In the last decades science has witnessed the so-called “Second Quantum Revolution”, by which the now well understood laws of quantum physics, namely the laws of nature at very small scales, are starting to be harnessed for technological applications. Among the most promising of these applications are quantum networks, namely networks, similar to the internet, where information could be transported and processed in much more efficient ways thanks to quantum physics. The design of such networks at a large scale has become a clear objective of global and European research, since achieving this goal would allow, among others, for ultra-fast ad ultra-secure distant communication, or the fabrication of computing systems with much larger computational power.
The most popular approaches to quantum networks and quantum technologies in general are based on light (photons) exchanging quantum information between information nodes such as, for instance, atoms. On the one hand, photons are good information carriers because they propagate fast and lose their quantum properties very slowly. On the other hand, they interact very weakly with atoms and other nodes. This motivates researchers to explore other possible carriers that can be used instead of, or in combination with, photons. Promising but so far unexplored candidates as carriers of quantum information are the “quantum particles of vibration”, called phonons. These phonons are in some aspects similar to photons, as they can propagate relatively fast and lose their quantum properties relatively slowly. However, they can also interact more strongly with other systems, and they could store more quantum information than photons.
In this project, we propose to explore the potential of phonons for quantum technologies. We set three main goals: first, to find, study, and design the “nodes” of a phononic quantum network, equivalent to the atoms in the case of light. Second, to explore the interaction between these nodes and phononic “wires” (waveguides) and how to modify the state of one using the other. Third, to devise particular applications relevant to quantum technologies: for instance, phononic diodes that allow phonons to flow only in one direction, or phononic “bandgaps” where phonons can be stopped at will.
