This is a joint experimental and theoretical research program, focusing on the elementary excitations of liquid helium in disordered environments and confined geometries. The aim is to investigate the effect of disorder and confinement on the fundamental physics of quantum fluids, with particular emphasis on superfluidity, Bose-Einstein condensation and disorder-driven localization. The experimental part consists of precision neutron scattering measurements on liquid helium in Vycor, aerogels and xerogels. The theoretical part, in parallel, will determine accurate path-integral Monte-Carlo simulations of realistic models of disordered liquid helium. %%% This is a joint experimental and theoretical research program, devoted to the study of quantum fluids in disordered environments. The goal is to gain understanding of the effect of disorder on microscopic physical phenomena relevant to materials science and technology. To this aim, the simplest quantum fluid, namely liquid helium, will be investigated experimentally in disordered systems such as Vycor, by means of precision neutron scattering measurements; in parallel, state-of-the art computer simulations on realistic models will be carried out. ***
