Parametric description of the quantum measurement process
by
Paola Verrucchi
→
Europe/Rome
248 (Building C, first floor)
248
Building C, first floor
Description
In this seminar I will present a description of the quantum measurement process based on a parametric representation in terms of generalised coherent states for the measuring apparatus[1]. The relation between quantum measurements and decoherence will be first investigated, in order to formally express the necessity of the latter for obtaining an informative output from the former. To this aim, I will refer to the dynamical behaviour of a particular model, which is often adopted in the literature for describing projector valued measures of discrete observables. Having made use of generalised coherent states for the apparatus, I will then consider the consequences of its being macroscopic, referring to the relation between classical and large-N limit of a quantum theory as established by G.Yaffe in Ref.[2]. This will finally lead us to a description of the actual production of the output that inherently includes both the probabilistic character of the process, with the Born rule properly recovered, and a symmetry breaking that entails the overall quantum state reduction[3].
[1] Proceedings of the National Academy of Sciences 110, 6748-6753 (2013)
[2] Rev. Mod. Phys. 54, 407 (1982)
[3] EPL 111, 40008 (2015)
