class HeisenbergModel(VMPSApp):
'''
Heisenberg model application for vMPS.
The Hamiltonian is: sum_i J/2*(S_i^+S_{i+1}^- + S_i^-S_{i+1}^+) + Jz*S_i^zS_{i+1}^z -h*S_i^z
Construct
-----------------
HeisenbergModel(J,Jz,h)
Attributes
------------------
J/Jz:
Exchange interaction at xy direction and z direction.
h:
The strength of weiss field.
*see VMPSApp for more attributes.*
'''
def __init__(self,J,Jz,h,nsite):
self.spaceconfig=SpinSpaceConfig([2,1])
I=OpUnitI(hndim=2)
scfg=SpinSpaceConfig([2,1])
Sz=opunit_Sz(spaceconfig=scfg)
Sp=opunit_Sp(spaceconfig=scfg)
Sm=opunit_Sm(spaceconfig=scfg)
wi=zeros((5,5),dtype='O')
wi[:,0],wi[4,1:]=(I,Sp,Sm,Sz,-h*Sz),(J/2.*Sm,J/2.*Sp,Jz*Sz,I)
WL=[copy.deepcopy(wi) for i in xrange(nsite)]
WL[0]=WL[0][4:]
WL[-1]=WL[-1][:,:1]
self.H=MPO(WL)
mpc=self.H.serialize()
mpc.compactify()
self.H_serial=mpc
class IsingModel(object):
'''
Heisenberg model application for vMPS.
The Hamiltonian is: sum_i J/2*(S_i^+S_{i+1}^- + S_i^-S_{i+1}^+) + Jz*S_i^zS_{i+1}^z -h*S_i^z
Construct
-----------------
HeisenbergModel(J,Jz,h)
Attributes
------------------
J/Jz:
Exchange interaction at xy direction and z direction.
h:
The strength of weiss field.
*see VMPSApp for more attributes.*
'''
def __init__(self,J,h,nsite):
self.spaceconfig=SpinSpaceConfig([2,1])
self.J,self.h,self.nsite=J,h,nsite
I=OpUnitI(hndim=2)
Sz=opunit_Sz(spaceconfig=self.spaceconfig)
Sx=opunit_Sx(spaceconfig=self.spaceconfig)
wi=zeros((3,3),dtype='O')
wi[:,0],wi[2,1:]=(I,Sx,-h*Sz),(Sx,I)
WL=[copy.deepcopy(wi) for i in xrange(nsite)]
WL[0]=WL[0][2:]
WL[-1]=WL[-1][:,:1]
self.H=MPO(WL)
mpc=self.H.serialize()
mpc.compactify()
if isinstance(mpc,(OpString,OpUnit)):
mpc=OpCollection([mpc])
self.H_serial=mpc
self.qnumber='R'
def get_str(self):
return get_name(self.J,self.h,self.nsite)
class Spin1Model(object):
'''
Heisenberg model application for vMPS.
The Hamiltonian is: sum_i J/2*(S_i^+S_{i+1}^- + S_i^-S_{i+1}^+) + Jz*S_i^zS_{i+1}^z -h*S_i^z
Construct
-----------------
HeisenbergModel(J,Jz,D)
Attributes
------------------
J/Jz:
Exchange interaction at xy direction and z direction.
D:
The strength of easy plane field.
*see VMPSApp for more attributes.*
'''
def __init__(self,J,Jz,D,nsite):
self.spaceconfig=SpinSpaceConfig([3,1])
self.J,self.Jz,self.D,self.nsite=J,Jz,D,nsite
I=OpUnitI(hndim=self.spaceconfig.hndim)
Sz=opunit_Sz(spaceconfig=self.spaceconfig)
Sp=opunit_Sp(spaceconfig=self.spaceconfig)
Sm=opunit_Sm(spaceconfig=self.spaceconfig)
wi=zeros((5,5),dtype='O')
wi[:,0],wi[4,1:]=(I,Sp,Sm,Sz,D*Sz*Sz),(J/2.*Sm,J/2.*Sp,Jz*Sz,I)
WL=[copy.deepcopy(wi) for i in xrange(nsite)]
WL[0]=WL[0][4:]
WL[-1]=WL[-1][:,:1]
self.H=MPO(WL)
mpc=self.H.serialize()
mpc.compactify()
self.H_serial=mpc
ion()
cla()
mpc.show_advanced()
pdb.set_trace()