31,940 research outputs found
The Possibility of Inflation in Asymptotically Safe Gravity
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
have the parametric relations generated as the power of the relative
energy scale of inflation to the ultraviolet cutoff , 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
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.
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
We introduce the self-dual abelian gauged 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
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
We explore self-dual Chern-Simons Higgs systems with the local and
global 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
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
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
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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