Abstract
Non-Hermitian systems having parity-time () symmetry can undergo a transition, spontaneously breaking the symmetry. Ultracold atomic gases provide an ideal platform to study interaction effects on the transition. We consider a model system of bosons of two components confined in a tight trap. Radio-frequency and laser fields are coupled to the bosons such that the single-particle Non-Hermitian Hamiltonian , which has symmetry, can be simulated in a passive way, namely, in the physical system there is only incurred atom loss but no gain. We show that when interatomic interactions are tuned to maintain the symmetry, the -symmetry-breaking transition is affected only by the SU(2) variant part of the interatomic interactions. We find that the transition point decreases as the strength of this interaction part or increases; in the strong strength limit for this interaction part, scales as the strength to the power of . We also give signatures of the -symmetric and the symmetry-breaking phases for the interacting bosons in experiment.
- Received 7 January 2019
DOI:https://doi.org/10.1103/PhysRevA.99.043412
©2019 American Physical Society