1,024 research outputs found
Supersymmetric non-Abelian noncommutative Chern-Simons theory
In this work, we study the three-dimensional non-Abelian noncommutative
supersymmetric Chern-Simons model with the U(N) gauge group. Using a superfield
formulation, we prove that, for the pure gauge theory, the Green functions are
one-loop finite in any gauge, if the gauge superpotential belongs to the
fundamental representation of ; this result also holds when matter in the
fundamental representation is included. However, the cancellation of both
ultraviolet and ultraviolet/infrared infrared divergences only happens in a
special gauge if the coupling of the matter is in the adjoint representation.
We also look into the finite one-loop quantum corrections to the effective
action: in the pure gauge sector the Maxwell together with its corresponding
gauge fixing action are generated; in the matter sector, the Chern-Simons term
is generated, inducing a shift in the classical Chern-Simons coefficient.Comment: 16 pages, 3 figures, revtex4, enhanced discussion, mainly of the
finite part of quantum corrections, and the shift in the Chern-Simons
coefficien
On the consistency of the three-dimensional noncommutative supersymmetric Yang-Mills theory
We study the one-loop quantum corrections to the U(N) noncommutative
supersymmetric Yang-Mills theory in three spacetime dimensions (NCSYM). We
show that the cancellation of the dangerous UV/IR infrared divergences only
takes place in the fundamental representation of the gauge group. Furthermore,
in the one-loop approximation, the would be subleading UV and UV/IR infrared
divergences are shown to vanish.Comment: 8 pages and 2 figure
Constructions of algebraic lattices
In this work we present constructions of algebraic lattices in Euclidean space with optimal center density in dimensions 2, 3, 4, 6, 8 and 12, which are rotated versions of the lattices Λn, for n = 2,3,4,6,8 and K12. These algebraic lattices are constructed through twisted canonical homomorphism via ideals of a ring of algebraic integers. Mathematical subject classification: 18B35, 94A15, 20H10.49350
Spontaneous breaking of superconformal invariance in (2+1)D supersymmetric Chern-Simons-matter theories in the large N limit
In this work it is studied the spontaneous breaking of superconformal and
gauge invariances in the Abelian N=1,2 three-dimensional supersymmetric
Chern-Simons-matter theories in a large N limit. It is computed the K\"ahlerian
effective superpotential at subleading order and shown that the
Coleman-Weinberg mechanism is the responsible for the dynamical generation of a
mass scale in the N=1 model. This effect appears due to two-loop diagrams that
are logarithmic divergent. In particular, the Coleman-Weinberg mechanism fails
when we lift the N=1 to N=2 Supersymmetric Chern-Simons-Matter model, like what
happens in a perturbative expansion in the coupling constants.Comment: 10 pages, 2 figures, PLB versio
Production of high purity silica by microfluidic-inclusion fracture using microwave pre-treatment
© 2018 Demand for high purity silica used in component manufacture is set to outstrip current supply in the near future. As such, alternative processing routes to feed-stock materials suitable for use in lighting and solar cell fabrication are required, without having to rely on reject material from semi-conductor manufacture. In this work, we report a facile, environmentally friendly method of producing quartz powder with a total residual impurity level of 30 ± 3 ppm from whole pebbles having an initial impurity level of 158 ± 22 ppm. This has been achieved using a metallurgical upgrading process incorporating microwave pre-treatment, crushing and milling, High Intensity Wet Magnetic Separation (HIWMS) and acid leaching. This process yielded a quartz powder having an 80% reduction in residual impurities compared to the untreated quartz pebbles. Pre-treatment of whole quartz pebbles in a multimode microwave cavity for 10 min yielded a reduction of the residual elemental impurity content associated with micro-fluidic inclusion sites containing calcium, potassium and sodium of 84, 78, and 50% respectively. Statistically significant reduction in residual aluminium phases was also observed (83%) compared to the as received material to below the IOTA® specification for Ultra High Pure Quartz produced by Sibleco. Mechanistically, this has been achieved by selectively heating impurity containing micro-fluidic inclusion sites. Resulting in their explosive decrepitation and enabling removal of the impurities in subsequent processing steps. It has been concluded that natural quartz pebbles can be upgraded through a combination of microwave treatment, magnetic and chemical refinement to produce a viable feedstock for the subsequent production of solar grade silicon
Do agri-food market incentives improve food security and nutrition indicators? a microsimulation evaluation for Kenya
The sustainable development goal #2 aims at ending hunger and malnutrition by 2030. Given the numbers of food insecure and malnourished people on the rise, the heterogeneity of nutritional statuses and needs, and the even worse context of COVID-19 pandemic, this has become an urgent challenge for food-related policies. This paper provides a comprehensive microsimulation approach to evaluate economic policies on food access, sufficiency (energy) and adequacy (protein, fat, carbohydrate) at household level. The improvement in market access conditions in Kenya is simulated as an application case of this method, using original insights from households’ surveys and biochemical and nutritional information by food item. Simulation’s results suggest that improving market access increases food purchasing power overall the country, with a pro-poor impact in rural areas. The daily energy consumption per capita and macronutrients intakes per capita increase at the national level, being the households with at least one stunted child under 5 years old, and poor households living areas outside Mombasa and Nairobi, those which benefit the most. The developed method and its Kenya's application contribute to the discussion on how to evaluate nutrition-sensitive policies, and how to cover most households suffering food insecurity and nutrition deficiencies in any given country
On the Geometry of Super Yang-Mills Theories: Phases and Irreducible Polynomials
We study the algebraic and geometric structures that underly the space of
vacua of N=1 super Yang-Mills theories at the non-perturbative level. Chiral
operators are shown to satisfy polynomial equations over appropriate rings, and
the phase structure of the theory can be elegantly described by the
factorization of these polynomials into irreducible pieces. In particular, this
idea yields a powerful method to analyse the possible smooth interpolations
between different classical limits in the gauge theory. As an application in
U(Nc) theories, we provide a simple and completely general proof of the fact
that confining and Higgs vacua are in the same phase when fundamental flavors
are present, by finding an irreducible polynomial equation satisfied by the
glueball operator. We also derive the full phase diagram for the theory with
one adjoint when Nc is less than or equal to 7 using computational algebraic
geometry programs.Comment: 87 pages; v2: typos and eq. (4.44) correcte
On the effective potential in higher-derivative superfield theories
We study the one-loop quantum corrections for higher-derivative superfield
theories, generalizing the approach for calculating the superfield effective
potential. In particular, we calculate the effective potential for two versions
of higher-derivative chiral superfield models. We point out that the
equivalence of the higher-derivative theory for the chiral superfield and the
one without higher derivatives but with an extended number of chiral
superfields occurs only when the mass term is contained in the general
Lagrangian. The presence of divergences can be taken as an indication of this
equivalence.Comment: 14 page
Constructions of algebraic lattices
In this work we present constructions of algebraic lattices in Euclidean space with optimal center density in dimensions 2, 3, 4, 6, 8 and 12, which are rotated versions of the lattices Λn, for n = 2,3,4,6,8 and K12. These algebraic lattices are constructed through twisted canonical homomorphism via ideals of a ring of algebraic integers. Mathematical subject classification: 18B35, 94A15, 20H10
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