Results for "W. C. Yu"

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Investigation of Micro Porosity Sintered wick in Vapor Chamber for Fan Less DesignJan 07 2008Micro Porosity Sintered wick is made from metal injection molding processes, which provides a wick density with micro scale. It can keep more than 53 % working fluid inside the wick structure, and presents good pumping ability on working fluid transmission ... More
Overscreening Diamagnetism in Cylindrical Superconductor-Normal Metal-HeterostructuresSep 23 2006We study the linear diamagnetic response of a superconducting cylinder coated by a normal-metal layer due to the proximity effect using the clean limit quasiclassical Eilenberger equations. We compare the results for the susceptibility with those for ... More
Field-induced structure transformation in electrorheological solidsMay 30 2001We have computed the local electric field in a body-centered tetragonal (BCT) lattice of point dipoles via the Ewald-Kornfeld formulation, in an attempt to examine the effects of a structure transformation on the local field strength. For the ground state ... More
Heterogeneous aggregation in binary colloidal alloysApr 06 2002Molecular dynamics (MD) simulation has been employed to study the nonequilibrium structure formation of two types of particles in a colloidal suspension, driven by type-dependent forces. We examined the time evolution of structure formation as well as ... More
Feedback of the electromagnetic environment on current and voltage fluctuations out of equilibriumJun 13 2003A theory is presented for low-frequency current and voltage correlators of a mesoscopic conductor embedded in a macroscopic electromagnetic environment. This Keldysh field theory evaluated at its saddle-point provides the microscopic justification for ... More
Distribution of voltage fluctuations in a current-biased conductorOct 28 2002We calculate the fluctuating voltage V(t) over a conductor driven out of equilibrium by a current source. This is the dual of the shot noise problem of current fluctuations I(t) in a voltage-biased circuit. In the single-channel case the distribution ... More
Temperature dependent third cumulant of tunneling noiseJan 24 2003Poisson statistics predicts that the shot noise in a tunnel junction has a temperature independent third cumulant e^2\I, determined solely by the mean current I. Experimental data, however, show a puzzling temperature dependence. We demonstrate theoretically ... More
Nernst effect beyond the relaxation-time approximationMay 06 2011Motivated by recent interest in the Nernst effect in cuprate superconductors, we calculate this magneto-thermo-electric effect for an arbitrary (anisotropic) quasiparticle dispersion relation and elastic scattering rate. The exact solution of the linearized ... More
Coherence and clock shifts in ultracold Fermi gases with resonant interactionsJul 05 2007Using arguments based on sum rules, we derive a general result for the average shifts of rf lines in Fermi gases in terms of interatomic interaction strengths and two-particle correlation functions. We show that near an interaction resonance shifts vary ... More
Manipulation of photon statistics of highly degenerate chaotic radiationJul 05 2001Highly degenerate chaotic radiation has a Gaussian density matrix and a large occupation number of modes $f $. If it is passed through a weakly transmitting barrier, its counting statistics is close to Poissonian. We show that a second identical barrier, ... More
Design and Construction of the 3.2 Mev Cathode Assembly for Darht IISep 11 2000Sep 28 2000A 3.2 MeV injector has been designed and built for the Darht II Project at Los Alamos Lab. The installation of the complete injector system is nearing completion at this time. The requirements for the injector are to produce a 3.2 MeV, 2000 ampere electron ... More
Distributed Dimensionality Reduction Fusion Estimation with Communication Delays in Cyber-Physical SystemsFeb 09 2018This paper studies the distributed dimensionality reduction fusion estimation problem with communication delays for a class of cyber-physical systems (CPSs). The raw measurements are preprocessed in each sink node to obtain the local optimal estimate ... More
Ergodic theorem for a Loeb space and hyperfinite approximations of dynamical systemsApr 01 2011Although the G.Birkhoff Ergodic Theorem (BET) is trivial for finite spaces, this does not help in proving it for hyperfinite Loeb spaces. The proof of the BET for this case, suggested by T. Kamae, works, actually, for arbitrary probability spaces, as ... More
A New Approach to Linear/Nonlinear Distributed Fusion Estimation ProblemAug 29 2017Jul 19 2018Disturbance noises are always bounded in a practical system, while fusion estimation is to best utilize multiple sensor data containing noises for the purpose of estimating a quantity--a parameter or process. However, few results are focused on the information ... More
On finite approximations of topological algebraic systemsNov 21 2003Jul 31 2006We introduce and discuss a definition of approximation of a topological algebraic system $A$ by finite algebraic systems of some class $\K$. For the case of a discrete algebraic system this definition is equivalent to the well-known definition of a local ... More
Dielectric behaviour of graded spherical cells with an intrinsic dispersionMay 21 2004The dielectric properties of single-shell spherical cells with an intrinsic dielectric dispersion has been investigated. By means of the dielectric dispersion spectral representation (DDSR) for the Clausius-Mossotti (CM) factor, we express the dispersion ... More
Computer simulations of polydisperse ER fluids in DID modelMar 20 2002The theoretical investigations on electrorheological (ER) fluids are usually concentrated on monodisperse systems. Real ER fluids must be polydisperse in nature, i.e., the suspended particles can have various sizes and/or different dielectric constants. ... More
Nonstandard analysis of the behavior of ergodic means of dynamical systems on very big finite probability spacesJan 26 2012The trivial proof of the ergodic theorem for a finite set $Y$ and a permutation $T:Y\to Y$ shows that for an arbitrary function $f:Y\to{\mathbb R}$ the sequence of ergodic means $A_n(f,T)$ stabilizes for $n \gg |T|$. We show that if $|Y|$ is very large ... More
First-principles calculations of a high-pressure synthesized compound PtCAug 23 2005Aug 26 2005First-principles density-functional method is used to study the recently high-pressure synthesized compound PtC. It is confirmed by our calculations that the platinum carbide has a zinc-blende ground-state phase at zero pressure and the rock-salt structure ... More
Distributed Randomized Gradient-Free Mirror Descent Algorithm for Constrained OptimizationMar 11 2019This paper is concerned with multi-agent optimization problem. A distributed randomized gradient-free mirror descent (DRGFMD) method is developed by introducing a randomized gradient-free oracle in the mirror descent scheme where the non-Euclidean Bregman ... More
Shot Noise and Proximity Effect in Superconductor--Normal-Metal HeterostructuresOct 06 2002Oct 15 2002Current noise provides useful information on correlations important for transport properties of mesoscopic systems. Of particular interest, both experimentally and theoretically, are heterostructures of normal metals and superconductors. We use an extended ... More
$π-0$ Transition in Superconductor-Ferromagnetic-Superconductor JunctionsAug 09 2001Feb 27 2002Superconductor-Ferromagnetic-Superconductor (SFS) Josephson junctions are known to exhibit a transition between $\pi$ and 0 states. In this note we find the $\pi-0$ phase diagram of an SFS junction depending on the transparency of an intermediate insulating ... More
Effects of geometric anisotropy on local field distribution: Ewald-Kornfeld formulationJan 24 2001We have applied the Ewald-Kornfeld formulation to a tetragonal lattice of point dipoles, in an attempt to examine the effects of geometric anisotropy on the local field distribution. The various problems encountered in the computation of the conditionally ... More
Protecting quantum states from decoherence of finite temperature using weak measurementAug 07 2013We show how to optimally protect quantum states and quantum entanglement under non-zero temperature based on measurement reversal from weak measurement. In particular, we present explicit formulas of the protection.
High quality electron bunch generation using a longitudinal density-tailored plasma-based accelerator in the three-dimensional blowout regimeOct 03 2016The generation of very high quality electron bunches (high brightness and low energy spread) from a plasma-based accelerator in the three-dimensional blowout regime using self-injection in tailored plasma density profiles is analyzed theoretically and ... More
A low-phase-noise 18 GHz Kerr frequency microcomb phase-locked over 65 THzFeb 18 2015Laser frequency combs are coherent light sources that simultaneously provide pristine frequency spacings for precision metrology and the fundamental basis for ultrafast and attosecond sciences. Recently, nonlinear parametric conversion in high-Q microresonators ... More
Smooth coherent Kerr frequency combs generation with broadly tunable pump by higher order mode suppressionFeb 02 2016High-Q microresonator has been suggested a promising platform for optical frequency comb generation, via dissipative soliton formation. To achieve a higher Q and obtain the necessary anomalous dispersion, $Si_3N_4$ microresonators made of multi-mode waveguides ... More
Competition and coexistence of bond and charge orders in (TMTTF)2AsF6May 02 2002(TMTTF)2AsF6 undergoes two phase transitions upon cooling from 300 K. At Tco=103 K a charge-ordering (CO) occurs, and at Tsp(B=9 T)=11 K the material undergoes a spin-Peierls (SP) transition. Within the intermediate, CO phase, the charge disproportionation ... More
Phase stabilization of Kerr frequency comb internally without nonlinear optical interferometryNov 09 2016Optical frequency comb (OFC) technology has been the cornerstone for scientific breakthroughs such as precision frequency metrology, redefinition of time, extreme light-matter interaction, and attosecond sciences. While the current mode-locked laser-based ... More
High-energy emissions from the gamma-ray binary 1FGL J1018.6-5856Mar 23 2017The gamma-ray binary 1FGL J1018.6-5856 is known to be composed of a massive star with a compact object with an orbital period of 16.54 days. We study mechanisms of high-energy emissions (X-ray, GeV, and TeV $\gamma$-rays) from this binary system. The ... More
Searching for Be Stars in the Open Cluster NGC 663Nov 20 2014We present Be star candidates in the open cluster NGC\,663, identified by H$\alpha$ imaging photometry with the Palomar Transient Factory Survey, as a pilot program to investigate how the Be star phenomena, the emission spectra, extended circumstellar ... More
The Magnetic Field Geometry of Small Solar Wind Flux Ropes Inferred from their Twist DistributionNov 26 2018This work extends recent efforts on the force-free modeling of large flux rope-type structures (magnetic clouds, MCs) to much smaller spatial scales. We first select small flux ropes (SFRs) by eye whose duration is unambiguous and which were observed ... More
Possible $s^{\pm}$-wave pairing evidenced by midgap surface bound states in Fe-pnictide superconductorsApr 28 2011Aug 08 2013A phenomenological theory of tunneling spectroscopy for Fe-pnictide superconductors is developed by taking into consideration of asymmetric interface scattering between particle and holes. It is shown that in consistent with anti-phase $s^{\pm}$-wave ... More
Theory of second-harmonic generation in colloidal crystalsNov 14 2006Mar 24 2008On the basis of the Edward-Kornfeld formulation, we study the effective susceptibility of secondharmonic generation (SHG) in colloidal crystals, which are made of graded metallodielectric nanoparticles with an intrinsic SHG susceptibility suspended in ... More
Topological Edge Plasmon Modes between Diatomic Chains of NanoparticlesJan 29 2014May 08 2015We study the topological edge plasmon modes between two "diatomic" chains of identical plasmonic nanoparticles. Zak phase for longitudinal plasmon modes in each chain is calculated analytically by solutions of macroscopic Maxwell's equations for particles ... More
Optical Study of the Free Carrier Response of LaTiO3/SrTiO3 SuperlatticesMar 15 2007Jan 07 2008We used infrared spectroscopic ellipsometry to investigate the electronic properties of LaTiO3/SrTiO3 superlattices (SLs). Our results indicated that, independent of the SL periodicity and individual layer-thickness, the SLs exhibited a Drude metallic ... More
Mesostructure anisotropy of bacterial cellulose-polyacrylamide hydrogels as studied by spin-echo small-angle neutron scatteringJul 29 2016The submicron- and micron-scale structures of composite hydrogels based on bacterial cellulose (BC) and polyacrylamide were studied by spin-echo small-angle neutron scattering (SESANS). These hydrogels were synthesized via free-radical polymerization ... More
Chemical doping and high pressure studies of layered beta-PdBi2 single crystalsJun 18 2015We have systematically grown large single crystals of layered compound beta-PdBi2, both the hole-doped PdBi2-xPbx and the electron-doped NaxPdBi2, and studied their magnetic and transport properties. Hall-effect measurement on PdBi2, PdBi1.8Pb0.2, and ... More
Observation of Multiple Thresholds in the Many-Atom Cavity QED MicrolaserDec 22 2004We report the observation of multiple laser thresholds in the many-atom cavity QED microlaser. Traveling-wave coupling and a supersonic atom beam are used to create a well-defined atom-cavity interaction. Multiple thresholds are observed as jumps in photon ... More
Mean Field Theory for Lossy Nonlinear CompositesNov 20 1997The mean-field theory for lossy nonlinear composites, described by complex and field-dependent dielectric functions, is presented. By using the spectral representation of linear composites with identical microstructure, we develop self-consistent equations ... More
Energy dependence of the band-limited noise in black hole X-ray binariesDec 11 2014Jul 09 2015Black hole low-mass X-ray binaries show a variety of variability features, which manifest themselves as narrow peak-like structures superposed on broad noise components in power density spectra in the hard X-ray emission. In this work we study variability ... More
Dielectric behaviors of corrugated membranesMar 01 2002We have employed our recently developed Green's function formalism to study the dielectric behavior of a model membrane, formed by two periodic interfaces separating two media of different dielectric constants. The Maxwell's equations are converted into ... More
Centralizers of distinguished nilpotent pairs and related problemsJan 23 2001Apr 22 2001In this paper, by establishing an explicit and combinatorial description of the centralizer of a distinguished nilpotent pair in a classical simple Lie algebra, we solve in the classical case Panyushev's Conjecture which says that distinguished nilpotent ... More
Using XMM-Newton to study the energy dependent variability of H 1743-322 during its 2014 outburstFeb 04 2016Apr 07 2016Black hole transients during bright outbursts show distinct changes of their spectral and variability properties as they evolve during an outburst, that are interpreted as evidence for changes in the accretion flow and X-ray emitting regions. We obtained ... More
Detection of distinct power spectra in soft and hard X-ray bands in the hard state of GRS 1915+105Mar 03 2014The well-known black hole X-ray binary GRS 1915+105 is a unique source in the sense that it cannot be classified within the standard picture of black hole binary states. In this work we study archival XMM-Newton observations taken between 2003 and 2004 ... More
Parity Forwarding for Multiple-Relay NetworksNov 17 2007This paper proposes a relaying strategy for the multiple-relay network in which each relay decodes a selection of transmitted messages by other transmitting terminals, and forwards parities of the decoded codewords. This protocol improves the previously ... More
On the sum of the index of a parabolic subalgebra and of its nilpotent radicalJun 12 2006Jun 13 2006In this short note, we investigate the following question of Panyushev : ``Is the sum of the index of a parabolic subalgebra of a semisimple Lie algebra $\mathfrak{g}$ and the index of its nilpotent radical always greater than or equal to the rank of ... More
The tunable quantum spin ladder Cu(Qnx)(Cl$_{(1-x)}$Br$_{x}$)$_{2}$Feb 11 2014Jul 12 2014We report magnetic, specific heat and ESR measurements on a series of $S=1/2$ spin ladder compounds Cu(Qnx)(Cl$_{(1-x)}$Br$_{x}$)$_{2}$. Down to $T=2$ K all the observables can be described by the spin ladder model with about 1% of $S=1/2$ impurities ... More
Observations of Spontaneous Raman Scattering in Silicon Slow-light Photonic Crystal WaveguidesJul 22 2008We report the observations of spontaneous Raman scattering in silicon photonic crystal waveguides. Continuous-wave measurements of Stokes emission for both wavelength and power dependence is reported in single line-defect waveguides in hexagonal lattice ... More
Enhanced inverse bremsstrahlung heating rates in a strong laser fieldMar 11 2002Jan 31 2003Test particle studies of electron scattering on ions, in an oscillatory electromagnetic field have shown that standard theoretical assumptions of small angle collisions and phase independent orbits are incorrect for electron trajectories with drift velocities ... More
Global scale-invariant dissipation in collisionless plasma turbulenceJun 16 2009A higher-order multiscale analysis of the dissipation range of collisionless plasma turbulence is presented using in-situ high-frequency magnetic field measurements from the Cluster spacecraft in a stationary interval of fast ambient solar wind. The observations, ... More
Nonlinear ac response of anisotropic compositesApr 15 2001When a suspension consisting of dielectric particles having nonlinear characteristics is subjected to a sinusoidal (ac) field, the electrical response will in general consist of ac fields at frequencies of the higher-order harmonics. These ac responses ... More
Observations of temporal group delays in slow-light multiple coupled photonic crystal cavitiesApr 20 2010We demonstrate temporal group delays in coherently-coupled high-Q multi-cavity photonic crystals, in an all-optical analogue to electromagnetically induced transparency. We report deterministic control of the group delay up to 4x the single cavity lifetime ... More
Cavity optomechanics with Si3N4 membranes at cryogenic temperaturesAug 31 2012We describe a cryogenic cavity-optomechanical system that combines Si3N4 membranes with a mechanically-rigid Fabry-Perot cavity. The extremely high quality-factor frequency products of the membranes allow us to cool a MHz mechanical mode to a phonon occupation ... More
Optical vault: reconfigurable bottle beam by conically refracted lightSep 05 2014We employ conical refraction of light in a biaxial crystal to create an optical bottle for trapping and manipulation of particles. We show that by just varying the polarization of the input light the bottle can be opened and closed at will. We experimentally ... More
Phase transition of light in circuit QED lattices coupled to nitrogen-vacancy centers in diamondApr 21 2015We propose a hybrid quantum architecture for engineering a photonicMott insulator-superfluid phase transition in a two-dimensional (2D) square lattice of a superconducting transmission line resonator (TLR) coupled to a single nitrogen-vacancy (NV) center ... More
h/e-Periodicity in Superconducting LoopsSep 26 2007Nov 29 2007The magnetic flux periodicity of superconducting loops as well as flux quantization itself are a manifestation of macroscopic quantum phenomena with far reaching implications. They provide the key to the understanding of many fundamental properties of ... More
Strong Optomechanical Squeezing of LightJun 05 2013Oct 21 2013We create squeezed light by exploiting the quantum nature of the mechanical interaction between laser light and a membrane mechanical resonator embedded in an optical cavity. The radiation pressure shot noise (fluctuating optical force from quantum laser ... More
A Unified Quantum NOT GateDec 02 2008We study the feasibility of implementing a quantum NOT gate (approximate) when the quantum state lies between two latitudes on the Bloch's sphere and present an analytical formula for the optimized 1-to-$M$ quantum NOT gate. Our result generalizes previous ... More
Influence of Charge Order on the Ground States of TMTTF Molecular SaltsDec 16 2003(TMTTF)2AsF6 and (TMTTF)2SbF6 are both known to undergo a charge ordering phase transition, though their ground states are different. The ground state of the first is Spin-Peierls, and the second is an antiferromagnet. We study the effect of pressure ... More
Fabrication of graphene nanodisk arrays using nanosphere lithographyDec 30 2008Ordered graphene nanodisk arrays have been successfully fabricated by combining nanosphere lithography (NSL) and reactive ion etching (RIE) processes. The dimension of graphene nanodisks can be effectively tuned by varying the size of polystyrene spheres, ... More
High-Pressure Induced Structural Phase Transition in CaCrO4: Evidence from Raman Scattering StudiesJun 06 2005Raman spectroscopic studies have been carried out on CaCrO4 under pressure up to 26GPa at ambient temperature. The Raman spectra showed CaCrO4 experienced a continuous structural phase transition started at near 6GPa, and finished at about 10GPa. It is ... More
Electron-lattice coupling and the broken symmetries of the molecular salt (TMTTF)$_2$SbF$_6$May 28 2004(TMTTF)$_2$SbF$_6$ is known to undergo a charge ordering (CO) phase transition at $T_{CO}\approx156K$ and another transition to an antiferromagnetic (AF) state at $T_N\approx 8K$. Applied pressure $P$ causes a decrease in both $T_{CO}$ and $T_N$. When ... More
A stabilized 18 GHz chip-scale optical frequency comb at 2.8x10-16 relative inaccuracyAug 31 2015Optical frequency combs, coherent light sources that connect optical frequencies with microwave oscillations, have become the enabling tool for precision spectroscopy, optical clockwork and attosecond physics over the past decades. Current benchmark systems ... More
The electronic structure of epitaxially stabilized 5d perovskite Ca_{1-x}Sr_xIrO_3 (x = 0, 0.5, and 1) thin films: the role of strong spin-orbit couplingNov 24 2009We have investigated the electronic structure of meta-stable perovskite Ca1-xSrxIrO3 (x = 0, 0.5, and 1) thin films using transport measurements, optical spectroscopy, and first-principles calculations. We artificially fabricated the perovskite phase ... More
Soft phonon modes in the vicinity of the structural quantum critical pointApr 26 2017The quasi-skutterudite superconductors $A_3T_4$Sn$_{13}$ ($A$=Sr, Ca; $T$=Ir, Rh, Co) are highly tunable featuring a structural quantum critical point. We construct a temperature-lattice constant phase diagram for these isovalent compounds, establishing ... More
Optomechanical Raman-Ratio ThermometryJun 27 2014The temperature dependence of the asymmetry between Stokes and anti-Stokes Raman scattering can be exploited for self-calibrating, optically-based thermometry. In the context of cavity optomechanics, we observe the cavity-enhanced scattering of light ... More
Coherent control of magnon radiative damping with local photon statesFeb 18 2019The collective excitation of ordered spins, known as spin waves or magnons, can in principle radiate by emitting travelling photons to an open system when decaying to the ground state. However, in contrast to the electric dipoles, magnetic dipoles contributed ... More
Low emittance electron beam generation from a laser wakefield accelerator using two laser pulses with different wavelengthsFeb 21 2014Ionization injection triggered by short wavelength laser pulses inside a nonlinear wakefield driven by a longer wavelength laser is examined via multi-dimensional particle-in-cell simulations. We find that very bright electron beams can be generated through ... More
Phase Space Dynamics of Ionization Injection in Plasma Based AcceleratorsJun 18 2013The evolution of beam phase space in ionization-induced injection into plasma wakefields is studied using theory and particle-in-cell (PIC) simulations. The injection process causes special longitudinal and transverse phase mixing leading initially to ... More
Heavy Quark and Chiral Symmetry Predictions for Semileptonic Decays B->D(D*),pi,l,nuMay 27 1993Aug 10 1993We study in detail the prediction for the semileptonic decays $\bar{B} \to D (D^*) \pi \ell \bar{\nu}$ by heavy quark and chiral symmetry. The branching ratio for $\bar{B} \to D \pi \ell \bar{\nu}$ is quite significant, as big as $(0.5-1)\%$. The branching ... More
Observation of ferromagnetic resonance in strontium ruthenate (SrRuO3)Dec 03 2008We report the observation of ferromagnetic resonance (FMR) in SrRuO3 using the time-resolved magneto-optical Kerr effect. The FMR oscillations in the time-domain appear in response to a sudden, optically induced change in the direction of easy-axis anistropy. ... More
Structural and Electronic Properties of Amorphous and Polycrystalline In2Se3 FilmsMar 19 2003Structural and electronic properties of amorphous and single-phase polycrystalline films of gamma- and kappa-In2Se3 have been measured. The stable gamma phase nucleates homogeneously in the film bulk and has a high resistivity, while the metastable kappa ... More
Harnessing quantum correlations for physics beyond the standard quantum limit in broadband displacement detectionJul 22 2016When one seeks knowledge of the full dynamics of the displacement of a harmonic oscillator, non-commutation of the two mechanical quadratures requires a minimum added noise equal to the mechanical resonator's zero point motion. This fundamental quantum ... More
Bandwidth-Controlled Insulator-Metal Transition and Correlated Metallic State in 5$d$ Transition Metal Oxides Sr$_{n+1}$Ir$_{n}$O$_{3n+1}$ ($n$=1, 2, and $\infty$)Jul 14 2008We investigated the electronic structures of the 5$d$ Ruddlesden-Popper series Sr$_{n+1}$Ir$_{n}$O$_{3n+1}$ ($n$=1, 2, and $\infty$) using optical spectroscopy and first-principles calculations. As 5$d$ orbitals are spatially more extended than 3$d$ or ... More
Magnetoplasmons in quasi-neutral epitaxial graphene nanoribbonsMay 21 2013Jun 29 2013We present infrared transmission spectroscopy study of the inter-Landau-level excitations in quasi-neutral epitaxial graphene nanoribbon arrays. We observed a substantial deviation in energy of the $L_{0(-1)}$$\to$$L_{1(0)}$ transition from the characteristic ... More
Improving broadband displacement detection with quantum correlationsJul 22 2016Mar 07 2017Interferometers enable ultrasensitive measurement in a wide array of applications from gravitational wave searches to force microscopes. The role of quantum mechanics in the metrological limits of interferometers has a rich history, and a large number ... More
Laser cooling of a micromechanical membrane to the quantum backaction limitOct 13 2015The radiation pressure of light can act to damp and cool the vibrational motion of a mechanical resonator. In understanding the quantum limits of this cooling, one must consider the effect of shot noise fluctuations on the final thermal occupation. In ... More
Kilo-hertz QPO and X-ray Bursts in 4U 1608-52 in Low Intensity StateOct 07 1997Oct 09 1997We present the results from RXTE/PCA observations of 4U 1608-52 in its island state on March 15, 18 and 22 of 1996. Three type I X-ray bursts were detected in one RXTE orbit on March 22. We observed QPO features peaking at 567-800 Hz on March 15 and 22, ... More
Kilo-hertz QPO in Island State of 4U1608-52 as Observed with RXTE/PCAOct 06 1997Oct 09 1997We report RXTE/PCA observations of 4U 1608-52 on March 15, 18 and 22 immediately after the outburst in early 1996. The persistent count rates ranged from 190 to 450 cps (1-60 keV). During this period of time, 4U 1608-52 was in the island state. We detected ... More
Time Dependent Development of the Coulomb GapApr 12 1999We show that the time development of the Coulomb gap in a Coulomb glass can involve very long relaxation times due to electron rearrangement and hopping. We find that an applied magnetic field reduces the rate of electron hopping and, hence, Coulomb gap ... More
The analysing powers in proton-deuteron elastic scatteringFeb 10 2019It is shown that the ratio of the deuteron and proton analysing powers in proton-deuteron elastic scattering at small angles is sensitive to subtle effects in a theoretical description. These include the transverse spin-spin term in the elementary nucleon-nucleon ... More
1/f Noise in a Coulomb GlassJul 05 2000At low temperatures electron hopping in a three dimensional Coulomb glass produces fluctuations in the single particle density of states and hence in the resistivity. This results in a low frequency resisitivity noise spectrum which goes as (1/f)^(alpha) ... More
Anisotropic magnetic entropy change in Cr$_2$X$_2$Te$_6$ (X = Si and Ge)Jan 09 2019Intrinsic, two-dimensional (2D) ferromagnetic semiconductors are an important class of materials for spintronics applications. Cr$_2$X$_2$Te$_6$ (X = Si and Ge) semiconductors show 2D Ising-like ferromagnetism, which is preserved in few-layer devices. ... More
The measurement of the pp->K+ n Sigma+ reaction near thresholdAug 20 2010It is shown that a recent extraction of the total cross section for pp->K+ n Sigma+ from inclusive K+ production data is in conflict with experimental data on the exclusive pp->K+ p Lambda reaction. The result may be interpreted as an upper bound which ... More
A Numerical Renormalization Group Study of a Kondo Hole in a One Dimensional Kondo InsulatorApr 24 1996We have studied a Kondo hole in a one-dimensional Kondo insulator at half-filling using a density matrix formulation of the numerical renormalization group. The Kondo hole introduces midgap states. The spin density introduced by the hole is localized ... More
Critical behavior and magnetocaloric effect in VI$_3$Mar 12 2019We investigated critical properties and magnetocaloric effect connected with ferromagnetic transition in VI$_3$ single crystals. We obtained critical exponents $\beta = 0.244(5)$ with a critical temperature $T_c = 50.10(2)$ K and $\gamma = 1.028(12)$ ... More
Why Study Noise due to Two Level Systems: A Suggestion for ExperimentalistsSep 01 2004Noise is often considered to be a nuisance. Here we argue that it can be a useful probe of fluctuating two level systems in glasses. It can be used to: (1) shed light on whether the fluctuations are correlated or independent events; (2) determine if there ... More
An Improved DFT-based Channel Estimation for Mobile Communication SystemsApr 28 2015Channel estimation is one of the most important parts in current mobile communication systems. Among the huge contributions in channel estimation studies, the discrete Fourier transform (DFT)-based channel estimation has attracted lots of interests since ... More
Room Geometry Estimation from Room Impulse Responses using Convolutional Neural NetworksApr 01 2019We describe a new method to estimate the geometry of a room given room impulse responses. The method utilises convolutional neural networks to estimate the room geometry and uses the mean square error as the loss function. In contrast to existing methods, ... More
Gauge-invariant theory of optical response to THz pulses in s-wave and ($s$+$p$)-wave superconducting semiconductor quantum wellsMay 17 2017We investigate the optical response to the THz pulses in the s-wave and ($s$+$p$)-wave superconducting semiconductor quantum wells by using the gauge-invariant optical Bloch equations, in which the gauge structure in the superconductivity is explicitly ... More
Gapped triplet $p$-wave superconductivity in strong spin-orbit-coupled semiconductor quantum wells in proximity to $s$-wave superconductorFeb 18 2016Apr 27 2016We show that the {\it gapped} triplet superconductivity, i.e., a triplet superconductor with triplet order parameter, can be realized in strong spin-orbit-coupled quantum wells in proximity to $s$-wave superconductor. It is revealed that with the singlet ... More
Hot-electron effect in spin relaxation of electrically injected electrons in intrinsic GermaniumOct 06 2014Mar 27 2015The hot-electron effect in the spin relaxation of electrically injected electrons in intrinsic Germanium is investigated by the kinetic spin Bloch equations both analytically and numerically. It is shown that in the weak-electric-field regime with $E\lesssim ... More
Search for Free Decay of Negative Pions in Water and Light MaterialsMay 30 2006We report on a search for the free decay component of pi- stopped in water and light materials. A non-zero value of this would be an indication of anomalous nu_e contamination to the nu_e and nu_mu_bar production at stopped-pion neutrino facilities. No ... More
Radiative corrections to the neutron star mass inferred from QPO frequenciesNov 10 2011The frequencies of kHz QPOs are widely interpreted as being indicative of the values of characteristic frequencies related to orbital motion around neutron stars, e.g., the radial epicyclic frequency. In regions directly exposed to the radiation from ... More
Spectral State Transitions in Aql X-1: Evidence for `Propeller' EffectsNov 24 1997Aql X-1 is a soft X-ray transient source and emits type I X-ray bursts. A spectral state transition was observed with RXTE during its outburst decay in February and March 1997. Its 10-30 keV and 5-10 keV count rate ratio increased suddenly when its luminosity ... More
Full Current Statistics in Diffusive Normal-Superconductor StructuresMar 10 2001Jul 24 2001We study the current statistics in normal diffusive conductors in contact with a superconductor. Using an extension of the Keldysh Green's function method we are able to find the full distribution of charge transfers for all temperatures and voltages. ... More
Entrance-channel potentials in the synthesis of the heaviest nucleiJun 07 2002Entrance-channel potentials in nucleus-nucleus collisions, relevant for the synthesis of superheavy elements, are systematically studied within a semi-microscopic approach, where microscopic nuclear densities of the colliding spherical or deformed nuclei ... More
A novel superconducting-velocity--tunable quasiparticle state and spin relaxation in GaAs (100) quantum wells in proximity to $s$-wave superconductorJul 25 2016We present a novel quasiparticle state driven by a supercurrent in GaAs (100) quantum wells in proximity to an $s$-wave superconductor, which can be tuned by the superconducting velocity. Rich features such as the suppressed Cooper pairings, large quasiparticle ... More
Spin relaxation in ultracold spin-orbit coupled $^{40}$K gasSep 03 2013Sep 30 2013We report the anomalous Dyakonov-Perel' spin relaxation in ultracold spin-orbit coupled $^{40}$K gas when the coupling between $|9/2,9/2\ >$ and $|9/2,7/2\ >$ states (atcing as the effective Zeeman magnetic field) is much stronger than the spin-orbit ... More