JCMS: Sequential quantum protocols and measurement correlations

by Giulio Foletto

Monday 6 Oct 2025, 11:00 → 12:00 Europe/Stockholm

Albano 3: 6228 - Mega (22 seats) (Albano Building 3)

Speaker: Giulio Foletto (KTH) Abstract: Several quantum information protocols, often applied in cryptography, exploit nonclassical correlations between measurement outcomes to obtain classical resources such as random numbers or keys. The paradigmatic example is the violation of a Bell inequality, which proves nonlocality and ensures the intrinsic randomness of the results. This relies solely on the correlation between measurement outcomes, with only broad assumptions on their generation. This independence from the specific functioning of the physical devices producing the correlations is appealing, as it reduces the need for detailed device characterization. Therefore, discovering methods to achieve these nonclassical correlations is both practically valuable and aids in exploring the intricate and fundamental connection between randomness and quantum features. Sequential protocols have recently drawn interest because they enable stronger nonclassical correlations by repeatedly measuring the same quantum state. Practically, this means extracting more resources from a single physical system; fundamentally, it indicates that quantum properties can endure multiple measurements. This talk gives an overview of sequential protocols in this context and presents recent works that investigate them experimentally.