Francesco Albergamo

High-frequency dynamics in metallic glasses

Using inelastic x-ray scattering we studied the collective dynamics of the glassy alloy Ni33Zr67 in the first pseudo-Brillouin-zone, an energy-momentum region still unexplored in metallic glasses. We determine key properties such as the momentum transfer dependence of the sound velocity and of the acoustic damping, discussing the results in the general context of recently proposed pictures for acoustic dynamics in glasses. Specifically, we demonstrate the existence in this strong glass of well defined (in the Ioffe-Regel sense) acoustic-like excitations well above the boson peak energy.

Collective excitations in liquid D2 confined within the mesoscopic pores of a MCM-41 molecular sieve

We present a comparative study of the excitations in bulk and liquid

Zero Sound Mode in Normal Liquid {sup 3}He

{\mathrm{D}}_{2}

Excitations in liquid 4 He in Geltech silica and localized Bose condensation

confined within the pores of MCM-41. The material (Mobile Crystalline Material-41) is a silicate obtained by means of a template that yields a partially crystalline structure composed by arrays of nonintersecting hexagonal channels of controlled width having walls made of amorphous

Zero sound mode in normal liquid 3He.

{\mathrm{SiO}}_{2}

Phonon-roton excitations in liquid 4He at negative pressures.

. Its porosity was characterized by means of adsorption isotherms and found to be composed by a regular array of pores having a narrow distribution of sizes with a most probable value of

Condensate fraction and atomic kinetic energy of liquid 3He-4He mixtures

2.45\phantom{\rule{0.3em}{0ex}}\mathrm{nm}

Elementary excitations in liquid 4 He confined in MCM-41

. The assessment of the precise location of the sample within the pores is carried out by means of pressure isotherms. The study was conducted at two pressures which correspond to pore fillings above the capillary condensation regime. Within the range of wave vectors where collective excitations can be followed up

Excitations of liquid 4 He in disorder and boson localization

(0.3\ensuremath{\leqslant}Q\ensuremath{\leqslant}3.0\phantom{\rule{0.3em}{0ex}}{\mathrm{\AA{}}}^{\ensuremath{-}1})

Albergamo etal. Reply

, we found confinement brings forward a large shortening of the excitation lifetimes that shifts the characteristic frequencies to higher energies. In addition, the coherent quasielastic scattering shows signatures of reduced diffusivity.