نتایج جستجو برای: dmft
تعداد نتایج: 1883 فیلتر نتایج به سال:
We revisit Nagaoka ferromagnetism in the two-dimensional U = ∞ Hubbard model using the dynamical mean-field theory (DMFT). A recently developed continuous time quantum Monte Carlo method is applied to solve the DMFT impurity problem. The stability of Nagaoka ferromagnetism is studied as a function of both the nearest-neighbor lattice hopping t and the next-nearest-neighbor lattice hopping t. It...
We develop a nanoscale dynamical mean-field theory (nano-DMFT) to deal with strong Coulomb interaction effects in physical systems that are intermediate in size between atoms and bulk materials, taking into account the tunneling into nearby electrodes. Focusing on a simplified treelike geometry, the usual DMFT loop simply stops when the finite lattice is fully covered, starting with an initial ...
In November 2013 the first dental epidemiological survey of 5, 12 and 15 year old children was undertaken on The Falkland Islands. The census survey used the ICDAS II system and achieved an overall response rate of 87.4%. To allow international comparisons obvious decay experience is reported. The mean dmft of 5-year-olds was 1.2 teeth, the prevalence of decay experience was 34.6%. The mean DMF...
We construct a functional for the single-particle Green’s function, which is a variant of the standard BaymKadanoff functional. The stability of the stationary solutions to the functional is directly related to aspects of the irreducible particle hole interaction through the Bethe-Salpeter equation. A startling aspect of this functional is that it allows a simple and rigorous derivation of both...
Iodine deficiency is a major determinant of endemic goiter which affects bone growth. The purpose of this study was to clarify the relationship between iodine deficiency and oral health. A cross-sectional survey was carried out on 181 inhabitants aged 17 to 40 years in two villages in an iodine-deficient area in Bali, Indonesia. Thyroid swelling, serum level of thyroid-stimulating hormone, DMFT...
We derive an exact mapping from the action of nonequilibrium dynamical mean-field theory (DMFT) to a single-impurity Anderson model (SIAM) with time-dependent parameters, which can be solved numerically by exact diagonalization. The representability of the nonequilibrium DMFT action by a SIAM is established as a rather general property of nonequilibrium Green functions. We also obtain the noneq...
These are introductory lectures to some aspects of the physics of strongly correlated electron systems. I first explain the main reasons for strong correlations in several classes of materials. The basic principles of dynamical mean-field theory (DMFT) are then briefly reviewed. I emphasize the formal analogies with classical mean-field theory and density functional theory, through the construc...
We address the nature of the Mott transition in the Hubbard model at half-filling using cluster dynamical mean field theory (DMFT). We compare cluster-DMFT results with those of single-site DMFT. We show that inclusion of the short-range correlations on top of the on-site correlations does not change the order of the transition between the paramagnetic metal and the paramagnetic Mott insulator,...
OBJECTIVE To describe the status of dental caries in a sample of Iranian adolescents aged 14 to 18 years in Qazvin, and to identify caries-related factors affecting this group. STUDY DESIGN Qazvin was divided into three zones according to socio-economic status. The sampling procedure used was a stratified cluster sampling technique; incorporating 3 stratified zones, for each of which a cluste...
مقدمه: دو شاخص مهم ارزیابی سلامت در کودکان شاخص توده بدنی و شاخص پوسیدگی های دندانی هستند. این مطالعه با هدف تعیین ارتباط بین این دو شاخص در کودکان 7 تا 11 ساله شهر یزد انجام شد. روش بررسی: در مطالعهای مقطعی با استفاده از روش نمونه گیری خوشهای 400 کودک 7 تا 11 ساله از مدارس شهر یزد انتخاب شدند. شاخص توده بدنی و شاخص dmft/dmft در آنها به دست آمد و سپس ارتباط بین این دو شاخص و همچنین تأثیر عوام...
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