TY - JOUR

T1 - Finitely correlated states on quantum spin chains

AU - Fannes, M.

AU - Nachtergaele, B.

AU - Werner, R. F.

PY - 1992

Y1 - 1992

N2 - We study a construction that yields a class of translation invariant states on quantum spin chains, characterized by the property that the correlations across any bond can be modeled on a finite-dimensional vector space. These states can be considered as generalized valence bond states, and they are dense in the set of all translation invariant states. We develop a complete theory of the ergodic decomposition of such states, including the decomposition into periodic Néel ordered states. The ergodic components have exponential decay of correlations. All states considered can be obtained as local functions of states of a special kind, so-called purely generated states, which are shown to be ground states for suitably chosen finite range VBS interactions. We show that all these generalized VBS models have a spectral gap. Our theory does not require symmetry of the state with respect to a local gauge group. In particular we illustrate our results with a one-parameter family of examples which are not isotropic except for one special case. This isotropic model coincides with the one-dimensional antiferomagnet, recently studied by Affleck, Kennedy, Lieb, and Tasaki.

AB - We study a construction that yields a class of translation invariant states on quantum spin chains, characterized by the property that the correlations across any bond can be modeled on a finite-dimensional vector space. These states can be considered as generalized valence bond states, and they are dense in the set of all translation invariant states. We develop a complete theory of the ergodic decomposition of such states, including the decomposition into periodic Néel ordered states. The ergodic components have exponential decay of correlations. All states considered can be obtained as local functions of states of a special kind, so-called purely generated states, which are shown to be ground states for suitably chosen finite range VBS interactions. We show that all these generalized VBS models have a spectral gap. Our theory does not require symmetry of the state with respect to a local gauge group. In particular we illustrate our results with a one-parameter family of examples which are not isotropic except for one special case. This isotropic model coincides with the one-dimensional antiferomagnet, recently studied by Affleck, Kennedy, Lieb, and Tasaki.

M3 - Article

VL - 144

SP - 443

EP - 490

JO - Comm. Math. Phys.

JF - Comm. Math. Phys.

SN - 1432-0916

IS - 3

ER -