Search

All our statements about the physical world are expressed in terms of everyday notions and thus in terms of classical physics. This necessity is behind each of our attempt to extract meaning out of empirical data and to communicate this knowledge to others. As such, it must apply also to the account of measurement arrangements and to the outcome in quantum experiments. On the other hand, however, if quantum mechanics is universally valid it should be possible to give a purely quantum mechanical description of objects of increasingly large sizes, eventually of the measurement devices themselves. It is suggested to resolve this dilemma by using the method of von Weizsaecker's circular and consistent movement in a reconstruction (Kreisgang) in which it is legitimate to recover the elements with which one started the reconstruction. The parameters entering the complex amplitudes of a quantum state have an operational meaning as parameters that specify the configuration of macroscopic instruments by which the state is prepared and measured. This classical aspect in each quantum description is at the "beginning" of the Kreisgang. The Kreisgang is "closed" by showing that under the every-day conditions of coarse-grained measurements a description of macroscopic instruments emerges in terminology of classical physics and the three-dimensional ordinary space from within quantum theory., Comment: 5 pages, to be published in the philosophy journal "UnoMolti" in Italian

In this Thesis I present a double slit experiment where two undistinguishable photons produced by type I PDC are sent each to a well defined slit. Data about the diffraction and interference patterns for coincidences are presented and discussed. An analysis of these data allows a first test of standard quantum mechanics against de Broglie-Bohm theory., Comment: My master thesis in italian