2013/3/15 <comp-phys-alps-users-request@lists.phys.ethz.ch>

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Today's Topics:

1. Kondo lattice DMRG input file (Bo-Nan JIANG)
2. the right way to define a harmonic trap (Bo-Nan JIANG)
3. truncation error in DMRG (Bo-Nan JIANG)
4. Question about simulation output (Prof. Dr. Thomas Pruschke)
5. Re: the right way to define a harmonic trap (Ryo IGARASHI)
6. TEBD in ALPS (Bo-Nan JIANG)
7. Re: TEBD in ALPS (Ryo IGARASHI)

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Message: 1
Date: Fri, 15 Mar 2013 08:16:25 +0800
From: Bo-Nan JIANG <bonanjiang@gmail.com>
To: "comp-phys-alps-users@lists.phys.ethz.ch"
<comp-phys-alps-users@lists.phys.ethz.ch>
Subject: [ALPS-users] Kondo lattice DMRG input file
Message-ID:
<CADqUQBPtKTLoVmWX-V7XRvNkgk=dpYa4TQ-SgB+rJ4__Mb2JZA@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

Hi,Matt
This is the input parameter file with your ALPS Kondo lattice model, the
DMRG parameters are chosen so that the calculation can finish in a short
time, thus be easy to be debugged :

--------------------------------INPUT PARAMETER FILE (FILE NAME
my_parm)-----------------------------------------

LATTICE_LIBRARY="my_lattices.xml"
LATTICE="chain lattice"
MODEL="Kondo lattice"
mu=0
t=1
J=0.2
{L=32
SWEEPS=4
MAXSTATES=40
NUMBER_EIGENVALUES=2}

-----------------------------END OF INPUT PARAMETER
FILE---------------------------------

-----------------------------my_lattices.xml--------------------------------------------------------------

<LATTICES>

<LATTICE name="chain lattice" dimension="1">
<PARAMETER name="a" default="1"/>
<BASIS><VECTOR>a</VECTOR></BASIS>
<RECIPROCALBASIS><VECTOR>2*pi/a</VECTOR></RECIPROCALBASIS>
</LATTICE>
<UNITCELL name="fermion" dimension="1">
<VERTEX type="0"/>
<VERTEX type="1"/>
<EDGE type="0"><SOURCE vertex="1" offset="0"/><TARGET vertex="1"
offset="1"/></EDGE>
<EDGE type="1"><SOURCE vertex="1" offset="0"/><TARGET vertex="2"
offset="0"/></EDGE>
</UNITCELL>
<LATTICEGRAPH name = "chain lattice">
<FINITELATTICE>
<LATTICE ref="chain lattice"/>
<PARAMETER name="L" default="4"/>
<EXTENT size="L"/>
<BOUNDARY type="open"/>
</FINITELATTICE>
<UNITCELL ref="fermion"/>
</LATTICEGRAPH>

</LATTICES>

-------------------------END OF
my_lattices.xml----------------------------------------

-------------------------COMMAND LINE
INPUT-----------------------------------------

parameter2xml my_parm

dmrg --write-xml my_parm.in.xml

------------------------END OF COMMAND LINE
INPUT-------------------------------

ERROR: site basis for type 2 not found. Hope you guys can find out what is
going on.

By the way, if I use wild card and my custom fermion code to reprogram
Model="Kondo lattice" in the fashion of your ALPS Model="spin", the DMRG
and ED both works. But the problem is with mu=0 t=1 and J=1, by DMRG, my
custom Kondo Lattice model shows the gap = 0.21, with 10^-10 truncation
error, while K.Ueda in Phys.Rev.B. 46, 3175 FIG.1 shows a energy gap
smaller than 0.2 under the same parameter condition by ED. (BOTH HALF
FILLING) I recheck my custom Kondo lattice model and find no obvious
mistakes. And I do not know why, can you help me here, too?

--------------------------INPUT FILE OF CUSTOM KONDO LATTICE
MODEL------------------------------

LATTICE_LIBRARY="my_lattices.xml"
LATTICE="chain lattice"
MODEL_LIBRARY="my_models.xml"
MODEL="Kondo lattice"
CONSERVED_QUANTUMNUMBERS="N"
N_total=128
MEASURE_LOCAL[local density]=n
local_max0=2
local_min0=0
local_max1=1
local_min1=1
mu=0
t=1
J=1
{L=64
SWEEPS=10
MAXSTATES=500
NUMBER_EIGENVALUES=2}

------------------------CUSTOM KONDO LATTICE MODEL--------------------------

<MODELS>
<SITEBASIS name="fermion">
<PARAMETER name="local_maximum" default="local_max"/>
<PARAMETER name="local_max" default="2"/>
<PARAMETER name="local_minimun" default="local_min"/>
<PARAMETER name="local_min" default="0"/>
<QUANTUMNUMBER name="N" min="local_minimum" max="local_maximum"
type="fermionic"/>
<QUANTUMNUMBER name="Sz" min="-N*(2-N)/2" max="N*(2-N)/2"/>
<QUANTUMNUMBER name="Nup" min="(N+2*Sz)/2" max="(N+2*Sz)/2"/>
<QUANTUMNUMBER name="Ndown" min="(N-2*Sz)/2" max="(N-2*Sz)/2"/>
<OPERATOR name="Splus" matrixelement="1">
<CHANGE quantumnumber="Nup" change="1"/>
<CHANGE quantumnumber="Ndown" change="-1"/>
<CHANGE quantumnumber="Sz" change="1"/>
</OPERATOR>
<OPERATOR name="Sminus" matrixelement="1">
<CHANGE quantumnumber="Nup" change="-1"/>
<CHANGE quantumnumber="Ndown" change="+1"/>
<CHANGE quantumnumber="Sz" change="-1"/>
</OPERATOR>
<OPERATOR name="Sz" matrixelement="Sz"/>
<OPERATOR name="c_down" matrixelement="1">
<CHANGE quantumnumber="Ndown" change="-1"/>
<CHANGE quantumnumber="N" change="-1"/>
<CHANGE quantumnumber="Sz" change="1/2"/>
</OPERATOR>
<OPERATOR name="cdag_down" matrixelement="1">
<CHANGE quantumnumber="Ndown" change="1"/>
<CHANGE quantumnumber="N" change="1"/>
<CHANGE quantumnumber="Sz" change="-1/2"/>
</OPERATOR>
<OPERATOR name="c_up" matrixelement="1">
<CHANGE quantumnumber="Nup" change="-1"/>
<CHANGE quantumnumber="N" change="-1"/>
<CHANGE quantumnumber="Sz" change="-1/2"/>
</OPERATOR>
<OPERATOR name="cdag_up" matrixelement="1">
<CHANGE quantumnumber="Nup" change="1"/>
<CHANGE quantumnumber="N" change="1"/>
<CHANGE quantumnumber="Sz" change="+1/2"/>
</OPERATOR>
<OPERATOR name="n" matrixelement="N"/>
<OPERATOR name="n_up" matrixelement="(N+2*Sz)/2"/>
<OPERATOR name="n_down" matrixelement="(N-2*Sz)/2"/>
</SITEBASIS>

<BASIS name="Kondo lattice">
<SITEBASIS ref="fermion">
<PARAMETER name="local_maximum" value="local_max#"/>
<PARAMETER name="local_max#" value="local_max"/>
<PARAMETER name="local_max" value="2"/>
<PARAMETER name="local_minimum" value="local_min#"/>
<PARAMETER name="local_min#" value="local_min"/>
<PARAMETER name="local_min" value="0"/>
</SITEBASIS>
<CONSTRAINT quantumnumber="N" value="N_total"/>

</BASIS>

<BONDOPERATOR name="exchange" source="x" target="y">
Sz(x)*Sz(y)+1/2*(Splus(x)*Sminus(y)+Sminus(x)*Splus(y))
</BONDOPERATOR>

<BONDOPERATOR name="fermion_hop" source="x" target="y">

cdag_up(x)*c_up(y)+cdag_up(y)*c_up(x)+cdag_down(x)*c_down(y)+cdag_down(y)*c_down(x)
</BONDOPERATOR>

<HAMILTONIAN name="Kondo lattice">
<PARAMETER name="mu" default="0"/>
<PARAMETER name="t" default="1"/>
<PARAMETER name="J" default="1"/>
<BASIS ref="Kondo lattice"/>
<SITETERM type="0" site="i">
-mu*n(i)
</SITETERM>
<SITETERM type="1">
0
</SITETERM>
<BONDTERM type="0" source="i" target="j">
-t*fermion_hop(i,j)
</BONDTERM>
<BONDTERM type="1" source="i" target="j">
J*exchange(i,j)
</BONDTERM>
</HAMILTONIAN>

</MODELS>

--------------------------CHAIN LATTICE IN my_lattices.xml
--------------------------------------

<LATTICES>

<LATTICE name="chain lattice" dimension="1">
<PARAMETER name="a" default="1"/>
<BASIS><VECTOR>a</VECTOR></BASIS>
<RECIPROCALBASIS><VECTOR>2*pi/a</VECTOR></RECIPROCALBASIS>
</LATTICE>
<UNITCELL name="fermion" dimension="1">
<VERTEX type="0"/>
<VERTEX type="1"/>
<EDGE type="0"><SOURCE vertex="1" offset="0"/><TARGET vertex="1"
offset="1"/></EDGE>
<EDGE type="1"><SOURCE vertex="1" offset="0"/><TARGET vertex="2"
offset="0"/></EDGE>
</UNITCELL>
<LATTICEGRAPH name = "chain lattice">
<FINITELATTICE>
<LATTICE ref="chain lattice"/>
<PARAMETER name="L" default="4"/>
<EXTENT size="L"/>
<BOUNDARY type="open"/>
</FINITELATTICE>
<UNITCELL ref="fermion"/>
</LATTICEGRAPH>

</LATTICES>

---------------------------------------END-------------------------------------------------------

Best,
Bo-Nan

--
Stay foolish,Stay hungry.
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Message: 2
Date: Fri, 15 Mar 2013 10:35:46 +0800
From: Bo-Nan JIANG <bonanjiang@gmail.com>
To: "comp-phys-alps-users@lists.phys.ethz.ch"
<comp-phys-alps-users@lists.phys.ethz.ch>
Subject: [ALPS-users] the right way to define a harmonic trap
Message-ID:
<CADqUQBMgZMcAX73Dvy4zdbBE1CTS7wUHnUGb=qiKhc3Gv2Eu_Q@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

Hi,all
I am confused about how to define a harmonic trap in ALPS, shall I add it
directly to the SITETERM as follows?

<SITETERM type="0" site="i">
<PARAMETER name="x" value="i"/>
-mu*n(i)+V*n(i)*(x-L/2)*(x-L/2)
</SITETERM>
where parameters mu and V, operator n(i) are defined in my_models.xml
but, L the length of lattice is defined in a separate independent file
my_lattices.xml.

Is this kind of definition of harmonic trap OK in ALPS?

Bo-Nan
--
Stay foolish,Stay hungry.
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Message: 3
Date: Fri, 15 Mar 2013 10:43:59 +0800
From: Bo-Nan JIANG <bonanjiang@gmail.com>
To: "comp-phys-alps-users@lists.phys.ethz.ch"
<comp-phys-alps-users@lists.phys.ethz.ch>
Subject: [ALPS-users] truncation error in DMRG
Message-ID:
<CADqUQBOVKAU8fR2xJ-cd_jp5EuN8V3g7YXsBjCnwYQbf5-rM2A@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

Hi,all
In DMRG, what does the sign of truncation error mean? In today's ALPS DMRG,
I have got a negative truncation error, wow! So, I think what does a
negative truncation error mean? the same as the positive one?

Bo-Nan

--
Stay foolish,Stay hungry.
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Message: 4
Date: Fri, 15 Mar 2013 04:55:21 +0100
From: "Prof. Dr. Thomas Pruschke"
<pruschke@theorie.physik.uni-goettingen.de>
To: comp-phys-alps-users@lists.phys.ethz.ch
Subject: [ALPS-users] Question about simulation output
Message-ID:
<787AC724-4EA0-4CB8-A69F-2C23F2A7B608@theorie.physik.uni-goettingen.de>

Content-Type: text/plain; charset=iso-8859-1

Simulations which use ALPS' RealObservable/RealVectorObservable return in the output file under /simulation/results/quantitiy/timeseries some data I guess/hope can be used to perform ones own data analysis. Unfortunately, even after undergoing the tedious work of finding out where and how things are written out, I still do not understand the actual background of this output. It seems that independent of the simulation time/number of measurements the number of data sets per MPI task is always 2, only the binsize varies (although even that is not really related to the simulation parameters). It also took me quite some time to find out by experiment how to access the binsize, as this is needed to normalize the data in each bin. Furthermore, in the case of vector observables the binsize parameter actually contains the value actual_binsize*len_of_vector instead of simply actual_binsize. Is this a bug or a feature? In any case, it makes the further processing a bit cumbersome as on
e always needs to check what type of observable this is.
My questions thus are:
1) What is the precise meaning of this timeseries output, i.e. does it provide (per MPI task) a set of statistically independent/normal distributed data for further data analysis?
2) How are the bins/timeseries sets generated, i.e. what controls their size, number and so on?
2) How can I (!) as a user control these quantities, in particular binsize and number of bins generated?

Best
Thomas Pruschke

--
Prof. Dr. Thomas Pruschke
Institute for Theoretical Physics
Friedrich-Hund-Platz 1
37077 Goettingen
Germany
Phone +49 551 39 7683
FAX +49 551 39 9263

------------------------------

Message: 5
Date: Fri, 15 Mar 2013 13:32:30 +0900
From: Ryo IGARASHI <rigarash@issp.u-tokyo.ac.jp>
To: comp-phys-alps-users <comp-phys-alps-users@lists.phys.ethz.ch>
Subject: Re: [ALPS-users] the right way to define a harmonic trap
Message-ID:
<CAHur-O_Bb_hY7FhtfdWP2QODwLtOTjbzaeZZ1buZkdxuUWKS2g@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Hi,

The harmonic trap which I used in (the ALPS part of) the calculation of
PRB82, 014202 (2010) (http://dx.doi.org/10.1103/PhysRevB.82.014202) are:

1. define "inhomogeneous chain lattice" as follows:

<LATTICEGRAPH name = "inhomogeneous open chain lattice">
<FINITELATTICE>
<LATTICE ref="chain lattice"/>
<EXTENT dimension="1" size ="L"/>
<BOUNDARY type="open"/>
</FINITELATTICE>
<UNITCELL ref="simple1d"/>
<INHOMOGENEOUS><VERTEX/></INHOMOGENEOUS>
</LATTICEGRAPH>

2. add site-dependent 'mu' term in the parameter file:

LATTICE="inhomogeneous open chain lattice"
MODEL="fermion Hubbard"
CONSERVED_QUANTUMNUMBERS="Nup,Ndown"
L=20
t=1
U=2
mu=-0.006*(x-L/2+0.5)^2
{ Nup_total=10; Ndown_total=10 }

At least the above setting works fine for ALPS DMRG code.
Of course you should check the convergence carefully by changing sweeps.

I don't think changing the model is necessary.

Best regards,
--
Ryo IGARASHI, Ph.D.
rigarash@issp.u-tokyo.ac.jp
OpenPGP fingerprint: BAD9 71E3 28F3 8952 5640 6A53 EC79 A280 6A19 2319

------------------------------

Message: 6
Date: Fri, 15 Mar 2013 15:21:59 +0800
From: Bo-Nan JIANG <bonanjiang@gmail.com>
To: "comp-phys-alps-users@lists.phys.ethz.ch"
<comp-phys-alps-users@lists.phys.ethz.ch>
Subject: [ALPS-users] TEBD in ALPS
Message-ID:
<CADqUQBMv_+x6gHR0dEJ8D04e+VbNJsmx=Y6G-8FmgdZsD7YM2A@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

Hi, all

I install the ALPS 2.1 in Windows XP, and find the TEBD function disable.
So, I search the C:\Progam File\ALPS\bin\ , there are dmrg.exe, dmft.exe,
but just no tebd.exe, I want to know why and how to fix this problem up.

Bo-Nan

--
Stay foolish,Stay hungry.
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Message: 7
Date: Fri, 15 Mar 2013 17:09:15 +0900
From: Ryo IGARASHI <rigarash@issp.u-tokyo.ac.jp>
To: comp-phys-alps-users <comp-phys-alps-users@lists.phys.ethz.ch>
Subject: Re: [ALPS-users] TEBD in ALPS
Message-ID:
<CAHur-O_522ax+nw0wXsRrnGMWCy3h2dQM0+uo=mz+9A9ZOmc5A@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Hi,

On Fri, Mar 15, 2013 at 4:21 PM, Bo-Nan JIANG <bonanjiang@gmail.com> wrote:
> I install the ALPS 2.1 in Windows XP, and find the TEBD function disable.
> So, I search the C:\Progam File\ALPS\bin\ , there are dmrg.exe, dmft.exe,
> but just no tebd.exe, I want to know why and how to fix this problem up.

Since pre-compiled ALPS for Windows is compiled with Visual C++,
and VC does not have Fortran compiler, so that currently
there is no way to include TEBD.

If you really want to use TEBD on Windows, compile on cygwin (maybe
possible, but not tested)
or use some virtual machine technology(e.g. VMware, VirtualBox, Hyper-V).

Best regards,
--
Ryo IGARASHI, Ph.D.
rigarash@issp.u-tokyo.ac.jp
OpenPGP fingerprint: BAD9 71E3 28F3 8952 5640 6A53 EC79 A280 6A19 2319

End of Comp-phys-alps-users Digest, Vol 84, Issue 13
****************************************************

--
Stay foolish,Stay hungry.