2004/06/30 by A. Hamma, R. Ionicioiu, P. Zanardi · 3 citations
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1016/j.physleta.2005.01.060
published as Phys.Lett. A 337, 22 (2005) · 4 pages, one fig, ReVTeX 4; updated to the published version
arxiv created 2005/02/28 · arxiv updated 2009/12/01
We study the entanglement properties of the ground state in Kitaev's model. This is a two-dimensional spin system with a torus topology and nontrivial four-body interactions between its spins. For a generic partition (A,B) of the lattice we calculate analytically the von Neumann entropy of the reduced density matrix ρA in the ground state. We prove that the geometric entropy associated with a region A is linear in the length of its boundary. Moreover, we argue that entanglement can probe the topology of the system and reveal topological order. Finally, no partition has zero entanglement and we find the partition that maximizes the entanglement in the given ground state.