Emergence of fluctuating hydrodynamics in chaotic quantum systems

Understand

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-of-equilibrium 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.