Scaling behaviour of trapped bosonic particles in two dimensions at finite temperature

In the framework of the trap-size scaling theory, we study the scaling properties of the Bose-Hubbard model in two dimensions in the presence of a trapping potential at finite temperature. In particular, we provide results for the particle density and the density-density correlator at the Mott transitions and within the superfluid phase. For the former quantity, numerical outcomes are also extensively compared to Local Density Approximation predictions.Comment: 8 pages, 9 figure

High loop renormalization constants by NSPT: a status report

We present an update on Numerical Stochastic Perturbation Theory projects for Lattice QCD, which are by now run on apeNEXT. As a first issue, we discuss a strategy to tackle finite size effects which can be quite sizeable in the computation of logarithmically divergent renormalization constants. Our first high loop determination of quark bilinears for Wilson fermions was limited to finite constants and finite ratios. A precise determination of Z_P and Z_S (and hence of Z_m) now becomes possible. We also give an account of computations for actions different from the standard regularization we have taken into account so far (Wilson gauge action and Wilson fermions). In particular, we present the status of computations for the Lattice QCD regularization defined by tree level Symanzik improved gauge action and Wilson fermions, which became quite popular in recent times. We also take the chance to discuss the related topic of the computation of the gluon and ghost propagators (which we undertook in collaboration with another group). This is relevant in order to better understand non-perturbative computations of propagators aiming at qualitative/quantitative understanding of confinement.Comment: 7 pages, poster presented at the XXV International Symposium on Lattice Field Theory, July 30 - August 4 2007, Regensburg, German

The Labyrinths of Venice: Environment and Identity in Anna Pavignano\u27s Novel Venezia, un sogno and Other Works in Literature and Film

This dissertation consists of the translation of Anna Pavignano\u27s novel Venezia, un sogno and of an essay presenting a comment and critical analysis of the work. The essay itself is divided into the following sections: --An introduction to my translation of Venezia, un sogno and a reflection on my choice of Venice as a setting and background for my dissertation work. --An introduction to the author and a description of her previous works. --A discussion on the theory of translation and its challenges. --A comparison between Venezia, un sogno and other literary and cinematic works set in Venice with a focus on the way the city of Venice lends itself to affecting, or in some cases, even transforming the identity of the main characters of related novels and films. --An exploration of the cinematographic aspects of Anna Pavignano\u27s novel and my challenges in translating its unusual colloquial style while maintaining fidelity to the original. --An afterthought and comment on the book\u27s general reception and the significance of its focus on environmental issues. Venezia, un sogno, Anna Pavignano\u27s third novel, was written after she had worked mostly as a screenwriter for Massimo Troisi\u27s films and was nominated for an Oscar for Il postino . The essay discusses the concept of identity in individuals removed from their hometown either by choice (as in the case of Pavignano\u27s main character Thomas) or by necessity (as in the case of individuals forced by financial, social, or military reasons). The city of Venice plays a major role in affecting this identity. The essay calls especial attention to the significance of environmental and social issues. An essential component to the development of part of the dissertation is the repeated reference to films and other works of literature connected to the novel. The themes of love, betrayal, and death are present in all these works and are used as points of comparison between Venezia, un sogno and other literary references. These include works that are represented as both novels and films such as Ian McEwan\u27s novel and Paul Schrader\u27s film The Comfort of Strangers, Daphne du Maurier\u27s novel and Nicholas Roeg\u27s film Don\u27t Look Now, Camillo Boito\u27s novella and Luchino Visconti\u27s film Senso , as well as Gabriele D\u27Annunzio\u27s novel Il fuoco. Particular attention is given to Thomas Mann\u27s novella Death in Venice and Luchino Visconti\u27s film of the same title, as well as Giuseppe Berto\u27s novel and Enrico Maria Salerno\u27s film Anonimo veneziano. The latter two play a major role in my essay. Finally, two further elements of this section of my dissertation concentrate firstly on the authors\u27s use of a colloquial style, including the regular use of idiomatic expressions and dialect which made the translation more challenging, and secondly, on the book\u27s potential for being reproduced as a film

Four-loop lattice-regularized vacuum energy density of the three-dimensional SU(3) + adjoint Higgs theory

The pressure of QCD admits at high temperatures a factorization into purely perturbative contributions from "hard" thermal momenta, and slowly convergent as well as non-perturbative contributions from "soft" thermal momenta. The latter can be related to various effective gluon condensates in a dimensionally reduced effective field theory, and measured there through lattice simulations. Practical measurements of one of the relevant condensates have suffered, however, from difficulties in extrapolating convincingly to the continuum limit. In order to gain insight on this problem, we employ Numerical Stochastic Perturbation Theory to estimate the problematic condensate up to 4-loop order in lattice perturbation theory. Our results seem to confirm the presence of "large" discretization effects, going like $a\ln(1/a)$, where $a$ is the lattice spacing. For definite conclusions, however, it would be helpful to repeat the corresponding part of our study with standard lattice perturbation theory techniques.Comment: 35 pages. v2: minor corrections, published versio