Speaker: Yiqiu Han (Boston College)

Date & Time: 10am, Jun 5, 2023.

Room: Online (Zoom)

Title: Entanglement dynamics in U(1)-symmetric hybrid quantum automaton circuits

Abstract: 

In this talk, I will discuss our recent work on the entanglement dynamics of quantum automaton (QA) circuits in the presence of U(1) symmetry (arXiv:2305.18141). We find that the second Rényi entropy grows diffusively with a logarithmic correction as \sqrt{t\ln t}, saturating the bound established by Huang [IOP SciNotes 1, 035205 (2020)]. Thanks to the special feature of QA circuits, we can understand this scaling in terms of a classical bit string model. In addition, we investigate the monitored entanglement dynamics by introducing a composite measurement that preserves both the U(1) symmetry and properties of QA circuits. Interestingly, we find that there is a transition from the volume-law phase to a critical phase as we increase the measurement rate, which is distinct from the volume-to-area-law phase transition of non-automaton circuits, e.g., U(1)-symmetric Haar random circuits.