Thin helium film on a glass substrate

We investigate by Monte Carlo simulations the structure, energetics and superfluid properties of thin helium-four films (up to four layers) on a glass substrate, at low temperature. The first adsorbed layer is found to be solid and "inert", i.e., atoms are localized and do not participate to quantum exchanges. Additional layers are liquid, with no clear layer separation above the second one. It is found that a single helium-three impurity resides on the outmost layer, not significantly further away from the substrate than helium-four atoms on the same layer.Comment: Six figures, submitted for publication to the Journal of Low Temperature Physic

On the possible "supersolid" character of parahydrogen clusters

We present results of a theoretical study of structural and superfluid properties of parahydrogen clusters comprising 25, 26 and 27 molecules at low temperature. The microscopic model utilized here is based on the Silvera-Goldman pair potential. Numerical results are obtained by means of Quantum Monte Carlo simulations, making use of the continuous-space Worm Algorithm. The clusters are superfluid in the low temperature limit, but display markedly different physical behaviours. For N=25 and 27, superfluidity at low temperature arises as clusters melt, i.e., become progressively liquid-like as a result of quantum effects. On the other hand, for N = 26 the cluster remains rigid and solid-like. We argue that this cluster can be regarded as a mesoscopic "supersolid". This physical picture is supported by results of simulations in which a single parahydrogen molecule in the cluster is isotopically substituted.Comment: 18 pages, 7 figure

The Italian Draft Law on the \u2018Provisions Concerning the Safeguarding of the Intangible Cultural Heritage\u2019

Intangible cultural heritage in Italy is still in need of a unified approach, capable of providing reliable criteria for identifying its assets and for indicating timescales and means by which they should be safeguarded. In the continued absence of up-to-date, ad hoc state legislation (since the content of those laws which do implement international Conventions is too generic in nature to be sufficiently effective), the Regions have proceeded to act in a somewhat scattered manner, giving rise to an extremely fragmented and very disorderly regulatory framework. The draft law N. 4486, "Provisions Concerning the Safeguarding of the Intangible Cultural Heritage", presented on 12th May 2017 at the Chamber of Deputies of the Italian Republic - as the result of the work of an interdisciplinary and inter-university research team coordinated by Marco Giampieretti, who has drafted the final text with the collaboration of Simona Pinton - seeks to fill the serious void that exists in Italian legal system by aligning it to the principles of international and European law, by redirecting the relevant State and Regional legislation, and by satisfying the fundamental requirements of the national community