On Jul 21, 2008, at 5:05 PM, Fritz Koermann wrote:
Dear Prof. Matthias Troyer,
many thanks for your answer :)!
Do you want to measure the real-space correlation function or is the magnetic susceptibility as an integrated measure enough?
We would like to measure the real-space correlation function in order to separate between short- and long-range interactions and their influence on the internal energy. Is it possible to measure such a function using alps?
The internal energy is just the short-range correlation.
We can add correlation measurements but that is lots of data and will slow down the code quote a bit. Do you actually need all correlations?
I have two more minor questions concerning the output: Is the susceptibility \chi given out by alps equivalent to \chi=\beta*(<m^2>-<m>^2)?
On any finite lattice actually <m>^2 is 0, and one would need to measure <|m|>^2. We actually only do \chi=\beta <m^2>, so that the estimate is valid only above Tc.
Is it possible to make a snapshot (spin position+spin alignment) of the spin system at a certain time-step?
This is easily possible. In which format would you like to see the snapshot?
Best regards
Matthias Troyer