DFG Research Unit FOR 5522

Kick-Off-Meeting

Our Kick-Off Meeting took place at MPI PKS in Dec. 2023 and covered science from the Research Unit and introductory lectures on thermalization and nonergodic dynamics. We enjoyed great discussions and a high spirit despite the strike!

Research highlight:
Emergence of fluctuating hydrodynamics in chaotic quantum systems

A fundamental principle of chaotic quantum dynamics is that local subsystems eventually approach a thermal equilibrium state. Large subsystems thermalize slower: their approach to equilibrium is limited by the hydrodynamic build-up of large-scale fluctuations. For classical out-ofequilibrium systems, the framework of macroscopic fluctuation theory (MFT) was recently developed to model the hydrodynamics of fluctuations. We perform large-scale quantum simulations that monitor the full counting statistics of particle-number fluctuations in hard-core boson ladders, contrasting systems with ballistic and chaotic dynamics. We find excellent agreement between our results and MFT predictions, which allows us to accurately extract diffusion constants from fluctuation growth. Our results suggest that large-scale fluctuations of isolated quantum systems display emergent hydrodynamic behavior, expanding the applicability of MFT to the quantum regime.

Group: I. Bloch, M. Aidelsburger (LMU Munich)