Una Finestra su: Tirana

L'Albania è nel mezzo di una profonda crisi identitaria. La tesi viene esposta attraverso una lettura dell’ambiente costruito in una particolare area tra Tirana e Durazzo, caratterizzata da una mistura di stili arhitettonici, presi in prestito da luoghi e tempi diversi. Le immagini che accompagnano questo articolo forniscono testimonianza visiva di questo cammino identitario del popolo albanese

Real-time extraction of growth rates from rotating substrates during molecular-beam epitaxy

We present a method for measuring molecular‐beam epitaxy growth rates in near real‐time on rotating substrates. This is done by digitizing a video image of the reflection high‐energy electron diffraction screen, automatically tracking and measuring the specular spot width, and using numerical techniques to filter the resulting signal. The digitization and image and signal processing take approximately 0.4 s to accomplish, so this technique offers the molecular‐beam epitaxy grower the ability to actively adjust growth times in order to deposit a desired layer thickness. The measurement has a demonstrated precision of approximately 2%, which is sufficient to allow active control of epilayer thickness by counting monolayers as they are deposited. When postgrowth techniques, such as frequency domain analysis, are also used, the reflection high‐energy electron diffraction measurement of layer thickness on rotating substrates improves to a precision of better than 1%. Since all of the components in the system described are commercially available, duplication is straightforward

Mueller-Navelet jets in high-energy hadron collisions

We consider within QCD collinear factorization the process $p+p\to {\rm jet} +{\rm jet} +X$, where two forward high-$p_T$ jets are produced with a large separation in rapidity $\Delta y$ (Mueller-Navelet jets [1]). The hard part of the reaction receives large higher-order corrections $\sim \alpha^n_s (\Delta y)^n$, which can be accounted for in the BFKL approach. We calculate cross section and azimuthal decorrelation, using the next-to-leading order jet vertices, in the small-cone approximation [2].Comment: 4 pages, 3 figures; presented at the International Workshop "Diffraction 2012", Puerto del Carmen (Spain), September 10-15, 201

The next-to-leading order jet vertex for Mueller-Navelet and forward jets revisited

We recalculate, completely within the original BFKL approach and at the next-to-leading order, the jet vertex relevant for the production of Mueller-Navelet jets in proton collisions and of forward jets in DIS. We consider both processes with incoming quark and gluon. The starting point is the definition of quark and gluon impact factors in the BFKL approach. Following this procedure we show explicitly that all infrared divergences cancel when renormalized parton densities are considered. We compare our results for the vertex with the former calculation of Refs. [1,2] and, in the case of the quark contribution, clarify the discrepancy present in the literature.Comment: 28 pages, 3 figures; a few references added; modified Abstract, Introduction and Summary to take into account that the equivalence between the results of Bartels et al. (Refs.[1,2]) and those of Colferai et al. (Ref.[23]) has been establishe

Edge Magnetoplasmons in Quantum Hall Line Junction Systems

A quantum Hall line junction system consists of a one-dimensional Luttinger liquid (LL) and two chiral channels that allow density waves incident upon and reflected by the LL to be measured separately. We demonstrate that interactions in a quantum Hall line junction system can be probed by studying edge magnetoplasmon absorption spectra and their polarization dependences. Strong interactions in the junction lead to collective modes that are isolated in either Luttinger liquid or contact subsystems.Comment: 4 pages, 3 figures, submitted to Phys. Rev. B Rapid Communicatio