Multipole Expansion in the Quantum Hall Effect

The effective action for low-energy excitations of Laughlin's states is obtained by systematic expansion in inverse powers of the magnetic field. It is based on the W-infinity symmetry of quantum incompressible fluids and the associated higher-spin fields. Besides reproducing the Wen and Wen-Zee actions and the Hall viscosity, this approach further indicates that the low-energy excitations are extended objects with dipolar and multipolar moments.Comment: 29 pages, 5 figures; v2: comments and references adde

Three-dimensional Topological Insulators and Bosonization

Massless excitations at the surface of three-dimensional time-reversal invariant topological insulators possess both fermionic and bosonic descriptions, originating from band theory and hydrodynamic BF gauge theory, respectively. We analyze the corresponding field theories of the Dirac fermion and compactified boson and compute their partition functions on the three-dimensional torus geometry. We then find some non-dynamic exact properties of bosonization in (2+1) dimensions, regarding fermion parity and spin sectors. Using these results, we extend the Fu-Kane-Mele stability argument to fractional topological insulators in three dimensions.Comment: 54 pages, 11 figure

Out-of-plane dynamic response of a tuff masonry wall. Shaking table testing and numerical simulation

The out-of-plane dynamic response of a masonry element is investigated, both experimentally and numerically. The results of shaking table tests on a tuff masonry wall, subjected to harmonic acceleration histories, are presented. An isotropic nonlocal damage-plastic model, accounting for the masonry strength-stiffness degrading and hysteresis mechanisms, is introduced in a finite element procedure to numerically describe the masonry structural response. A simplified scheme is analysed, where the wall is completely restrained at the base and free at the top. The measured top displacement history is compared with that numerically evaluated, obtaining a satisfactory agreement. Moreover, the effects of the onset and evolution of the degrading mechanisms in the masonry wall are highlighted

Innovative olive tree leaves shredder prototype for the valorization of wasted leaves: An application to high-quality compost production

Extra virgin olive oil is considered worldwide as one of the most important products, a standard bearer of the Mediterranean diet. Despite this, the production chain of extra virgin olive oil generates four times more waste than quantity of oil. For this reason, the disposal of olive mill wastes represents a significant environmental problem in all the Mediterranean countries. In this direction, several innovations and improvement strategies were proposed in the literature to correctly manage these by-products and, in some cases, to valorize them by the recovery of polyphenols and other interesting substances. However, innovations and improvement strategies for the valorization of olive tree leaves are definitely neglected in the literature, thus motivating this work. The aims of this work are as follow: firstly, to develop and test an innovative olive tree leaves shredder prototype to help olive oil millers in the management of waste leaves deriving from pruning and olive oil production; secondly, to test the combination of the minced olive tree leaves with other by-products in the production of high-quality compost. The results showed the effectiveness of the tested olive tree leaves shredder in significantly reducing the volume occupied by the leaves by 40%. Moreover, the mixing of the minced olive tree leaves with other by-products lead to a high-quality compost which, in accordance with Italian legislation, could even be certified and labeled with this denomination. Future research will investigate the quantification of the benefits in terms of environmental impacts using life cycle assessment