YQI Seminar - Soonwon Choi - UC Berkeley

Event time: 
Wednesday, February 12, 2020 - 10:30am to 11:30am
YQI Seminar Room See map
Event description: 

Phase Transitions in the Dynamics of Quantum Information

Quantum information science seeks to understand and control quantum systems with high entanglement and complexity, defining a new frontier of physics. In this talk, we discuss a novel phenomenon that arises in this regime: a phase transition in the dynamics of quantum entanglement and information. We consider a generic quantum many-body system coupled to a noisy environment, which we model with random unitary circuits interspersed by projective measurements. The interplay between unitary evolution and measurements leads to a phase transition: at high measurement rates, any coherent information in the system is completely lost, while at sufficiently low rates, an extensive amount of information is robustly protected. The nature of the phase transition can be understood from two complementary perspectives: firstly, by using the quantum error-correcting properties of scrambling unitary dynamics; and secondly, by using a mapping to ordering transitions in classical statistical mechanics. The implications of our work for on-going experiments as well as for broad future research directions will be discussed.