Fractional quantum Hall effect in higher Landau levels

We investigate, using finite size numerical calculations, the spin-polarized fractional quantum Hall effect (FQHE) in the first excited Landau level (LL). We find evidence for the existence of an incompressible state at $\nu = \frac{7}{3} = 2+\frac{1}{3}$, but not at $\nu = 2+\frac{2}{5}$. Surprisingly, the 7/3 state is found to be strongest at a finite thickness. The structure of the low- lying excited states is found to be markedly different from that in the lowest LL. This study also rules out FQHE at a large number of odd-denominator fractions in the lowest LL.Comment: 7 pages RevTex, 4 figure

A case study of global agency innovation rankings: implications on current definitions of innovation

In this paper, the authors analyze global innovation rankings as provided by Strategy& over the last 7 years. They first explore the raw ranks and report variations in year-over-year (YOY) ranks for top ten ranking companies. The normalized innovation ranks are then used to calculate the Innovation Power (inP) to assess if these companies maintained or improved their ranks over time. An interesting classification of innovations for the top 10 emerges from this analysis. The constant top innovators were Apple and Google. The rising innovators were Tesla, 3M and Facebook. Other classifications are discussed. The authors propose a non-statistical predictive model, which is reminiscent of a kinematic model using a novel concept of Innovation Momentum (inM) and predict that for 2017, Apple and Google will hold their first and second place, followed by Amazon, Samsung and Tesla. Facebook is also expected to rise in its rank. Companies that reach out and serve end-user needs with service innovations appear rising in ranks, far more than R&D intensive patent filing innovators in these ranks. Tesla is an interesting top ranker to watch. There are implications for software focused companies gaining importance given their flexibility over hardware dominant ones. Some bottom innovators are further declining. Although the rankings are perception-based, there is a pattern that implies it is not random or merely subjective. The analysis highlights the need for leaders and consultants to put in perspective the complex management problem of measuring innovation

From Cooper Pairs to Composite Bosons: A Generalized RPA Analysis of Collective Excitations

The evolution of the ground state and the excitation spectrum of the two and three dimensional attractive Hubbard model is studied as the system evolves from a Cooper pair regime for weak attraction to a composite boson regime for a strong attraction.Comment: 20 pages RevTex, 7 figures on reques

Spontaneous Interlayer Coherence in Double-Layer Quantum Hall Systems: Symmetry Breaking Interactions, In-Plane Fields and Phase Solitons

At strong magnetic fields double-layer two-dimensional-electron-gas systems can form an unusual broken symmetry state with spontaneous inter-layer phase coherence. The system can be mapped to an equivalent system of pseudospin $1/2$ particles with pseudospin-dependent interactions and easy-plane magnetic order. In this paper we discuss how the presence of a weak interlayer tunneling term alters the properties of double-layer systems when the broken symmetry is present. We use the energy functional and equations of motion derived earlier to evaluate the zero-temperature response functions of the double-layer system and use our results to discuss analogies between this system and Josephson-coupled superconducting films. We also present a qualitative picture of the low-energy charged excitations of this system. We show that parallel fields induce a highly collective phase transition to an incommensurate state with broken translational symmetry.Comment: 26 pages, RevTex, 8 postscript figures (submitted to Phys. Rev. B

An in vitro evaluation of apical sealing ability of endorez® cement and endorez® resin coated gutta-percha using single cone technique and cold lateral condensation

The aim of the present study was to compare the sealing ability of zinc-oxide sealer and resin-based sealer (EndoREZ®)using two different root canal filling techniques, the cold lateral condensation and the single cone technique. Forty-five root canals of human incisors, canines and premolars were selected and prepared using RaCe rotary files (FKG, La Chaux-de-Fonds, Switzerland). The specimens were randomly divided into 3 groups (

Quantum and Many-Body Effects on the Capacitance of a Quantum Dot

We calculate exactly, using finite size techniques, the quantum mechanical and many-body effects to the self-capacitance of a spherical quantum dot in the regime of extreme confinement, where the radius of the sphere is much smaller than the effective Bohr radius. We find that the self-capacitance oscillates as a function of the number of electrons close to its classical value. We also find that the electrostatic energy extrapolates to zero when $N=1$, suggesting that the energy scales like $e^{2}N(N-1)$. This establishes, at least for this configuration, that the semiclassical description of Coulomb charging effects in terms of capacitances holds to a good approximation even at very small scales.Comment: 7 pages RevTex, 5 figures on reques