Spinless Hartree-Fock model of persistent current in rings with single   scatterer: Comparison with correlated models
  Using the self-consistent Hartree-Fock approximation for spinless electrons at zero temperature, we study the persistent current of the interacting electron gas in a one-dimensional continuous ring containing a single $\delta$ barrier. We calculate the persistent current as a function of the ring circumference, magnetic flux threading the ring, barrier strength, etc. We compare our results with the results of correlated models like the Luttinger liquid model and the Hubbard model solved by means of the renormalization group. A good agreement is found. First, the persistent current decays with the increasing ring circumference ($L$) faster than $L^{-1}$ and eventually like $L^{-\alpha-1}$, where $\alpha>0$ depends only on the electron-electron interaction. Second, the persistent current is a sine-shaped function of magnetic flux. This sine-like dependence and in particular the universal power law $L^{-\alpha-1}$ have sofar been believed to arise only in the correlated many-body models. Observation of these features within the Hartree-Fock model is a surprising result. 
Radoslav Nemeth & Martin Mosko