Entanglement of finite spin chains at transverse factorizing field

R. ROSSIGNOLI; N. CANOSA; J.M. MATERA

Paraty, Brasil

Workshop; II QUANTUM INFORMATION SCHOOL AND WORKSHOP.; 2009

CNPq - Institute for Quantum Computing

We examine the entanglement of finite spin chains with anisotropic XYZ  couplings of arbitrary range at transverse factorizing fields, where the  system exhibits a degenerate parity-breaking separable ground state (GS).  It is shown, however, that the side limits of the ground state pairwise  entanglement at these fields are actually non-zero in finite chains, corresponding  such fields to a GS spin-parity transition. These limits exhibit universal  properties like being independent of the interaction range and pair separation,  and are directly related to the magnetization step. Illustrative exact results  for chains with full range and nearest neighbor couplings will be shown.  Other entanglement properties at such points will also be discussed.