Electron - hole asymmetry and activation energy in quantum Hall   ferromagnets
  We argue that the dissipative transport in ferromagnetic quantum Hall effect liquids at $\nu=2N+1$ is dominated by the thermal activation of pairs consisting of an electron and an antiskyrmion (topological texture which represents a hole with 'screened' exchange interaction), thus manifesting the lack of electron-hole symmetry in quantum Hall ferromagnets. We find that the activation energy of such a pair is not the exchange energy, but is determined by the interplay between the excess Zeeman energy of a skyrmion and the charging energy of its topological texture: $${\cal E}=a\epsilon_{{\rm Z}}^{1/3}E_{{\rm C}}^{2/3}\ln ^{1/3}(\frac{\Im_{i}}{E_{{\rm C}}^{2/3}\epsilon_{{\rm Z}}^{1/3}}), E_{{\rm C}}=\frac{e^{2}}{\chi \lambda}, $$ with $ a\approx 1.75$. 
Vladimir I. Fal'ko (Lancaster U), S.V. Iordanski (Landau Institute,   Moscow)