Ricerc@Sapienza

The relentless progress in the field of photonic quantum technologies has revealed how powerful the paradigm of encoding information in single particles of light is. Several institutions around the world are investing in facilities to host quantum networks, motivated by advantages in secure communication and distributed computing. Whether this vision will ultimately lead to a quantum internet, it depends on the development of basic hardware elements with several crucial features - device scalability, on-demand operation and entanglement distribution above all.
While no operating quantum network is currently based in Italy, Sapienza hosts a unique set of different know-hows in quantum communication. By merging quantum optics, nanoscale optoelectronics, and nonlinear photonics we envision the opportunity of building an original approach to quantum networking.
We propose the development of a free-space optical communication system connecting the Marconi and Fermi buildings of the Physics Department at Sapienza. The infrastructure transfers quantum signals with minimal losses in an urban environment and is easily interfaced with existing equipment for the generation and detection of photons. Its purpose is to support entanglement distribution between the two end nodes with high channel fidelity. While this enables functionalities beyond first-generation quantum networks, we also devise a strategy aimed at scaling down the basic building blocks of the network, combining semiconductor nanostructures for signal generation and integrated photonic circuits for processing. The challenge of facing realistic conditions involving atmospheric turbulence is backed up by strong theoretical expertise in the modeling of optical wave propagation in non-linear media. The successful demonstration of a quantum link between the Marconi and Fermi buildings will open the way towards the construction of a functional quantum network at Sapienza, the first in an Italian University.