Separability and entanglement in finite dimer-type chains in general transverse fields

• Autores: Canosa, Norma Beatriz; Rossignoli, Raúl Dante; Matera, Juan Mauricio
• Año de publicación: 2010
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Física; Quantum entanglement; Physics; Eigenvalues and eigenvectors; Field (physics); Spins; Squashed entanglement; Quantum mechanics; Ground state; Quantum phase transition; Spin-½
• Institución: Universidad Nacional de La Plata

We determine the conditions under which general dimer-type spin chains with XYZ couplings of arbitrary range in a general transverse field will exhibit an exactly separable parity-breaking eigenstate. We also provide sufficient conditions which ensure that it will be a ground state. We then examine the exact side limits at separability of the entanglement between any two spins in a finite chain, showing that in the vicinity of separability, the system will loose all signatures of dimerization, with pairwise entanglement approaching infinite range and becoming independent of separation and interaction range. The possibility of a nonuniform exactly separable ground state induced by an alternating field is also shown. As illustration, we examine the behavior of the pairwise entanglement in a finite XY dimer chain under a uniform as well as alternating field. Related aspects of the magnetization are also discussed.
Instituto de Física La Plata