Glassy dynamics in kinetically constrained monitored quantum dynamics
Marcel Cech (Tubingen University)
Kinetically constrained models are built from simple dynamic rules, whereby the state changes of one constituent depend on the state of its neighbors. The dynamics are highly correlated in space and time, which significantly slows down the relaxation. Analyzing this behavior has provided valuable insights into the understanding of the glass transition as a dynamic phenomenon.
In this talk, I will focus on so-called East models, where a spin to the “East” can only flip if its predecessor is in the excited state. I start with classical, and in most cases stochastic, dynamics and discuss the concept of trajectories and their thermodynamically inspired analysis that shapes the notion of dynamical phase transitions in glass formers. Based on our recent works [1,2], I demonstrate how this concept can be extended to quantum many-body dynamics by using monitored circuit models. These models are much harder to explore computationally, given that the Hilbert space grows exponentially. I present results from tensor network calculations and simulations on the publicly accessible ibm_kingston quantum processor, and argue that these methods are complementary tools for studying the emergence of glassy dynamics in quantum many-body systems.
[1] M. Cech, J. du Buisson, C. De Fazio, F. Carollo, and I. Lesanovsky, From Classical Stochastic to Monitored Quantum Dynamics: Dynamical Phase Coexistence in East Circuit Models, arXiv:2603.18227 (2026).
[2] M. Cech, I. Lesanovsky, and F. Carollo, Glassy dynamics with softened kinetic constraints on a noisy quantum computer, arXiv:2608.19335 (2026).