Results for "J. Orenstein"
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Finite-sample Guarantees for Winsorized Importance SamplingOct 25 2018Importance sampling is a widely used technique to estimate the properties of a distribution. The resulting estimator is always unbiased, but may sometimes incur huge variance. This paper investigates trading-off some bias for variance by winsorizing the ... More Fredholm operators in the Toeplitz Algebra $\mathcal{I}(QC)$Sep 09 2014May 04 2016We will give a complete description of $\mathcal{I}$, the set of invertible quasicontinuous functions on the unit circle. After doing this, we will then classify the path-connected components of $\mathcal{I}$ and show that $\mathcal{I}$ has uncountably ... More Toeplitz Operators in a Symmetrically-Normed IdealSep 08 2014Jun 27 2018We look at Toeplitz operators $T_\nu$ on the Fock Space (also known as the Segal-Bargmann space) which have a positive Borel measure $\nu$ as a symbol. We characterize when $\left(T_\nu\right)^s$ for $0<s\leq 1$ is in the symmetrically normed ideal associated ... More Toeplitz Operators in a Symmetrically-Normed IdealSep 08 2014May 03 2016We will give necessary and sufficient conditions for a Toeplitz operator $T_\nu$, having a positive Borel measure $\nu$ for a symbol, on the Fock Space (also known as the Segal-Bargmann space) to be in the symmetrically-normed ideal $\mathcal{C}_\Phi$ ... More Optical conductivity of a superfluid density waveJan 04 2002We present a calculation of the low frequency optical conductivity of a superconductor in the presence of quenched inhomogeneity in both the superfluid and normal fluid densities. We find that inhomogeneity in the superfluid density displaces spectral ... More Low Temperature AC Conductivity in BSCCO (2212)Aug 26 1999Jan 26 2000We report measurements of anamolously large dissipative conductivities in BiSrCaCuO(2212) at low temperatures. We have measured the complex conductivity of BSCCO thin films at 100-600 GHz as a function of doping from the underdoped to the overdoped state. ... More Measurement of Transport Lifetime in a Cuprate SuperconductorJun 01 2000Oct 27 2000We report measurements of the phase of the conductivity, $\phi_\sigma\equiv arg(\sigma)$, in the normal state of a $Bi_{2}Sr_{2}CaCu_{2}O_{8+\delta}$ (BSCCO) thin film from 0.2-1.0 THz. From $\phi_\sigma$ we obtain the time delay of the current response, ... More Vanishing of phase coherence in underdoped Bi_2Sr_2CaCu_2O_8+dOct 21 1998Aug 25 1999Coherent time-domain spectroscopy is used to measure the screening and dissipation of high-frequency electromagnetic fields in a set of underdoped Bi_2Sr_2CaCu_2O_8+d thin films. The measurements provide direct evidence for a phase-fluctuation driven ... More Kerr effect as evidence of gyrotropic order in the cupratesDec 11 2012The Kerr effect can arise in a time-reversal invariant dissipative medium that is "gyrotropic", i.e. one that breaks inversion ($\mathcal I$) and all mirror symmetries. Examples of such systems include electron analogs of cholesteric liquid crystals, ... More Non-diffusive spin dynamics in a two-dimensional electron gasOct 03 2006We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs/GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves in the wavevector ... More Plasmon-SolitonMay 17 2006Apr 15 2008Formation of a novel hybrid-vector spatial plasmon-soliton in a Kerr slab embedded in-between metal plates is predicted and analyzed with a modified NLSE, encompassing hybrid vector field characteristics. Assisted by the transverse plasmonic effect, the ... More Antiferromagnetic resonance and terahertz continuum in $α-$RuCl$_3$Apr 24 2017Oct 09 2017We report measurements of optical absorption in the zig-zag antiferromagnet $\alpha$-RuCl$_3$ as a function of temperature, $T$, magnetic field, $B$, and photon energy, $\hbar\omega$ in the range $\sim$ 0.3 to 8.3 meV, using time-domain terahertz spectroscopy. ... More Optical gyrotropy from axion electrodynamics in momentum spaceMar 09 2015Oct 05 2015Several emergent phenomena and phases in solids arise from configurations of the electronic Berry phase in momentum space that are similar to gauge field configurations in real space such as magnetic monopoles. We show that the momentum-space analogue ... More Negative Group Velocity: Is It a Backward wave or Fast Light?Jul 30 2008When a negative slope of the dispersion curve is encountered, the propagating light may be either 'fast light' or 'backward propagating'. We show that causality considerations select only one of which for each scenario, and demonstrate that the same photonic ... More Two-Photon Emission from SemiconductorsJan 16 2007Oct 25 2007We report the first experimental observations of two-photon emission from semiconductors, to the best of our knowledge, and develop a corresponding theory for the room-temperature process. Spontaneous two-photon emission is demonstrated in optically-pumped ... More Single DNG Interface Makes a Better Perfect LensJan 01 2013Oct 10 2014We show that a single-interface between regular and double-negative (DNG) media constitutes the core structure of a perfect lens and, furthermore, substantially outperforms the highly discussed DNG slab-based lens under imperfect conditions, maintaining ... More Linearly Dichroic Plasmonic Lens and Hetero-Chiral StructuresMay 31 2014We present theoretical and experimental study of plasmonic Hetero-Chiral structures, comprised of constituents with opposite chirality. We devise, simulate and experimentally demonstrate different schemes featuring selective surface plasmon polariton ... More Surface Plasmon Polariton Self-Focusing by Ponderomotive ForcesAug 29 2007Nonlinear properties of Surface Plasmon Polaritons stemming from the inherent electron plasma nonlinearity of the metal layers are investigated. A fluid-mechanics plasma model is used to describe the electron motion in metals. The nonlinear ponderomotive ... More Resonances On-Demand for Plasmonic Nano-ParticlesJan 10 2011A method for designing plasmonic particles with desired resonance spectra is presented. The method is based on repetitive perturbations of an initial particle shape while calculating the eigenvalues of the various quasistatic resonances. The method is ... More Non-local Ponderomotive Nonlinearity in PlasmonicJul 22 2009We analyze an inherent nonlinearity of Surface Plasmon Polaritons at the interface of Fermi-Dirac metal plasma, stemming from the depletion of electron density in high-field intensity regions. The derived optical nonlinear coefficients are comparable ... More Linear and Nonlinear Optical constants of BiFeO_3Jan 10 2008Using spectroscopic ellipsometry, the refractive index and absorption versus wavelength of the ferroelectric antiferromagnet Bismuth Ferrite, BiFeO_3 is reported. The material has a direct band-gap at 442 nm wavelength (2.81 eV). Using optical second ... More Stability of spherical stellar systems I : Analytical resultsNov 22 1995The so-called ``symplectic method'' is used for studying the linear stability of a self-gravitating collisionless stellar system, in which the particles are also submitted to an external potential. The system is steady and spherically symmetric, and its ... More Vortex matter in mesoscopic superconductorsSep 03 1998Superconducting mesoscopic devices in magnetic fields present novel properties which can only be accounted for by both the quantum confinement of the Cooper pairs and by the interaction between the magnetic-field-induced vortices. Sub-micrometer disks, ... More Globally controlled fault tolerant quantum computationJul 08 2007We describe a method to execute globally controlled quantum information processing which admits a fault tolerant quantum error correction scheme. Our scheme nominally uses three species of addressable two-level systems which are arranged in a one dimensional ... More Strangeness and Quark Gluon PlasmaMay 25 2003A brief summary of strangeness mile stones is followed by a chemical non-equilibrium statistical hadronization analysis of strangeness results at SPS and RHIC. Strange particle production in AA interactions at \sqrt{s_{NN}}\ge 8.6 GeV can be understood ... More Breakdown of step-flow growth in unstable homoepitaxyJan 13 2004Two mechanisms for the breakdown of step flow growth, in the sense of the appearance of steps of opposite sign to the original vicinality, are studied by kinetic Monte Carlo simulations and scaling arguments. The first mechanism is the nucleation of islands ... More Parton-Hadron duality in event generatorsAug 28 1992Sep 04 1992The validity of local parton-hadron duality within the framework of HERWIG and JETSET event generators is investigated. We concentrate on ${\rm e}^{+}{\rm e}^{-}$ annihilations in LEP 2 energy range as these interactions provide theoretically the cleanest ... More Accretion by GalaxiesMar 14 2000Both theory and observation indicate that galaxies like the Milky Way accrete matter at the rate of a few Msun per year. Complexity fits the fittestDec 11 2012In this paper we shall relate computational complexity to the principle of natural selection. We shall do this by giving a philosophical account of complexity versus universality. It seems sustainable to equate universal systems to complex systems or ... More