5,482 research outputs found
A note on the phase transition in a topologically massive Ginzburg-Landau theory
We consider the phase transition in a model which consists of a
Ginzburg-Landau free energy for superconductors including a Chern-Simons term.
The mean field theory of Halperin, Lubensky and Ma [Phys. Rev. Lett. 32, 292
(1974)] is applied for this model. It is found that the topological mass,
, drives the system into different regimes of phase transition. For
instance, there is a such that for a
fluctuation induced first order phase transition occurs. On the other hand, for
only the second order phase transition exists. The 1-loop
renormalization group analysis gives further insight to this picture. The fixed
point structure exhibits tricritical and second order fixed points.Comment: Revised version; uses a more physical parametrization of the
renormalization group equations; new references added; one figure added;
EuroLatex, 6 page
A non-perturbative approach to the Coleman- Weinberg mechanism in massless scalar QED
We rederive non-perturbatively the Coleman-Weinberg expression for the
effective potential for massless scalar QED. Our result is not restricted to
small values of the coupling constants. This shows that the Coleman- Weinberg
result can be established beyond the range of validity of perturbation theory.
Also, we derive it in a manifestly renormalization group invariant way. It is
shown that with the derivation given no Landau ghost singularity arises. The
finite temperature case is discussed.
Pacs number: 11.10.Ef,11.10.Gh
Towards a knowledge-based system to assist the Brazilian data-collecting system operation
A study is reported which was carried out to show how a knowledge-based approach would lead to a flexible tool to assist the operation task in a satellite-based environmental data collection system. Some characteristics of a hypothesized system comprised of a satellite and a network of Interrogable Data Collecting Platforms (IDCPs) are pointed out. The Knowledge-Based Planning Assistant System (KBPAS) and some aspects about how knowledge is organized in the IDCP's domain are briefly described
Comportamento de híbridos de coqueiro nos Tabuleiros Costeiros do Piauí.
Com o objetivo de avaliar o comportamento de híbridos de coqueiro nas condições de clima e solo dos Tabuleiros Costeiros do Piauí, conduziu-se um experimento no Campo Experimental da Embrapa Meio-Norte em Parnaíba-PI, no período de 2002 a 2004. Utilizou-se o delineamento experimental de blocos ao acaso, com sete tratamentos e quatro repetições. Os tratamentos foram constituídos por cinco híbridos entre coqueiro-anão e coqueiro-gigante: AAG x GBrPF, AVG x GBrPF, AVeJ x GBrRN, AAG x GOA e AVG x GOA) e os dois parentais (GBrRN e AVeJ) como testemunha. As características vegetativas, avaliadas semestralmente, foram o número de folhas vivas (NFV) emitidas (NFE), e as reprodutivas, avaliadas mensalmente, foram o número de inflorescências emitidas (NIE), número de flores femininas por inflorescência (NFFI) e número de frutos colhidos/planta (NFC). Os híbridos AAG x GBrPF; AVG x GBrP e AVG x GOA apresentam maior potencial de adaptação às condições edafoclimáticas dos Tabuleiros Costeiros do Piauí.bitstream/item/35881/1/BP61.pd
Comportamento de cultivares de coqueiro-anão nos Tabuleiros Costeiros do Piauí.
bitstream/CPAMN-2009-09/20331/1/BOLP60.pd
Microbiological quality of Portuguese yogurts
The microbiological quality of four brands of natural yogurts and two probiotic yogurts available in the Portuguese
market, was evaluated during the shelf-life period. Although the specific flora decreased during storage it was always
within the range of recommended values. No coliforms and an insignificant number of fungi were detected
Multimode Hong-Ou-Mandel Interferometry
We review some recent experiments based upon multimode two-photon
interference of photon pairs created by spontaneous parametric down-conversion.
The new element provided by these experiments is the inclusion of the
transverse spatial profiles of the pump, signal and idler fields. We discuss
multimode Hong-Ou-Mandel interference, and show that the transverse profile of
the pump beam can be manipulated in order to control two-photon interference.
We present the basic theory and experimental results as well as several
applications to the field of quantum information.Comment: 20 pages, 14 figures, Brief Review to be published in Modern Physics
Letters
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