Revisiting the Heisenberg Microscope
N.D. Hari Dass
Chennai Mathematical Institute.
I shall first review Von Neumann meaurements in quantum mechanics emphasizing their conceptual aspects like nature of the apparatus and its pointer states, nature of the measurement interactions as well as the nature of the one-one correspondence between states of the system and states of the apparatus. I shall then turn to the classic Heisenberg Microscope, examine it from the perspectives of quantum measurements as we understand them today. I shall describe in detail the modern variant, proposed by Arthurs and Kelly, for simultaneously measuring position and momentum. I will end with a brief discussion of various outstanding issues.