Tufts/CfA/MIT Cosmology Seminar, at MIT:

William Unruh, University of British Columbia

Title: Varieties of Quantum Measurements

Abstract:
Quantum Measurement theory is usually concerned with the link between 
observations in the world and the process often called "reduction of the 
wave packet". However, the notion of measurement has a much broader meaning. 
Defining a measurement to be a situation in which one gains information 
about one system by coupling it to another, there exist many measurement 
situations which differ radically from the usual text book example. For 
example I will argue that the prototypical example of a textbook measurement, 
the Stern Gerlach experiment, is nothing of the sort. This talk will discuss 
a number of cases of general measurements, with the purpose of making people 
think more deeply about what quantum measurement means.