Nagoya University Team Models Non-Ergodic Phase Transitions for Atomic Josephson Junctions

Koichiro Furutani from Nagoya University and colleagues have identified a breakdown of process within a Bose-Josephson junction, revealing a new non-ergodic dynamical phase transition into a 'running state' not observed in Markov systems. Their exact non-Markov Langevin simulations pinpoint a zero-mode exceptional point arising from non-Markov friction as the key driver of this transition, characterised by the winding of the response function. This topological origin proves strong against quantum fluctuations and environmental backaction, as confirmed by simulations of an equivalent driven XXZ spin chain, offering potential for developing long-lived quantum memories in challenging, dissipative environments. A sophisticated numerical technique, the Markov embedding…