Comp-phys-alps-users

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1244 discussions

Summer School
by Matthias Troyer 10 Dec '07

10 Dec '07

Dear ALPS developers and users I would like to draw your attention to the 2008 International Summer School "Numerical Methods for Correlated Systems in Condensed Matter". The School will be held over an intensive two-week period May 25 to June 6, 2008 in Sherbrooke. It will hold to the high standards of the Les Houches and Boulder Schools. This 45 hours PhD level School is aimed at advanced graduate students, postdocs and Faculty. In addition to formal lectures by renowned speakers, it includes hands-on training on freely available software packages for both ab-initio methods and for model Hamiltonians of interacting systems. There is no registration fee. Room and board will be 1000 CAD for single occupancy and 750 CAD for double occupancy (1 CAD ~ 1 USD). Students can register for transferable PhD level course credit with Universit? de Sherbrooke. For more details on the list of speakers and registration, please consult http://pitp.physics.ubc.ca/confs/sherbrooke/index.html Sincerely yours, Andre'-Marie Tremblay Massimo Boninsegni Michel Cote David Senechal Matthias Troyer

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extractxmgr on Ubuntu Gutsy Gibbon
by MICHEL Laurent 05 Dec '07

05 Dec '07

Hi, I am new on ALPS and I don't know where to find support for the following problem : I am making some simulations using the ALPS libraries, and, at the end, when I want to use extractxmgr, if I type something like zadigus@ubuntu:~/apps/dyqm-1.0/tutorial/tebd$ bash extractxmgr ../xml/plot.sz.xml neel1a.task1.eval0.xml neel1a.task1.eval1.xml I get the following error : test: 28: ==: unexpected operator tail: Warning: "+number" syntax is deprecated, please use "-n +number" tail: Warning: "+number" syntax is deprecated, please use "-n +number" test: 28: ==: unexpected operator test: 28: ==: unexpected operator /tmp/plot26738:2: parser error : Opening and ending tag mismatch: meta line 2 and head <head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head> ^ /tmp/plot26738:4: parser error : Opening and ending tag mismatch: head line 2 and html </html> ^ /tmp/plot26738:5: parser error : Premature end of data in tag html line 1 ^ cannot parse /tmp/plot26738 What can I do for this to work ? I have the latest updated version of Ubuntu (7.10) and I am working now with the ALPS library provided by Ubuntu. I first tried with the beta version which can found on your website (alps-1.3b6), but the problem is exactly the same. Best regards, L. -- MICHEL Laurent Physicien presque accompli www.cjcaesar.ch/ Petits-Quartiers 4 1680 ROMONT laurent.michel(a)unifr.ch

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staggered magnetization: special definition of a bipartite lattice necessary?
by Björn Vogt 26 Nov '07

26 Nov '07

Hello, I am interested in using ALPS for Heisenberg systems including higher order on-site-anisotropies. To measure the staggered magnetization in an antiferromagnetic model: Do I have to define a special bipartite lattice or do the usual lattices in lattices.xml work? Yours, Björn Vogt -- Björn Vogt I. Institut für Theoretische Physik Universität Hamburg Jungiusstr. 9 Raum 122 040/42838-2056 http://www.physnet.uni-hamburg.de/hp/bvogt ____________________________________________________ This mail was sent through PHYSnet-WebMailer http://www.PHYSnet.uni-hamburg.de/mail

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1D open chains with "defects"
by Cristian Degli Esposti Boschi 16 Nov '07

16 Nov '07

I would like to use ALPS to study a spin model defined on an open chain in which one or two sites in the middle of the chain can host "defects", for istance the local magnetic field and/or the exchange with neighbouring sites are different from all the other interactions in the chains. Can it be done by proper definitions in the lattice.xml file? (and of course then also in models.xml) Thanks a lot for your work. Cheers, Cristian -- ___________________________________________________ Cristian Degli Esposti Boschi CNR, CNISM, Unita' di Ricerca di Bologna, c/o Dipartimento di Fisica, Universita' di Bologna viale Berti-Pichat, 6/2, 40127, Bologna, Italia tel. ++39 051 2095114 fax ++39 051 2095113 e-mail: cristian.degliesposti -AT- unibo.it web: http://www.df.unibo.it/ricerca-01/theory ___________________________________________________

2 1

Magnetization histogram from exact diagonalization?
by Austen Lamacraft 07 Nov '07

07 Nov '07

Hello, Is there a simple way to get at the histogram of the distribution of the magnetization in the ground state of (say) the transverse field Ising model? Or failing that, a way to get out the full ground state eigenvector obtained by exact diagonalization? A related question: Is there a simple way to take the expectation value of an arbitrary function of spin at a single site in Monte Carlo? I guess this comes under "Definition of custom measurements", and that tutorial isn't finished yet. Thanks, Austen

1 0

dmrg tutorial example is not running
by Aniket Kulkarni 03 Nov '07

03 Nov '07

Hi all, I am trying to run dmrg tutorial example but it is showing error. The error is as follows: $ simple_dmrg <parm1 error: ALPS noninteractiong DMRG application version 1.0 available from http://alps.comp-phys.org/ copyright (c) 2003-2004 by Salvatore R. Manmana <Salva(a)theo3.physik.uni-stuttg art.de> Reinhard M. Noack <Reinhard.Noack(a)physik.uni-marbur g.de> Ian McCulloch <ianmcc(a)physik.rwth-aachen.de> for details see the publication: F. Alet et al., Report cond-mat/0410407. EXCEPTION: bad lexical cast: source type value could not be interpreted as target t Please see the error and tell me the problem. Thanks in advance with regards, Aniket

2 2

basis set
by Aniket Kulkarni 29 Oct '07

29 Oct '07

hi all, Which basis set is used for QMC calculation in ALPS? thanks, Aniket

2 1

Cannot convert fermionic operator to a bosonic matrix
by Aniket Kulkarni 20 Oct '07

20 Oct '07

Dear all, I am new user to alps. I want to calculate magnetic susceptibility for the square model(4 * 4) using Hamiltonian fermion Hubbard. For this I am using looper and dirloop_sse algorithm. But it is not running at all. It is showing following error Cannot convert fermionic operator to a bosonic matrix So please tell me how to calculate? Thanks in advance with regards, Aniket

2 1

Single site DMRG
by Justin David Peel 12 Oct '07

12 Oct '07

Hi, Thanks for the answer about the truncation error. I felt kind of dumb that I hadn't thought of that before, but I don't use unix all that often. I just read through Steven White's 2005 paper "Density matrix renormalization group algorithms with a single center site." I was looking through the dmrg code trying to figure out how to implement the single site method. I was wondering what the general consensus is about this method before I continue trying to implement it. Here is my goal: I would like to try to find the Haldane gap in S=1 Heisenberg ladders. I know that the accepted method for doing this in 1D is to make the ends of the chain be S=1/2 to avoid the end effects. Will this work in ladders as well? I was thinking that the single site method would just allow me to use periodic boundary conditions and avoid the end site problems. I also don't know how to put S=1/2 sites at the ends of the lattice in ALPS. Does anyone know how to do this? Can I just set local_S for each site of the lattice? Thanks, Justin

2 1

uniform susceptibility
by GANG CHEN 02 Oct '07

02 Oct '07

Hello, all I use "fulldiag" to diagonalize my hamiltonian. Because in my problem Sz is not a conserved quantum number, so when I try to use "fulldiag_evaluate" to treat my output xml file, I cannot get uniform_susceptibility file. In order to get the uniform_susceptibility curve, I can probably introduce magnetic field, and change the magnitude of magnetic field, measure the magnetization, see how M changes with h, and use \Delta{M} / \Delta{h} to find chi. Besides this tedious way, is there any other thing I can try in ALPS? Thanks, Gang

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Comp-phys-alps-users