Relaxation and aging in quantum spin systems
Gunter Markus Schutz, Steffen Trimper
The nonthermal quantum relaxation of the magnetization under nonequilibrium initial conditions is studied for the transverse Ising chain and for the one-dimensional isotropic XY model. In the absence of a heat bath the transverse Ising system exhibits an oscillating relaxation with a decaying amplitude. At the critical transverse field some stationary properties become independent of the initial state. The isotropic XY chain with a spatially inhomogeneous initial state shows a slow, modulated algebraic decay of the magnetization. Analysis of the two-time autocorrelation function reveals the phenomenon of aging.
Europhysics Letters (EPL)•Jul 15, 1999•25 citations