Physics Paradigm Challenge

Our best mathematical models for chaos predict that systems should settle down instantly, which is physically impossible.

March 31, 2026

Original Paper

Average Equilibration Time for Gaussian Unitary Ensemble Hamiltonians

Emanuel Schwarzhans, Alessandro Candeloro, Felix C. Binder, Maximilian P. E. Lock, Pharnam Bakhshinezhad

arXiv · 2603.28587

The Takeaway

Physicists use 'Random Matrix Theory' to describe how chaotic systems reach equilibrium, but this paper finds the theory contains an error that makes the process happen at infinite speed. This highlights a fundamental missing 'speed limit' in our current understanding of how the universe transitions from chaos to stability.

From the abstract

Understanding equilibration times in closed quantum systems is essential for characterising their approach to equilibrium. Chaotic many-body systems are paradigmatic in this context: they are expected to thermalise according to the eigenstate thermalisation hypothesis and exhibit spectral properties well described by random matrix theory (RMT). While RMT successfully captures spectral correlations, its ability to provide quantitative predictions for equilibration timescales has remained largely