26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Dark-state phase transition to a dark soliton in a dissipative Bose–Hubbard chain

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Contributed Oral AIP | Quantum Science and Technology (QST)

Speaker

Prof. Matthew Davis (University of Queensland)

Description

Novel nonequilibrium states of superfluids can be engineered by the controlled application of dissipation. In this work we show that a Bose–Hubbard model with local loss exhibits a first-order dark-state phase transition between a dark soliton and a uniform superfluid. Semiclassical simulations and stability analysis reveal that the soliton acts as a many‑body dark state, whose suppressed fluctuations modify the transition relative to the comparable phenomenon of optical bistability in Kerr resonators. This mechanism quantitatively captures the bistable phase boundary observed in the experiment of Labouvie et al. [Phys. Rev. Lett. 116, 235302 (2016)], resolving long‑standing discrepancies in previous theoretical modeling. Our results identify a general route by which spatial coherence and engineered loss can generate new nonequilibrium phase transitions in ultracold gases.