ntau = 20
imtime = MeshImTime(beta, 'Fermion', ntau)
prodmesh = MeshProduct(imtime, imtime, imtime)
g40_tau = Gf(name='g40_tau', mesh=prodmesh, target_shape=[1, 1, 1, 1])
g4_tau = Gf(name='g4_tau', mesh=prodmesh, target_shape=[1, 1, 1, 1])
ed.set_g40_tau(g40_tau, g_tau[0,0])
ed.set_g4_tau(g4_tau[0,0,0,0], c(up,0), c_dag(up,0), c(up,0), c_dag(up,0))
# ------------------------------------------------------------------
# -- Two particle Green's functions (equal times)
prodmesh = MeshProduct(imtime, imtime)
g3pp_tau = Gf(name='g4_tau', mesh=prodmesh, target_shape=[1, 1, 1, 1])
ed.set_g3_tau(g3pp_tau[0,0,0,0], c(up,0), c_dag(up,0), c(up,0)*c_dag(up,0))
# ------------------------------------------------------------------
# -- Store to hdf5
with HDFArchive('data_ed.h5','w') as res:
res["G_tau"] = g_tau
res["G_iw"] = g_iwn
res["G20_tau"] = g40_tau
res["G2_tau"] = g4_tau
res["G3pp_tau"] = g3pp_tau
# ----------------------------------------------------------------------
ntau = 20
imtime = MeshImTime(beta, 'Fermion', ntau)
prodmesh = MeshProduct(imtime, imtime, imtime)
g40_tau = Gf(name='g40_tau', mesh=prodmesh, target_shape=[1, 1, 1, 1])
g4_tau = Gf(name='g4_tau', mesh=prodmesh, target_shape=[1, 1, 1, 1])
ed.set_g40_tau(g40_tau, g_tau)
ed.set_g4_tau(g4_tau, c(up, 0), c_dag(up, 0), c(up, 0), c_dag(up, 0))
# ------------------------------------------------------------------
# -- Two particle Green's functions (equal times)
prodmesh = MeshProduct(imtime, imtime)
g3pp_tau = Gf(name='g4_tau', mesh=prodmesh, target_shape=[1, 1, 1, 1])
ed.set_g3_tau(g3pp_tau, c(up, 0), c_dag(up, 0), c(up, 0) * c_dag(up, 0))
# ------------------------------------------------------------------
# -- Store to hdf5
with HDFArchive('data_ed.h5', 'w') as res:
res["G_tau"] = g_tau
res["G_iw"] = g_iwn
res["G20_tau"] = g40_tau
res["G2_tau"] = g4_tau
res["G3pp_tau"] = g3pp_tau
# ----------------------------------------------------------------------
def make_calc(U=10):
# ------------------------------------------------------------------
# -- Hubbard atom with two bath sites, Hamiltonian
params = dict(
beta=2.0,
V1=2.0,
V2=5.0,
epsilon1=0.00,
epsilon2=4.00,
mu=2.0,
U=U,
ntau=40,
niw=15,
)
# ------------------------------------------------------------------
class Dummy():
def __init__(self):
pass
d = Dummy() # storage space
d.params = params
print '--> Solving SIAM with parameters'
for key, value in params.items():
print '%10s = %-10s' % (key, str(value))
globals()[key] = value # populate global namespace
# ------------------------------------------------------------------
up, do = 0, 1
docc = c_dag(up, 0) * c(up, 0) * c_dag(do, 0) * c(do, 0)
nA = c_dag(up, 0) * c(up, 0) + c_dag(do, 0) * c(do, 0)
nB = c_dag(up, 1) * c(up, 1) + c_dag(do, 1) * c(do, 1)
nC = c_dag(up, 2) * c(up, 2) + c_dag(do, 2) * c(do, 2)
d.H = -mu * nA + epsilon1 * nB + epsilon2 * nC + U * docc + \
V1 * (c_dag(up,0)*c(up,1) + c_dag(up,1)*c(up,0) + \
c_dag(do,0)*c(do,1) + c_dag(do,1)*c(do,0) ) + \
V2 * (c_dag(up,0)*c(up,2) + c_dag(up,2)*c(up,0) + \
c_dag(do,0)*c(do,2) + c_dag(do,2)*c(do,0) )
# ------------------------------------------------------------------
# -- Exact diagonalization
fundamental_operators = [
c(up, 0), c(do, 0),
c(up, 1), c(do, 1),
c(up, 2), c(do, 2)
]
ed = TriqsExactDiagonalization(d.H, fundamental_operators, beta)
# ------------------------------------------------------------------
# -- Single-particle Green's functions
Gopt = dict(beta=beta, statistic='Fermion', indices=[1])
d.G_tau = GfImTime(name=r'$G(\tau)$', n_points=ntau, **Gopt)
d.G_iw = GfImFreq(name='$G(i\omega_n)$', n_points=niw, **Gopt)
ed.set_g2_tau(d.G_tau, c(up, 0), c_dag(up, 0))
ed.set_g2_iwn(d.G_iw, c(up, 0), c_dag(up, 0))
# chi2pp = + < c^+_u(\tau^+) c_u(0^+) c^+_d(\tau) c_d(0) >
# = - < c^+_u(\tau^+) c^+_d(\tau) c_u(0^+) c_d(0) >
chi2opt = dict(beta=beta, statistic='Fermion', indices=[1], n_points=ntau)
d.chi2pp_tau = GfImTime(name=r'$\chi^{(2)}_{PP}(\tau)$', **chi2opt)
ed.set_g2_tau(d.chi2pp_tau,
c_dag(up, 0) * c_dag(do, 0),
c(up, 0) * c(do, 0))
d.chi2pp_tau *= -1.0 * -1.0 # commutation sign and gf sign
d.chi2pp_iw = g_iw_from_tau(d.chi2pp_tau, niw)
# chi2ph = < c^+_u(\tau^+) c_u(\tau) c^+_d(0^+) c_d(0) >
d.chi2ph_tau = GfImTime(name=r'$\chi^{(2)}_{PH}(\tau)$', **chi2opt)
#d.chi2ph_tau = Gf(name=r'$\chi^{(2)}_{PH}(\tau)$', **chi2opt)
ed.set_g2_tau(d.chi2ph_tau,
c_dag(up, 0) * c(up, 0),
c_dag(do, 0) * c(do, 0))
d.chi2ph_tau *= -1.0 # gf sign
d.chi2ph_iw = g_iw_from_tau(d.chi2ph_tau, niw)
# ------------------------------------------------------------------
# -- Two particle Green's functions
imtime = MeshImTime(beta, 'Fermion', ntau)
prodmesh = MeshProduct(imtime, imtime, imtime)
G2opt = dict(mesh=prodmesh, target_shape=[1, 1, 1, 1])
d.G02_tau = Gf(name='$G^{(2)}_0(\tau_1, \tau_2, \tau_3)$', **G2opt)
ed.set_g40_tau(d.G02_tau, d.G_tau)
d.G02_iw = chi4_iw_from_tau(d.G02_tau, niw)
d.G2_tau = Gf(name='$G^{(2)}(\tau_1, \tau_2, \tau_3)$', **G2opt)
ed.set_g4_tau(d.G2_tau, c_dag(up, 0), c(up, 0), c_dag(do, 0), c(do, 0))
#ed.set_g4_tau(d.G2_tau, c(up,0), c_dag(up,0), c(do,0), c_dag(do,0)) # <cc^+cc^+>
d.G2_iw = chi4_iw_from_tau(d.G2_tau, niw)
# -- trying to fix the bug in the fft for w2
d.G02_iw.data[:] = d.G02_iw.data[:, ::-1, ...].conj()
d.G2_iw.data[:] = d.G2_iw.data[:, ::-1, ...].conj()
# ------------------------------------------------------------------
# -- 3/2-particle Green's functions (equal times)
prodmesh = MeshProduct(imtime, imtime)
chi3opt = dict(mesh=prodmesh, target_shape=[1, 1, 1, 1])
# chi3pp = <c^+_u(\tau) c_u(0^+) c^+_d(\tau') c_d(0) >
# = - <c^+_u(\tau) c^+_d(\tau') c_u(0^+) c_d(0) >
d.chi3pp_tau = Gf(name='$\Chi^{(3)}_{PP}(\tau_1, \tau_2, \tau_3)$',
**chi3opt)
ed.set_g3_tau(d.chi3pp_tau, c_dag(up, 0), c_dag(do, 0),
c(up, 0) * c(do, 0))
d.chi3pp_tau *= -1.0 # from commutation
d.chi3pp_iw = chi3_iw_from_tau(d.chi3pp_tau, niw)
# chi3ph = <c^+_u(\tau) c_u(\tau') c^+_d(0^+) c_d(0) >
d.chi3ph_tau = Gf(name='$\Chi^{(3)}_{PH}(\tau_1, \tau_2, \tau_3)$',
**chi3opt)
ed.set_g3_tau(d.chi3ph_tau, c_dag(up, 0), c(up, 0),
c_dag(do, 0) * c(do, 0))
d.chi3ph_iw = chi3_iw_from_tau(d.chi3ph_tau, niw)
# ------------------------------------------------------------------
# -- Store to hdf5
filename = 'data_ed.h5'
with HDFArchive(filename, 'w') as res:
for key, value in d.__dict__.items():
res[key] = value