Critical phase and spin sharpening in SU(2)-symmetric monitored quantum circuits
Abstract
Monitored quantum circuits exhibit entanglement transitions at certain measurement rates. Such a transition separates phases characterized by how much information an observer can learn from the measurement outcomes. We study SU(2)-symmetric monitored quantum circuits, using exact numerics and a mapping onto an effective statistical-mechanics model. Due to the symmetry's non-Abelian nature, measuring qubit pairs allows for nontrivial entanglement scaling even in the measurement-only limit. We find a transition between a volume-law entangled phase and a critical phase whose diffusive purification dynamics emerge from the non-Abelian symmetry. Additionally, we numerically identify a "spin-sharpening transition." On one side is a phase in which the measurements can efficiently identify the system's total spin quantum number; on the other side is a phase in which measurements cannot.
Keywords
Cite
@article{arxiv.2305.13356,
title = {Critical phase and spin sharpening in SU(2)-symmetric monitored quantum circuits},
author = {Shayan Majidy and Utkarsh Agrawal and Sarang Gopalakrishnan and Andrew C. Potter and Romain Vasseur and Nicole Yunger Halpern},
journal= {arXiv preprint arXiv:2305.13356},
year = {2023}
}
Comments
8 pages (6 figures) + appendices (11.5 pages)