Reality and the Role of the Wave Function in Quantum Mechanics

          @misc{ pirsa_09090093,
            doi = {10.48660/09090093},
            url = {https://pirsa.org/09090093},
            author = {Goldstein, Sheldon},
            keywords = {Quantum Foundations},
            language = {en},
            title = {Reality and the Role of the Wave Function in Quantum Mechanics},
            publisher = {Perimeter Institute},
            year = {2009},
            month = {sep},
            note = {PIRSA:09090093 see, \url{https://pirsa.org}}
          }
          

Abstract

The most puzzling issue in the foundations of quantum mechanics is perhaps that of the status of the wave function of a system in a quantum universe. Is the wave function objective or subjective? Does it represent the physical state of the system or merely our information about the system? And if the former, does it provide a complete description of the system or only a partial description? I shall address these questions here mainly from a Bohmian perspective, and shall argue that part of the difficulty in ascertaining the status of the wave function in quantum mechanics arises from the fact that there are two different sorts of wave functions involved. The most fundamental wave function is that of the universe, which, I argue, has a law-like character. From the wave function of the universe together with its configuration one can define the wave function of a subsystem of the universe. This, while objective, does indeed have a strong informational/subjective aspect.