2,174 research outputs found
Stochastic quantization and holographic Wilsonian renormalization group
We study relation between stochastic quantization and holographic Wilsonian
renormalization group flow. Considering stochastic quantization of the boundary
on-shell actions with the Dirichlet boundary condition for certain bulk
gravity theories, we find that the radial flows of double trace deformations in
the boundary effective actions are completely captured by stochastic time
evolution with identification of the radial coordinate `' with the
stochastic time '' as . More precisely, we investigate Langevin
dynamics and find an exact relation between radial flow of the double trace
couplings and 2-point correlation functions in stochastic quantization. We also
show that the radial evolution of double trace deformations in the boundary
effective action and the stochastic time evolution of the Fokker-Planck action
are the same. We demonstrate this relation with a couple of examples:
(minimally coupled)massless scalar fields in and U(1) vector fields in
.Comment: 1+30 pages, a new subsection is added, references are adde
Comment on "Quantum mechanics of smeared particles"
In a recent article, Sastry has proposed a quantum mechanics of smeared
particles. We show that the effects induced by the modification of the
Heisenberg algebra, proposed to take into account the delocalization of a
particle defined via its Compton wavelength, are important enough to be
excluded experimentally.Comment: 2 page
A branch-point approximant for the equation of state of hard spheres
Using the first seven known virial coefficients and forcing it to possess two
branch-point singularities, a new equation of state for the hard-sphere fluid
is proposed. This equation of state predicts accurate values of the higher
virial coefficients, a radius of convergence smaller than the close-packing
value, and it is as accurate as the rescaled virial expansion and better than
the Pad\'e [3/3] equations of state. Consequences regarding the convergence
properties of the virial series and the use of similar equations of state for
hard-core fluids in dimensions are also pointed out.Comment: 6 pages, 4 tables, 3 figures; v2: enlarged version, extension to
other dimensionalities; v3: typos in references correcte
Spin and a Running Radius in RS1
We develop a renormalization group formalism for the compactified
Randall-Sundrum scenario wherein the extra-dimensional radius serves as the
scaling parameter. Couplings on the hidden brane scale as we move within local
effective field theories with varying size of the warped extra dimension. We
consider this RG approach applied to U(1) gauge theories and gravity. We use
this method to derive a low energy effective theory.Comment: 18 pages, minor changes, references adde
Epidemiology of depression with psychotic experiences and its association with chronic physical conditions in 47 low- and middle-income countries
BackgroundThe co-existence of depression and psychotic experiences (PEs) is associated with more pronounced adverse health outcomes compared to depression alone. However, data on its prevalence and correlates are lacking in the general adult population, and there is no published data on its association with chronic physical conditions.MethodCross-sectional, community-based data from 201 337 adults aged ⩾18 years from 47 low- and middle-income countries from the World Health Survey were analyzed. The presence of past 12-month PE and DSM-IV depression was assessed with the Composite International Diagnostic Interview (CIDI). Information on six chronic medical conditions (chronic back pain, edentulism, arthritis, angina, asthma, diabetes) were obtained by self-report. Multivariable logistic regression analysis was performed.ResultsThe crude overall prevalence of co-morbid depression/PEs was 2.5% [95% confidence interval (CI) 2.3–2.7%], with the age- and sex-adjusted prevalence ranging from 0.1% (Sri Lanka, Vietnam) to 9.03% (Brazil). Younger age, urban setting, current smoking, alcohol consumption, and anxiety were significant correlates of co-existing depression/PEs. Co-occurring depression/PEs was associated with significantly higher odds for arthritis, angina, and diabetes beyond that of depression alone after adjusting for sociodemographics, anxiety, and country, with odds ratios (depression/PEs v. depression only) being: arthritis 1.30 (95% CI 1.07–1.59, p = 0.0086); angina 1.40 (95% CI 1.18–1.67, p = 0.0002); diabetes 1.65 (95% CI 1.21–2.26, p = 0.0017).ConclusionsThe prevalence of co-existing depression/PEs was non-negligible in most countries. Our study suggests that when depression/PE or a chronic condition (e.g. arthritis, angina, diabetes) is detected, screening for the other may be important to improve clinical outcomes.</jats:sec
The Intrinsically X-ray Weak Quasar PHL 1811. II. Optical and UV Spectra and Analysis
This is the second of two papers reporting observations and analysis of the
unusually bright (m_b=14.4), luminous (M_B=-25.5), nearby (z=0.192) narrow-line
quasar PHL 1811. The first paper reported that PHL 1811 is intrinsically X-ray
weak, and presented a spectral energy distribution (SED). Here we present HST
STIS optical and UV spectra, and ground-based optical spectra. The optical and
UV line emission is very unusual. There is no evidence for forbidden or
semiforbidden lines. The near-UV spectrum is dominated by very strong FeII and
FeIII, and unusual low-ionization lines such as NaID and CaII H&K are observed.
High-ionization lines are very weak; CIV has an equivalent width of 6.6A, a
factor of ~5 smaller than measured from quasar composite spectra. An unusual
feature near 1200A can be deblended in terms of Ly\alpha, NV, SiII, and CIII*
using the blueshifted CIV profile as a template. Photoionization modeling shows
that the unusual line emission can be explained qualitatively by the unusually
soft SED. Principally, a low gas temperature results in inefficient emission of
collisionally excited lines, including the semiforbidden lines generally used
as density diagnostics. The emission resembles that of high-density gas; in
both cases this is a consequence of inefficient cooling. PHL 1811 is very
unusual, but we note that quasar surveys are generally biased against finding
similar objects.Comment: Accepted for publication in ApJS. Full resolution figures available
here: http://www.nhn.ou.edu/~leighly/phl1811_paper1.pd
Duality and ontology
A ‘duality’ is a formal mapping between the spaces of solutions of two empirically equivalent theories. In recent times, dualities have been found to be pervasive in string theory and quantum field theory. Naïvely interpreted, duality-related theories appear to make very different ontological claims about the world—differing in e.g. space-time structure, fundamental ontology, and mereological structure. In light of this, duality-related theories raise questions familiar from discussions of underdetermination in the philosophy of science: in the presence of dual theories, what is one to say about the ontology of the world? In this paper, we undertake a comprehensive and non-technical survey of the landscape of possible ontological interpretations of duality-related theories. We provide a significantly enriched and clarified taxonomy of options—several of which are novel to the literature
Réponse à la double inoculation mycorhizienne et rhizobienne du niébé (variété, KVX396-4-5-2D) cultivé au Burkina Faso
Le niébé vit en symbiose avec des champignons mycorhiziens arbusculaires (CMA) et rhizobiums du sol susceptibles d’améliorer sa nutrition hydrominérale et sa croissance. Cette étude avait pour objectif d’évaluer la réponse du niébé (variété KVX 396-4-5-2D) à l’inoculation rhizobienne et/ou mycorhizienne. KVX 396-4-5-2D (KVX) a été inoculée en serre avec cinq inoculums de CMA [Glomus aggregatum (Ga), Glomus mossae (Gm), Rhizophagus irregularis (Ri), Glomus fasciculatum (Gf), Glomus verrucullosum (Gv)] et une souche de rhizobium (ORS 3409). Après 45 jours de culture, les plants ont été récoltés et les paramètres de croissance (hauteur et biomasses), de mycorhization et de nodulation ont été mesurés. Les résultats montrent que l’inoculation améliore la croissance en hauteur et la biomasse totale des plants de KVX. La souche Ga améliore de 70% la production de biomasse totale de KVX. Aussi, la double inoculation ORS3409+Ga est plus bénéfique aux plants de la variété de niébé utilisée avec une amélioration de la croissance en hauteur de 8,82%. De ces résultats, il ressort que l’inoculum Ga améliore significativement la croissance de la variété de niébé KVX au stade floraison-fructification.Mots clés : Champignons mycorhiziens arbusculaires, rhizobium, inoculation, niébé
Thermodynamics of a Kerr Newman de Sitter Black Hole
We compute the conserved quantities of the four-dimensional Kerr-Newman-dS
(KNdS) black hole through the use of the counterterm renormalization method,
and obtain a generalized Smarr formula for the mass as a function of the
entropy, the angular momentum and the electric charge. The first law of
thermodynamics associated to the cosmological horizon of KNdS is also
investigated. Using the minimal number of intrinsic boundary counterterms, we
consider the quasilocal thermodynamics of asymptotic de Sitter
Reissner-Nordstrom black hole, and find that the temperature is equal to the
product of the surface gravity (divided by ) and the Tolman redshift
factor. We also perform a quasilocal stability analysis by computing the
determinant of Hessian matrix of the energy with respect to its thermodynamic
variables in both the canonical and the grand-canonical ensembles and obtain a
complete set of phase diagrams. We then turn to the quasilocal thermodynamics
of four-dimensional Kerr-Newman-de Sitter black hole for virtually all possible
values of the mass, the rotation and the charge parameters that leave the
quasilocal boundary inside the cosmological event horizon, and perform a
quasilocal stability analysis of KNdS black hole.Comment: REVTEX4, 12 pages, 12 figures, references added and some points in
Sec II have been clarified, version to appear in Can. J. Phy
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