# On the Evolution of States in a Quantum-Mechanical Model of Experiments

Jürg Fröhlich, Zhou Gang

Jürg Fröhlich, Zhou Gang

**5/12/22**Published in : arXiv:2212.02599

The postulates of von Neumann and Lüders concerning measurements in quantum mechanics are discussed and criticized in the context of a simple model proposed by Gisin. The main purpose of our paper is to analyze some mathematical aspects of that model and to draw some general lessons on the so-called "measurement problem'' in quantum mechanics pointing towards the need to introduce general principles that determine the law for the stochastic time evolution of states of individual physical systems.