def enforce_eh(h, mf):
"""Enforce eh symmetry in a mean field Hamiltonian"""
from superconductivity import eh_operator
eh = eh_operator(h.intra) # get the function
for key in mf:
mf[key] = np.matrix(mf[key]) # dense matrix
mfout = dict()
for key in mf:
mkey = (-key[0], -key[1], -key[2])
mfout[key] = (mf[key] - eh(mf[mkey].H)) / 2.
return mfout
def electron_hole_symmetry(h,tol=1e-5,ntries=10):
"""Check that a system has electron-hole symmetry"""
if not h.has_eh: return # skip if there is no e-h sector
from superconductivity import eh_operator
ehop = eh_operator(h.intra) # get the operator
def ehsym(m1,m2):
"""Test eh symmetry"""
diff = m1 + ehop(m2)
diff = np.sum(np.abs(diff))
if diff>tol: raise
ehsym(h.intra,h.intra) # do it for the intra matrix
if h.dimensionality>0:
for i in range(ntries):
hkgen = h.get_hk_gen() # generator
k = np.random.random(h.dimensionality) # kpoint
ehsym(hkgen(k),hkgen(-k))
print("Checking k-point",k)
print("Electron-hole symmetry is ok")
def check_hamiltonian(h):
"""Do various checks in Hamiltonian, to ensure that nothing weird happens"""
hk = h.get_hk_gen() # get generator
m = hk(np.random.random(3)) # random k-point
if not equal(m, m.H):
print("CHECK FAILED, Hamiltonian is not Hermitian")
raise # not hermitian
if h.has_eh: # if it has electron hole degree of freedom
v = np.random.random(3) # random kpoint
m1 = hk(v) # Hamiltonian
m2 = hk(-v) # Hamiltonian in time reversal
from superconductivity import eh_operator
eh = eh_operator(m1) # get the function
if not equal(m1, -eh(m2)):
print(
"CHECK FAILED, Hamiltonian does not have electron-hole symmetry"
)
raise
print("CHECKED that the Hamiltonian has electron-hole symmetry")
def enforce_eh(self):
"""Enforce electron-hole symmetry in the Hamiltonian"""
self.turn_multicell() # turn to multicell mode
from superconductivity import eh_operator
f = eh_operator(self.intra) # electron hole operator
raise # not implemented