Re: [ALPS-users] Comp-phys-alps-users Digest, Vol 84, Issue 13 - Comp-phys-alps-users

16 Mar 2013

      First, Thanks a lot, Ryo.
And second, I am still waiting the answer of DMRG error of Kondo lattice
from Matthias, since I have sent you guys parameter file, lattice file and
model file.
Best,
Bo-Nan
2013/3/15 comp-phys-alps-users-request@lists.phys.ethz.ch
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Today's Topics:

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

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"/>
  <!-- <CONSTRAINT quantumnumber="Sz" value="Sz_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.