Non-equilibrium Fractional Hall Response After a Topological Quench
  We theoretically study the Hall response of a lattice system following a quench where the topology of a filled band is suddenly changed. In the limit where the physics is dominated by a single Dirac cone, we find that the change in the Hall conductivity is two-thirds of the quantum of conductivity. We explore this universal behavior in the Haldane model, and discuss cold-atom experiments for its observation. Beyond linear response, the Hall effect crosses over from fractional to integer values. We investigate finite-size effects, and the role of the harmonic confinement. 
F. Nur \"Unal, Erich J. Mueller, M. \"O. Oktel
cond-mat.quant-gas cond-mat.mes-hall