31,940 research outputs found

    The Possibility of Inflation in Asymptotically Safe Gravity

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    We examine the inflationary modes in the cubic curvature theories in the context of asymptotically safe gravity. On the phase space of the Hubble parameter, there exists a critical point which corresponds to the slow-roll inflation in Einstein frame. Most of the e-foldings are attained around the critical point for each inflationary trajectories. If the coupling constants gig_i have the parametric relations generated as the power of the relative energy scale of inflation H0H_0 to the ultraviolet cutoff Λ\Lambda, a successful inflation with more than 60 e-foldings occurs near the critical point.Comment: 14 pages, 4 figure

    Study of Strangeness Condensation by Expanding About the Fixed Point of the Harada-Yamawaki Vector Manifestation

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    Building on, and extending, the result of a higher-order in-medium chiral perturbation theory combined with renormalization group arguments and a variety of observations of the vector manifestation of Harada-Yamawaki hidden local symmetry theory, we obtain a surprisingly simple description of kaon condensation by fluctuating around the "vector manifestation (VM)" fixed point identified to be the chiral restoration point. Our development establishes that strangeness condensation takes place at about 3 n_0 where n_0 is nuclear matter density. This result depends only on the renoramlization-group (RG) behavior of the vector interactions, other effects involved in fluctuating about the bare vacuum in so many previous calculations being "irrelevant" in the RG about the fixed point. Our results have major effects on the collapse of neutron stars into black holes.Comment: 4 page

    Psychometric properties of a short self-reported measure of medication adherence among patients with hypertension treated in a busy clinical setting in Korea.

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    BackgroundWe examined the psychometric properties of the Korean version of the 8-item Morisky Medication Adherence Scale (MMAS-8) among adults with hypertension.MethodsA total of 373 adults with hypertension were given face-to-face interviews in 2 cardiology clinics at 2 large teaching hospitals in Seoul, South Korea. Blood pressure was measured twice, and medical records were reviewed. About one-third of the participants (n = 109) were randomly selected for a 2-week test-retest evaluation of reliability via telephone interview.ResultsInternal consistency reliability was moderate (Cronbach α = 0.56), and test-retest reliability was excellent (intraclass correlation = 0.91; P < 0.001), although a ceiling effect was detected. The correlation of MMAS-8 scores with scores for the original 4-item scale indicated that convergent validity was good (r = 0.92; P < 0.01). A low MMAS-8 score was significantly associated with poor blood pressure control (χ(2) = 29.86; P < 0.001; adjusted odds ratio = 5.08; 95% CI, 2.56-10.08). Using a cut-off point of 6, sensitivity and specificity were 64.3% and 72.9%, respectively. Exploratory factor analysis identified 3 dimensions of the scale, with poor fit for the 1-dimensional construct using confirmatory factory analysis.ConclusionsThe MMAS-8 had satisfactory reliability and validity and thus might be suitable for assessment and counseling regarding medication adherence among adults with hypertension in a busy clinical setting in Korea

    Anyonic Bogomol'nyi Solitons in a Gauged O(3) Sigma Model

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    We introduce the self-dual abelian gauged O(3)O(3) sigma models where the Maxwell and Chern-Simons terms constitute the kinetic terms for the gauge field. These models have quite rich structures and various limits. Our models are found to exhibit both symmetric and broken phases of the gauge group. We discuss the pure Chern-Simons limit in some detail and study rotationally symmetric solitons.Comment: 14 pages, 6 Postscript figures uuencoded, written in REVTe

    Holographic aspects of three dimensional QCD from string theory

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    We study two aspects of 3D QCD with massless fermions in a holographic set-up from string theory, based on D3/D7 branes; parity anomaly and baryons as baby Skyrmions. We first give a novel account of parity anomaly of 3D QCD with odd number of flavors from the IR holographic viewpoint by observing a subtle point in D7 brane embeddings with a given fixed UV theory. We also discuss its UV origin in terms of weakly coupled D-brane pictures. We then focus on the parity-symmetric case of even number of N_F flavors, and study baryons in the holographic model. We identify the monopoles of U(N_F) gauge theory dynamically broken down to U(N_F/2)x U(N_F/2) in the holographic 4 dimensional bulk as a holographic counter-part of 3D baby-Skyrmions for baryons in large N limit, and work out some details how the mapping goes. In particular, we show that the correct baryon charges emerge from the Witten effect with a space-varying theta angle.Comment: 33 pages, 10 figures; v2: references added with comments, typos corrected; v3: more references added; v4: holographic baryon profile and the analysis of its baryon charge is significantly revised, correcting errors in the previous discussio

    Self-DUal SU(3) Chern-Simons Higgs Systems

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    We explore self-dual Chern-Simons Higgs systems with the local SU(3)SU(3) and global U(1)U(1) symmetries where the matter field lies in the adjoint representation. We show that there are three degenerate vacua of different symmetries and study the unbroken symmetry and particle spectrum in each vacuum. We classify the self-dual configurations into three types and study their properties.Comment: Columbia Preprint CU-TP-635, 19 page

    Gauge symmetry enhancement in Hamiltonian formalism

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    We study the Hamiltonian structure of the gauge symmetry enhancement in the enlarged CP(N) model coupled with U(2) Chern-Simons term, which contains a free parameter governing explicit symmetry breaking and symmetry enhancement. After giving a general discussion of the geometry of constrained phase space suitable for the symmetry enhancement, we explicitly perform the Dirac analysis of our model and compute the Dirac brackets for the symmetry enhanced and broken cases. We also discuss some related issues.Comment: 8 pages, typos correcte

    The BPS Domain Wall Solutions in Self-Dual Chern-Simons-Higgs Systems

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    We study domain wall solitons in the relativistic self-dual Chern-Simons Higgs systems by the dimensional reduction method to two dimensional spacetime. The Bogomolny bound on the energy is given by two conserved quantities in a similar way that the energy bound for BPS dyons is set in some Yang-Mills-Higgs systems in four dimensions. We find the explicit soliton configurations which saturate the energy bound and their nonrelativistic counter parts. We also discuss the underlying N=2 supersymmetry.Comment: 16 pages, LaTeX, no figure, a minor change in acknowledgment

    1.57 μm InGaAsP/InP surface emitting lasers by angled focus ion beam etching

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    The characteristics of 1.57 μm InGaAsP/InP surface emitting lasers based on an in-plan ridged structure and 45° beam deflectors defined by angled focused ion beam (FIB) etching are reported. With an externally integrated beam deflector, threshold currents and emission spectra identical to conventional edge emitting lasers are achieved. These results show that FIB etching is a very promising technique for the definition of high quality mirrors and beam deflectors on semiconductor heterostructures for a variety of integrated optoelectronic devices
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