Long-range correlations in the nonequilibrium quantum relaxation of a spin chain.
We consider the nonstationary quantum relaxation of the Ising spin chain in a transverse field of strength h. Starting from a homogeneously magnetized initial state the system approaches a stationary state by a process possessing quasi-long-range correlations in time and space, independent of the value of h. In particular, the system exhibits aging (or lack of time-translational invariance on intermediate time scales) although no indications of coarsening are present.
Iglói
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Research Institute for Solid State Physics and Optics, H-1525 Budapest, P.O. Box 49, Hungary.
Rieger
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