Physical Unitarity for Massive Non-abelian Gauge Theories in the Landau Gauge: Stueckelberg and Higgs

We discuss the problem of unitarity for Yang-Mills theory in the Landau gauge with a mass term a la Stueckelberg. We assume that the theory (non-renormalizable) makes sense in some subtraction scheme (in particular the Slavnov-Taylor identities should be respected!) and we devote the paper to the study of the space of the unphysical modes. We find that the theory is unitary only under the hypothesis that the 1-PI two-point function of the vector mesons has no poles (at p^2=0). This normalization condition might be rather crucial in the very definition of the theory. With all these provisos the theory is unitary. The proof of unitarity is given both in a form that allows a direct transcription in terms of Feynman amplitudes (cutting rules) and in the operatorial form. The same arguments and conclusions apply verbatim to the case of non-abelian gauge theories where the mass of the vector meson is generated via Higgs mechanism. To the best of our knowledge, there is no mention in the literature on the necessary condition implied by physical unitarity.Comment: References added. 22 pages. Final version to appear in the journa

Landau-Ginzburg Description of Boundary Critical Phenomena in Two Dimensions

The Virasoro minimal models with boundary are described in the Landau-Ginzburg theory by introducing a boundary potential, function of the boundary field value. The ground state field configurations become non-trivial and are found to obey the soliton equations. The conformal invariant boundary conditions are characterized by the reparametrization-invariant data of the boundary potential, that are the number and degeneracies of the stationary points. The boundary renormalization group flows are obtained by varying the boundary potential while keeping the bulk critical: they satisfy new selection rules and correspond to real deformations of the Arnold simple singularities of A_k type. The description of conformal boundary conditions in terms of boundary potential and associated ground state solitons is extended to the N=2 supersymmetric case, finding agreement with the analysis of A-type boundaries by Hori, Iqbal and Vafa.Comment: 42 pages, 13 figure

Role of chaos for the validity of statistical mechanics laws: diffusion and conduction

Several years after the pioneering work by Fermi Pasta and Ulam, fundamental questions about the link between dynamical and statistical properties remain still open in modern statistical mechanics. Particularly controversial is the role of deterministic chaos for the validity and consistency of statistical approaches. This contribution reexamines such a debated issue taking inspiration from the problem of diffusion and heat conduction in deterministic systems. Is microscopic chaos a necessary ingredient to observe such macroscopic phenomena?Comment: Latex, 27 pages, 10 eps-figures. Proceedings of the Conference "FPU 50 years since" Rome 7-8 May 200

The impact of perceived message complexity and need for cognition on information processing and attitudes

10.1016/j.jrp.2009.04.006Journal of Research in Personality435880-889JRPR

Affective and Cognitive Meta-Bases of Attitudes: Unique Effects on Information Interest and Persuasion

10.1037/0022-3514.94.6.938Journal of Personality and Social Psychology946938-955JPSP

Chronic haloperidol-induced changes in regional dopamine release and metabolism and neurotensin content in rats

Chronic neuroleptic administration has previously been shown to alter in vivo measures of dopaminergic function and lead to regionally selective increases in neurotensin levels. In the current study, female rats were administered chronic haloperidol for 6 months via subcutaneous silastic implants. After 24 weeks of administration, microdialysis probes were inserted into the lateral caudate putamen and the medial prefrontal cortex. Basal samples were collected prior to infusion of a high K+ concentration (100 mM KCI). Extracellular concentrations of dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid were assessed using HPLC. Chronic haloperidol-treated rats showed increased basal dopamine metabolite levels in the caudate putamen and an altered response to the effects of high K+ on 3,4-dihydroxyphenylacetic acid; no significant differences were seen with other analytes in the caudate putamen. Although basal concentrations were not different between groups in the prefrontal cortex, haloperidol-treated rats showed a significant attenuation of response to the effects of high K+ infusion on dopamine metabolite concentrations. Radioimmunoassay measurement of tissue neurotensin content showed highly significant elevations of neurotensin concentrations in the caudate putamen and nucleus accumbens, but not in other brain regions analyzed. These results suggest a confluence of altered dopamine and neurotensin function in the caudate putamen which may be related to motor side effects of haloperidol, whereas changes in prefrontal dopamine function are not associated with altered neurotensin levels