Damian Wozniak, Johann Kroha, and Anna Posazhennikova:
Phys. Rev. A 106, 033316 (2022)
🔓 arXiv:2203.14625 (2022)
We consider large rings of weakly coupled Bose-Einstein condensates, analyzing their transition to chaotic dynamics and loss of coherence. Initially, a ring is considered to be in an eigenstate, i.e., in a commensurate configuration with equal site fillings and equal phase differences between neighboring sites. Such a ring should exhibit a circulating current whose value will depend on the initial, nonzero phase difference. The appearance of such currents is a signature of an established coherence along the ring. If phase difference falls between π/2 and 3π/2 and interparticle interaction in condensates exceeds a critical interaction value uc, the coherence is supposed to be quickly destroyed because the system enters a chaotic regime due to inherent instabilities. This is, however, only part of the story. It turns out that chaotic dynamics and resulting averaging of circular current to zero are generally offset by a critical timescale tc, which is almost two orders of magnitude larger than the one expected from the linear stability analysis. We study the critical timescale in detail in a broad parameter range.