March 2017 - Comp-phys-alps-users

measuring truncation errors in mps_optim
by Robertson Esperanza 07 Dec '17

07 Dec '17

Thank you for all the help so far, now I'm trying to check for convergence of my results. First, is it enough to just check how the truncation error changes with sweeps (at a certain MAXSTATE value) or I need to both check the iteration history of the ground state energy and the truncation error? Second, checking the supplementary materials provided (Computer Physics Communications 185 (2014) 3430–3440) for the Hubbard ladder, why are there 381 values of energy and truncation weights for every iteration? Why is the total truncation error for that iteration is the sum of all the 381 truncation weight values (based on iteration.py)? How is truncation error defined (e.g. is it 1 - sum of all reduced density eigenvalues corresponding to all the picked states?) ? As far as I understand the DMRG algorithm every iteration/sweep has a corresponding bond dimension in which as you progress through iterations (until you reach the "SWEEPS"th iteration), bond dimension increases until you reach "MAXSTATES" at the "SWEEPS"th iteration. Regards, Robertson Esperanza

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Question on harmonic trap in mps_optim
by xiaofanlaohu 12 Apr '17

12 Apr '17

Dear all, I define a lattice with harmonic trap. In the lattice one cell has two subsite A and B. When I use the mps_optim to calculate a lattice. There exist error "Segmentation fault (core dumped)". I want to know how to solve the problem. All files are attached. Thanks! Best, Xiaofan 2017-03-30 xiaofanlaohu

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Binary disorder
by Alexey Sizanov 30 Mar '17

30 Mar '17

Dear All, I would like to ask how can set up a binary disorder in chemical potential for QMC simulations? I want to obtain a system with certain concentration of impurities with modified potential. I use inhomogeneous lattice, then I should somehow set the function for chemical potential. How can I do it for binary disorder? Another way is to create my own graph for every realisation of the disorder, but then simulations don’t measure stiffness (0 winding number) because there don’t know that my graph is a 3D periodic lattice. While stiffness is important for me. May be there is some way to give simulation know that my graph is a lattice? Thank you in advance for any suggestions. Best regards Alexey Sizanov.

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Convenience Script collectXY
by Dominik Schildknecht 29 Mar '17

29 Mar '17

Dear all, I wanted to know if it's already implemented to plot two observables against each other with the combination of pyalps.collectXY and pyalps.plot.plot. As an example I would like to be able to plot energy vs. magnetization in an example like MC-07. This mainly arises as a question if I want to use the exchange Monte Carlo formalism (thanks for that, it seems to work great with very little modification to my code). There the optimized temperature set is saved as an observable. If I still want to be able to plot M vs. T I would need the ability to plot two observables against each other. However it crashes in alps/lib/pyalps/tools.py in the function collectXY at the line xvalue = np.array([data.props[x] for i in range(len(data.y))]) Is what I intend to do possible with collectXY? Best, Dominik -- Paul Scherrer Institut Dominik Schildknecht PhD Student WHGA/129 CH-5232 Villigen-PSI Phone: +41 56 310 55 68

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Question on "MEASURE_LOCAL_AT" in MPS codes
by Desmond 29 Mar '17

29 Mar '17

Dear all, I'm asking about the custom measurement "MEASURE_LOCAL_AT" in the MPS codes. For simplicity, let's consider one measurement on the ground state. From the documentation, the Syntax reads Op1:Op2:Op3 | (i1, i2, i3) My question is: what is the order of operation? Do we operate Op1 to the ground state first or do we operate Op3 to the ground state first? In another word, does it correspond to <gs|Op1 Op2 Op3|gs> or <gs|Op3 Op2 Op1|gs>? Thanks! Desmond

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Free fermion models and diagonalisation
by Anya Weng 25 Mar '17

25 Mar '17

Dear All, I am new to ALPS and would really appreciate any help on the following - 1. I am trying to numerically reproduce the results in this paper by Chen and Nussinov (https://arxiv.org/abs/cond-mat/0703633) - the part where they describe free fermion on the kitaev model. One can see that the lattice of the fermions is a square one with 2 bond types(anisotropy). How do I mention that in ALPS? 2. Can I see the matrix elements of the matrix that ALPS diagonalises? 3. Also, does ALPS dmrg, sparsediag, full diag etc use fourier transform for free fermion models? Where can I see the source codes? What if I don't want to FT to momentum space because k will not be a good quantum number if I introduce some translation symmetry destroying disorder? Thank you very much, Anya Weng

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Fwd: Re: diagonal correlations
by julien 25 Mar '17

25 Mar '17

I forgot the corresponding python script ... On 07/02/2017 17:04, Robertson Esperanza wrote: > Yes, it is intended when I attached it, so it can be changed. When i > run the script, I put the filepath, but I still get the x = [0], y = > [0] result. Can I see what's the result when you run the script? Thank > you for the help. > > On Tue, Feb 7, 2017 at 6:53 PM, Julien > <julien.despres(a)institutoptique.fr > <mailto:julien.despres@institutoptique.fr>> wrote: > > yes, there is no path ... > > Julien > > > On 07/02/2017 09:53, Robertson Esperanza wrote: >> the line where I put the file path of the xml file (i.e. >> 'MODEL_LIBRARY':) ? >> >> On Tue, Feb 7, 2017 at 4:04 PM, Julien >> <julien.despres(a)institutoptique.fr >> <mailto:julien.despres@institutoptique.fr>> wrote: >> >> I tested your file after modifying this line. It works >> >> On 07/02/2017 09:01, Julien wrote: >>> >>> Hi, >>> >>> there is a little problem in your python script; have a look >>> to the line where you include the xml file for the models. >>> >>> Julien >>> >>> >>> - >>> __________________________________ >>> >>> DESPRES Julien >>> Ph.D. student >>> >>> Center for Theoretical Physics >>> Quantum Matter Theory team >>> Ecole Polytechnique >>> 91128 Palaiseau Cedex >>> France, EU >>> Office : 00.10.06 (ground floor) >>> Phone :+33 1 64 33 42 81 <tel:+33%201%2064%2033%2042%2081> >>> >>> Laboratoire Charles Fabry >>> Atom Optics group >>> Institut d'Optique Graduate School >>> 2 Avenue Augustin Fresnel >>> 91127 Palaiseau Cedex >>> France, EU >>> Office : R2.29 (1st floor) >>> Phone:+33 1 64 53 33 49 <tel:+33%201%2064%2053%2033%2049> >>> __________________________________ >>> On 07/02/2017 04:24, Robertson Esperanza wrote: >>>> I tried to print the result of taking the local measurement >>>> for n_i^2 but it only shows >>>> x = [0], y = [0], instead of x = [0 1 2 3 4 5 6 7 8 9], y = >>>> [10 scalar values] (since i'm using a 10-site open chain). >>>> I attached my python script and mymodels.xml. Thank you for >>>> the help. >>>> On Mon, Feb 6, 2017 at 4:29 PM, Julien >>>> <julien.despres(a)institutoptique.fr >>>> <mailto:julien.despres@institutoptique.fr>> wrote: >>>> >>>> Hi, >>>> >>>> you can do it in this way but in your parameter file >>>> you have to write : >>>> >>>> model['MODEL_LIBRARY'] = 'my_own_models.xml' >>>> >>>> or you can put it wherever you want but in this case : >>>> model['MODEL_LIBRARY'] = 'path_to_the_xml_file' Julien >>>> On 06/02/2017 09:21, Robertson Esperanza wrote: >>>>> When creating a new model file, is it necessary that >>>>> the new model file be saved on the same folder of the >>>>> default models.xml file? >>>>> On Mon, Feb 6, 2017 at 3:55 PM, Michele Dolfi >>>>> <dolfim(a)phys.ethz.ch <mailto:dolfim@phys.ethz.ch>> wrote: >>>>> >>>>> MEASURE_AVERAGE is compute the average among all >>>>> sites, i.e. a scalar value. >>>>> MEASURE_LOCAL returns a list of measurements on >>>>> all sites. >>>>> Best, >>>>> Michele >>>>> -- >>>>> ETH Zurich >>>>> Dr.Michele Dolfi >>>>> Institute for Theoretical Physics >>>>> HIT G 32.4 >>>>> Wolfgang-Pauli-Str. 27 >>>>> 8093 Zurich >>>>> Switzerland >>>>> dolfim(a)phys.ethz.ch <mailto:dolfim@phys.ethz.ch> >>>>> www.itp.phys.ethz.ch <http://www.itp.phys.ethz.ch> >>>>> +41 44 633 78 56 <tel:+41%2044%20633%2078%2056> phone >>>>> +41 44 633 11 15 <tel:+41%2044%20633%2011%2015> fax >>>>>> On 6 Feb 2017, at 08:50, Robertson Esperanza >>>>>> <robbie.esperanza(a)gmail.com >>>>>> <mailto:robbie.esperanza@gmail.com>> wrote: >>>>>> Oh, I forgot to mention that I'm using mps_optim >>>>>> application. How does the result of >>>>>> MEASURE_AVERAGE differ from MEASURE_LOCAL, if >>>>>> let's say I use "n" for these parameters? Thanks >>>>>> On Mon, Feb 6, 2017 at 3:08 PM, Michele Dolfi >>>>>> <dolfim(a)phys.ethz.ch >>>>>> <mailto:dolfim@phys.ethz.ch>> wrote: >>>>>> >>>>>> Hello, >>>>>> Could you please be a bit more specific about >>>>>> the application you are running? >>>>>> You are right about the local measurement, >>>>>> but you need MEASURE_LOCAL, since you want to >>>>>> value at each site. Since the n_i^2 operator >>>>>> is not yet defined in the model library, you >>>>>> need to add it yourself. Basically I would do >>>>>> as follow: >>>>>> 1. Copy the file models.xml from >>>>>> ALPS_ROOT/lib/xml/models.xml, where ALPS_ROOT >>>>>> is the root location of your alps installation. >>>>>> 2. Add this definition to your local copy, it >>>>>> defines the n^2 operator >>>>>> <SITEOPERATOR name=“n_squared" site="x"> >>>>>> n(x)*n(x) </SITEOPERATOR> >>>>>> 3. In your input parameters you have now to >>>>>> link to your new model file. >>>>>> MODEL_LIBRARY=“path/to/models.xml” >>>>>> 4. And add your measurement >>>>>> MEASURE_LOCAL[Density^2] = “ n_squared" >>>>>> Hope this helps. >>>>>> Best, >>>>>> Michele >>>>>> -- >>>>>> ETH Zurich >>>>>> Dr.Michele Dolfi >>>>>> Institute for Theoretical Physics >>>>>> HIT G 32.4 >>>>>> Wolfgang-Pauli-Str. 27 >>>>>> 8093 Zurich >>>>>> Switzerland >>>>>> dolfim(a)phys.ethz.ch <mailto:dolfim@phys.ethz.ch> >>>>>> www.itp.phys.ethz.ch >>>>>> <http://www.itp.phys.ethz.ch> >>>>>> +41 44 633 78 56 >>>>>> <tel:+41%2044%20633%2078%2056> phone >>>>>> +41 44 633 11 15 >>>>>> <tel:+41%2044%20633%2011%2015> fax >>>>>>> On 6 Feb 2017, at 07:26, Robertson Esperanza >>>>>>> <robbie.esperanza(a)gmail.com >>>>>>> <mailto:robbie.esperanza@gmail.com>> wrote: >>>>>>> Hello, I only started studying many-body >>>>>>> physics, so there might be gaps in my >>>>>>> knowledge. When using the >>>>>>> MEASURE_CORRELATION, why does the >>>>>>> measurement goes for only site i<j, is it >>>>>>> because there will be "blowing up"? >>>>>>> Alternatively, to measure for i=j, i think I >>>>>>> could use MEASURE_AVERAGE, of let's say >>>>>>> (n_i)^2 where n - n_up + n_down. How could I >>>>>>> define such measurement, where you use an >>>>>>> operator successively? Thank you for replying >>>>>>> Robertson Esperanza >>>>>>> ---- Comp-phys-alps-users Mailing List for >>>>>>> the ALPS Project http://alps.comp-phys.org/ >>>>>>> List info: >>>>>>> https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>>>>>> Archive: >>>>>>> https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>>>>>> Unsubscribe by writing a mail to >>>>>>> comp-phys-alps-users-leave(a)lists.phys.ethz.ch >>>>>>> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >>>>>> ---- Comp-phys-alps-users Mailing List for >>>>>> the ALPS Project http://alps.comp-phys.org/ >>>>>> List info: >>>>>> https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>>>>> Archive: >>>>>> https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>>>>> Unsubscribe by writing a mail to >>>>>> comp-phys-alps-users-leave(a)lists.phys.ethz.ch >>>>>> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >>>>>> >>>>>> >>>>>> ---- Comp-phys-alps-users Mailing List for the >>>>>> ALPS Project http://alps.comp-phys.org/ List >>>>>> info: >>>>>> https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>>>>> Archive: >>>>>> https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>>>>> Unsubscribe by writing a mail to >>>>>> comp-phys-alps-users-leave(a)lists.phys.ethz.ch >>>>>> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >>>>> ---- Comp-phys-alps-users Mailing List for the >>>>> ALPS Project http://alps.comp-phys.org/ List info: >>>>> https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>>>> <https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users> >>>>> Archive: >>>>> https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>>>> <https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users> >>>>> Unsubscribe by writing a mail to >>>>> comp-phys-alps-users-leave(a)lists.phys.ethz.ch >>>>> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >>>>> >>>>> >>>>> ---- >>>>> Comp-phys-alps-users Mailing List for the ALPS Project >>>>> http://alps.comp-phys.org/ >>>>> >>>>> List info:https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>>>> <https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users> >>>>> Archive:https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>>>> <https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users> >>>>> >>>>> Unsubscribe by writing a mail tocomp-phys-alps-users-leave(a)lists.phys.ethz.ch >>>>> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >>>> >>>> -- >>>> __________________________________ >>>> >>>> DESPRES Julien >>>> Ph.D. student >>>> >>>> Center for Theoretical Physics >>>> Quantum Matter Theory team >>>> Ecole Polytechnique >>>> 91128 Palaiseau Cedex >>>> France, EU >>>> Office : 00.10.06 (ground floor) >>>> Phone :+33 1 64 33 42 81 <tel:+33%201%2064%2033%2042%2081> >>>> >>>> Laboratoire Charles Fabry >>>> Atom Optics group >>>> Institut d'Optique Graduate School >>>> 2 Avenue Augustin Fresnel >>>> 91127 Palaiseau Cedex >>>> France, EU >>>> Office : R2.29 (1st floor) >>>> Phone:+33 1 64 53 33 49 <tel:+33%201%2064%2053%2033%2049> >>>> __________________________________ >>>> >>>> ---- Comp-phys-alps-users Mailing List for the ALPS >>>> Project http://alps.comp-phys.org/ List info: >>>> https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>>> <https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users> >>>> Archive: >>>> https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>>> <https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users> >>>> Unsubscribe by writing a mail to >>>> comp-phys-alps-users-leave(a)lists.phys.ethz.ch >>>> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >>>> >>>> ---- >>>> Comp-phys-alps-users Mailing List for the ALPS Project >>>> http://alps.comp-phys.org/ >>>> >>>> List info:https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>>> <https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users> >>>> Archive:https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>>> <https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users> >>>> >>>> Unsubscribe by writing a mail tocomp-phys-alps-users-leave(a)lists.phys.ethz.ch >>>> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >>> - >>> >>> ---- >>> Comp-phys-alps-users Mailing List for the ALPS Project >>> http://alps.comp-phys.org/ >>> >>> List info:https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>> <https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users> >>> Archive:https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>> <https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users> >>> >>> Unsubscribe by writing a mail tocomp-phys-alps-users-leave(a)lists.phys.ethz.ch >>> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >> -- >> __________________________________ >> >> DESPRES Julien >> Ph.D. student >> >> Center for Theoretical Physics >> Quantum Matter Theory team >> Ecole Polytechnique >> 91128 Palaiseau Cedex >> France, EU >> Office : 00.10.06 (ground floor) >> Phone :+33 1 64 33 42 81 <tel:+33%201%2064%2033%2042%2081> >> >> Laboratoire Charles Fabry >> Atom Optics group >> Institut d'Optique Graduate School >> 2 Avenue Augustin Fresnel >> 91127 Palaiseau Cedex >> France, EU >> Office : R2.29 (1st floor) >> Phone:+33 1 64 53 33 49 <tel:+33%201%2064%2053%2033%2049> >> __________________________________ >> >> ---- Comp-phys-alps-users Mailing List for the ALPS Project >> http://alps.comp-phys.org/ List info: >> https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >> <https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users> >> Archive: >> https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >> <https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users> >> Unsubscribe by writing a mail to >> comp-phys-alps-users-leave(a)lists.phys.ethz.ch >> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. >> >> ---- >> Comp-phys-alps-users Mailing List for the ALPS Project >> http://alps.comp-phys.org/ >> >> List info:https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >> <https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users> >> Archive:https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >> <https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users> >> >> Unsubscribe by writing a mail tocomp-phys-alps-users-leave(a)lists.phys.ethz.ch >> <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. > -- > __________________________________ > > DESPRES Julien > Ph.D. student > > Center for Theoretical Physics > Quantum Matter Theory team > Ecole Polytechnique > 91128 Palaiseau Cedex > France, EU > Office : 00.10.06 (ground floor) > Phone :+33 1 64 33 42 81 <tel:+33%201%2064%2033%2042%2081> > > Laboratoire Charles Fabry > Atom Optics group > Institut d'Optique Graduate School > 2 Avenue Augustin Fresnel > 91127 Palaiseau Cedex > France, EU > Office : R2.29 (1st floor) > Phone: +33 1 64 53 33 49 > __________________________________ > > ---- Comp-phys-alps-users Mailing List for the ALPS Project > http://alps.comp-phys.org/ List info: > https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users > <https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users> > Archive: > https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users > <https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users> > Unsubscribe by writing a mail to > comp-phys-alps-users-leave(a)lists.phys.ethz.ch > <mailto:comp-phys-alps-users-leave@lists.phys.ethz.ch>. > > ---- > Comp-phys-alps-users Mailing List for the ALPS Project > http://alps.comp-phys.org/ > > List info:https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users > Archive:https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users > > Unsubscribe by writing a mail tocomp-phys-alps-users-leave(a)lists.phys.ethz.ch. -- __________________________________ DESPRES Julien Ph.D. student Center for Theoretical Physics Quantum Matter Theory team Ecole Polytechnique 91128 Palaiseau Cedex France, EU Office : 00.10.06 (ground floor) Phone : +33 1 64 33 42 81 Laboratoire Charles Fabry Atom Optics group Institut d'Optique Graduate School 2 Avenue Augustin Fresnel 91127 Palaiseau Cedex France, EU Office : R2.29 (1st floor) Phone: +33 1 64 53 33 49 __________________________________

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Local measurements in ALPS
by Axel Gagge 14 Mar '17

14 Mar '17

I am trying to do local measurements on a DMRG state, and thought of using (using Python): parms[0]['MEASURE_LOCAL_AT[n_0]'] = "n|(0)" In this case the operator "n" should have support only on the sites labeled by even integers, but the DMRG run does not return any output. Trying 'MEASURE_LOCAL' of course returns something like "operator n not recognized" since it does not work for odd sites. Is the output not supposed to be included with "pyalps.loadEigenstateMeasurements()"? Is there a way to measure local properties (and correlation functions) between even sites only? Can (and should) operators be defined on the unit cell as well as the sites? /Axel Gagge

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Re: [ALPS-users] XY
by vitbka konef 10 Mar '17

10 Mar '17

I am trying to obtain results from this article. Spin stiffness is not drop to zero at vicinity B(h)=7. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.98.227201 2017-03-09 14:43 GMT+05:00 vitbka konef <konefvitbka53(a)gmail.com>: > I am trying to obtain results from this article. > Spin stiffness is not drop to zero at vicinity B(h)=7. > > > 2017-03-09 14:09 GMT+05:00 vitbka konef <konefvitbka53(a)gmail.com>: > >> I am attached files for simulation. >> >> 2017-03-09 11:06 GMT+05:00 Matthias Troyer <troyer(a)phys.ethz.ch>: >> >>> What do you call Jxy and what is Jyx? >>> >>> > On 8 Mar 2017, at 19:14, vitbka konef <konefvitbka53(a)gmail.com> wrote: >>> > >>> > Dear all. >>> > I am trying calculate the energy of the spin model for Jxy=1 and >>> Jxy=-1. >>> > Why that energy does not depend on the sign of the Jxy (worm , >>> dirloop_sse , fulldiag)? >>> > >>> > Best wishes. >>> > >>> > >>> > >>> > >>> > >>> > ---- >>> > Comp-phys-alps-users Mailing List for the ALPS Project >>> > http://alps.comp-phys.org/ >>> > >>> > List info: https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>> > Archive: https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>> > >>> > Unsubscribe by writing a mail to comp-phys-alps-users-leave@lis >>> ts.phys.ethz.ch. >>> >>> >>> >>> ---- >>> Comp-phys-alps-users Mailing List for the ALPS Project >>> http://alps.comp-phys.org/ >>> >>> List info: https://lists.phys.ethz.ch//listinfo/comp-phys-alps-users >>> Archive: https://lists.phys.ethz.ch//pipermail/comp-phys-alps-users >>> >>> Unsubscribe by writing a mail to comp-phys-alps-users-leave@lis >>> ts.phys.ethz.ch. >>> >> >> >

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XY
by vitbka konef 09 Mar '17

09 Mar '17

Dear all. I am trying calculate the energy of the spin model for Jxy=1 and Jxy=-1. Why that energy does not depend on the sign of the Jxy (worm , dirloop_sse , fulldiag)? Best wishes.

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