Entanglement of finite cyclic chains at factorizing fields

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

PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS

The American Physical Society

Lugar: New York; Año: 2008 vol. 77 p. 523221 - 523226

1050-2947

We examine the entanglement of cyclic spin 1/2 chains with anisotropic $XYZ$Heisenberg couplings of arbitrary range at transverse factorizing magneticfields. At these fields the system exhibits a degenerate symmetry-breakingseparable ground state (GS). It is shown, however, that the side limits ofthe GS pairwise entanglement at these fields are actually non-zero infinite chains, corresponding such fields to a GS spin-parity transition. These limits exhibit universal properties like being independent of the pair separation and interaction range, and are directly related to the magnetization jump. Exact results illustrating this behavior are shown for chains with (I) full range and (II) nearest neighbor couplings. Global entanglement properties at such points are also discussed.