428 research outputs found

    The modular S-matrix as order parameter for topological phase transitions

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    We study topological phase transitions in discrete gauge theories in two spatial dimensions induced by the formation of a Bose condensate. We analyse a general class of euclidean lattice actions for these theories which contain one coupling constant for each conjugacy class of the gauge group. To probe the phase structure we use a complete set of open and closed anyonic string operators. The open strings allow one to determine the particle content of the condensate, whereas the closed strings enable us to determine the matrix elements of the modular SS-matrix, also in the broken phase. From the measured broken SS-matrix we may read off the sectors that split or get identified in the broken phase, as well as the sectors that are confined. In this sense the modular SS-matrix can be employed as a matrix valued non-local order parameter from which the low-energy effective theories that occur in different regions of parameter space can be fully determined. To verify our predictions we studied a non-abelian anyon model based on the quaternion group H=D2ˉH=\bar{D_2} of order eight by Monte Carlo simulation. We probe part of the phase diagram for the pure gauge theory and find a variety of phases with magnetic condensates leading to various forms of (partial) confinement in complete agreement with the algebraic breaking analysis. Also the order of various transitions is established.Comment: 37 page

    A theory of topological edges and domain walls

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    We investigate domain walls between topologically ordered phases in two spatial dimensions and present a simple but general framework from which their degrees of freedom can be understood. The approach we present exploits the results on topological symmetry breaking that we have introduced and presented elsewhere. After summarizing the method, we work out predictions for the spectrum of edge excitations and for the transport through edges in some representative examples. These include domain walls between the Abelian and non-Abelian topological phases of Kitaev's honeycomb lattice model in a magnetic field, as well as recently proposed domain walls between spin polarized and unpolarized non-Abelian fractional quantum Hall states at different filling fractions.Comment: 4 pages, 1 figure, late

    Interacting non-Abelian anyons as Majorana fermions in the honeycomb lattice model

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    We study the collective states of interacting non-Abelian anyons that emerge in Kitaev's honeycomb lattice model. Vortex-vortex interactions are shown to lead to the lifting of the topological degeneracy and the energy is discovered to exhibit oscillations that are consistent with Majorana fermions being localized at vortex cores. We show how to construct states corresponding to the fusion channel degrees of freedom and obtain the energy gaps characterizing the stability of the topological low energy spectrum. To study the collective behavior of many vortices, we introduce an effective lattice model of Majorana fermions. We find necessary conditions for it to approximate the spectrum of the honeycomb lattice model and show that bi-partite interactions are responsible for the degeneracy lifting also in many vortex systems.Comment: 22 pages, 12 figures, published versio

    The relation between non-occupational physical activity and years lived with and without disability

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    Objectives: The effects of non-occupational physical activity were assessed on the number of years lived with and without disability between age 50 and 80 years. Methods: Using the GLOBE study and the Longitudinal Study of Aging, multi-state life tables were constructed yielding the number of years with and without disability between age 50 and 80 years. To obtain life tables by level of physical activity (low, moderate, high), hazard ratios were derived for different physical activity levels per transition (non-disabled to disabled, non-disabled to death, disabled to non-disabled, disabled to death) adjusted for age, sex and confounders. Results: M

    Composite Fermion Wavefunctions Derived by Conformal Field Theory

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    The Jain theory of hierarchical Hall states is reconsidered in the light of recent analyses that have found exact relations between projected Jain wavefunctions and conformal field theory correlators. We show that the underlying conformal theory is precisely given by the W-infinity minimal models introduced earlier. This theory involves a reduction of the multicomponent Abelian theory that is similar to the projection to the lowest Landau level in the Jain approach. The projection yields quasihole excitations obeying non-Abelian fractional statistics. The analysis closely parallels the bosonic conformal theory description of the Pfaffian and Read-Rezayi states.Comment: 4 pages, 1 figur

    Fourier transform and the Verlinde formula for the quantum double of a finite group

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    A Fourier transform S is defined for the quantum double D(G) of a finite group G. Acting on characters of D(G), S and the central ribbon element of D(G) generate a unitary matrix representation of the group SL(2,Z). The characters form a ring over the integers under both the algebra multiplication and its dual, with the latter encoding the fusion rules of D(G). The Fourier transform relates the two ring structures. We use this to give a particularly short proof of the Verlinde formula for the fusion coefficients.Comment: 15 pages, small errors corrected and references added, version to appear in Journal of Physics

    Use of FreeStyle Libre Flash Monitor Register in the Netherlands (FLARE-NL1):Patient Experiences, Satisfaction, and Cost Analysis

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    In patients with diabetes mellitus (DM), adequate glucose control is of major importance. When treatment schemes become more complicated, proper self-management through intermittent self-measurement of blood glucose (SMBG), among others, becomes crucial in achieving this goal. In the last decade, continuous glucose monitoring (CGM) has been on the rise, providing not only intermittent information but also information on continuous glucose trends. The FreeStyle Libre (FSL) Flash CGM system is a CGM system mainly used for patients with DM and is designed based on the same techniques as early CGMs. Compared with earlier CGMs, the FSL is factory calibrated, has no automated readings or direct alarms, and is cheaper to use. Although less accurate compared with the gold standard for SMBG, users report high satisfaction because it is easy to use and can help users monitor glucose trends. The Flash Monitor Register in the Netherlands (FLARE-NL) study aims to assess the effects of FSL Flash CGM use in daily practice. The study has a before-after design, with each participant being his or her own control. Users will be followed for at least 1 year. The endpoints include changes in HbA1c, frequency and severity of hypoglycemias, and quality of life. In addition, the effects of its use on work absenteeism rate, diabetes-related hospital admission rate, and daily functioning (including sports performance) will be studied. Furthermore, cost-benefit analysis based on the combination of registered information within the health insurance data will be investigated. Ultimately, the data gathered in this study will help increase the knowledge and skills of the use of the Flash CGM in daily practice and assess the financial impact on the use of the Flash CGM within the Dutch healthcare system
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