Jeudi 14 novembre 2013 à 10h15
Salle 234, Ecole de Physique

Estimating the dimension of classical and quantum systems in a prepare-and-measure scenario with independent devices

Joseph Bowles, Université de Genève, Département de Physique Théorique

Current research in quantum information has seen an increase in 'device independent physics'. Here, the aim is to construct protocols which allow the user to make statements about the properties of physical systems purely from the raw experimental data, without placing any assumptions on the workings of the devices used to prepare and measure the systems. Such approaches are thus experimentally attractive, since any experimental set up will include devices that are not fully characterised and subject to unknown errors. We apply this method in order to asses the dimension - loosely speaking the number of (relevant) degrees of freedom - of quantum and classical systems. We introduce one natural additional assumption that separate devices should act in an uncorrelated manner and show that under this assumption quantum systems can vastly outperform classical systems of the same dimension. I will then discuss a possible application of our result to that of random number generation.