Barmettler, PeterPunk, MatthiasGritsev, VladimirDemler, EugeneAltman, Ehud2012-01-092009Barmettler, Peter, Matthias Punk, Vladimir Gritsev, Eugene Demler, and Ehud Altman. 2009. Relaxation of antiferromagnetic order in spin-1/2 chains following a quantum quench. Physical Review Letters 102(13): 130603.0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:7349757We study the unitary time evolution of antiferromagnetic order in anisotropic Heisenberg chains that are initially prepared in a pure quantum state far from equilibrium. Our analysis indicates that the antiferromagnetic order imprinted in the initial state vanishes exponentially. Depending on the anisotropy parameter, oscillatory or non-oscillatory relaxation dynamics is observed. Furthermore, the corresponding relaxation time exhibits a at the critical point, in contrast to the usual notion of critical slowing down, from which a maximum is expected.en-USJournal Article2012-01-0910.1103/PhysRevLett.102.130603