal phase in high-mobility Cd3As2Sep 30 2013Jan 29 2015Experimental identification of three-dimensional (3D) Dirac semimetals in solid state systems is critical for realizing exotic topological phenomena and quantum transport such as the Weyl phases, high temperature linear quantum magnetoresistance and topological ... More
Magnetic Studies of End-Chain Spin Effects in the Haldane Gap Material Ni(C3H10N2)2N3(ClO4)Oct 15 1997Jul 11 1998Electron spin resonance (ESR), at 9, 94, and 190 GHz, and magnetization studies on polycrystalline, powder, and ultrafine powder samples of Ni(C3H10N2)2N3(ClO4) (NINAZ) have revealed several effects arising from the Haldane phase. Using the g value of ... More
Violating Bell's inequality with remotely-connected superconducting qubitsAug 09 2018Oct 17 2018Quantum communication relies on the efficient generation of entanglement between remote quantum nodes, due to entanglement's key role in achieving and verifying secure communications. Remote entanglement has been realized using a number of different probabilistic ... More
Phonon-mediated quantum state transfer and remote qubit entanglementMar 13 2019Phonons, and in particular surface acoustic wave phonons, have been proposed as a means to coherently couple distant solid-state quantum systems. Recent experiments have shown that superconducting qubits can control and detect individual phonons in a ... More
Direct proof of unique magnetic and superconducting phases in superoxygenated high-Tc cupratesJun 10 2013Jul 17 2013We present a combined magnetic neutron scattering and muon spin rotation study of the nature of the magnetic and superconducting phases in electronically phase separated La(2-x)Sr(x)CuO(4+y), x = 0.04, 065, 0.09. For all samples, we find long-range modulated ... More
Coexistence of orbital degeneracy lifting and superconductivity in iron-based superconductorsOct 17 2013Oct 29 2013In contrast to conventional superconducting (SC) materials, superconductivity in high-temperature superconductors (HTCs) usually emerges in the presence of other fluctuating orders with similar or higher energy scales, thus instigating debates over their ... More
Control of decoherence in the generation of photon pairs from atomic ensemblesJul 13 2005We report an investigation to establish the physical mechanisms responsible for decoherence in the generation of photon pairs from atomic ensembles, via the protocol of Duan et. al for long distance quantum communication [Nature (London) 414, 413 (2001)] ... More
Anisotropy in the thermal hysteresis of resistivity and charge density wave nature of single crystal SrFeO3-delta: X-ray absorption and photoemission studiesMar 02 2017The local electronic and atomic structures of the high-quality single crystal of SrFeO3-{delta} ({delta}~0.19) were studied using temperature-dependent x-ray absorption and valence-band photoemission spectroscopy (VB-PES) to investigate the origin of ... More
THz Generation and Detection on Dirac Fermions in Topological InsulatorsJan 26 2013This study shows that a terahertz (THz) wave can be generated from the (001) surface of cleaved Bi$_{\textrm{2}}$Se$_{\textrm{3}}$ and Cu-doped Bi$_{\textrm{2}}$Se$_{\textrm{3}}$ single crystals using 800 nm femtosecond pulses. The generated THz power ... More
Strong FUV fields drive the [CII]/FIR deficit in z~3 dusty, star-forming galaxiesJan 28 2019We present 0.15-arcsec (1 kpc) resolution ALMA observations of the [CII] 157.74 um line and rest-frame 160-um continuum emission in two z~3 dusty, star-forming galaxies - ALESS 49.1 and ALESS 57.1, combined with resolved CO(3-2) observations. In both ... More
Magic-angle semimetalsSep 12 2018We introduce and characterize a class of `magic-angle' semimetal models and, as an application, propose multiple cold atomic quantum emulators of twisted bilayer graphene. The models are defined in one to three dimensions and all contain momentum space ... More
Heralded Entanglement between Atomic Ensembles: Preparation, Decoherence, and ScalingJun 04 2007Sep 19 2007Heralded entanglement between collective excitations in two atomic ensembles is probabilistically generated, stored, and converted to single photon fields. By way of the concurrence, quantitative characterizations are reported for the scaling behavior ... More
Direct measurement of decoherence for entanglement between a photon and stored atomic excitationJun 30 2006Nov 06 2006Violations of a Bell inequality are reported for an experiment where one of two entangled qubits is stored in a collective atomic memory for a user-defined time delay. The atomic qubit is found to preserve the violation of a Bell inequality for storage ... More
Emergence of charge density waves and a pseudogap in single-layer TiTe2May 14 2018Two-dimensional materials constitute a promising platform for developing nanoscale devices and systems. Their physical properties can be very different from those of the corresponding three-dimensional materials because of extreme quantum confinement ... More
Water alignment, dipolar interactions, and multiple proton occupancy during water-wire proton transportOct 29 2003A discrete multistate kinetic model for water-wire proton transport is constructed and analyzed using Monte-Carlo simulations. The model allows for each water molecule to be in one of three states: oxygen lone pairs pointing leftward, pointing rightward, ... More
Enhancement of charged macromolecule capture by nanopores in a salt gradientMay 08 2009Nanopores spanning synthetic membranes have been used as key components in proof-of-principle nanofluidic applications, particularly those involving manipulation of biomolecules or sequencing of DNA. The only practical way of manipulating charged macromolecules ... More
Kelvin-Helmholtz instabilities across periodic platesSep 14 2006We consider the linear stability of two inviscid fluids, in the presence of gravity, sheared past each other and separated by an flexible plate. Conditions for exponential growth of velocity perturbations are found as functions of the flexural rigidity ... More
Kinetics of nanopore transportJan 31 1998A nonlinear kinetic exclusion model is used to study osmosis and pressure driven flows through nearly single file pores such as antibiotic channels, aquaporins, zeolites and nanotubules. Two possible maxima in the steady state flux as a function of pore-solvent ... More
Numerical Analysis of Magnetic Field Amplification by TurbulenceDec 20 2000Apr 23 2001We apply a Fourier spectral numerical method to 3D incompressible MHD turbulence with a magnetic Prandtl number $Pr \geq 1$. We examine the processes by which an initially weak, large-scale seed magnetic field and an initially weak, small-scale, impulse-like ... More
Conditional control of the quantum states of remote atomic memories for quantum networkingSep 25 2006Nov 16 2006Quantum networks hold the promise for revolutionary advances in information processing with quantum resources distributed over remote locations via quantum-repeater architectures. Quantum networks are composed of nodes for storing and processing quantum ... More
Universality of the Electronic Structure from a Half Filled CuO_2 PlaneSep 27 2002We present angle resolved photoemission (ARPES) data from insulating A_2CuO_2X_2 (A=Sr, Ca; X=Cl, Br), Sr_2Cu_3O_4Cl_2, and Bi_2Sr_2MCu_2O_8 (M=Er, Dy) single crystals which illustrate that the low energy electronic structure of the half-filled cuprates ... More
Time-resolved magnetophotoluminescence studies of magnetic polaron dynamics in type-II quantum dotsOct 15 2015We used continuous wave photoluminescence (cw-PL) and time resolved photoluminescence (TR-PL) spectroscopy to compare the properties of magnetic polarons (MP) in two related spatially indirect II-VI epitaxially grown quantum dot systems. In the ZnTe/(Zn,Mn)Se ... More
A length-dynamic Tonks gas theory of histone isothermsDec 17 2002We find exact solutions to a new one-dimensional (1D) interacting particle theory and apply the results to the adsorption and wrapping of polymers (such as DNA) around protein particles (such as histones). Each adsorbed protein is represented by a Tonks ... More