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added an operator named expiSz, which represents exp(i\pi S_z) used to compute string order parameter #193

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added an operator named expiSz, which represents exp(i\pi S_z) used to compute string order parameter #193

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03cbe32
added an operator named expiSz,
Jan 2, 2019
b24e04a
added kondo.h for Kondo lattice model
Jan 2, 2019
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376 changes: 376 additions & 0 deletions itensor/mps/sites/kondo.h
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@@ -0,0 +1,376 @@
// Created 2017/09/16
// Modified from hubbard.h in the ITensor Library.

#ifndef __ITENSOR_KONDO_H
#define __ITENSOR_KONDO_H
#include "itensor/mps/siteset.h"

namespace itensor {

class KondoSite;

using Kondo = BasicSiteSet<KondoSite>;

class KondoSite
{
IQIndex s;
public:

KondoSite() { }

KondoSite(IQIndex I) : s(I) { }

KondoSite(int n, Args const& args = Args::global())
{
auto conserveNf = args.getBool("ConserveNf",true);
auto conserveSz = args.getBool("ConserveSz",true); //total Sz
int Up = (conserveSz ? +1 : 0),
Dn = -Up;
if(conserveNf)
{
s = IQIndex{nameint("site=",n),
Index(nameint("Emp.Up ",n),1,Site), QN("Sz=", Up,"Nf=",0), //Sz is the total Sz,
Index(nameint("Up.Up ",n),1,Site), QN("Sz=",2*Up,"Nf=",1), //including that of
Index(nameint("Dn.Up ",n),1,Site), QN("Sz=",0,"Nf=",1), //local spin
Index(nameint("UpDn.Up ",n),1,Site),QN("Sz=", Up,"Nf=",2),
Index(nameint("Emp.Dn ",n),1,Site), QN("Sz=", Dn,"Nf=",0),
Index(nameint("Up.Dn ",n),1,Site), QN("Sz=",0,"Nf=",1),
Index(nameint("Dn.Dn ",n),1,Site), QN("Sz=",2*Dn,"Nf=",1),
Index(nameint("UpDn.Dn ",n),1,Site),QN("Sz=", Dn,"Nf=",2)};


}
else //don't conserve Nf, only fermion parity
{
if(!conserveSz) Error("One of ConserveSz or ConserveNf must be true for Kondo sites");

s = IQIndex{nameint("site=",n),
Index(nameint("Emp.Up ",n),1,Site), QN("Sz=", 1,"Pf=",0),
Index(nameint("Up.Up ",n),1,Site), QN("Sz=",2,"Pf=",1),
Index(nameint("Dn.Up ",n),1,Site), QN("Sz=",0,"Pf=",1),
Index(nameint("UpDn.Up ",n),1,Site),QN("Sz=", 1,"Pf=",0),
Index(nameint("Emp.Dn ",n),1,Site), QN("Sz=", -1,"Pf=",0),
Index(nameint("Up.Dn ",n),1,Site), QN("Sz=",0,"Pf=",1),
Index(nameint("Dn.Dn ",n),1,Site), QN("Sz=",-2,"Pf=",1),
Index(nameint("UpDn.Dn ",n),1,Site),QN("Sz=", -1,"Pf=",0)};
}
}

IQIndex
index() const { return s; }

IQIndexVal
state(std::string const& state)
{
if(state == "0+" || state == "Emp.Up")
{
return s(1);
}
else
if(state == "++" || state == "Up.Up")
{
return s(2);
}
else
if(state == "-+" || state == "Dn.Up")
{
return s(3);
}
else
if(state == "S+" || state == "UpDn.Up")
{
return s(4);
}
else
if(state == "0-" || state == "Emp.Dn")
{
return s(5);
}
else
if(state == "+-" || state == "Up.Dn")
{
return s(6);
}
else
if(state == "--" || state == "Dn.Dn")
{
return s(7);
}
else
if(state == "S-" || state == "UpDn.Dn")
{
return s(8);
}
else
{
Error("State " + state + " not recognized");
}
return IQIndexVal{};
}

IQTensor
op(std::string const& opname,
Args const& args) const
{
auto sP = prime(s);

IQIndexVal Em_Up(s(1)), // Up local spin
Em_Up_P(sP(1)), // P ~ prime
Up_Up(s(2)),
Up_Up_P(sP(2)),
Dn_Up(s(3)),
Dn_Up_P(sP(3)),
UD_Up(s(4)),
UD_Up_P(sP(4)),
Em_Dn(s(5)),
Em_Dn_P(sP(5)),
Up_Dn(s(6)),
Up_Dn_P(sP(6)),
Dn_Dn(s(7)),
Dn_Dn_P(sP(7)),
UD_Dn(s(8)),
UD_Dn_P(sP(8));

IQTensor Op(dag(s),sP);

if(opname == "Nup")
{
Op.set(Up_Up,Up_Up_P,1);
Op.set(UD_Up,UD_Up_P,1);
Op.set(Up_Dn,Up_Dn_P,1);
Op.set(UD_Dn,UD_Dn_P,1);
}
else
if(opname == "Ndn")
{
Op.set(Dn_Up,Dn_Up_P,1);
Op.set(UD_Up,UD_Up_P,1);
Op.set(Dn_Dn,Dn_Dn_P,1);
Op.set(UD_Dn,UD_Dn_P,1);
}
else
if(opname == "Nupdn")
{
Op.set(UD_Up,UD_Up_P,1);
Op.set(UD_Dn,UD_Dn_P,1);
}
else
if(opname == "Ntot")
{
Op.set(Up_Up,Up_Up_P,1);
Op.set(Dn_Up,Dn_Up_P,1);
Op.set(UD_Up,UD_Up_P,2);
Op.set(Up_Dn,Up_Dn_P,1);
Op.set(Dn_Dn,Dn_Dn_P,1);
Op.set(UD_Dn,UD_Dn_P,2);
}
else
if(opname == "Cup")
{
Op.set(Up_Up,Em_Up_P,1);
Op.set(UD_Up,Dn_Up_P,1);
Op.set(Up_Dn,Em_Dn_P,1);
Op.set(UD_Dn,Dn_Dn_P,1);
}
else
if(opname == "Cdagup")
{
Op.set(Em_Up,Up_Up_P,1);
Op.set(Dn_Up,UD_Up_P,1);
Op.set(Em_Dn,Up_Dn_P,1);
Op.set(Dn_Dn,UD_Dn_P,1);
}
else
if(opname == "Cdn")
{
Op.set(Dn_Up,Em_Up_P,1);
Op.set(UD_Up,Up_Up_P,-1);
Op.set(Dn_Dn,Em_Dn_P,1);
Op.set(UD_Dn,Up_Dn_P,-1);
}
else
if(opname == "Cdagdn")
{
Op.set(Em_Up,Dn_Up_P,1);
Op.set(Up_Up,UD_Up_P,-1);
Op.set(Em_Dn,Dn_Dn_P,1);
Op.set(Up_Dn,UD_Dn_P,-1);
}
else
if(opname == "Aup")
{
Op.set(Up_Up,Em_Up_P,1);
Op.set(UD_Up,Dn_Up_P,1);
Op.set(Up_Dn,Em_Dn_P,1);
Op.set(UD_Dn,Dn_Dn_P,1);
}
else
if(opname == "Adagup")
{
Op.set(Em_Up,Up_Up_P,1);
Op.set(Dn_Up,UD_Up_P,1);
Op.set(Em_Dn,Up_Dn_P,1);
Op.set(Dn_Dn,UD_Dn_P,1);
}
else
if(opname == "Adn")
{
Op.set(Dn_Up,Em_Up_P,1);
Op.set(UD_Up,Up_Up_P,1);
Op.set(Dn_Dn,Em_Dn_P,1);
Op.set(UD_Dn,Up_Dn_P,1);
}
else
if(opname == "Adagdn")
{
Op.set(Em_Up,Dn_Up_P,1);
Op.set(Up_Up,UD_Up_P,1);
Op.set(Em_Dn,Dn_Dn_P,1);
Op.set(Up_Dn,UD_Dn_P,1);
}
else
if(opname == "FermiPhase" || opname == "F")
{
Op.set(Em_Up,Em_Up_P,+1);
Op.set(Up_Up,Up_Up_P,-1);
Op.set(Dn_Up,Dn_Up_P,-1);
Op.set(UD_Up,UD_Up_P,+1);

Op.set(Em_Dn,Em_Dn_P,+1);
Op.set(Up_Dn,Up_Dn_P,-1);
Op.set(Dn_Dn,Dn_Dn_P,-1);
Op.set(UD_Dn,UD_Dn_P,+1);
}
else
if(opname == "Fup")
{
Op.set(Em_Up,Em_Up_P,+1);
Op.set(Up_Up,Up_Up_P,-1);
Op.set(Dn_Up,Dn_Up_P,+1);
Op.set(UD_Up,UD_Up_P,-1);

Op.set(Em_Dn,Em_Dn_P,+1);
Op.set(Up_Dn,Up_Dn_P,-1);
Op.set(Dn_Dn,Dn_Dn_P,+1);
Op.set(UD_Dn,UD_Dn_P,-1);
}
else
if(opname == "Fdn")
{
Op.set(Em_Up,Em_Up_P,+1);
Op.set(Up_Up,Up_Up_P,+1);
Op.set(Dn_Up,Dn_Up_P,-1);
Op.set(UD_Up,UD_Up_P,-1);

Op.set(Em_Dn,Em_Dn_P,+1);
Op.set(Up_Dn,Up_Dn_P,+1);
Op.set(Dn_Dn,Dn_Dn_P,-1);
Op.set(UD_Dn,UD_Dn_P,-1);
}
else
if(opname == "Sz")
{
Op.set(Up_Up,Up_Up_P,+0.5);
Op.set(Dn_Up,Dn_Up_P,-0.5);
Op.set(Up_Dn,Up_Dn_P,+0.5);
Op.set(Dn_Dn,Dn_Dn_P,-0.5);
}
else
if(opname == "S+")
{
Op.set(Dn_Up,Up_Up_P,1);
Op.set(Dn_Dn,Up_Dn_P,1);
}
else
if(opname == "S-")
{
Op.set(Up_Up,Dn_Up_P,1);
Op.set(Up_Dn,Dn_Dn_P,1);
}
else
if(opname == "S2")
{
//S dot S on-site
Op.set(Up_Up,Up_Up_P,0.75);
Op.set(Dn_Up,Dn_Up_P,0.75);
Op.set(Up_Dn,Up_Dn_P,0.75);
Op.set(Dn_Dn,Dn_Dn_P,0.75);
}
else
if(opname == "LSz") // L ~ local spin
{
Op.set(Em_Up,Em_Up_P,+0.5);
Op.set(Em_Dn,Em_Dn_P,-0.5);
Op.set(Up_Up,Up_Up_P,+0.5);
Op.set(Up_Dn,Up_Dn_P,-0.5);
Op.set(Dn_Up,Dn_Up_P,+0.5);
Op.set(Dn_Dn,Dn_Dn_P,-0.5);
Op.set(UD_Up,UD_Up_P,+0.5);
Op.set(UD_Dn,UD_Dn_P,-0.5);
}
else
if(opname == "LSx")
{
Op.set(Em_Up,Em_Dn_P,+0.5);
Op.set(Em_Dn,Em_Up_P,+0.5);
Op.set(Up_Up,Up_Dn_P,+0.5);
Op.set(Up_Dn,Up_Up_P,+0.5);
Op.set(Dn_Up,Dn_Dn_P,+0.5);
Op.set(Dn_Dn,Dn_Up_P,+0.5);
Op.set(UD_Up,UD_Dn_P,+0.5);
Op.set(UD_Dn,UD_Up_P,+0.5);
}
else
if(opname == "LSy")
{
Op.set(Em_Up,Em_Dn_P,-0.5*Cplx_i);
Op.set(Em_Dn,Em_Up_P,+0.5*Cplx_i);
Op.set(Up_Up,Up_Dn_P,-0.5*Cplx_i);
Op.set(Up_Dn,Up_Up_P,+0.5*Cplx_i);
Op.set(Dn_Up,Dn_Dn_P,-0.5*Cplx_i);
Op.set(Dn_Dn,Dn_Up_P,+0.5*Cplx_i);
Op.set(UD_Up,UD_Dn_P,-0.5*Cplx_i);
Op.set(UD_Dn,UD_Up_P,+0.5*Cplx_i);
}
else
if(opname == "LS+")
{
Op.set(Em_Dn,Em_Up_P,1);
Op.set(Up_Dn,Up_Up_P,1);
Op.set(Dn_Dn,Dn_Up_P,1);
Op.set(UD_Dn,UD_Up_P,1);
}
else
if(opname == "LS-")
{
Op.set(Em_Up,Em_Dn_P,1);
Op.set(Up_Up,Up_Dn_P,1);
Op.set(Dn_Up,Dn_Dn_P,1);
Op.set(UD_Up,UD_Dn_P,1);
}
else
if(opname == "LS2")
{
//S dot S on-site
Op.set(Em_Up,Em_Up_P,0.75);
Op.set(Em_Dn,Em_Dn_P,0.75);
Op.set(Up_Up,Up_Up_P,0.75);
Op.set(Up_Dn,Up_Dn_P,0.75);
Op.set(Dn_Up,Dn_Up_P,0.75);
Op.set(Dn_Dn,Dn_Dn_P,0.75);
Op.set(UD_Up,UD_Up_P,0.75);
Op.set(UD_Dn,UD_Dn_P,0.75);
}
else
{
Error("Operator \"" + opname + "\" name not recognized");
}

return Op;
}
};


} //namespace itensor

#endif
7 changes: 7 additions & 0 deletions itensor/mps/sites/spinone.h
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Original file line number Diff line number Diff line change
Expand Up @@ -180,6 +180,13 @@ class SpinOneSite
Op.set(Dn,DnP,1);
}
else
if(opname == "expiSz") //exp(i*pi*Sz)
{
Op.set(Z0,Z0P,1);
Op.set(Up,UpP,-1);
Op.set(Dn,DnP,-1);
}
else
if(opname == "XUp")
{
//m = +1 state along x axis
Expand Down