Topological aspects in non-Abelian gauge theory

We discuss the BRST cohomology and exhibit a connection between the Hodge decomposition theorem and the topological properties of a two dimensional free non-Abelian gauge theory having no interaction with matter fields. The topological nature of this theory is encoded in the vanishing of the Laplacian operator when equations of motion are exploited. We obtain two sets of topological invariants with respect to BRST and co-BRST charges on the two dimensional manifold and show that the Lagrangian density of the theory can be expressed as the sum of terms that are BRST- and co-BRST invariants.Comment: (1+11) pages, LaTeX, no figure

Verso un sistema integrato di documentazione dell’arte rupestre. L’esperienza AKAP (Egitto)

Since 2005 the Aswan-Kom Ombo Archaeological Project (AKAP), managed by Yale and Bologna Universities, has investigated a number of selected areas in the region between Aswan and Kom Ombo. Many of the rock art sites identified within the concession areas are under threat, due to the impact of modern human activities. Three-dimensional technologies, such as digital surveying, laser scanning and photogrammetry, were used for the first time in the Egyptian Nile Valley in order to obtain a highly detailed image of the rock art and its environmental setting. The aim of the project is to improve data recording and analysis while saving economic resources and reducing time in the fieldwork

Playing the flashbulb memory game: A comment on Cubelli and Della Sala

Flashbulb memory (FBM) is a term coined in 1977 by Brown and Kulik referring to vivid, detailed, and long-lasting memories for the reception context of important public events. Across the years, different authors have tried to establish that FBMs either exist or are virtually indistinguishable from ordinary autobiographical memory formations. In the present study we review studies in favour/against the FBM hypothesis focusing on two main issues: First, FBM accuracy appears to be difficult if not impossible to prove; secondly memory distortions and forgetting do not exclude that FBMs are formed and maintained. Personal and social consequentiality are considered to be crucial factors in determining real FBMs, although reconstructive processes also operate on these formations. We finally propose that, striving to play a kind of FBM game, researchers have sometimes failed to focus on real FBMs, misinterpreting the meaning of the camera metaphor and adopting research strategies open to criticisms and invalidation

N=1 Super Yang-Mills on the Lattice in the Strong Coupling Limit

We study the N=1 supersymmetric SU(N) Yang-Mills theory on the lattice at strong coupling. We analyse and discuss the recent results obtained at strong coupling and large N for the mesonic and fermionic propagators and spectrum.Comment: Latex 3 pages. Contribution to the Lattice99 Proceeding

Superfield Approach To Nilpotent Symmetries For QED From A Single Restriction: An Alternative To The Horizontality Condition

We derive together the exact local, covariant, continuous and off-shell nilpotent Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for the U(1) gauge field (A_\mu), the (anti-)ghost fields ((\bar C)C) and the Dirac fields (\psi, \bar\psi) of the Lagrangian density of a four (3 + 1)-dimensional QED by exploiting a single restriction on the six (4, 2)-dimensional supermanifold. A set of four even spacetime coordinates x^\mu (\mu = 0, 1, 2, 3) and two odd Grassmannian variables \theta and \bar\theta parametrize this six dimensional supermanifold. The new gauge invariant restriction on the above supermanifold owes its origin to the (super) covariant derivatives and their intimate relations with the (super) 2-form curvatures (\tilde F^{(2)})F^{(2)} constructed with the help of (super) 1-form gauge connections (\tilde A^{(1)})A^{(1)} and (super) exterior derivatives (\tilde d)d. The results obtained separately by exploiting (i) the horizontality condition, and (ii) one of its consistent extensions, are shown to be a simple consequence of this new single restriction on the above supermanifold. Thus, our present endeavour provides an alternative to (and, in some sense, generalization of) the horizontality condition of the usual superfield formalism applied to the derivation of BRST symmetries.Comment: LaTeX file, 15 pages, journal-versio

Hybrid Molecular Dynamics for Lattice Supersymmetry

We present the first results obtained with a Hybrid Molecular Dynamics algorithm applied to an $N=1$ SU(2) Super-Yang--Mills on the lattice. We derive the Hamilton equations of motion for the system with Wilson gluinos and present preliminary results on small lattices.Comment: 8 pages, uuencoded file containing latex source and two ps figure

Interacting Vector-Spinor and Nilpotent Supersymmetry

We formulate an interacting theory of a vector-spinor field that gauges anticommuting spinor charges \{Q_\alpha{}^I, Q_\beta{}^J \} = 0 in arbitrary space-time dimensions. The field content of the system is (\psi_\mu{}^{\alpha I}, \chi^{\alpha I J}, A_\mu{}^I), where \psi_\mu{}^{\alpha I} is a vector-spinor in the adjoint representation of an arbitrary gauge group, and A_\mu{}^I is its gauge field, while \chi^{\alpha I J} is an extra spinor with antisymmetric adjoint indices I J. Amazingly, the consistency of the vector-spinor field equation is maintained, despite its non-trivial interactions.Comment: 10 pages, no figure

Limits on Lorentz Violation from the Highest Energy Cosmic Rays

We place several new limits on Lorentz violating effects, which can modify particles' dispersion relations, by considering the highest energy cosmic rays observed. Since these are hadrons, this involves considering the partonic content of such cosmic rays. We get a number of bounds on differences in maximum propagation speeds, which are typically bounded at the 10^{-21} level, and on momentum dependent dispersion corrections of the form v = 1 +- p^2/Lambda^2, which typically bound Lambda > 10^{21} GeV, well above the Planck scale. For (CPT violating) dispersion correction of the form v = 1 + p/Lambda, the bounds are up to 15 orders of magnitude beyond the Planck scale.Comment: 24 pages, no figures. Added references, very slight changes. Version published in Physical Review

An experimental investigation of the misinformation effect in crime-related amnesia claims

Research suggests that both internal (i.e., lying) and external (i.e., misinformation) factors can affect memory for a crime. We aimed to explore the effects of post-event misinformation on crime-related amnesia claims. We showed participants a mock crime and asked them to either simulate amnesia (simulators) or confess to it (confessors). Next, some participants were provided with misinformation. Finally, all participants were requested to genuinely recollect the crime. Overall, simulators reported less correct information than confessors. Moreover, these two groups were equally vulnerable to misinformation. In addition, exploratory analyses on strategies adopted by simulators revealed that those who previously, mostly omitted information while simulating amnesia exhibited the lowest amount of correct details. Simulators who instead used a mixed strategy disclosed more fabricated memory errors. Findings suggest that legal professionals and jurors should take into account that even offenders, irrespective of confessing or simulating memory loss for a crime, can be susceptible to post-event misinformation

Quenched Supersymmetry

We study the effects of quenching in Super-Yang-Mills theory. While supersymmetry is broken, the lagrangian acquires a new flavour $U(1 \mid 1)$ symmetry. The anomaly structure thus differs from the unquenched case. We derive the corresponding low-energy effective lagrangian. As a consequence, we predict the mass splitting expected in numerical simulations for particles belonging to the lowest-lying supermultiplet.Comment: LATTICE98(yukawa), minor change