Equilibration of Complex Quantum Systems in the Thermodynamic and Macroscopic Limits

          @misc{ pirsa_PIRSA:12040106,
            doi = {10.48660/12040106},
            url = {https://pirsa.org/12040106},
            author = {Emerson, Joseph},
            keywords = {},
            language = {en},
            title = {Equilibration of Complex Quantum Systems in the Thermodynamic and Macroscopic Limits},
            publisher = {Perimeter Institute},
            year = {2012},
            month = {apr},
            note = {PIRSA:12040106 see, \url{https://pirsa.org}}
          }
          

Abstract

There has been some significant recent progress on the long-standing problem of identifying the conditions under which equilibrium statistical mechanics can arise from an exact quantum mechanical treatment of the dynamics. I will give an overview of this progress, describing in particular how random matrix models and the associated concentration of measure phenomena imply that equilibration is generic even for the closed system evolution of pure quantum states. I will then discuss the relevance of these models to clarifying the conditions for quantum-classical correspondence of few-body chaotic systems. In particular, I will show that the Newtonian description of the dynamics of chaotic macroscopic bodies, remarkably, does not emerge from the underlying quantum mechanical description. These results suggest, under reasonable assumptions, that pure quantum states require a statistical interpretation.