Quantum discord in finite XY chains
- Departamento de Fisica-IFLP, Universidad Nacional de La Plata, C.C. 67, La Plata 1900 (Argentina)
We examine the quantum discord between two spins in the exact ground state of finite spin-1/2 arrays with anisotropic XY couplings in a transverse field B. It is shown that in the vicinity of the factorizing field B{sub s}, the discord approaches a common finite non-negligible limit which is independent of the pair separation and the coupling range. An analytic expression of this limit is provided. The discord of a mixture of aligned pairs in two different directions, crucial for the previous results, is analyzed in detail, including the evaluation of coherence effects, relevant in small samples and responsible for a parity splitting at B{sub s}. Exact results for finite chains with first-neighbor and full-range couplings and their interpretation in terms of such mixtures are provided.
- OSTI ID:
- 21450734
- Journal Information:
- Physical Review. A, Vol. 82, Issue 4; Other Information: DOI: 10.1103/PhysRevA.82.042316; (c) 2010 The American Physical Society; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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