Macroscopic Realism, Noninvasiveness and Weak Measurement

          @misc{ pirsa_PIRSA:11070089,
            doi = {10.48660/11070089},
            url = {https://pirsa.org/11070089},
            author = {Leggett, Anthony},
            keywords = {Quantum Foundations},
            language = {en},
            title = {Macroscopic Realism, Noninvasiveness and Weak Measurement},
            publisher = {Perimeter Institute},
            year = {2011},
            month = {jul},
            note = {PIRSA:11070089 see, \url{https://pirsa.org}}
          }
          

Abstract

This is a very informal talk about some of the issues associated with the notion of "macroscopic realism" (MR) and its relation to quantum mechanics (QM). After a brief discussion of the motivation for attempts to modify QM at some point between the level of the atom and that of our own direct experience, and a survey of some candidate experimental systems, I will discuss attempts to quantify the notion of "macroscopic distinctness", the use of temporal Bell inequalities to discriminate between the predictions of QM and those of MR, the related concept of "noninvasive measurement" and existing and possible ways to implement it. I will also comment briefly on the relation between Bell-EPR experiments and those on MR.