Arrangementer

N.D. Hari Dass, Indian Institute of Science, Bangalore and  Chennai Mathematical Institute, Siruseri, India  

The first explicit model for quantum measurements was given by von Neumann, strongly influenced by Dirac, for the type of measurements that have come to be known as Projective measurements. In these, the outcomes are always eigenvalues and the post-measurement state is the corresponding eigenstate. This has led to a widespread ’belief’ that quantum measurements always ’irretrievably disturb’ the state of the system. But a number of very interesting measurement schemes have emerged since the von Neumann model, and I shall present these varieties of quantum measurements and critically assess them.