All’interno del Piano Nazionale di Ripresa e Resilienza è previsto il finanziamento di 14 partenariati estesi con l’obiettivo di finanziare progetti di ricerca di base per rafforzare le filiere della ricerca a livello nazionale e promuovere la loro partecipazione alle catene di valore strategiche europee e globali. Durante questo incontro verrà presentato il progetto di partenariato esteso in Scienze e Tecnologie Quantistiche, che verrà implementato attraverso il National Quantum Science and Technology Institute (NQSTI). Si parlerà delle diverse linee di ricerca nelle quali si articola il progetto e del ruolo del nostro Ateneo in questa importante iniziativa.

Simone Severini guidera' una conversazione aperta a tutti su cos'è la computazione quantistica, sulle prospettive delle tecnologie quantistiche e sullo stato dell'arte attuale. Simone gestisce la divisione di Tecnologie Quantistiche per Amazon Web Services (AWS) a Seattle.

High-order harmonics are generated from the interaction of intense femtosecond laser pulses with noble gases. Recently, high-order Harmonic Generation (HHG) led to the realization of table-top sources of coherent XUV and Soft-X Ray radiation. With these sources, ultrafast spectroscopy can be performed with extreme temporal resolutions, down to the attosecond regime (1 as = 10^-18 s), and with the site and chemical selectivity. These features grant access to purely electronic dynamics in molecules and solids and fundamental processes of light-matter interaction. Furthermore, HHG has been successfully used as a spectroscopic tool in the gas phase and condensed matter, allowing the study of electron dynamics in a cation following sudden ionization, all-optical band structure reconstruction, and berry phase retrieval. These findings demonstrate the flexibility and potentiality of this technique.

In this colloquium, I will introduce the principle of high-order harmonic generation as a source of XUV radiation and its application for ultrafast XUV spectroscopy and high-order harmonic spectroscopy. I will also report on the most recent developments in ultrafast XUV spectroscopy based on HHG in the Udyni labs [1] at CNR-IFN.

I will describe our recent developments in efficient XUV generation in microfluidic devices fabricated by femtosecond laser irradiation followed by chemical etching [2]. With this approach, we were able to control the harmonic generation process in the gas on the micro-meter scale with high flexibility, enabling a high photon flux and phase matching on broadband harmonics up to 200 eV. This source is part of a new beamline for transient absorption/reflectivity measurements in molecules and solids. I will also describe the beamline developed for HHG spectroscopy in solids available at CNR-IFN and report on preliminary results in dielectrics and semiconductors.

[1] www.udyni.eu

[2] A. G. Ciriolo et al., J. Phys. Photonics 2, 024005 (2020); https://doi.org/10.1088/2515-7647/ab7d81

[3] A. G. Ciriolo et al., APL Photonics 7, 110801 (2022); https://doi.org/10.1063/5.0118199

Metodi di intelligenza artificiale utilizzati nelle scienze fisiche, dalle transizione di fase fino alle previsioni del meteo in (quasi) tempo reale.
Relatore: Diego Maragnano

Incontro organizzato dall'AISF (Associazione Italiana Studenti di Fisica)

Course contents:

1. Metals and free electron excitations (plasmons); localised and propagating surface plasmons, surface plasmon-polaritons (SPPs).

2. Graphene: crystal structure, chemical bonds, electron energy spectrum and electronic properties; brief overview of other properties and applications.

3. SPPs in graphene-based structures: dispersion relation, excitation methods; working principles of some sensing and optoelectronic devices.

4. Brief introduction to the non-linear optical properties of graphene.

5. (depending on time availability) Nearly 2D semiconductors, the transition metal dichalcogenides (TMDs): electronic properties, excitons, selected applications.

Nanostructures, such a quantum dots or nanoparticles, made of three-dimensional
topological insulators (3DTIs) [1-5] have been recently attracting increasing interest,
especially for their optical properties. We present results for the energy spectrum,
the surface states and the dipole matrix elements for optical transitions with in-
plane polarisation of 3DTI nanowires of finite height L and radius R. We first derive
an effective 2D Hamiltonian by exploiting the cylindrical symmetry of the problem.
We develop two approaches: The first one is an exact numerical tight-binding model
obtained by discretising the Hamiltonian; The second one, which allows us to obtain
analytical results, is an approximated model based on a large-R expansion and on
an effective boundary condition to account for the finite height of the nanowire.
We find that the agreement between the two models, as far as eigenenergies and
eigenfunctions are concerned, is excellent for the lowest absolute value of the
longitudinal component of the angular momentum. Finally, we derive analytical
expressions for the dipole matrix elements by first considering the lateral surface
alone and the bases alone, and then for the whole nanowire. In particular, we focus
on the two limiting cases of tall and squat nanowires. The latter case is compared
with the numerical results finding a good agreement

Titolo
Dall'immagine diagnostica al paziente: evoluzione di un trattamento BNCT

Relatori
I.Postuma, B.Marcaccio, S.Fatemi

Ai confini dell’indivisibile.

Relatori: C.Aimè, D.Rebuzzi, A.Negri

Titolo
Particelle elementari e interazioni fondamentali.

Relatori
E.Budassi, C.Del Pio, A.Gurgone