Quantum Probability Team 
Workshops and Seminars
(for other seminars related to Quantum Information in the
"CittÃ Studi" area see also Open Systems & Quantum Information Seminars)
13  02  2018 ore 14:30  Aula Seminari III piano Caterina Foti (UniversitÃ degli Studi di Firenze): Macroscopic quantum systems & Measuring apparatuses The emergence of classicality is the mechanism that makes us to observe a classical reality despite the fundamental laws of physics being quantum.
Apart from the neverending diatribe between different interpretations of Quantum Mechanics, what can be considered more or less accepted is that we experience a classical reality due to the continuos interaction between each microscopic component of any physical system and its environment, that can be regarded as the measuring apparatus and must be macroscopic since it contains us as observers. Among the various approaches proposed over the years by different authors to deal with the "quantumtoclassical" crossover, a useful tool is provided by the general method introduced by L. G. Yaffe in 1982 for finding the classical limits as largeN limits of arbitrary quantum theories with N dynamical variables. Such method isolates the minimal structure that any quantum theory should possess in order to have a classical limit. By using Yaffe's results in the framework of open quantum systems dynamics, one can show that whenever quantum environments have a sensible largeN limit, they evolve as if they were the same measuring apparatus in the classical limit.

