%0 Journal Article
%T Non-zero entropy density in the XY chain out of equilibrium
%A Walter H. Aschbacher
%J Mathematics
%D 2006
%I arXiv
%R 10.1007/s11005-006-0115-1
%X The von Neumann entropy density of a block of n spins is proved to be non-zero for large n in the non-equilibrium steady state of the XY chain constructed by coupling a finite cutout of the chain to the two infinite parts to its left and right which act as thermal reservoirs at different temperatures. Moreover, the non-equilibrium density is shown to be strictly greater than the density in thermal equilibrium.
%U http://arxiv.org/abs/math-ph/0603049v2