def f(N, options):
wa = 1
wc = 0.9
delta = wa - wc
g = 2
kappa = 0.5
gamma = 0.1
n_th = 0.75
tspan = np.linspace(0, 10, 11)
Ia = qt.qeye(2)
Ic = qt.qeye(N)
a = qt.destroy(N)
at = qt.create(N)
sm = qt.sigmam()
sp = qt.sigmap()
# H = wc*qt.tensor(n, Ia) + qt.tensor(Ic, wa/2.*sz) + g*(qt.tensor(at, sm) + qt.tensor(a, sp))
Ha = g * qt.tensor(at, sm)
Hb = g * qt.tensor(a, sp)
H = [[Ha, lambda t, args: np.exp(-1j*delta*t)],
[Hb, lambda t, args: np.exp(1j*delta*t)]]
c_ops = [
qt.tensor(np.sqrt(kappa*(1+n_th)) * a, Ia),
qt.tensor(np.sqrt(kappa*n_th) * at, Ia),
qt.tensor(Ic, np.sqrt(gamma) * sm),
]
psi0 = qt.tensor(qt.fock(N, 0), (qt.basis(2, 0) + qt.basis(2, 1)).unit())
exp_n = qt.mesolve(H, psi0, tspan, c_ops, [qt.tensor(a, sp)], options=options).expect[0]
return np.real(exp_n)
def test_jumpBinary(self): tStart = 0 psi0 = qutip.basis(2, 0) psi0 = psi0.full() sp = qutip.sigmap() sm = qutip.sigmam() jumpOps = [] #Decay jumpOps.append(5 * sm) jumpOps.append(5 * sp) for i, jumpOp in enumerate(jumpOps): jumpOps[i] = jumpOp.full() jumpOps[i]= scipy.sparse.csc_matrix(jumpOps[i]) jumpOpsPaired = QJMCSetUp.jumpOperatorsPaired(jumpOps) sx = qutip.sigmax() H = sx #All objects must be in a scipy sparse format H = H.full() H = scipy.sparse.csc_matrix(H) settings = QJMCAA.Settings() settings.smallestDt = 0.0001 HEffExponentDtSet, dtSet = QJMCSetUp.HEffExponentSetProductionBinary(H, jumpOpsPaired, 0.1, settings) for _ in range(1000): r = 0.5 t, _, r = QJMCJump.jumpBinary(tStart, psi0, r, jumpOps, jumpOpsPaired, dtSet, HEffExponentDtSet) self.assertAlmostEqual(t,0.1)
def test_measure(self):
#Defines all needed variables for a test
index = 0
psi = qutip.basis(2, 1)
psi = psi.full()
eResults = []
eResults.append(numpy.zeros(1))
sp = qutip.sigmap()
sm = qutip.sigmam()
no = sp * sm
eOps = []
eOps.append(no)
for i, eOp in enumerate(eOps):
eOps[i] = eOp.full()
eOps[i] = scipy.sparse.csc_matrix(eOps[i])
histograms = []
savingSettings = QJMCAA.SavingSettings()
#Tests with no histograms set
QJMCMeasure.measure(index, psi, eResults, eOps, histograms,
savingSettings)
self.assertEqual(histograms, [])
self.assertEqual(eResults, [[0.]])
def setup_collapse_operators(self):
print("Setup Collapse Operators in Lindblad form", end=" ")
#Reference: http://qutip.org/docs/4.1/guide/dynamics/dynamics-time.html
collapse = []
#Empty list for collapse operators
# Collapse coefficients from the dictionary
k_Dwn = pars['kDwn']
k_Up = pars['kUp']
G_e2g = pars['Gamma_E2G']
G_g2e = pars['Gamma_G2E']
print("for the parameters")
print("kDwn = 2pi * %.3lg [GHz],\nkUp = 2pi * %.3lg [GHz]"\
%(k_Dwn/(2*np.pi), k_Up/(2*np.pi)))
print("Ge2g = %.3lg [GHz],\nGg2e = %.3lg [GHz]\n" % (G_e2g, G_g2e))
#------------------------------------------------
# Collapse operators in Lindblad Master Equation
#------------------------------------------------
a = self.a
sp = tensor(sigmap(), qeye(pars['N'])) # sigma+
sm = tensor(sigmam(), qeye(pars['N'])) # sigma-
#if isLindblad == True:
collapse.append(np.sqrt(k_Dwn) * a)
#[sqrt(2p*Gzh)]
collapse.append(np.sqrt(k_Up) * a.dag())
#[sqrt(2p*Gzh)]
collapse.append(np.sqrt(G_e2g) * sm)
#[sqrt(2p*Gzh)]
collapse.append(np.sqrt(G_g2e) * sp)
#[sqrt(2p*Gzh)]
#DISREGARDED#collapse.append(np.sqrt(Gamma_varphi) * sz);#[dimensionless]
return collapse
def test_expect_noisy():
np.random.seed(123)
bad_op = qutip.tensor([qutip.qeye(2), qutip.sigmap()])
with pytest.raises(ValueError, match="non-diagonal"):
results_noisy.expect([bad_op])
op = qutip.tensor([qutip.qeye(2), qutip.basis(2, 0).proj()])
assert np.isclose(results_noisy.expect([op])[0][-1], 0.6933333333333334)
def test_jumpOperatorsPaired(self):
#Sets up the jump operators
sp = qutip.sigmap()
sm = qutip.sigmam()
no = sp*sm
jumpOps = []
jumpOps.append(sm)
jumpOps.append(sp)
jumpOps.append(no)
for i, jumpOp in enumerate(jumpOps):
jumpOps[i] = jumpOp.full()
jumpOps[i]= scipy.sparse.csc_matrix(jumpOps[i])
#Runs the function
jumpOpsPaired = QJMCSetUp.jumpOperatorsPaired(jumpOps)
#Calculating what they should be
jumpOpsExpect = []
jumpOpsExpect.append(scipy.sparse.csc_matrix([[complex(1,0),0.0],[0.0,0.0]]))
jumpOpsExpect.append(scipy.sparse.csc_matrix([[0.0,0.0],[0.0,complex(1,0)]]))
jumpOpsExpect.append(scipy.sparse.csc_matrix([[complex(1,0),0.0],[0.0,0.0]]))
fail = -1
for i in range(len(jumpOps)):
if (jumpOpsPaired[i] - jumpOpsExpect[i]).nnz == complex(0,0):
continue
else:
fail = i
break
self.assertEqual(fail,-1)
def test_jmat_12():
spinhalf = qutip.jmat(1 / 2.)
paulix = np.array([[0. + 0.j, 1. + 0.j], [1. + 0.j, 0. + 0.j]])
pauliy = np.array([[0. + 0.j, 0. - 1.j], [0. + 1.j, 0. + 0.j]])
pauliz = np.array([[1. + 0.j, 0. + 0.j], [0. + 0.j, -1. + 0.j]])
sigmap = np.array([[0. + 0.j, 1. + 0.j], [0. + 0.j, 0. + 0.j]])
sigmam = np.array([[0. + 0.j, 0. + 0.j], [1. + 0.j, 0. + 0.j]])
np.testing.assert_allclose(spinhalf[0].full() * 2, paulix)
np.testing.assert_allclose(spinhalf[1].full() * 2, pauliy)
np.testing.assert_allclose(spinhalf[2].full() * 2, pauliz)
np.testing.assert_allclose(qutip.jmat(1 / 2., '+').full(), sigmap)
np.testing.assert_allclose(qutip.jmat(1 / 2., '-').full(), sigmam)
np.testing.assert_allclose(qutip.spin_Jx(1 / 2.).full() * 2, paulix)
np.testing.assert_allclose(qutip.spin_Jy(1 / 2.).full() * 2, pauliy)
np.testing.assert_allclose(qutip.spin_Jz(1 / 2.).full() * 2, pauliz)
np.testing.assert_allclose(qutip.spin_Jp(1 / 2.).full(), sigmap)
np.testing.assert_allclose(qutip.spin_Jm(1 / 2.).full(), sigmam)
np.testing.assert_allclose(qutip.sigmax().full(), paulix)
np.testing.assert_allclose(qutip.sigmay().full(), pauliy)
np.testing.assert_allclose(qutip.sigmaz().full(), pauliz)
np.testing.assert_allclose(qutip.sigmap().full(), sigmap)
np.testing.assert_allclose(qutip.sigmam().full(), sigmam)
spin_set = qutip.spin_J_set(0.5)
for i in range(3):
assert spinhalf[i] == spin_set[i]
def test_jaynes_cummings_zero_temperature():
"""
brmesolve: Jaynes-Cummings model, zero temperature
"""
N = 10
a = qutip.tensor(qutip.destroy(N), qutip.qeye(2))
sp = qutip.tensor(qutip.qeye(N), qutip.sigmap())
psi0 = qutip.ket2dm(qutip.tensor(qutip.basis(N, 1), qutip.basis(2, 0)))
a_ops = [[(a + a.dag()), lambda w: kappa * (w >= 0)]]
e_ops = [a.dag() * a, sp.dag() * sp]
w0 = 1.0 * 2 * np.pi
g = 0.05 * 2 * np.pi
kappa = 0.05
times = np.linspace(0, 2 * 2 * np.pi / g, 1000)
c_ops = [np.sqrt(kappa) * a]
H = w0 * a.dag() * a + w0 * sp.dag() * sp + g * (a + a.dag()) * (sp +
sp.dag())
me = qutip.mesolve(H, psi0, times, c_ops, e_ops)
brme = qutip.brmesolve(H, psi0, times, a_ops, e_ops)
for me_expectation, brme_expectation in zip(me.expect, brme.expect):
# Accept 5% error.
np.testing.assert_allclose(me_expectation, brme_expectation, atol=5e-2)
def get_H_XY_terms(N):
""" Returns local terms, without coupling coefficients, that make up the XY hamiltonian.
returns: Hx, Hz, HPM
Hx = list of pauli X's
Hz = list of Pauli Z's
HPM = list of sigma_plus * sigma_minus """
I = qt.tensor([qt.qeye(2)] * N)
c = list(it.combinations(range(N), 2))
Hz, Hx, HPM = [0 * I for x in range(N)], [0 * I for x in range(N)
], [0 * I for x in c]
for i in range(N):
l = [qt.qeye(2)] * N
l[i] = qt.sigmaz()
Hz[i] = qt.tensor(l)
l[i] = qt.sigmax()
Hx[i] = qt.tensor(l)
for s in range(len(c)):
i, j = c[s]
l = [qt.qeye(2)] * N
l[i] = qt.sigmap()
l[j] = qt.sigmam()
HPM[s] = qt.tensor(l)
HPM[s] += HPM[s].dag()
return Hx, Hz, HPM
def objective_with_c_ops():
u1 = lambda t, args: 1.0
u2 = lambda t, args: 1.0
a1 = np.random.random(100) + 1j * np.random.random(100)
a2 = np.random.random(100) + 1j * np.random.random(100)
H = [
tensor(sigmaz(), identity(2)) + tensor(identity(2), sigmaz()),
[tensor(sigmax(), identity(2)), u1],
[tensor(identity(2), sigmax()), u2],
]
C1 = [[tensor(identity(2), sigmap()), a1]]
C2 = [[tensor(sigmap(), identity(2)), a2]]
ket00 = ket((0, 0))
ket11 = ket((1, 1))
obj = krotov.Objective(
initial_state=ket00, target=ket11, H=H, c_ops=[C1, C2]
)
return obj
def num_focks(self, value):
self._num_focks = value
sigma_plus: Qobj = tensor(sigmap(), qeye(value))
a: Qobj = tensor(qeye(2), destroy(value))
self._ctrl_ops: List[Qobj] = [sigma_plus, sigma_plus * a, sigma_plus * a.dag()]
self._ctrl_ops_full = [op.full() for op in self._ctrl_ops]
self._e: Callable[[int], Qobj] = lambda n: tensor(basis(2, 0), basis(value, n))
self._g: Callable[[int], Qobj] = lambda n: tensor(basis(2, 1), basis(value, n))
def tls_control_system():
"""Non-trivial control system defined on a TLS"""
eps1 = lambda t, args: 0.5
eps2 = lambda t, args: 1
H1 = [0.5 * sigmaz(), [sigmap(), eps1], [sigmam(), eps1]]
H2 = [0.5 * sigmaz(), [sigmaz(), eps2]]
c_ops = [0.1 * sigmap()]
objectives = [
krotov.Objective(
initial_state=ket('0'), target=ket('1'), H=H1, c_ops=c_ops
),
krotov.Objective(
initial_state=ket('0'), target=ket('1'), H=H2, c_ops=c_ops
),
]
controls = [eps1, eps2]
controls_mapping = krotov.conversions.extract_controls_mapping(
objectives, controls
)
return objectives, controls, controls_mapping
def test_exact_solution_for_simple_methods(method, kwargs):
# this tests that simple methods correctly determine the steadystate
# with high accuracy for a small Liouvillian requiring correct weighting.
H = qutip.identity(2)
c_ops = [qutip.sigmam(), 1e-8 * qutip.sigmap()]
rho_ss = qutip.steadystate(H, c_ops, method=method, **kwargs)
expected_rho_ss = np.array([
[1.e-16 + 0.j, 0.e+00 - 0.j],
[0.e+00 - 0.j, 1.e+00 + 0.j],
])
np.testing.assert_allclose(expected_rho_ss, rho_ss, atol=1e-16)
assert rho_ss.tr() == pytest.approx(1, abs=1e-14)
def test_hamiltonian_order_unimportant():
# Testing for regression on issue 1048.
sp = qutip.sigmap()
H = [[qutip.sigmax(), lambda t, _: _step(t-2)],
[qutip.qeye(2), lambda t, _: _step(-(t-2))]]
start = qutip.basis(2, 0)
times = np.linspace(0, 5, 6)
forwards = qutip.correlation_2op_2t(H, start, times, times, [sp],
sp.dag(), sp)
backwards = qutip.correlation_2op_2t(H[::-1], start, times, times, [sp],
sp.dag(), sp)
np.testing.assert_allclose(forwards, backwards, atol=1e-6)
def Hamiltonian(parameters, lattice):
#Constructs the operators
#(these are the essential operators that are needed for spin)
si = qutip.qeye(2)
sx = qutip.sigmax()
#sy = qutip.sigmay()
#sz = qutip.sigmaz()
sp = qutip.sigmap()
sm = qutip.sigmam()
no = sp * sm
#Constructs operators for the chain of length N
#si_list = []
sx_list = []
#sy_list = []
#sz_list = []
#sp_list = []
#sm_list = []
no_list = []
#Runs over each site defining the operator on that site
for k in range(lattice.numberOfSites):
#Puts an indentity on every site
op_list = [si] * lattice.numberOfSites
#Defines the sigma_x on site k
op_list[k] = sx
sx_list.append(qutip.tensor(op_list))
#op_list[k] = sy
#sy_list.append(qutip.tensor(op_list))
#op_list[k] = sz
#sz_list.append(qutip.tensor(op_list))
#op_list[k] = sp
#sp_list.append(qutip.tensor(op_list))
#op_list[k] = sm
#sm_list.append(qutip.tensor(op_list))
op_list[k] = no
no_list.append(qutip.tensor(op_list))
#Constructs the Hamiltonian
H = 0
#Periodic boundary conditions
#TODO define the periodic boundary conditions and closed in QJMCMath.neighbour operator with a choice
for k in range(lattice.numberOfSites):
H += (parameters.omega *
(no_list[QJMCMath.neighbour(k, lattice.numberOfSites, -1)] +
no_list[QJMCMath.neighbour(k, lattice.numberOfSites, 1)]) *
sx_list[k])
#All objects must be in a scipy sparse format
H = H.full()
H = scipy.sparse.csc_matrix(H)
return H
def expectationOperators(lattice, settings):
#Constructs the operators
si = qutip.qeye(2)
#sx = qutip.sigmax()
#sy = qutip.sigmay()
#sz = qutip.sigmaz()
sp = qutip.sigmap()
sm = qutip.sigmam()
no = sp * sm
#print no
#Constructs operators for the chain of length N
#si_list = []
#sx_list = []
#sy_list = []
#sz_list = []
#sp_list = []
#sm_list = []
no_list = []
#si_list.append(qutip.tensor([si] * N))
for k in range(lattice.numberOfSites):
op_list = [si] * lattice.numberOfSites
#op_list[k] = sx
#sx_list.append(qutip.tensor(op_list))
#op_list[k] = sy
#sy_list.append(qutip.tensor(op_list))
#op_list[k] = sz
#sz_list.append(qutip.tensor(op_list))
#op_list[k] = sp
#sp_list.append(qutip.tensor(op_list))
#op_list[k] = sm
#sm_list.append(qutip.tensor(op_list))
op_list[k] = no
no_list.append(qutip.tensor(op_list))
#Defines the expectation operators
e_op_list = []
#This adds on the measurement of the average population per site
e_op_list.append(no_list[0])
for i in range(1, lattice.numberOfSites):
e_op_list[0] += no_list[i]
e_op_list[0] /= lattice.numberOfSites
for i, eOp in enumerate(e_op_list):
e_op_list[i] = eOp.full()
e_op_list[i] = scipy.sparse.csc_matrix(e_op_list[i])
return e_op_list
def _2ls_g2_0(H, c_ops):
sp = qutip.sigmap()
start = qutip.basis(2, 0)
times = _2ls_times
correlation = qutip.correlation_3op_2t(H, start, times, times, [sp],
sp.dag(), sp.dag()*sp, sp,
args=_2ls_args)
n_expectation = qutip.mesolve(H, start, times, [sp] + c_ops,
e_ops=[qutip.num(2)],
args=_2ls_args).expect[0]
integral_correlation = _trapz_2d(np.real(correlation), times)
integral_n_expectation = np.trapz(n_expectation, times)
# Factor of two from negative time correlations.
return 2 * integral_correlation / integral_n_expectation**2
def test_pull_572_error():
"""
brmesolve: Check for #572 bug.
"""
w1, w2, w3 = 1, 2, 3
gamma2, gamma3 = 0.1, 0.1
id2 = qutip.qeye(2)
# Hamiltonian for three uncoupled qubits
H = (w1 / 2. * qutip.tensor(qutip.sigmaz(), id2, id2) +
w2 / 2. * qutip.tensor(id2, qutip.sigmaz(), id2) +
w3 / 2. * qutip.tensor(id2, id2, qutip.sigmaz()))
# White noise
def S2(w):
return gamma2
def S3(w):
return gamma3
qubit_2_x = qutip.tensor(id2, qutip.sigmax(), id2)
qubit_3_x = qutip.tensor(id2, id2, qutip.sigmax())
# Bloch-Redfield tensor including dissipation for qubits 2 and 3 only
R, ekets = qutip.bloch_redfield_tensor(H,
[[qubit_2_x, S2], [qubit_3_x, S3]])
# Initial state : first qubit is excited
grnd2 = qutip.sigmam() * qutip.sigmap() # 2x2 ground
exc2 = qutip.sigmap() * qutip.sigmam() # 2x2 excited state
ini = qutip.tensor(exc2, grnd2, grnd2) # Full system
# Projector on the excited state of qubit 1
proj_up1 = qutip.tensor(exc2, id2, id2)
# Solution of the master equation
times = np.linspace(0, 10. / gamma3, 1000)
sol = qutip.bloch_redfield_solve(R, ekets, ini, times, [proj_up1])
np.testing.assert_allclose(sol[0], np.ones_like(times))
def compute_free_evolution_hamiltonian(nb_qubits, nb_drives, omega, omega0,
hbar):
H_res = qt.qzero([[2, 2]])
for index_qubit in range(nb_qubits):
H_qubit_tmp = qt.Qobj(np.zeros((2, 2)))
for index_drive in range(nb_drives):
delta = omega[index_drive] - omega0[index_qubit]
H_qubit_tmp += -hbar * delta * (qt.sigmam() * qt.sigmap())
H_res = H_res + compute_multiqbt_hamil(H_qubit_tmp, nb_qubits,
index_qubit, 2)
return H_res
def expectationOperators():
#si = qutip.qeye(2)
sp = qutip.sigmap()
sm = qutip.sigmam()
no = sp * sm
eOps = []
eOps.append(no)
for i, eOp in enumerate(eOps):
eOps[i] = eOp.full()
eOps[i] = scipy.sparse.csc_matrix(eOps[i])
return eOps
def get_spin_hamiltonian(op_terms: List[Op]):
sigma_dict = {
"sigma_+": qutip.sigmap(),
"sigma_-": qutip.sigmam(),
"sigma_z": qutip.sigmaz()
}
terms = []
for op in op_terms:
qutip_list = []
for symbol in op.split_symbol:
qutip_list.append(sigma_dict[symbol])
qutip_term = qutip.tensor(qutip_list)
qutip_term *= op.factor
terms.append(qutip_term)
return sum(terms)
def hamiltonians_n_atoms_C2(NH1, NH2, N_atoms):
#Contructs the Jaynes_cummings hamiltonians for the interaction of each atom with C2
#The result is given as a list of hamiltonians in the same order as in the tensor product
hamiltonians = []
Hd_temp = qt.tensor(qt.qeye(NH1), qt.destroy(NH2))
Hc_temp = qt.tensor(qt.qeye(NH1), qt.create(NH2))
for i in range(N_atoms):
for j, H in enumerate(hamiltonians):
hamiltonians[j] = qt.tensor(qt.qeye(2), hamiltonians[j])
hamiltonians = [
.5 *
(qt.tensor(qt.sigmap(), Hd_temp) + qt.tensor(qt.sigmam(), Hc_temp))
] + hamiltonians
Hd_temp = qt.tensor(qt.qeye(2), Hd_temp)
Hc_temp = qt.tensor(qt.qeye(2), Hc_temp)
return (hamiltonians)
def test_addExpectationSquared(self):
sp = qutip.sigmap()
sm = qutip.sigmam()
no = sp*sm
eOps = []
eOps.append(no)
for i in range(len(eOps)):
eOps[i] = eOps[i].full()
eOps[i] = scipy.sparse.csc_matrix(eOps[i])
initialLen = len(eOps)
QJMCSetUp.addExpectationSquared(eOps)
self.assertEqual(2*initialLen,len(eOps))
def __init__(self, init_state, target_state, num_focks, num_steps, alpha_list=[1]):
self.init_state = init_state
self.target_state = target_state
self.num_focks = num_focks
Sp = tensor(sigmap(), qeye(num_focks))
Sm = tensor(sigmam(), qeye(num_focks))
a = tensor(qeye(2), destroy(num_focks))
adag = tensor(qeye(2), create(num_focks))
# Control Hamiltonians
self._ctrl_hamils = [Sp + Sm, Sp * a + Sm * adag, Sp * adag + Sm * a,
1j * (Sp - Sm), 1j * (Sp * a - Sm * adag), 1j * (Sp * adag - Sm * a)]
# Number operator
self._adaga = adag * a
self.num_steps = num_steps
self.alpha_list = np.array(alpha_list + [0] * (3 - len(alpha_list)))
def get_sigma_list(sigma, nsites):
sigma_list = []
for i in range(nsites):
basis = []
for j in range(nsites):
if j == i:
if sigma == "sigma_+":
state = qutip.sigmap()
elif sigma == "sigma_-":
state = qutip.sigmam()
elif sigma == "sigma_z":
state = qutip.sigmaz()
else:
assert False
else:
state = qutip.identity(2)
basis.append(state)
sigma_list.append(qutip.tensor(basis))
return sigma_list
def to_pauli(s):
# Input format:
# s: take value from 'X', 'Y', 'Z', '+' and '-'
# Return:
# Pauli-X, Pauli-Y, Pauli-Z, flip-up or flip-down, according to the input
if s == 'X':
return qutip.sigmax()
elif s == 'Y':
return qutip.sigmay()
elif s == 'Z':
return qutip.sigmaz()
elif s == '+':
return qutip.sigmap()
elif s == '-':
return qutip.sigmam()
else:
return qutip.qeye(2) # For unidentified input, return identity
def tls_control_system_tdcops(tls_control_system):
"""Control system with time-dependent collapse operators"""
objectives, controls, _ = tls_control_system
c_op = [[0.1 * sigmap(), controls[0]]]
c_ops = [c_op]
H1 = objectives[0].H
H2 = objectives[1].H
objectives = [
krotov.Objective(
initial_state=ket('0'), target=ket('1'), H=H1, c_ops=c_ops
),
krotov.Objective(
initial_state=ket('0'), target=ket('1'), H=H2, c_ops=c_ops
),
]
controls_mapping = krotov.conversions.extract_controls_mapping(
objectives, controls
)
return objectives, controls, controls_mapping
def jumpOperators(parameters):
sp = qutip.sigmap()
sm = qutip.sigmam()
no = sp * sm
jumpOps = []
#Decay
if parameters.kappa > 0:
jumpOps.append(numpy.sqrt(parameters.kappa) * sm)
#Dephasing
if parameters.gamma > 0:
jumpOps.append(numpy.sqrt(parameters.gamma) * no)
for i, jumpOp in enumerate(jumpOps):
jumpOps[i] = jumpOp.full()
jumpOps[i] = scipy.sparse.csc_matrix(jumpOps[i])
return jumpOps
def run():
from mpi4py import MPI
comm = MPI.COMM_WORLD
size = comm.Get_size()
rank = comm.Get_rank()
print "Process number", rank, "of", size, "total."
neq = 2
gamma = 1.0
psi0 = qt.basis(neq,neq-1)
H = qt.sigmax()
c_ops = [np.sqrt(gamma)*qt.sigmax()]
e_ops = [qt.sigmam()*qt.sigmap()]
tlist = np.linspace(0,10,100)
ntraj=100
# One CPU per MPI process
opts = qt.Odeoptions()
opts.num_cpus = 1
# Solve
sols = mcf90.mcsolve_f90(H,psi0,tlist,c_ops,e_ops,ntraj=ntraj,options=opts)
#sols = qt.mcsolve(H,psi0,tlist,c_ops,e_ops,ntraj=ntraj,options=opts)
# Gather data
sols = comm.gather(sols,root=0)
if (rank==0):
sol = sols[0]
sol.expect = np.array(sols[0].expect)
plt.figure()
plt.plot(tlist,sols[0].expect[0],'r',label='proc '+str(0))
for i in range(1,size):
plt.plot(tlist,sols[i].expect[0],'r',label='proc '+str(i))
sol.expect += np.array(sols[i].expect)
sol.expect = sol.expect/size
plt.plot(tlist,sol.expect[0],'b',label='average')
plt.legend()
plt.show()
def test_hamiltonian_taking_arguments():
N = 10
w0 = 1.0 * 2 * np.pi
g = 0.75 * 2 * np.pi
kappa = 0.05
a = qutip.tensor(qutip.destroy(N), qutip.qeye(2))
sp = qutip.tensor(qutip.qeye(N), qutip.sigmap())
psi0 = qutip.tensor(qutip.basis(N, 1), qutip.basis(2, 0))
psi0 = qutip.ket2dm(psi0)
times = np.linspace(0, 5 * 2 * np.pi / g, 1000)
a_ops = [[(a + a.dag()), "{kappa}*(w > 0)".format(kappa=kappa)]]
e_ops = [a.dag() * a, sp.dag() * sp]
H = w0 * a.dag() * a + w0 * sp.dag() * sp + g * (a + a.dag()) * (sp +
sp.dag())
args = {'ii': 1}
no_args = qutip.brmesolve(H, psi0, times, a_ops, e_ops)
args = qutip.brmesolve([[H, 'ii']], psi0, times, a_ops, e_ops, args=args)
for arg, no_arg in zip(args.expect, no_args.expect):
assert np.array_equal(arg, no_arg)
def f(N, options):
wa = 1
wc = 1
g = 2
kappa = 0.5
gamma = 0.1
n_th = 0.75
tspan = np.linspace(0, 10, 11)
Ia = qt.qeye(2)
Ic = qt.qeye(N)
a = qt.destroy(N)
at = qt.create(N)
n = at * a
sm = qt.sigmam()
sp = qt.sigmap()
sz = qt.sigmaz()
H = wc * qt.tensor(n, Ia) + qt.tensor(
Ic, wa / 2. * sz) + g * (qt.tensor(at, sm) + qt.tensor(a, sp))
c_ops = [
qt.tensor(np.sqrt(kappa * (1 + n_th)) * a, Ia),
qt.tensor(np.sqrt(kappa * n_th) * at, Ia),
qt.tensor(Ic,
np.sqrt(gamma) * sm),
]
psi0 = qt.tensor(qt.fock(N, 0), (qt.basis(2, 0) + qt.basis(2, 1)).unit())
exp_n = qt.mcsolve(H,
psi0,
tspan,
c_ops, [qt.tensor(n, Ia)],
ntraj=evals,
options=options).expect[0]
return np.real(exp_n)
def test():
gamma = 1.
neq = 2
psi0 = qt.basis(neq,neq-1)
#a = qt.destroy(neq)
#ad = a.dag()
#H = ad*a
#c_ops = [gamma*a]
#e_ops = [ad*a]
H = qt.sigmax()
c_ops = [np.sqrt(gamma)*qt.sigmax()]
#c_ops = []
e_ops = [qt.sigmam()*qt.sigmap(),qt.sigmap()*qt.sigmam()]
#e_ops = []
# Times
T = 2.0
dt = 0.1
nstep = int(T/dt)
tlist = np.linspace(0,T,nstep)
ntraj=100
# set options
opts = qt.Odeoptions()
opts.num_cpus=2
#opts.mc_avg = True
#opts.gui=False
#opts.max_step=1000
#opts.atol =
#opts.rtol =
sol_f90 = qt.Odedata()
start_time = time.time()
sol_f90 = mcf90.mcsolve_f90(H,psi0,tlist,c_ops,e_ops,ntraj=ntraj,options=opts)
print "mcsolve_f90 solutiton took", time.time()-start_time, "s"
sol_me = qt.Odedata()
start_time = time.time()
sol_me = qt.mesolve(H,psi0,tlist,c_ops,e_ops,options=opts)
print "mesolve solutiton took", time.time()-start_time, "s"
sol_mc = qt.Odedata()
start_time = time.time()
sol_mc = qt.mcsolve(H,psi0,tlist,c_ops,e_ops,ntraj=ntraj,options=opts)
print "mcsolve solutiton took", time.time()-start_time, "s"
if (e_ops == []):
e_ops = [qt.sigmam()*qt.sigmap(),qt.sigmap()*qt.sigmam()]
sol_f90expect = [np.array([0.+0.j]*nstep)]*len(e_ops)
sol_mcexpect = [np.array([0.+0.j]*nstep)]*len(e_ops)
sol_meexpect = [np.array([0.+0.j]*nstep)]*len(e_ops)
for i in range(len(e_ops)):
if (not opts.mc_avg):
sol_f90expect[i] = sum([qt.expect(e_ops[i],
sol_f90.states[j]) for j in range(ntraj)])/ntraj
sol_mcexpect[i] = sum([qt.expect(e_ops[i],
sol_mc.states[j]) for j in range(ntraj)])/ntraj
else:
sol_f90expect[i] = qt.expect(e_ops[i],sol_f90.states)
sol_mcexpect[i] = qt.expect(e_ops[i],sol_mc.states)
sol_meexpect[i] = qt.expect(e_ops[i],sol_me.states)
elif (not opts.mc_avg):
sol_f90expect = sum(sol_f90.expect,0)/ntraj
sol_mcexpect = sum(sol_f90.expect,0)/ntraj
sol_meexpect = sol_me.expect
else:
sol_f90expect = sol_f90.expect
sol_mcexpect = sol_mc.expect
sol_meexpect = sol_me.expect
plt.figure()
for i in range(len(e_ops)):
plt.plot(tlist,sol_f90expect[i],'b')
plt.plot(tlist,sol_mcexpect[i],'g')
plt.plot(tlist,sol_meexpect[i],'k')
return sol_f90, sol_mc
import cascade
gamma = 1.0 # coupling strength to reservoir
phi = 1.*np.pi # phase shift in fb loop
eps = 2.0*np.pi*gamma # eps/2 = Rabi frequency
delta = 0. # detuning
# time delay
tau = np.pi/(eps)
print 'tau =',tau
dim_S = 2
Id = qt.spre(qt.qeye(dim_S))*qt.spost(qt.qeye(dim_S))
# Hamiltonian and jump operators
H_S = delta*qt.sigmap()*qt.sigmam() + eps*(qt.sigmam()+qt.sigmap())
L1 = sp.sqrt(gamma)*qt.sigmam()
L2 = sp.exp(1j*phi)*L1
# initial state
rho0 = qt.ket2dm(qt.basis(2,0))
# times to evaluate rho(t)
tlist=np.arange(0.0001,2*tau,0.01)
def run(rho0=rho0,tau=tau,tlist=tlist):
# run feedback simulation
opts = qt.Options()
opts.nsteps = 1e7
sol = np.array([rho0]*len(tlist))
for i,t in enumerate(tlist):
def spin_algebra(N, op=None):
"""Create the list [sx, sy, sz] with the spin operators.
The operators are constructed for a collection of N two-level systems
(TLSs). Each element of the list, i.e., sx, is a vector of `qutip.Qobj`
objects (spin matrices), as it cointains the list of the SU(2) Pauli
matrices for the N TLSs. Each TLS operator sx[i], with i = 0, ..., (N-1),
is placed in a :math:`2^N`-dimensional Hilbert space.
Notes
-----
sx[i] is :math:`\\frac{\\sigma_x}{2}` in the composite Hilbert space.
Parameters
----------
N: int
The number of two-level systems.
Returns
-------
spin_operators: list or :class: qutip.Qobj
A list of `qutip.Qobj` operators - [sx, sy, sz] or the
requested operator.
"""
# 1. Define N TLS spin-1/2 matrices in the uncoupled basis
N = int(N)
sx = [0 for i in range(N)]
sy = [0 for i in range(N)]
sz = [0 for i in range(N)]
sp = [0 for i in range(N)]
sm = [0 for i in range(N)]
sx[0] = 0.5 * sigmax()
sy[0] = 0.5 * sigmay()
sz[0] = 0.5 * sigmaz()
sp[0] = sigmap()
sm[0] = sigmam()
# 2. Place operators in total Hilbert space
for k in range(N - 1):
sx[0] = tensor(sx[0], identity(2))
sy[0] = tensor(sy[0], identity(2))
sz[0] = tensor(sz[0], identity(2))
sp[0] = tensor(sp[0], identity(2))
sm[0] = tensor(sm[0], identity(2))
# 3. Cyclic sequence to create all N operators
a = [i for i in range(N)]
b = [[a[i - i2] for i in range(N)] for i2 in range(N)]
# 4. Create N operators
for i in range(1, N):
sx[i] = sx[0].permute(b[i])
sy[i] = sy[0].permute(b[i])
sz[i] = sz[0].permute(b[i])
sp[i] = sp[0].permute(b[i])
sm[i] = sm[0].permute(b[i])
spin_operators = [sx, sy, sz]
if not op:
return spin_operators
elif op == 'x':
return sx
elif op == 'y':
return sy
elif op == 'z':
return sz
elif op == '+':
return sp
elif op == '-':
return sm
else:
raise TypeError('Invalid type')
