Data / Hora
Date(s) - 30/06/2022
17:00
Categorias
Quantum Non-Locality in Networks
Prof. Nicolas Gisin
Group of Applied Physics, University of Geneva, Switzerland
Conectem no “zoom” com o seguinte link para assistir o seminário:
https://puc-rio.zoom.us/j/96015223853?pwd=UDBGMGxuWmRqWkMwUnVSckxMbDVXdz09Meeting
ID: 960 1522 3853
Passcode: 979585
Quantum non-locality, i.e. the violation of some Bell inequality, has proven to be an extremely useful concept in analyzing entanglement, quantum randomness and cryptography, among others. In particular, it led to the fascinating field of device-independent quantum information processing. Historically, the idea was that the particles emitted by various quantum sources carry additional variables, known as local hidden variables. The more modern view, strongly influenced by computer science, refers to these additional variables as shared randomness. This, however, leads to ambiguity when there is more than one source, as in quantum networks. Should the randomness produced by each source be considered as fully correlated, as in most common analyses, or should one analyze the situation assuming that each source produces independent randomness, closer to the historical spirit? The latter is known, for the case of n independent sources, as n-locality. For example, in entanglement swapping there are two sources, hence “quantumness” should be analyzed using 2 locality (or, equivalently, bi-locality). The situation when the network has loops is especially interesting. Recent results for triangular networks will be presented.