Applied Physics/Physics Colloquium: Matthew P.A. Fisher - "Emergence of Hydrodynamics from Open Quantum Dynamics"

Abstract: Hydrodynamics provides a remarkably universal description of matter in terms of a few continuous fields. But how does this continuum description emerge from the dynamics of discrete quantum particles? I will address this question in open quantum systems of bosons with a conserved particle-number symmetry. In mixed states this symmetry can be either strong or weak, and distinct dynamical phases can be characterized by the spontaneous breaking of these symmetries. A strong-to-weak spontaneous symmetry-breaking (SW-SSB) transition can be diagnosed by information-theoretic quantities tha