Rotating Bose-Einstein condensate with attractive interaction in one dimension: Single-L states and mesoscopics

We present the results of an exact numeric simulation of N one-dimensional bosons with attractive delta-functional interaction in a rotating ring. We prove that even at intermediate values of N, the system can be described by conventional methods of weakly interacting gas, the dimensionless parameter of weak interaction being just 1/N. When the strength of interaction is less than a certain threshold value, the dependence of angular momentum on the rotation frequency features plateaus characteristic of the irrotational fluid.