Dear Matthias:
Thank you very much for your reply.
This random result is obtained by my DMRG code rather than ALPS.
Do you mean that as parts of the Hamiltonian (H), all terms should be converged ? In fact, the term included in H is S1S2, thus S1S2=(SxSx+SySy+SzSz) acts as a whole in H. What I find is that: SxSx, SySy and SzSz are random, however, I think S1S2(=SxSx+SySy+SzSz) as a whole should have already be converged. I will check whether or not S1S2 is converged and present the result as soon as possible.
Thank you again !
------------------ Original ------------------ From: "comp-phys-alps-users-request"comp-phys-alps-users-request@lists.phys.ethz.ch; Date: Tue, Apr 12, 2011 06:00 PM To: "comp-phys-alps-users"comp-phys-alps-users@lists.phys.ethz.ch;
Subject: Comp-phys-alps-users Digest, Vol 61, Issue 2
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1. Would all the pairwise correlations be converged after the gound-state energy converges ? (???) 2. Re: Would all the pairwise correlations be converged after the gound-state energy converges ? (Matthias Troyer)
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Message: 1 Date: Tue, 12 Apr 2011 09:40:50 +0800 From: ??? sunzhaoyu2000@gmail.com Subject: [ALPS-users] Would all the pairwise correlations be converged after the gound-state energy converges ? To: comp-phys-alps-users@lists.phys.ethz.ch Message-ID: BANLkTi=5kxfMAFzVhTNYK5i67CT=znarrQ@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1
Dear ALPS users and developers:
I want to study a spin ladder with four-site interaction. [ ? ?Phys. Rev. B 67, 100409(R) (2003), http://prb.aps.org/abstract/PRB/v67/i10/e100409 ? ? ]
As ALPS 2.0 do not support 4-site terms, I code DMRG myself. For small size system(L=2,4,6,8,10) and the four-site interaction is zero, I have checked my DMRG code by comparing the obtained ground-state energy with that obtained by ED in ALPS. The two are fairly consistent.
Then I move on to larger systems and four-body term are included. However, I am confused by the DMRG results: in the staggered dimer state of the system(see Phys. Rev. B 67, 100409(R) (2003), Fig. 2), when the ground-state of the ladder has converged, I check the two-site correlations, and find that the correlation function [ G_leg ] between nearest-neighboring two sites on the leg converges very well, meanwhile the correlation function [ G_rung ] between the two sites on the same rung does not converge at all ( G_rung seems to be random with the increase of size L, L = 100 ).
I wonder is this a reasonable result ( is it possible that G_rung becomes undefined or because of some other physical reason, leading to a random average value for G_rung ) ? Or all the pairwise correlations in the system should always be converged after the gound-state energy converges ? Any suggestion would be appreciated.
sunzhaoyu2000@gmail.com
------------------------------
Message: 2 Date: Tue, 12 Apr 2011 06:58:27 +0200 From: Matthias Troyer troyer@phys.ethz.ch Subject: Re: [ALPS-users] Would all the pairwise correlations be converged after the gound-state energy converges ? To: comp-phys-alps-users@lists.phys.ethz.ch Message-ID: 639622C3-988E-44CB-9E33-7329CC65A19F@phys.ethz.ch Content-Type: text/plain; charset=utf-8
Hi,
was this random result obtained by ALPS or by your code? Could you please send us the input files if it was with ALPS? Since the rung correlation function is actually part of the Hamiltonian I don't think that the energy is converged in your case.
Matthias
On 12 Apr 2011, at 03:40, ??? wrote:
Dear ALPS users and developers:
I want to study a spin ladder with four-site interaction. [ Phys. Rev. B 67, 100409(R) (2003), http://prb.aps.org/abstract/PRB/v67/i10/e100409 ]
As ALPS 2.0 do not support 4-site terms, I code DMRG myself. For small size system(L=2,4,6,8,10) and the four-site interaction is zero, I have checked my DMRG code by comparing the obtained ground-state energy with that obtained by ED in ALPS. The two are fairly consistent.
Then I move on to larger systems and four-body term are included. However, I am confused by the DMRG results: in the staggered dimer state of the system(see Phys. Rev. B 67, 100409(R) (2003), Fig. 2), when the ground-state of the ladder has converged, I check the two-site correlations, and find that the correlation function [ G_leg ] between nearest-neighboring two sites on the leg converges very well, meanwhile the correlation function [ G_rung ] between the two sites on the same rung does not converge at all ( G_rung seems to be random with the increase of size L, L = 100 ).
I wonder is this a reasonable result ( is it possible that G_rung becomes undefined or because of some other physical reason, leading to a random average value for G_rung ) ? Or all the pairwise correlations in the system should always be converged after the gound-state energy converges ? Any suggestion would be appreciated.
sunzhaoyu2000@gmail.com
End of Comp-phys-alps-users Digest, Vol 61, Issue 2 ***************************************************
Yes, that can easily happen - your code is not fully converged and still breaks the SU(2) symmetry. To be safe you shgould always measure the symmetrized correlaction function (SxSx+SySy+SzSz)
Matthias
On Apr 12, 2011, at 3:12 PM, sunzhaoyu2000 wrote:
Dear Matthias:
Thank you very much for your reply.
This random result is obtained by my DMRG code rather than ALPS.
Do you mean that as parts of the Hamiltonian (H), all terms should be converged ? In fact, the term included in H is S1S2, thus S1S2=(SxSx+SySy+SzSz) acts as a whole in H. What I find is that: SxSx, SySy and SzSz are random, however, I think S1S2(=SxSx+SySy+SzSz) as a whole should have already be converged. I will check whether or not S1S2 is converged and present the result as soon as possible.
Thank you again !
------------------ Original ------------------ From: "comp-phys-alps-users-request"comp-phys-alps-users-request@lists.phys.ethz.ch; Date: Tue, Apr 12, 2011 06:00 PM To: "comp-phys-alps-users"comp-phys-alps-users@lists.phys.ethz.ch; Subject: Comp-phys-alps-users Digest, Vol 61, Issue 2
Send Comp-phys-alps-users mailing list submissions to comp-phys-alps-users@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@lists.phys.ethz.ch
You can reach the person managing the list at comp-phys-alps-users-owner@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:
- Would all the pairwise correlations be converged after the gound-state energy converges ? (???)
- Re: Would all the pairwise correlations be converged after the gound-state energy converges ? (Matthias Troyer)
Message: 1 Date: Tue, 12 Apr 2011 09:40:50 +0800 From: ??? sunzhaoyu2000@gmail.com Subject: [ALPS-users] Would all the pairwise correlations be converged after the gound-state energy converges ? To: comp-phys-alps-users@lists.phys.ethz.ch Message-ID: BANLkTi=5kxfMAFzVhTNYK5i67CT=znarrQ@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1
Dear ALPS users and developers:
I want to study a spin ladder with four-site interaction. [ ? ?Phys. Rev. B 67, 100409(R) (2003), http://prb.aps.org/abstract/PRB/v67/i10/e100409 ? ? ]
As ALPS 2.0 do not support 4-site terms, I code DMRG myself. For small size system(L=2,4,6,8,10) and the four-site interaction is zero, I have checked my DMRG code by comparing the obtained ground-state energy with that obtained by ED in ALPS. The two are fairly consistent.
Then I move on to larger systems and four-body term are included. However, I am confused by the DMRG results: in the staggered dimer state of the system(see Phys. Rev. B 67, 100409(R) (2003), Fig. 2), when the ground-state of the ladder has converged, I check the two-site correlations, and find that the correlation function [ G_leg ] between nearest-neighboring two sites on the leg converges very well, meanwhile the correlation function [ G_rung ] between the two sites on the same rung does not converge at all ( G_rung seems to be random with the increase of size L, L = 100 ).
I wonder is this a reasonable result ( is it possible that G_rung becomes undefined or because of some other physical reason, leading to a random average value for G_rung ) ? Or all the pairwise correlations in the system should always be converged after the gound-state energy converges ? Any suggestion would be appreciated.
sunzhaoyu2000@gmail.com
Message: 2 Date: Tue, 12 Apr 2011 06:58:27 +0200 From: Matthias Troyer troyer@phys.ethz.ch Subject: Re: [ALPS-users] Would all the pairwise correlations be converged after the gound-state energy converges ? To: comp-phys-alps-users@lists.phys.ethz.ch Message-ID: 639622C3-988E-44CB-9E33-7329CC65A19F@phys.ethz.ch Content-Type: text/plain; charset=utf-8
Hi,
was this random result obtained by ALPS or by your code? Could you please send us the input files if it was with ALPS? Since the rung correlation function is actually part of the Hamiltonian I don't think that the energy is converged in your case.
Matthias
On 12 Apr 2011, at 03:40, ??? wrote:
Dear ALPS users and developers:
I want to study a spin ladder with four-site interaction. [ Phys. Rev. B 67, 100409(R) (2003), http://prb.aps.org/abstract/PRB/v67/i10/e100409 ]
As ALPS 2.0 do not support 4-site terms, I code DMRG myself. For small size system(L=2,4,6,8,10) and the four-site interaction is zero, I have checked my DMRG code by comparing the obtained ground-state energy with that obtained by ED in ALPS. The two are fairly consistent.
Then I move on to larger systems and four-body term are included. However, I am confused by the DMRG results: in the staggered dimer state of the system(see Phys. Rev. B 67, 100409(R) (2003), Fig. 2), when the ground-state of the ladder has converged, I check the two-site correlations, and find that the correlation function [ G_leg ] between nearest-neighboring two sites on the leg converges very well, meanwhile the correlation function [ G_rung ] between the two sites on the same rung does not converge at all ( G_rung seems to be random with the increase of size L, L = 100 ).
I wonder is this a reasonable result ( is it possible that G_rung becomes undefined or because of some other physical reason, leading to a random average value for G_rung ) ? Or all the pairwise correlations in the system should always be converged after the gound-state energy converges ? Any suggestion would be appreciated.
sunzhaoyu2000@gmail.com
End of Comp-phys-alps-users Digest, Vol 61, Issue 2
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