April 2007 - Comp-phys-alps-users

Structure factor and unit cell
by Jean-David Picon 16 Apr '07

16 Apr '07

Hi, Regarding my last questions, if I put 2 vertices in the unit cell without giving their respective positions, what is then the meaning of the structure factor calculated by ALPS ? In other words, what positions of the 2 spins does ALPS use ? Finally, if I give these positions, will I get the structure factor of the crystal of spins ? Thanks a lot. Jean-David

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Unitcell and graphs
by Jean-David Picon 11 Apr '07

11 Apr '07

Hi, I am trying to build a lattice composed of 2 layers of spins where the spins of layer 1 do not play the same role (ie the next neighbour edges J//1 and J//2 in the layers are different) as those in the layer 2. I guess I cannot just use an "anisotropic 3d" latticegraph so I am trying with a unitcell with 2 spins. Can I just create a unitcell as follows <UNITCELL name="dimer_along_Z" dimension="3"> <VERTEX type="1"> <COORDINATE> 0 0 0</COORDINATE> </VERTEX> <VERTEX type="2"> <COORDINATE> 0 0 1 </COORDINATE> </VERTEX> <EDGE type="0"><SOURCE vertex="1" offset="0 0 0"/><TARGET vertex="2" offset="0 0 0"/></EDGE> <EDGE type="1"><SOURCE vertex="1" offset="0 0 0"/><TARGET vertex="1" offset="1 0 0"/></EDGE> <EDGE type="2"><SOURCE vertex="2" offset="0 0 0"/><TARGET vertex="2" offset="1 0 0"/></EDGE> <EDGE type="3"><SOURCE vertex="1" offset="0 0 0"/><TARGET vertex="2" offset="1 0 0"/></EDGE> <EDGE type="4"><SOURCE vertex="2" offset="0 0 0"/><TARGET vertex="2" offset="1 0 0"/></EDGE> <EDGE type="1"><SOURCE vertex="1" offset="0 0 0"/><TARGET vertex="1" offset="0 1 0"/></EDGE> <EDGE type="2"><SOURCE vertex="2" offset="0 0 0"/><TARGET vertex="2" offset="0 1 0"/></EDGE> <EDGE type="3"><SOURCE vertex="1" offset="0 0 0"/><TARGET vertex="2" offset="0 1 0"/></EDGE> <EDGE type="4"><SOURCE vertex="2" offset="0 0 0"/><TARGET vertex="2" offset="0 1 0"/></EDGE> </UNITCELL> and then choose a 2d lattice as LATTICE ? Thanks, Jean-David

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parameter values
by bkeith＠clarku.edu 10 Apr '07

10 Apr '07

Hello, I am using alps version 2 and I have been trying to compare some simulations to experimental data but I can't find out what the units on the parameters are. Is this written somewhere? For instance, is Temperature in kelvin and is the exchange strength J in units of energy or kelvins? -Brian Keith

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Tools
by Jean-David Picon 10 Apr '07

10 Apr '07

Hi, Two questions about extracting data from the output files of dirloop_sse calculations. 1- I used the convert2html tool on a .task*.out.xml file but it would be even more useful if I could convert a whole archive file to html. Is this possible ? 2- Can we build "multiple"plots that is to say not only one y-axis but more e.g. h Mz Stiffness 6.0 31 ... ... ... ... Many thanks, Jean-David Picon

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MC heisenberg follow up/ lattices
by David Miller 09 Apr '07

09 Apr '07

Hi, Thanks for the reply. I would also like to know if the anisotropy can be varied throughout the lattice, i.e. different values for different sites, or is only one value throughout the whole lattice allowed? Additionally I would like some points regarding the lattice definitions to be confirmed. 1. The edge type 0,1,2 corresponds to bond type J0, J1 ,J2 parameters? Edge type default = 0? 2. The edge offset is in units of 'basis vectors' specified in the <BASIS> tags? Default = 0 0 0? Allowing both -ve and +ve numbers? Thanks, David Miller >From: comp-phys-alps-users-request(a)phys.ethz.ch >Reply-To: comp-phys-alps-users(a)phys.ethz.ch >To: comp-phys-alps-users(a)phys.ethz.ch >Subject: Comp-phys-alps-users Digest, Vol 12, Issue 2 >Date: Wed, 28 Mar 2007 12:00:02 +0200 > >Send Comp-phys-alps-users mailing list submissions to > comp-phys-alps-users(a)phys.ethz.ch > >To subscribe or unsubscribe via the World Wide Web, visit > https://webmail.phys.ethz.ch/mailman/listinfo/comp-phys-alps-users >or, via email, send a message with subject or body 'help' to > comp-phys-alps-users-request(a)phys.ethz.ch > >You can reach the person managing the list at > comp-phys-alps-users-owner(a)phys.ethz.ch > >When replying, please edit your Subject line so it is more specific >than "Re: Contents of Comp-phys-alps-users digest..." > > >Today's Topics: > > 1. Re: Classical MC Heisenberg help (Matthias Troyer) > > >---------------------------------------------------------------------- > >Message: 1 >Date: Tue, 27 Mar 2007 17:23:54 +0200 >From: Matthias Troyer <troyer(a)phys.ethz.ch> >Subject: Re: [ALPS-users] Classical MC Heisenberg help >To: comp-phys-alps-users(a)phys.ethz.ch >Message-ID: <531DC60A-E501-4263-ACD0-ECD3FF56F0CB(a)phys.ethz.ch> >Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed > >It should work by specifying the parameter > >D="0 0 1" > >The three components are Dx, Dy and Dz. Please be aware however that >in that case only local updates can be used. > > >Matthias > > >On Mar 27, 2007, at 1:30 AM, David Miller wrote: > > > Dear all, > > > > I am doing classical MC simulations using the Heisenberg model with > > Alps-1.3b2. I would like to include an easy axis/plane anisotropy > > in the Heisenberg Hamiltonian of the form (-/+)D*sum_i((Sz_i)^2), > > how would I acheive this? > > > > Thanks, > > > > David Miller > > > > _________________________________________________________________ > > Solve the Conspiracy and win fantastic prizes. http:// > > www.theconspiracygame.co.uk/ > > > >End of Comp-phys-alps-users Digest, Vol 12, Issue 2 >*************************************************** _________________________________________________________________ Solve the Conspiracy and win fantastic prizes. http://www.theconspiracygame.co.uk/

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