977 research outputs found
Entanglement Entropy in Non-Relativistic Field Theories
We calculate entanglement entropy in a non-relativistic field theory
described by the Schr\"odinger operator. We demonstrate that the entropy is
characterized by i) the area law and ii) UV divergences that are identical to
those in the relativistic field theory. These observations are further
supported by a holographic consideration. We use the non-relativistic symmetry
and completely specify entanglement entropy in large class of non-relativistic
theories described by the field operators polynomial in derivatives. We suggest
that the area law of the entropy can be tested in experiments with condensed
matter systems such as liquid helium.Comment: 4 pages; v2: discussion of interacting fields include
Holographic chiral magnetic spiral
We study the ground state of baryonic/axial matter at zero temperature
chiral-symmetry broken phase under a large magnetic field, in the framework of
holographic QCD by Sakai-Sugimoto. Our study is motivated by a recent proposal
of chiral magnetic spiral phase that has been argued to be favored against
previously studied phase of homogeneous distribution of axial/baryonic currents
in terms of meson super-currents dictated by triangle anomalies in QCD. Our
results provide an existence proof of chiral magnetic spiral in strong coupling
regime via holography, at least for large axial chemical potentials, whereas we
don't find the phenomenon in the case of purely baryonic chemical potential.Comment: 24 pages, 15 figure
Eating Disorder Behaviors Are Increasing: Findings from Two Sequential Community Surveys in South Australia
Background: evidence for an increase in the prevalence of eating disorders is inconsistent. Our aim was to determine change in the population point prevalence of eating disorder behaviors over a 10-year period. \ud
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Methodology/Principal Findings: eating disorder behaviors were assessed in consecutive general population surveys of men and women conducted in 1995 (n = 3001, 72% respondents) and 2005 (n = 3047, 63.1% respondents). Participants were randomly sampled from households in rural and metropolitan South Australia. There was a significant (all p,0.01) and over two-fold increase in the prevalence of binge eating, purging (self-induced vomiting and/or laxative or diuretic misuse) and strict dieting or fasting for weight or shape control among both genders. The most common diagnosis in 2005 was either binge eating disorder or other ‘‘eating\ud
disorders not otherwise specified’’ (EDNOS; n = 119, 4.2%). \ud
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Conclusions/Significance: in this population sample the point prevalence of eating disorder behaviors increased over the past decade. Cases of anorexia nervosa and bulimia nervosa, as currently defined, remain uncommon
Exploring T and S parameters in Vector Meson Dominance Models of Strong Electroweak Symmetry Breaking
We revisit the electroweak precision tests for Higgsless models of strong
EWSB. We use the Vector Meson Dominance approach and express S and T via
couplings characterizing vector and axial spin-1 resonances of the strong
sector. These couplings are constrained by the elastic unitarity and by
requiring a good UV behavior of various formfactors. We pay particular
attention to the one-loop contribution of resonances to T (beyond the chiral
log), and to how it can improve the fit. We also make contact with the recent
studies of Conformal Technicolor. We explain why the second Weinberg sum rule
never converges in these models, and formulate a condition necessary for
preserving the custodial symmetry in the IR.Comment: 35 pages, 7 figures; v3: refs added, to appear in JHE
The Gluonic Field of a Heavy Quark in Conformal Field Theories at Strong Coupling
We determine the gluonic field configuration sourced by a heavy quark
undergoing arbitrary motion in N=4 super-Yang-Mills at strong coupling and
large number of colors. More specifically, we compute the expectation value of
the operator tr[F^2+...] in the presence of such a quark, by means of the
AdS/CFT correspondence. Our results for this observable show that signals
propagate without temporal broadening, just as was found for the expectation
value of the energy density in recent work by Hatta et al. We attempt to shed
some additional light on the origin of this feature, and propose a different
interpretation for its physical significance. As an application of our general
results, we examine when the quark undergoes oscillatory motion,
uniform circular motion, and uniform acceleration. Via the AdS/CFT
correspondence, all of our results are pertinent to any conformal field theory
in 3+1 dimensions with a dual gravity formulation.Comment: 1+38 pages, 16 eps figures; v2: completed affiliation; v3: corrected
typo, version to appear in JHE
Perceptions and behaviors related to hand hygiene for the prevention of H1N1 influenza transmission among Korean university students during the peak pandemic period
<p>Abstract</p> <p>Background</p> <p>This study was performed to better assess the perceptions, motivating factors, and behaviors associated with the use of hand washing to prevent H1N1 influenza transmission during the peak pandemic period in Korea.</p> <p>Methods</p> <p>A cross-sectional survey questionnaire was completed by 942 students at a university campus in Suwon, Korea, between December 1 and 8, 2009. The survey included questions regarding individual perceptions, motivating factors, and behaviors associated with hand washing for the prevention of H1N1 influenza transmission.</p> <p>Results</p> <p>Compared to one year prior, 30.3% of participants reported increasing their hand washing frequency. Female students were more likely to practice more frequent hand washing. Women also perceived the effectiveness of hand washing to be lower, and illness severity and personal susceptibility to H1N1 infection to be higher. Study participants who were female (OR: 1.79-3.90) who perceived of hand washing to be effective (OR: 1.34-12.15) and illness severity to be greater (OR: 1.00-3.12) washed their hands more frequently.</p> <p>Conclusions</p> <p>Korean students increased their frequency of hand hygiene practices during the pandemic, with significant gender differences existing in the attitudes and behaviors related to the use of hand hygiene as a means of disease prevention. Here, the factors that affected hand washing behavior were similar to those identified at the beginning of the H1N1 or SARS pandemics, suggesting that public education campaigns regarding hand hygiene are effective in altering individual hand hygiene habits during the peak periods of influenza transmission.</p
Lifshitz black holes in Brans-Dicke theory
We present an exact asymptotically Lifshitz black hole solution in
Brans-Dicke theory of gravity in arbitrary dimensions in presence of
a power-law potential. In this solution, the dynamical exponent is
determined in terms of the Brans-Dicke parameter and . Asymptotic
Lifshitz condition at infinity requires , which corresponds to
. On the other hand, the no-ghost condition
for the scalar field in the Einstein frame requires . We
compute the Hawking temperature of the black hole solution and discuss the
problems encountered and the proposals in defining its thermodynamic
properties. A generalized solution charged under the Maxwell field is also
presented.Comment: 32 pages, no figure. v2: revised version. Section 3.1 and Appendix B
improved. The argument in Appendix A clarified. v3: References added. v4:
analysis on the black hole thermodynamical properties corrected. Final
version to appear in JHE
Composite Higgs Sketch
The coupling of a composite Higgs to the standard model fields can deviate
substantially from the standard model values. In this case perturbative
unitarity might break down before the scale of compositeness is reached, which
would suggest that additional composites should lie well below this scale. In
this paper we account for the presence of an additional spin 1 custodial
triplet of rhos. We examine the implications of requiring perturbative
unitarity up to the compositeness scale and find that one has to be close to
saturating certain unitarity sum rules involving the Higgs and the rho
couplings. Given these restrictions on the parameter space we investigate the
main phenomenological consequences of the spin 1 triplet. We find that they can
substantially enhance the Higgs di-photon rate at the LHC even with a reduced
Higgs coupling to gauge bosons. The main existing LHC bounds arise from
di-boson searches, especially in the experimentally clean channel where the
charged rhos decay to a W-boson and a Z, which then decay leptonically. We find
that a large range of interesting parameter space with 700 GeV < m(rho) < 2 TeV
is currently experimentally viable.Comment: 37 pages, 12 figures; v4: sum rule corrected, conclusions unchange
Novel Solutions of Finite-Density D3/D5 Probe Brane System and Their Implications for Stability
In this article we present a novel set of solutions of the probe brane system
consisting of Nf-D5 probe branes embedded in the near-horizon geometry
generated by Nc-D3 branes, with the D5 worldvolume U(1) gauge fields turned on.
Our system is holographically dual to a supersymmetric defect field theory at
finite density in non-trivial vacua. We find that a large class of vacua turns
out to satisfy a no-force condition, even with supersymmetry explicitly broken
by the finite density; our solutions include configuration in which charge
separates from the horizon and is instead carried by probe branes outside the
horizon. The free energy is lowered in this process. Whether this corresponds
to a genuine instability of the finite-density probe brane system remains to be
seen.Comment: 11 pages, 1 figure
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