Monday, July 2, 2012

Kagome lattice antiferromagnet IS a Z_2 spin liquid

At the Journal Club for Condensed Matter there is a very nice and clear commentary Identifying a spin liquid on Kagome lattice by quantum entanglement by Ashvin Vishwanath. I learnt a lot from reading it.

It reviews two recent preprints which use numerical methods (density matrix renormalisation group = DMRG) to establish topological order in the ground state of the Heisenberg spin-1/2 model on the Kagome lattice.

An earlier post considered earlier DMRG evidence that was suggestive of a spin liquid, with an energy gap, but did not establish topological order.

1 comment:

  1. The appendices in the Balents paper are great.

    Entanglement spectra in fractional quantum Hall systems and Chern insulators has popped up a lot over the last couple of years. My understanding is that a gap in the entanglement spectrum can give information about topological order and is some sort of generalization of entanglement entropy (Haldane?).

    The commentary by Vishvanath was very helpful.