Dear Alvise,

I'm using ALPS to simulate three-dimensional Ising, XY and Heisenberg models. I've never studied the helicity modulus but if you need it I can copy and paste here after the input file I use to run my simulations. While you waiting for the help of someone more expert then me, you can use it to run a simulations on your own and see if in the results you'll get you'll find something useful for your purposes...
Good work and all the best
Rachele Nerattini

LATTICE="simple cubic lattice"
T=2.20167
J=1
THERMALIZATION=200000
SWEEPS=1000000
UPDATE="cluster"
MODEL="XY"
BOUNDARY type="periodic"
S=1
{L=10;}

This is the input file you need to simulate the classical XY model defined on a three dimensional lattice of edge 10 (total number of spins = 10*10*10). You can change the number of thermalization and sweeps steps as you prefer. The model has been simulated at the critical temperature and I used the cluster algorithm to perform the simulation. If you need to simulate a given lattice for different values of the temperature you can do the following:

LATTICE="simple cubic lattice"
L=10;
J=1
THERMALIZATION=200000
SWEEPS=1000000
UPDATE="cluster"
MODEL="XY"
BOUNDARY type="periodic"
S=1
{T=1.5;
T=2.0;
T=2.20167;
T=3.0;
T=...?}
The values of the parameters that you give out of braces hold for every simulations, those which are in braces are tipical of a particular simulation.

2012/7/1 Alvise Scarpa <scalvis@gmail.com>

Hi,

I'd need to simulate a three-dimensional XY model, studying the helicity modulus as a function of temperature.
(3D XY means that the sites are defined on a cubic lattice, while the spins are constrained on a plane)

I'd have a few questions:

0) Can I do that with ALPS? (I suppose the answer will be yes...)
1) Is it possible to do that just from a parameter file, without using the Python interface? In particular, how is it possibile to measure the helicity modulus?
2) Is there any place where I could find a relevant parameter file, or one I could adapt to fit my needs?

Thanks in advance (and sorry if the question is too silly, I have been playing with ALPS for a couple of days so far! I have searched for my issues in the documentation by I could not find relevant examples!)

Best Regards,
Alvise