When chaos turns orderly: tracking a hidden transition in quantum systems

The team studied a quantum model that can be tuned from chaotic to integrable, looking only at special quantum states called BPS states that respect the model's symmetries. As parameters shift, the statistical signature of these states changes from random-matrix behavior—the hallmark of chaos—to Poisson statistics characteristic of orderly, integrable systems. This demonstrates that chaos-to-order transitions can happen in hidden subspaces, visible only if you know where to look.