7,813 research outputs found
Detection of Spiral photons in Quantum Optics
We show that a new type of photon detector, sensitive to the gradients of
electromagnetic fields, should be a useful tool to characterize the quantum
properties of spatially-dependent optical fields. As a simple detector of such
a kind, we propose using magnetic dipole or electric quadrupole transitions in
atoms or molecules and apply it to the detection of spiral photons in
Laguerre-Gauss (LG) beams. We show that LG beams are not true hollow beams, due
to the presence of magnetic fields and gradients of electric fields on beam
axis. This approach paves the way to an analysis at the quantum level of the
spatial structure and angular momentum properties of singular light beams.Comment: 5 pages, 4 figure
Doenças do girassol.
Mancha de Alternaria - Alternaria spp.; Podridao branca - Sclerotinia sclerotiorum (Lib.) de Bary; Mildio - Plasmopara halstedii (Farl.) Berl. & de Toni; Ferrugem - Puccinia helianthi Schw.; Bolha branca - Albugo tragopogi (Pers.) Schroet; Oidio - Erysiphe cichoracearum DC; Mancha cinzenta da haste - Phomopsis helianthi Munth. - Cvet. et al.; Mancha preta da haste - Phoma oleracea var. helianthi tuberosi Sacc.; Outras podridoes radiculares e murchas - Sclerotium rolfsii Sacc., Macrophomina phaseolina (Tass.) Goid e Verticillium dahliae Klebahn; Podridao cinza do capitulo - Botrytis cinerea Pers. ex Fr.; Mancha bacteriana e crestamento bacteriano - Pseudomonas syringae pv. helianthi (Kawamura) Dye, Wilkie et Young; Pseudomonas cichorii (Swingle) Stapp; Podridao da medula da haste - Erwinia sp.; Mosaico comum do girassol - virus do mosaico do picao ("sunflower mosaic virus"); Controle de doencas.bitstream/item/40506/1/Doencas-do-girassol.pd
Variabilidade de Alternaria helianthi e avaliação da resistência de girassol `a mancha de Alternaria (06.04.02.334.03).
Topological Dilatonic Supergravity Theories
We present a central extension of the super-Poincar\'e algebra in two
dimensions. Besides the usual Poincar\'e generators and the
supersymmetry generators we have Grassmann generators, a bosonic
internal symmetry generator and a central charge. We then build up the
topological gauge theory associated to this algebra. We can solve the classical
field equations for the fields which do not belong to the supergravity
multiplet and to a Lagrange multiplier multiplet. The resulting topological
supergravity theory turns out to be non-local in the fermionic sector.Comment: 11 pages, plain TeX, IFUSP-P/112
Specific heat amplitude ratios for anisotropic Lifshitz critical behaviors
We determine the specific heat amplitude ratio near a -axial Lifshitz
point and show its universal character. Using a recent renormalization group
picture along with new field-theoretical -expansion techniques,
we established this amplitude ratio at one-loop order. We estimate the
numerical value of this amplitude ratio for and . The result is in
very good agreement with its experimental measurement on the magnetic material
. It is shown that in the limit it trivially reduces to the
Ising-like amplitude ratio.Comment: 8 pages, RevTex, accepted as a Brief Report in Physical Review
Numerical solution of linear models in economics: The SP-DG model revisited
In general, complex and large dimensional models are needed to solve real economic problems. Due to these characteristics, there is either no analytical solution for them or they are not attainable. As a result, solutions can be only obtained through numerical methods. Thus, the growing importance of computers in Economics is not surprising. This paper focuses on an implementation of the SP-DG model, using Matlab,developed by the students as part of the Computational Economics course. We also discuss some of our teaching/learning experience within the course, given for the first time in the FEP Doctoral Programme in Economics.SP-DG Model, Output, Inflation, Numerical Simulation, Teaching of Economics
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