Kadanoff Seminar: Open Quantum Dynamics and Spontaneous Symmetry Breaking. - Jong Yeon Lee, UIUC

Open Quantum Dynamics and Spontaneous Symmetry Breaking.

Open quantum systems fundamentally differ from closed systems in that they allow for the creation and destruction of information. This unique property has led to discovering of various information-theoretic phase transitions, sparking significant interest and research in the field. In this talk, I will introduce strong-to-weak spontaneous symmetry breaking (SSB) as a unifying framework for understanding these information-theoretic transitions. By outlining this general framework, we explore how it generalizes the concept of thermalization and applies to several key phenomena, including fault-tolerance thresholds of topological codes (e.g., the Toric code) and approximate codes (e.g., the Sachdev-Ye-Kitaev code), as well as the emergence of hydrodynamics. If time permits, I will also discuss how charge-sharpening or purification transitions can be incorporated into this framework. This approach unifies disparate concepts and advances our understanding of open quantum dynamics.