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.

    ReplyDelete

Emergence and protein folding

Proteins are a distinct state of matter. Globular proteins are tightly packed with a density comparable to a crystal but without the spatia...