Comp-phys-alps-users

comp-phys-alps-users@lists.phys.ethz.ch

1244 discussions

QMC simulation of time-dependent hamiltonian
by Dan Thompson 03 Aug '11

03 Aug '11

Hello, I was just wondering if there was a way to simulate the quantum annealing of a spin chain/lattice. Namely, adjust the parameters in a model file so that over the course of the quantum monte carlo simulation I could start with one hamiltonian (a simple heisenberg hamiltonian with nearest neighbour couplings and a transverse magnetic field) and finish with a different one (transverse field turned off). Cheers, -Dan

2 1

Where is the measurements defined in hybridization dmft?
by Brains Chen 29 Jul '11

29 Jul '11

Dear all, I want to modify the measurement in the hybridization expansion of dmft and I looked through the source code in alps/applications/dmft/qmc and its two subdirectories hybridization/ and interaction_expansion/. In the hybridization/impurity.h, a paragraph of codes looks // create measurement objects measurements << RealVectorObservable("n"); measurements << RealVectorObservable("order"); measurements << vec_obs_t("Greens"); measurements << vec_obs_t("Greens_4point"); measurements << vec_obs_t("Greens_4point_ud"); measurements << RealObservable("sign"); measurements << RealObservable("MatrixSize"); measurements << RealVectorObservable("overlap"); Where is the 'measurements' defined? -- Kuang-Shing Chen

5 7

Quantum Monte Carlo for Ising in transverse field
by zhian asadzadeh 29 Jul '11

29 Jul '11

Dear Synge, > > no I don't have magnetic field in z direction, but looper results always > gives a finite Magnetization in the z direction. > > also I noticed that if we define the model like this > H=-J \sum_{i,j}S^{x}_{i}S^{x}_{j}-h \sum_{i}S^{z}_{i} > the looper doesn't work, I don't know why? > > Thanks, > Zhian. > Message: 3 Date: Wed, 27 Jul 2011 10:04:54 +0900 From: Synge Todo <wistaria(a)comp-phys.org> Subject: Re: [ALPS-users] Quantum Monte Carlo for Ising in transverse field To: comp-phys-alps-users(a)lists.phys.ethz.ch Message-ID: <17A32C75-B3B0-41ED-9F58-0304E71B8A3F(a)comp-phys.org> Content-Type: text/plain; charset=us-ascii On 2011/07/27, at 1:42, zhian asadzadeh wrote: > @Synge > I took it from Magnetization density, I think also Magnetization in z direction is not zero, > ok, thanks I will try that. Strange. Do you have a finite magnetic field along the z-axis, too? Synge

2 1

ALPS binary installer and MacOS X Lion
by Matthias Troyer 27 Jul '11

27 Jul '11

Dear ALPS users, The ALPS binary installers currently do not work on MacOS X Lion since Apple no longer includes the MPI libraries with MacOS X. You need to build ALPS from source on MacOS X Lion. We hope to release ALPS 2.0.2 soon, which will include support for Lion. Matthias

1 0

Quantum Monte Carlo for Ising in transverse field
by zhian asadzadeh 27 Jul '11

27 Jul '11

Dear Matthias and Synge I understood why there is that discrepancy for small clusters, it is true that we can write the thermal energy as : E(T)=\sum_{k} E(k)(2*n(k,T)-1) but this expression is true for thermodynamic limit, because we know the model has an even and odd parity sectors which they must be diagonalized separately, for T=0 the ground state is in even sector, so the sum over K points are for anti periodic boundary conditions, but for finite temperature we cant arrive to that expression, unless with this approximation that H(odd)=H(even) which is true in the thermodynamic limit, because the dispersion will be continuous and there is no much difference between odd and even space K points. for small sizes I checked the looper and exact diagonalization are same but with large difference with exact, but for large lattices the looper converges to exact result which is thermodynamic result: for L=200, h=0.3 looper:: -0.9238482(6.21e-05) with SWEEPS=4000000 exact:: -0.92385063 @Synge I took it from Magnetization density, I think also Magnetization in z direction is not zero, ok, thanks I will try that. Thanks, Zhian On Mon, Jul 25, 2011 at 12:00 PM, < comp-phys-alps-users-request(a)lists.phys.ethz.ch> wrote: > Send Comp-phys-alps-users mailing list submissions to > comp-phys-alps-users(a)lists.phys.ethz.ch > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.phys.ethz.ch/listinfo/comp-phys-alps-users > or, via email, send a message with subject or body 'help' to > comp-phys-alps-users-request(a)lists.phys.ethz.ch > > You can reach the person managing the list at > comp-phys-alps-users-owner(a)lists.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. Quantum Monte Carlo for Ising in transverse field > (zhian asadzadeh) > 2. Re: Quantum Monte Carlo for Ising in transverse field > (Matthias Troyer) > 3. Re: Quantum Monte Carlo for Ising in transverse field (Synge Todo) > 4. Custom measurements (Alexander Herzog) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 24 Jul 2011 12:48:03 +0200 > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > Subject: [ALPS-users] Quantum Monte Carlo for Ising in transverse > field > To: comp-phys-alps-users(a)lists.phys.ethz.ch > Message-ID: > <CAEw6G6sEs2aaE8oY5S+dFob35edARq12xKp9=4h4BUdrZZ1i7g(a)mail.gmail.com > > > Content-Type: text/plain; charset="iso-8859-1" > > Dear Matthias, > > by \Sigma_{i,j}, I mean \sum_{i,j}, > > for the exact result, we know the model is integrable, so by fermionization > and finally diagonalizing the Hamiltonian we will end up to an Hamiltonian > with sum over independent modes, > H=\sum_{k} E(k) (2 a_{k}^{dagger} a_{k}-1) > > for the T=0 ground state energy, I have compared with DMRG results which > are > exactly same, so I am sure up to this point the form of E(k) and my > summation over k space is correct. > > so finally for E(T) simply we have: > E(T)=\sum_{k} E(k)(2*n(k,T)-1) in which n(k,T)=1/(exp(E(k)/T)+1) ::with > Boltzmann constant=1 > > > Regards, > Zhian. > > > On Sun, Jul 24, 2011 at 12:00 PM, < > comp-phys-alps-users-request(a)lists.phys.ethz.ch> wrote: > > > Send Comp-phys-alps-users mailing list submissions to > > comp-phys-alps-users(a)lists.phys.ethz.ch > > > > To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.phys.ethz.ch/listinfo/comp-phys-alps-users > > or, via email, send a message with subject or body 'help' to > > comp-phys-alps-users-request(a)lists.phys.ethz.ch > > > > You can reach the person managing the list at > > comp-phys-alps-users-owner(a)lists.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. Quantum Monte Carlo for Ising in transverse field > > (zhian asadzadeh) > > 2. Re: Quantum Monte Carlo for Ising in transverse field > > (Matthias Troyer) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Sat, 23 Jul 2011 16:29:39 +0200 > > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > > Subject: [ALPS-users] Quantum Monte Carlo for Ising in transverse > > field > > To: comp-phys-alps-users(a)lists.phys.ethz.ch > > Message-ID: > > <CAEw6G6sPavSO0RMreyy701xo+LN4M4LGrBzOLJkonEKs9S= > Wkw(a)mail.gmail.com > > > > > Content-Type: text/plain; charset="iso-8859-1" > > > > Dear Matthias, > > > > my intention is doing finite T QMC for 2D ising in transverse field > with > > the following Hamiltonian: > > H=-J \Sigma_{i,j} S_{i}^{z} S_{j}^{z}-h \Sigma_{i} S_{i}^{x} > > but for checking the accuracy of the numeric I did some checks for 1D > > case which we can have an exact results, > > probably I am expecting too much accuracy, for example: > > > > L=100, T=0.32859 > > Exact:: E(T)=-105.29789708270407, Mx(T)=0.27030367598168420 > > looper:: E(T)=-105.61795 (0.00554), M(T)=0.4093185 (0.000138) ( I > > think it is in z direction) > > with SWEEPS:6000000, THERMALIZATION=2000000 > > > > I have checked also for other sizes and very large SWEEPS. > > I don't expect to get exact result but I need much more accuracy in > the > > calculated energy. > > > > and also other question: that magnetization which looper calculates > is > > in the z direction? > > can I also measure M_{x} just with declaring it in parm file? > > > > Thanks a lot, > > Zhian. > > > > > > On Sat, Jul 23, 2011 at 12:00 PM, < > > comp-phys-alps-users-request(a)lists.phys.ethz.ch> wrote: > > > > > Send Comp-phys-alps-users mailing list submissions to > > > comp-phys-alps-users(a)lists.phys.ethz.ch > > > > > > To subscribe or unsubscribe via the World Wide Web, visit > > > https://lists.phys.ethz.ch/listinfo/comp-phys-alps-users > > > or, via email, send a message with subject or body 'help' to > > > comp-phys-alps-users-request(a)lists.phys.ethz.ch > > > > > > You can reach the person managing the list at > > > comp-phys-alps-users-owner(a)lists.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. restarting Lanczos iteration (jessica.alfonsi(a)unipd.it) > > > 2. Quantum Monte Carlo for Ising in transvers field (zhian asadzadeh) > > > 3. Re: Quantum Monte Carlo for Ising in transvers field > > > (Matthias Troyer) > > > 4. Re: restarting Lanczos iteration (Matthias Troyer) > > > > > > > > > ---------------------------------------------------------------------- > > > > > > Message: 1 > > > Date: Fri, 22 Jul 2011 12:22:47 +0200 > > > From: jessica.alfonsi(a)unipd.it > > > Subject: [ALPS-users] restarting Lanczos iteration > > > To: comp-phys-alps-users(a)lists.phys.ethz.ch > > > Message-ID: > > > <5b0ae17b0813c63a97720e0fbc6cc1c6.squirrel(a)webmail.unipd.it> > > > Content-Type: text/plain;charset=utf-8 > > > > > > Hi all, > > > I'd like to modify the Lanczos *.cpp examples in IETL example folder to > > be > > > able to restart the iteration from any interruption point during the > > > Lanczos iteration. I suppose first one has to dump some information, > for > > > instance the cofficients of T-matrix and the starting vector, however > the > > > more difficult part would be the resuming of the iteration. Can > somebody > > > give me some hints on how accomplishing this task? Thanks in advance... > > > > > > Best regards, > > > > > > Jessica Alfonsi > > > > > > > > > > > > > > > > > > ------------------------------ > > > > > > Message: 2 > > > Date: Fri, 22 Jul 2011 13:03:23 +0200 > > > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > > > Subject: [ALPS-users] Quantum Monte Carlo for Ising in transvers field > > > To: comp-phys-alps-users(a)lists.phys.ethz.ch > > > Message-ID: > > > < > > CAEw6G6vLtP2G8kviZ97cxgZy9Dv1x_MqyUzFWs9ejnM8WvwnmA(a)mail.gmail.com > > > > > > > Content-Type: text/plain; charset="iso-8859-1" > > > > > > Dear All, > > > > > > I am trying to do QMC at finite temperature for calculating the > > > magnetization of *Ising model in transverse field*, but I realized just > > > looper code is working for this model, ( the others codes doesn't work > > with > > > off diagonal matrix elements) but the result are not so good. > > > I am interested to modify dirloop_sse for this model, is it possible? > > > I appreciate your help, > > > Thanks, > > > zhian. > > >

3 2

TEBD: kink state problem
by juan florez 26 Jul '11

26 Jul '11

Dear Matthias Troyer and ALPS developers, I've been testing the TEBD routines by using python programs as the ones present in the tutorials. I wanted to go further from what we can find in such tutorials because of my research interests and according to the possibilities of the TEBD routines of the ALPS 2.0 illustrated in the paper: The ALPS project release 2.0: open source software for strongly correlated systems. What I just found is that if I use a general spin value in the spin chains (TEBD-02) let say S, the initial "kink" state of the chain does not represent a general down,down,....,up,up.... states for the system but just a partial spin flit is performed in the initial aligned state. I check the numerical results at the very initial moment of the spin dynamics calculation and the "kink" state for a S system turns out to be S S S......, S-0.5 S-0.5 S-0.5 ....... which means a 0.5 less in the second part of the vector state instead of being S S S......, -S -S -S as it should be. I read the ALPS web page and paper and I couldn't see anything expressing that the TEBD routines are just working for spin 1/2 in the case of the kink state. If it is so, how can I modify such a situation in order to work with different spin values?. The ALPS paper says that the TEBD routines should work for the "spin" models in the ALPS and such models allow modifications of the spin value. Thanks for your answer. JM.

1 0

Quantum Monte Carlo for Ising in transverse field
by zhian asadzadeh 25 Jul '11

25 Jul '11

Dear Matthias, by \Sigma_{i,j}, I mean \sum_{i,j}, for the exact result, we know the model is integrable, so by fermionization and finally diagonalizing the Hamiltonian we will end up to an Hamiltonian with sum over independent modes, H=\sum_{k} E(k) (2 a_{k}^{dagger} a_{k}-1) for the T=0 ground state energy, I have compared with DMRG results which are exactly same, so I am sure up to this point the form of E(k) and my summation over k space is correct. so finally for E(T) simply we have: E(T)=\sum_{k} E(k)(2*n(k,T)-1) in which n(k,T)=1/(exp(E(k)/T)+1) ::with Boltzmann constant=1 Regards, Zhian. On Sun, Jul 24, 2011 at 12:00 PM, < comp-phys-alps-users-request(a)lists.phys.ethz.ch> wrote: > Send Comp-phys-alps-users mailing list submissions to > comp-phys-alps-users(a)lists.phys.ethz.ch > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.phys.ethz.ch/listinfo/comp-phys-alps-users > or, via email, send a message with subject or body 'help' to > comp-phys-alps-users-request(a)lists.phys.ethz.ch > > You can reach the person managing the list at > comp-phys-alps-users-owner(a)lists.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. Quantum Monte Carlo for Ising in transverse field > (zhian asadzadeh) > 2. Re: Quantum Monte Carlo for Ising in transverse field > (Matthias Troyer) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 23 Jul 2011 16:29:39 +0200 > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > Subject: [ALPS-users] Quantum Monte Carlo for Ising in transverse > field > To: comp-phys-alps-users(a)lists.phys.ethz.ch > Message-ID: > <CAEw6G6sPavSO0RMreyy701xo+LN4M4LGrBzOLJkonEKs9S=Wkw(a)mail.gmail.com > > > Content-Type: text/plain; charset="iso-8859-1" > > Dear Matthias, > > my intention is doing finite T QMC for 2D ising in transverse field with > the following Hamiltonian: > H=-J \Sigma_{i,j} S_{i}^{z} S_{j}^{z}-h \Sigma_{i} S_{i}^{x} > but for checking the accuracy of the numeric I did some checks for 1D > case which we can have an exact results, > probably I am expecting too much accuracy, for example: > > L=100, T=0.32859 > Exact:: E(T)=-105.29789708270407, Mx(T)=0.27030367598168420 > looper:: E(T)=-105.61795 (0.00554), M(T)=0.4093185 (0.000138) ( I > think it is in z direction) > with SWEEPS:6000000, THERMALIZATION=2000000 > > I have checked also for other sizes and very large SWEEPS. > I don't expect to get exact result but I need much more accuracy in the > calculated energy. > > and also other question: that magnetization which looper calculates is > in the z direction? > can I also measure M_{x} just with declaring it in parm file? > > Thanks a lot, > Zhian. > > > On Sat, Jul 23, 2011 at 12:00 PM, < > comp-phys-alps-users-request(a)lists.phys.ethz.ch> wrote: > > > Send Comp-phys-alps-users mailing list submissions to > > comp-phys-alps-users(a)lists.phys.ethz.ch > > > > To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.phys.ethz.ch/listinfo/comp-phys-alps-users > > or, via email, send a message with subject or body 'help' to > > comp-phys-alps-users-request(a)lists.phys.ethz.ch > > > > You can reach the person managing the list at > > comp-phys-alps-users-owner(a)lists.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. restarting Lanczos iteration (jessica.alfonsi(a)unipd.it) > > 2. Quantum Monte Carlo for Ising in transvers field (zhian asadzadeh) > > 3. Re: Quantum Monte Carlo for Ising in transvers field > > (Matthias Troyer) > > 4. Re: restarting Lanczos iteration (Matthias Troyer) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Fri, 22 Jul 2011 12:22:47 +0200 > > From: jessica.alfonsi(a)unipd.it > > Subject: [ALPS-users] restarting Lanczos iteration > > To: comp-phys-alps-users(a)lists.phys.ethz.ch > > Message-ID: > > <5b0ae17b0813c63a97720e0fbc6cc1c6.squirrel(a)webmail.unipd.it> > > Content-Type: text/plain;charset=utf-8 > > > > Hi all, > > I'd like to modify the Lanczos *.cpp examples in IETL example folder to > be > > able to restart the iteration from any interruption point during the > > Lanczos iteration. I suppose first one has to dump some information, for > > instance the cofficients of T-matrix and the starting vector, however the > > more difficult part would be the resuming of the iteration. Can somebody > > give me some hints on how accomplishing this task? Thanks in advance... > > > > Best regards, > > > > Jessica Alfonsi > > > > > > > > > > > > ------------------------------ > > > > Message: 2 > > Date: Fri, 22 Jul 2011 13:03:23 +0200 > > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > > Subject: [ALPS-users] Quantum Monte Carlo for Ising in transvers field > > To: comp-phys-alps-users(a)lists.phys.ethz.ch > > Message-ID: > > < > CAEw6G6vLtP2G8kviZ97cxgZy9Dv1x_MqyUzFWs9ejnM8WvwnmA(a)mail.gmail.com > > > > > Content-Type: text/plain; charset="iso-8859-1" > > > > Dear All, > > > > I am trying to do QMC at finite temperature for calculating the > > magnetization of *Ising model in transverse field*, but I realized just > > looper code is working for this model, ( the others codes doesn't work > with > > off diagonal matrix elements) but the result are not so good. > > I am interested to modify dirloop_sse for this model, is it possible? > > I appreciate your help, > > Thanks, > > zhian. > >

3 2

Quantum Monte Carlo for Ising in transverse field
by zhian asadzadeh 25 Jul '11

25 Jul '11

Dear Matthias, my intention is doing finite T QMC for 2D ising in transverse field with the following Hamiltonian: H=-J \Sigma_{i,j} S_{i}^{z} S_{j}^{z}-h \Sigma_{i} S_{i}^{x} but for checking the accuracy of the numeric I did some checks for 1D case which we can have an exact results, probably I am expecting too much accuracy, for example: L=100, T=0.32859 Exact:: E(T)=-105.29789708270407, Mx(T)=0.27030367598168420 looper:: E(T)=-105.61795 (0.00554), M(T)=0.4093185 (0.000138) ( I think it is in z direction) with SWEEPS:6000000, THERMALIZATION=2000000 I have checked also for other sizes and very large SWEEPS. I don't expect to get exact result but I need much more accuracy in the calculated energy. and also other question: that magnetization which looper calculates is in the z direction? can I also measure M_{x} just with declaring it in parm file? Thanks a lot, Zhian. On Sat, Jul 23, 2011 at 12:00 PM, < comp-phys-alps-users-request(a)lists.phys.ethz.ch> wrote: > Send Comp-phys-alps-users mailing list submissions to > comp-phys-alps-users(a)lists.phys.ethz.ch > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.phys.ethz.ch/listinfo/comp-phys-alps-users > or, via email, send a message with subject or body 'help' to > comp-phys-alps-users-request(a)lists.phys.ethz.ch > > You can reach the person managing the list at > comp-phys-alps-users-owner(a)lists.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. restarting Lanczos iteration (jessica.alfonsi(a)unipd.it) > 2. Quantum Monte Carlo for Ising in transvers field (zhian asadzadeh) > 3. Re: Quantum Monte Carlo for Ising in transvers field > (Matthias Troyer) > 4. Re: restarting Lanczos iteration (Matthias Troyer) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 22 Jul 2011 12:22:47 +0200 > From: jessica.alfonsi(a)unipd.it > Subject: [ALPS-users] restarting Lanczos iteration > To: comp-phys-alps-users(a)lists.phys.ethz.ch > Message-ID: > <5b0ae17b0813c63a97720e0fbc6cc1c6.squirrel(a)webmail.unipd.it> > Content-Type: text/plain;charset=utf-8 > > Hi all, > I'd like to modify the Lanczos *.cpp examples in IETL example folder to be > able to restart the iteration from any interruption point during the > Lanczos iteration. I suppose first one has to dump some information, for > instance the cofficients of T-matrix and the starting vector, however the > more difficult part would be the resuming of the iteration. Can somebody > give me some hints on how accomplishing this task? Thanks in advance... > > Best regards, > > Jessica Alfonsi > > > > > > ------------------------------ > > Message: 2 > Date: Fri, 22 Jul 2011 13:03:23 +0200 > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > Subject: [ALPS-users] Quantum Monte Carlo for Ising in transvers field > To: comp-phys-alps-users(a)lists.phys.ethz.ch > Message-ID: > <CAEw6G6vLtP2G8kviZ97cxgZy9Dv1x_MqyUzFWs9ejnM8WvwnmA(a)mail.gmail.com > > > Content-Type: text/plain; charset="iso-8859-1" > > Dear All, > > I am trying to do QMC at finite temperature for calculating the > magnetization of *Ising model in transverse field*, but I realized just > looper code is working for this model, ( the others codes doesn't work with > off diagonal matrix elements) but the result are not so good. > I am interested to modify dirloop_sse for this model, is it possible? > I appreciate your help, > Thanks, > zhian. >

3 2

restarting Lanczos iteration
by jessica.alfonsi＠unipd.it 22 Jul '11

22 Jul '11

Hi all, I'd like to modify the Lanczos *.cpp examples in IETL example folder to be able to restart the iteration from any interruption point during the Lanczos iteration. I suppose first one has to dump some information, for instance the cofficients of T-matrix and the starting vector, however the more difficult part would be the resuming of the iteration. Can somebody give me some hints on how accomplishing this task? Thanks in advance... Best regards, Jessica Alfonsi

2 1

Quantum Monte Carlo for Ising in transvers field
by zhian asadzadeh 22 Jul '11

22 Jul '11

Dear All, I am trying to do QMC at finite temperature for calculating the magnetization of *Ising model in transverse field*, but I realized just looper code is working for this model, ( the others codes doesn't work with off diagonal matrix elements) but the result are not so good. I am interested to modify dirloop_sse for this model, is it possible? I appreciate your help, Thanks, zhian.

2 1

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Comp-phys-alps-users