- Comp-phys-alps-users - lists.phys.ethz.ch

Version of Boost in the ALPS+Boost download
by evanloon＠physnet.uni-hamburg.de 24 Jan '13

24 Jan '13

Dear all, It seems that the alps src-with-boost downloads still contain an old (1.40) version of the boost src, which will not allow to compile ALPS. Best regards, Erik

6 9

DMRG simulations of Fermi Hubbard models
by Giuliano Orso 24 Jan '13

24 Jan '13

Dear ALPS users, I want to run some DMRG simulations on 1D Fermi Hubbard models. I tried to work in the gran canonical ensemble, giving the chemical potential mu instead of the density and without specifying that Nup and Ndown are conserved quantities. The code is running but it produces strange results, in particular the calculated energy is varying a lot within the same sweep and the error oscillates from 10-15 to 10-2. Any ideas why ? Puzzled by that, I tried to do the same for the Bose Hubbard model, but there everything works perfectly. Can you help me on that ? My best regards, Giuliano

1 0

TEBD and custom lattices
by Deepak Iyer 21 Jan '13

21 Jan '13

Hi I'm trying to define a custom lattice to use with the tebd code. I've tested the lattice with sparsediag and it works as I want it to. However, TEBD seems to completely ignore any information about the lattice. It seems to look at only the model, and I guess assumes an open chain of length L with only nearest neighbor hopping. Is there a way to get around this? Thanks! Deepak

1 0

site and bond-operators in the models.xml file
by Deepak Iyer 20 Jan '13

20 Jan '13

Hi I'm confused as to how the system knows what i and j should be (like nearest neighbor, next nearest, etc) for a particular model, since the bond-operators just go from i to j. Also, when there are wild cards in parameters, e.g., mu# in the boson Hubbard Hamiltonian, where are the different types defined? Do I need to define a new lattice type to allow for spatially varying mu, e.g.? Thanks Deepak

2 2

Quenching 'L' in TEBD code
by Deepak Iyer 19 Jan '13

19 Jan '13

Hi I'm trying to quench 'L' in the TEBD code in the Bose-Hubbard model. I start with L=2 and quench to L=10. I'm interested in looking at what happens to the local occupation numbers. But the code only outputs 'Local Number' for 2 sites. I'm using an L=2 initial state to force the system into a particular initial state. I see that this is a bit ambiguous since its not clear what 'L' is midway in the quench, but is there any way I can get occupation for all 10 sites after the completion of the quench? I first quickly quench it and then hold the quench at a fixed U and L for sometime. Thanks! Deepak

2 4

tebd hardcoded measurements
by Deepak Iyer 18 Jan '13

18 Jan '13

Hi I've been trying to find some documentation on hardcoded measurements in the tebd code. The docs don't seem to have anything. I did end up looking in the fortran code and found something but I am not sure how these things are defined. Would be great if there's some doc sitting somewhere on this. Thanks! Deepak

1 0

Winding number histogram
by "Michał Maik" 12 Jan '13

12 Jan '13

Hi all, I was curious if there is an easy way to get the winding number histogram from both the worm code as well as the SSE code. I noticed that in the files Wmeas.C and evaluate.C there are references to the winding number histogram. What do I need to write in the parameter file to be able to get values of this histogram? In advance, thank you. Best Regards Michal Maik

1 0

retrieving eigenvectors from sparsediag
by Rafał 09 Jan '13

09 Jan '13

Dear Alps Team and all Alps users I am trying to recreate results from the paper of Yi-Fei Wang , Zheng-Cheng Gu , Chang-De Gong and D. N. Sheng (please see http://arxiv.org/abs/1103.1686v1) I have already implemented a model into xml file and successfully generated phase diagram for 24 sites checkerboard model (FIG 1 (b)). Now I plan to calculate Berry curvature and Chern number (please see the FIG. 3 (c) and paragraph below it). And there comes my problem: I'm little confused how to calculate F(θ1 , θ2) [ F(\theta_1,\theta_2) ]. I have an idea how to calculate differentiation of the eigenvectors numerically and then calculate dot product but I don't know how to access to eigenvectors from sparsediag. I would be grateful for any advice. Best wishes Rafał Skolasiński

1 0

Re: [ALPS-users] installing ALPS 2.1.1 on win7 and Mac
by Ben LI 03 Jan '13

03 Jan '13

Dear ALPS members and developers: I have been trying to install ALPS 2.1.1 (Binary package) on windows 7 (32-bit) and Mac OS X 10.6.8 (64-bit), but I met same problem when I open VirTrails: CRITICAL 2013-01-03 12:00:29,721 /Applications/VisTrails/VisTrails.app/Contents/Resources/lib/python2.7/core/packagemanager.py, line 501 Dependencies of package ALPS are missing so it will be disabled Package 'ALPS' has unmet dependencies: edu.utah.sci.vistrails.control_flow edu.utah.sci.vistrails.vtlcreator I will appreciate if you could help me fix the problem. Best regards, Ben LI

2 4

questions about wavefucntion
by 黄口口 01 Jan '13

01 Jan '13

Dear alps users: Now I am learning ALPS. It's useful for me. But I have question: How to get the wave function or some calculation about it, for example, 1.the participation ratio(=1 / \sum_i ｜< i | \psi > |^4 ) 2.calculation of entropy. I search in the mail group, some people face the same difficulty, but I cannot find the answer, can any of you provide me the solution? Thank you! Best wishes to you! xin 2012.11.08

2 1