Sprecher
Beschreibung
I will provide a framework for computing time-averaged dynamics in locally interacting systems in any dimension. It is based on pseudolocal dynamical symmetries generalising pseudolocal charges and unifies seemingly disparate manifestations of quantum non-ergodic dynamics including quantum many-body scars, continuous, discrete and dissipative time crystals, Hilbert space fragmentation, lattice gauge theories, and disorder-free localization. Using the theory two novel types of phase transitions are introduced: 1) The "scarring phase transition" where the order parameter is the locality of the projected local quantities - for certain initial states persistent oscillations are present. 2) The "fragmentation phase transition" for which long-range order is established in an entire phase due to presence of certain non-local strings. Two prototypical, but otherwise mostly intractable, models are solved exactly using the theory: 1) a spin 1 scarred model and 2) the t-J_z model with fragmentation. I will further discuss a novel method for using Krylov subspace methods to construct the dynamical symmetries - in particular, by introducing an environment to the Krylov chain.
References:
N. Loizeau, B. Buca, D. Sels.arXiv:2503.07403 (2025).
B. Buca. Phys. Rev. X 13, 031013 (2023).
D. E. Parker, X. Cao, A. Avdoshkin, T. Scaffidi, E. Altman. Phys. Rev. X 9, 041017 (2019).
B. Doyon. Commun. Math. Phys. 351, 155 (2017).
