Dear Kubila, Absolutely correct. Please look at the comment about the generalized susceptibility in the looper documentation http://wistaria.comp-phys.org/alps-looper/ Best, Synge On 2010/07/28, at 13:47, Kubila wrote:

Hi all

Currently I am studying spin-1/2 XY model using the loop algorithm in ALPS. The staggered susceptibility measured using the loop algorithm does not grow with space-time volume. On the other hand, the generalized susceptibility measured using the loop algorithm seems to scale with space-time volume. I was wondering is the generalized susceptibility exactly the correlator of the X-component of the staggered magnetization M_s = \sum_{x} (-1)^{x_1+x_2}\vec{S}_x?, here \vec{S}_x is the spin-1/2 operator at site x. Also is the z-direction the quantized direction in the loop algorithm? Thanks in advance.

kubila