Algebraic Characterization of Vector Supersymmetry in Topological Field Theories

An algebraic cohomological characterization of a class of linearly broken Ward identities is provided. The examples of the topological vector supersymmetry and of the Landau ghost equation are discussed in detail. The existence of such a linearly broken Ward identities turns out to be related to BRST exact antifield dependent cocycles with negative ghost number.Comment: 30 pages, latex2e file, subm. to Journ. of Math. Phy

Laser surfasse patterning using a Michelson interferometer and a femtosecond laser radiation

We report on a simple method to obtain surface gratings using a Michelson interferometer and femtosecond laser radiation. In the optical setup used, two parallel laser beams are generated using a beam splitter and then focused using the same focusing lens. An interference pattern is created in the focal plane of the focusing lens, which can be used to pattern the surface of materials. The main advantage of this method is that the optical paths difference of the interfering beams is independent of the distance between the beams. As a result, the fringes period can be varied without a need for major realignment of the optical system and the time coincidence between the interfering beams can be easily monitored. The potential of the method was demonstrated by patterning surface gratings with different periods on titanium surfaces in air

On the Renormalizability of Noncommutative U(1) Gauge Theory - an Algebraic Approach

We investigate the quantum effects of the nonlocal gauge invariant operator $\frac{1}{{}{D}^{2}}{F}_{\mu \nu}\ast \frac{1}{{}{D}^{2}}{F}^{\mu \nu}$ in the noncommutative U(1) action and its consequences to the infrared sector of the theory. Nonlocal operators of such kind were proposed to solve the infrared problem of the noncommutative gauge theories evading the questions on the explicit breaking of the Lorentz invariance. More recently, a first step in the localization of this operator was accomplished by means of the introduction of an extra tensorial matter field, and the first loop analysis was carried out $(Eur.Phys.J.\textbf{C62}:433-443,2009)$. We will complete this localization avoiding the introduction of new degrees of freedom beyond those of the original action by using only BRST doublets. This will allow us to make a complete BRST algebraic study of the renormalizability of the theory, following Zwanziger's method of localization of nonlocal operators in QFT.Comment: standard Latex no figures, version2 accepted in J. Phys A: Math Theo

Let's Twist Again: N=2 Super Yang Mills Theory Coupled To Matter

We give the twisted version of N=2 Super Yang Mills theory coupled to matter, including quantum fields, supersymmetry transformations, action and algebraic structure. We show that the whole action, coupled to matter, can be written as the variation of a nilpotent operator, modulo field equations. An extended Slavnov-Taylor identity, collecting gauge symmetry and supersymmetry, is written, which allows to define the web of algebraic constraints, in view of the algebraic renormalization and of the extension of the non-renormalization theorems holding for N=2 SYM theory without matter.Comment: 28 pages, final version to be published on CQ

General Solution Of Linear Vector Supersymmetry

We give the general solution of the Ward identity for the linear vector supersymmetry which characterizes all topological models. Such solution, whose expression is quite compact and simple, greatly simplifies the study of theories displaying a supersymmetric algebraic structure, reducing to a few lines the proof of their possible finiteness. In particular, the cohomology technology usually involved for the quantum extension of these theories, is completely bypassed. The case of Chern-Simons theory is taken as an example.Comment: 18 pages, LaTeX, no figure

Renormalizability of Nonrenormalizable Field Theories

We give a simple and elegant proof of the Equivalence Theorem, stating that two field theories related by nonlinear field transformations have the same S matrix. We are thus able to identify a subclass of nonrenormalizable field theories which are actually physically equivalent to renormalizable ones. Our strategy is to show by means of the BRS formalism that the "nonrenormalizable" part of such fake nonrenormalizable theories, is a kind of gauge fixing, being confined in the cohomologically trivial sector of the theory.Comment: 3 pages, revtex, no figure

Performance of hybrid systems coupling advanced oxidation processes and ultrafiltration for oxytetracycline removal

In this study, the efficiency of three different hybrid systems coupling ultrafiltration (UF) with (i) UVC/H2O2, (ii) UVC/TiO2, and (iii) UVC was evaluated for the treatment of a secondary effluent (SE) from a municipal wastewater treatment plant and a surface water (SW) from Miedwie Lake, both spiked with 5 mg L-1 of oxytetracycline (OTC). A ceramic membrane made of TiO2 was tested. The effect of H2O2 concentration (30 to 120 mg L-1) on the UVC/H2O2-UF system and of P25-TiO2 loading (0.5 to 1.5 g L-1) in suspension on the photocatalytic UVC/TiO2-UF system were investigated. A photonic flux of 5.1 J s(-1) was provided in all systems. The maximum pure water flux (PWF) was 111 L m(-2) h(-1). Adsorption on the photocatalyst particles and/or on the membrane surface was found to be an important contribution for the removal of OTC and dissolved organic carbon (DOC). The UF membrane contributed significantly to photocatalyst and pollutants rejection in the photocatalytic membrane reactor (PMR) with the UVC/TiO2 system; whereas when using the UVC/H2O2 process, with the highest H2O2 dose, the membrane effect was negligible. Using SE as reaction matrix in the UVC/ TiO2-UF system with 1.0 g L-1 of TiO2, the complete OTC removal was achieved in 5 h with a mineralization of 49%. For the same reaction period, a DOC removal of 52% was achieved with the UVC/H2O2-UF system (120 mg H2O2 L-1). A similar permeate flux decrease (ca. 40%) was observed in both cases. Furthermore, the highest reduction of permeate flux (60%) was observed when using the UVC-UF system. Using SW as reaction matrix, higher OTC degradation rates and percentage of mineralization were reached for the same reaction period, when compared with SE, due to the lower COD and inorganic salts concentration present in the surface water