5,973 research outputs found
Comments on lattice gauge theories with infrared-attractive fixed points
Theories of interacting gauge fields and fermions can possess a running gauge
coupling with an infrared attractive fixed point (IRFP). We present a minimal
description of the physics of these systems and comment on some simple
expectations for results from lattice simulations done within the basin of
attraction of the IRFP in these theories.Comment: 10 pages, 2 figures. Published version, fixed typos in version
Editorial: Beyond embodied cognition: Intentionality, affordance, and environmental adaptation
The paper describes the contents of the contributions contained in the special topi
Spin-orbital polarons in electron doped copper oxides
Present work demonstrates the formation of spin-orbital polarons in electron
doped copper oxides, that arise due to doping-induced polarisation of the
oxygen orbitals in the CuO planes. The concept of such polarons is
fundamentally different from previous interpretations. The novel aspect of
spin-orbit polarons is best described by electrons becoming self-trapped in
one-dimensional channels created by polarisation of the oxygen orbitals. The
one-dimensional channels form elongated filaments with two possible
orientations, along the diagonals of the elementary CuO square plaquette.
As the density of doped electrons increases multiple filaments are formed.
These may condense into a single percollating filamentary phase. Alternatively,
the filaments may cross perpendicularly to create an interconnected conducting
quasi-one-dimensional web. At low electron doping the antiferromagnetic (AFM)
state and the polaron web coexist. As the doping is increased the web of
filaments modifies and transforms the AFM correlations leading to a series of
quantum phase transitions - which affect the normal and superconducting state
properties.Comment: Please cite this article as: A. Kusmartseva, H. Yu, K. Jin, F.V.
Kusmartsev, Spin-orbital polarons in electron doped copper oxides, Journal of
Magnetism and Magnetic Materials (2017), doi: https://doi.org/10.1016/j.jmmm.
2017.11.02
Does a Leapfrogging Growth Strategy Raise Growth Rate? Some International Evidence
While openness to trade is a well-recognized hallmark of the Asian growth model, another component of the model is a leapfrogging strategy—the use of policies to guide industrial structural transformation ahead of a country's factor endowment. Does the leapfrogging strategy work? Opinions vary but the evidence is scarce in part because it is more difficult to measure the degree of leapfrogging than the extent of trade openness. We undertake a systematic look at the evidence both across countries and subregions within a large regional Asian economy to assess the efficacy of such a strategy. We conclude that there is no strong and robust evidence that this strategy works reliably.growth; trade openness; leapfrogging
Conformal or Walking? Monte Carlo renormalization group studies of SU(3) gauge models with fundamental fermions
Strongly coupled gauge systems with many fermions are important in many
phenomenological models. I use the 2-lattice matching Monte Carlo
renormalization group method to study the fixed point structure and critical
indexes of SU(3) gauge models with 8 and 12 flavors of fundamental fermions.
With an improved renormalization group block transformation I am able to
connect the perturbative and confining regimes of the N_f=8 flavor system, thus
verifying its QCD-like nature. With N_f=12 flavors the data favor the existence
of an infrared fixed point and conformal phase, though the results are also
consistent with very slow walking. I measure the anomalous mass dimension in
both systems at several gauge couplings and find that they are barely different
from the free field value.Comment: 26 pages, 11 figure
Cool marble building envelopes. The effect of aging on energy performance and aesthetics
Marble envelopes represent a relatively common architectural solution used in variety of historic, modern and contemporary building facades. White marble envelopes have been shown to reduce solar heat gains, while improving indoor thermal comfort and energy efficiency in summer time. While marble is useful in this context, the urban atmosphere accelerates the degradation of marble elements. This leads to changes in optical characteristics, hence the aesthetics, and affects the energy efficiency benefits offered by white marble facades. These issues are investigated in order to predict the impact of degradation on energy performance and to the aesthetic value, such as change of color and luminosity. In this study, surface degradation of white marble is analyzed by means of accelerated weathering in the laboratory while examining changes to the optical characteristics of the materials. A dynamic simulation is carried out to assess the energy performance of a building as a case study
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