Critical phase and spin sharpening in SU(2)-symmetric monitored quantum circuits

Shayan Majidy, Utkarsh Agrawal, Sarang Gopalakrishnan, Andrew C. Potter, Romain Vasseur, Nicole Yunger Halpern

Research output: Contribution to journalArticlepeer-review

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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 identify a "spin-sharpening transition."Across the transition, the rate at which measurements reveal information about the total spin quantum number changes parametrically with system size.

Original languageEnglish (US)
Article number054307
JournalPhysical Review B
Issue number5
StatePublished - Aug 1 2023

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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