Correlated ground states with (spontaneously) broken time-reversal   symmetry
  We propose a self-consistent scheme for the determination of the ground-state (GS) properties of interacting electrons in a magnetic field, and of systems whose GS's time-reversal-symmetry (TRS) is spontaneously broken. It is based on a newly-developed many-body perturbation theory that is valid, irrespective of the strength of correlation, provided the GS number densities $n_{\uparrow}({\bf r})$, $n_{\downarrow}({\bf r})$, and the {\sl total} paramagnetic particle flux density are pure-state non-interacting $v$-representable. Our approach can in particular be applied to (modulated) two-dimensional electron systems in the fractional quantum-Hall regime. 
Behnam Farid (Max-Planck Institute, Stuttgart)