  We report on a Hartree-Fock approximation study of the meron
pseudospin-texture excitations of the broken-symmetry incompressible ground
states of double-layer quantum Hall states at $\nu =1$. We have obtained
results for meron core energies and core sizes. We use these to estimate the
charge gap which determines the activation energy for dissipation in the
quantum Hall effect.

Condensed Matter