Recorded 06 November 2023. Shankar Balasubramanian of the Massachusetts Institute of Technology presents "Ultraslow dynamics, fragile fragmentation, exotic entanglement, and geometric group theory" at IPAM's Many-body Quantum Systems via Classical and Quantum Computation Workshop. Abstract: We first introduce a class of 1D translationally invariant and local classical and quantum dynamics that have an unusual approach to equilibrium. In one of our examples, expectation values of local operators relax in a time which is exponentially large in system size, implying an unusual kind of hydrodynamics. In another example, a system can only relax when coupled to a bath which is at least exponentially large in the system's size, a phenomenon that we call fragile fragmentation. A field of mathematics called geometric group theory plays an important role in constructing these examples. We then consider ground states of a two-dimensional generalizations of these models and find a plethora of unusual entanglement properties such as (1) area laws emerging entirely from long range correlations and (2) power law violations of area law scaling. Learn more online at: https://www.ipam.ucla.edu/programs/workshops/workshop-iii-many-body-quantum-systems-via-classical-and-quantum-computation/