def test_spectrum_espi():
"""
correlation: comparing spectrum from es and pi methods
"""
# use JC model
N = 4
wc = wa = 1.0 * 2 * np.pi
g = 0.1 * 2 * np.pi
kappa = 0.75
gamma = 0.25
n_th = 0.01
a = tensor(destroy(N), qeye(2))
sm = tensor(qeye(N), destroy(2))
H = wc * a.dag() * a + wa * sm.dag() * sm + \
g * (a.dag() * sm + a * sm.dag())
c_ops = [
np.sqrt(kappa * (1 + n_th)) * a,
np.sqrt(kappa * n_th) * a.dag(),
np.sqrt(gamma) * sm
]
wlist = 2 * pi * np.linspace(0.5, 1.5, 100)
spec1 = spectrum(H, wlist, c_ops, a.dag(), a, solver='es')
spec2 = spectrum(H, wlist, c_ops, a.dag(), a, solver='pi')
assert_(max(abs(spec1 - spec2)) < 1e-3)
def test_spectrum_espi():
"""
correlation: comparing spectrum from es and pi methods
"""
# use JC model
N = 4
wc = wa = 1.0 * 2 * np.pi
g = 0.1 * 2 * np.pi
kappa = 0.75
gamma = 0.25
n_th = 0.01
a = tensor(destroy(N), qeye(2))
sm = tensor(qeye(N), destroy(2))
H = wc * a.dag() * a + wa * sm.dag() * sm + \
g * (a.dag() * sm + a * sm.dag())
c_ops = [np.sqrt(kappa * (1 + n_th)) * a,
np.sqrt(kappa * n_th) * a.dag(),
np.sqrt(gamma) * sm]
wlist = 2 * pi * np.linspace(0.5, 1.5, 100)
spec1 = spectrum(H, wlist, c_ops, a.dag(), a, solver='es')
spec2 = spectrum(H, wlist, c_ops, a.dag(), a, solver='pi')
assert_(max(abs(spec1 - spec2)) < 1e-3)
def find_expect(phi=0.1, Omega_vec=3.0, wd=wd):
Ej = (phi**2) / (
8 * Ec
) #Ejmax*absolute(cos(pi*phi)) #; % Josephson energy as function of Phi.
wTvec = -Ej + sqrt(8.0 * Ej * Ec) * (nvec + 0.5) + Ecvec
#wdvec=nvec*sqrt(8.0*Ej*Ec)
#wdvec=nvec*wd
wT = wTvec - wdvec
transmon_levels = Qobj(diag(wT[range(N)]))
H = transmon_levels + Omega_vec #- 0.5j*(Omega_true*adag - conj(Omega_true)*a)
#final_state = steadystate(H, c_op_list)
#print H.shape
#print dir(H)
#U,D = eig(H.full())
#print D
#Uinv = Qobj(inv(D))
#U=Qobj(D)
# Doing the chi integral (gives the susceptibility)
#Dint = 1.0/(1.0j*(wp-wd)) #Qobj(1.0/(1.0j*(wp-wd)*diag(qeye(N**2))))# + diag(D))))
#Hint = H.expm() #U*H*Uinv
#Chi_temp(i,j) += (1.0/theta_steps)*1j*trace(reshape(tm_l*Lint*(p_l - p_r)*rho_ss_c,dim,dim))
#exp1=correlation_2op_1t(H, None, wlist2, c_op_list, a, p, solver="es")
#exp2=correlation_2op_1t(H, None, wlist2, c_op_list, p, a, solver="es", reverse=True)
#exp1=correlation_2op_1t(H, None, wlist2, c_op_list, a, p_l-p_r, solver="es")
#exp1=correlation_ss(H, wlist2, c_op_list, a, p)
#exp2=correlation_ss(H, wlist2, c_op_list, p, a, reverse=True)
exp1 = spectrum(H, wlist2, c_op_list, a, p, solver="pi", use_pinv=False)
exp2 = spectrum(H, wlist2, c_op_list, p, a, solver="pi", use_pinv=False)
return exp1 - exp2
return expect(a, final_state) #tm_l
def find_expect(phi=0.1, Omega_vec=3.0, wd=wd):
Ej = (phi**2)/(8*Ec) #Ejmax*absolute(cos(pi*phi)) #; % Josephson energy as function of Phi.
wTvec = -Ej + sqrt(8.0*Ej*Ec)*(nvec+0.5)+Ecvec
#wdvec=nvec*sqrt(8.0*Ej*Ec)
#wdvec=nvec*wd
wT = wTvec-wdvec
transmon_levels = Qobj(diag(wT[range(N)]))
H=transmon_levels +Omega_vec #- 0.5j*(Omega_true*adag - conj(Omega_true)*a)
#final_state = steadystate(H, c_op_list)
#print H.shape
#print dir(H)
#U,D = eig(H.full())
#print D
#Uinv = Qobj(inv(D))
#U=Qobj(D)
# Doing the chi integral (gives the susceptibility)
#Dint = 1.0/(1.0j*(wp-wd)) #Qobj(1.0/(1.0j*(wp-wd)*diag(qeye(N**2))))# + diag(D))))
#Hint = H.expm() #U*H*Uinv
#Chi_temp(i,j) += (1.0/theta_steps)*1j*trace(reshape(tm_l*Lint*(p_l - p_r)*rho_ss_c,dim,dim))
#exp1=correlation_2op_1t(H, None, wlist2, c_op_list, a, p, solver="es")
#exp2=correlation_2op_1t(H, None, wlist2, c_op_list, p, a, solver="es", reverse=True)
#exp1=correlation_2op_1t(H, None, wlist2, c_op_list, a, p_l-p_r, solver="es")
#exp1=correlation_ss(H, wlist2, c_op_list, a, p)
#exp2=correlation_ss(H, wlist2, c_op_list, p, a, reverse=True)
exp1=spectrum(H, wlist2, c_op_list, a, p, solver="pi", use_pinv=False)
exp2=spectrum(H, wlist2, c_op_list, p, a, solver="pi", use_pinv=False)
return exp1-exp2
return expect( a, final_state) #tm_l
def find_expect(phi=0.2, Omega=3.0, wd=wd, use_other=True):
Ej = (phi**2)/(8*Ec) #Ejmax*absolute(cos(pi*phi)) #; % Josephson energy as function of Phi.
wTvec = -Ej + sqrt(8.0*Ej*Ec)*(nvec+0.5)+Ecvec
wT = wTvec-wdvec
transmon_levels = Qobj(diag(wT[range(N)]))
Omega_vec=- 0.5j*(Omega*adag - conj(Omega)*a)
H=transmon_levels +Omega_vec #- 0.5j*(Omega_true*adag - conj(Omega_true)*a)
if use_other:
exp1=spectrum(H, wlist2, c_op_list, a, p, solver="pi", use_pinv=False)
else:
exp1=_spectrum_pi(H, wlist2, c_op_list, a, p, use_pinv=False)
return exp1
def test_spectrum_solver_equivalence_to_es(spectrum):
"""Test equivalence of the spectrum solvers to the base "es" method."""
# Jaynes--Cummings model.
dimension = 4
wc = wa = 1.0 * 2*np.pi
g = 0.1 * 2*np.pi
kappa = 0.75
gamma = 0.25
n_th = 0.01
a = qutip.tensor(qutip.destroy(dimension), qutip.qeye(2))
sm = qutip.tensor(qutip.qeye(dimension), qutip.sigmam())
H = wc*a.dag()*a + wa*sm*sm.dag() + g*(a.dag()*sm.dag() + a*sm)
c_ops = [np.sqrt(kappa * (n_th+1)) * a,
np.sqrt(kappa * n_th) * a.dag(),
np.sqrt(gamma) * sm.dag()]
test, frequencies = spectrum(H, c_ops, a.dag(), a)
base = qutip.spectrum(H, frequencies, c_ops, a.dag(), a, solver="es")
np.testing.assert_allclose(base, test, atol=1e-3)
#Uinv=inv(U) #print "Uinv", Uinv #Lint=U*MMR*Uinv #print "Lint", diag(Lint) #Lop=Qobj(U)#.expm() #print diag(Lop*MMR*Lop.dag()) #print Lop rho_ss = steadystate(L) rho = transpose(mat2vec(rho_ss.full())) print p.shape print transpose(rho) print spectrum(H, [3.0], c_op_list, a, p, solver="pi", use_pinv=True) #print "p", dot(p, transpose(rho)) s = dot(tr_vec, dot(a_sup, dot(MMR1, dot(b_sup, transpose(rho))))) print s print -2 * real(s[0, 0]) #spectrum[idx] = -2 * real(s[0, 0]) # Chi_temp[i,j] += (1/theta_steps) sol = a * p * rho_ss print D.shape print U.shape #print MMR.shape #print Lint.shape print sol.shape print rho_ss.shape print rho.shape
def two_tone(vg):
phi, wd=vg
Ej = Ejmax*absolute(cos(pi*phi))#(phi**2)/(8*Ec) # #; % Josephson energy as function of Phi.
wTvec = -Ej + sqrt(8.0*Ej*Ec)*(nvec+0.5)+Ecvec
wdvec=nvec*wd
wT = wTvec-wdvec
transmon_levels = Qobj(diag(wT[range(N)]))
for Om in Omega_op:
H = transmon_levels + Om
exp1=spectrum(H, wlist2, c_op_list, a, p, solver="pi", use_pinv=False)
exp2=spectrum(H, wlist2, c_op_list, p, a, solver="pi", use_pinv=False)
return exp1-exp2
#H_comm = -1j*(kron(It,H) - kron(transpose(H),It));
#L = H_comm + Lindblad_tm + Lindblad_tp #+ Lindblad_deph;
#print L
#L2 = [reshape(eye(N),1,N**2); L]; %Add the condition trace(rho) = 1
#rho_ss = L2\[1;zeros(dim^2,1)]; % Steady state density matrix
#rho_ss_c = rho_ss; %Column vector form
L = liouvillian(H, c_op_list)
#D, V=L.eigenstates()
#print "D", D.shape
#print "V", V.shape
#print L.diag()
#print L.diag().shape
#raise Exception
A = L.full()
rho_ss = steadystate(L)
rho = transpose(mat2vec(rho_ss.full()))
P = kron(transpose(rho), tr_vec)
Q = I - P
if 1:
w=wp-wd
#MMR = pinv(-1.0j * w * I + A)
MMR = dot(Q, solve(-1.0j * w * I + A, Q))
#Lexp=L.expm()
#MMR=Lexp*MMR*Lexp.dag()
# MMR = np.dot(Q, np.linalg.solve(-1.0j * w * I + A, Q))
#print p_l.shape
#print p_l
#print transpose(rho).shape
#print dot(p_l.full(), transpose(rho))
s = dot(tr_vec,
dot(tm_l, dot(MMR, dot(p_l_m_p_r, transpose(rho)))))
return -2 * real(s[0, 0])
D,U = eig(L.full())
Uinv = inv(U)
Dint = diag(1.0/(1.0j*(wp-wd)*Idiag + diag(D)))
Lint = U*Dint*Uinv
#H_comm = -1.0j*(kron(It,H) - kron(transpose(H),It))
#print H
#print H.shape, H.full().shape
#print H_comm, H_comm.shape
#L = H_comm + Lindblad_tm + Lindblad_tp + Lindblad_deph
#p_l=spre(p)
#p_r=spost(p)
#tm_l=spre(a)
#print L.shape, A.shape,
#print dir(L)
#print L.eigenenergies().shape
#print L.eigenstates()#.shape
#L2 = [reshape(eye(dim),1,dim^2);L]; %Add the condition trace(rho) = 1
#rho_ss = L2\[1;zeros(dim^2,1)]; % Steady state density matrix
#rho_ss_c = rho_ss; %Column vector form
#print "tm_l", tm_l.full().shape
#print "Lint", Lint.shape
#print "pl", p_l.full().shape
#print "pr", p_r.full().shape
#print rho.shape, to_super(rho_ss).full().shape
#print "rho", to_super(rho_ss) #rho_ss.full().shape #rho.shape
#print (tm_l.full()*Lint*(p_l.full() - p_r.full())*rho).shape
#raise Exception
return 1j*trace(tm_l*Lint*(p_l_m_p_r)*rho_ss)
def plot2ab(hamiltonian, omega_range=np.linspace(1000, 6000, 501)):
"""Constructs and displays the plot of Figure 2 (a) and (b) of
the paper "Signatures..."
:param hamiltonian: <code>HamiltonianSystem</code> object,
containing the various Hamiltonian operators
:param omega_range: List or array of frequencies for which to evaluate
the spectra
"""
print('Making plot figure 2')
model_space = hamiltonian.space
collapse_operators = hamiltonian.collapse_ops()
# Get spectra
xdat = omega_range
print(' Getting spectrum for weak coupling...')
ydat_weak = qt.spectrum(
H=hamiltonian.H(coupling=False),
wlist=-xdat,
c_ops=collapse_operators,
a_op=model_space.create_all_elec(),
b_op=model_space.destroy_all_elec()) / model_space.n
print(' Done')
print(' Getting spectrum for strong coupling...')
ydat_strong = qt.spectrum(
H=hamiltonian.H(coupling=True),
wlist=-xdat,
c_ops=collapse_operators,
a_op=model_space.create_all_elec(),
b_op=model_space.destroy_all_elec()) / model_space.n
print(' Done')
# Print output
title = 'S(omega)/N vs omega_L - omega'
print('\n\nFigure: {}'.format(title))
lab1 = 'S(omega), weak corr.'
print('\nPlot: {}'.format(lab1))
for xi, yi in zip(xdat, ydat_weak):
print(' {:16.8f} {:16.8E}'.format(xi, yi))
lab2 = 'S(omega), strong corr.'
print('\nPlot: {}'.format(lab2))
for xi, yi in zip(xdat, ydat_strong):
print(' {:16.8f} {:16.8E}'.format(xi, yi))
# Make plot figure
print('Displaying plot figure')
fig, ax1 = plt.subplots(1, 1)
divider = make_axes_locatable(ax1)
ax2 = divider.new_vertical(size='100%', pad=0.05)
fig.add_axes(ax2)
ax2.plot(xdat, ydat_weak, '-', label=lab1)
ax1.plot(xdat, ydat_strong, '-', label=lab2)
# Plot vertical lines
omega_plus = hamiltonian.omega_up()
omega_minus = hamiltonian.omega_lp()
for n in count(1):
vline = n * hamiltonian.omega_v
if vline < min(xdat):
continue
elif vline > max(xdat):
break
else:
ax1.axvline(vline, color='orange')
ax2.axvline(vline, color='orange')
for k in range(n + 1):
l = n - k
ax1.axvline(k * omega_plus + l * omega_minus,
linestyle='dashed',
color='green')
ax1.set_title(title)
ax1.set_xlabel('omega_L - omega')
ax2.set_ylabel('S(omega)/N, weak')
ax1.set_ylabel('S(omega)/N, strong')
ax1.set_yscale('log')
ax2.set_yscale('log')
plt.show()
return xdat, ydat_weak, ydat_strong
def plot3(hamiltonian, omega_range=np.linspace(1500, 2000, 501)):
"""Create and display Figure 3 of "Signatures..." based on the given
Hamiltonian
:param hamiltonian: <code>HamiltonianSystem</code> object. Note that
the number of particles will be mutated in order to create the plots
:param omega_range: Range of frequencies for which to compute the
spectrum
"""
print('Making plot figure 3')
ms = hamiltonian.space
num_molecules_original = ms.n
xdat = omega_range
# Print
title = 'First Stokes lines for N=1, N=2'
print('\n\nFigure: {}'.format(title))
# Get data for N=1
ms.set_num_molecules(1)
# First plot: N=1
ydat1 = qt.spectrum(H=hamiltonian.H(),
wlist=-xdat,
c_ops=hamiltonian.collapse_ops(),
a_op=ms.create_all_elec(),
b_op=ms.destroy_all_elec())
# Print
lab1 = ' N=1'
print('\n BEGIN Plot: {}'.format(lab1))
for xi, yi in zip(xdat, ydat1):
print(' {:16.8f} {:16.8E}'.format(xi, yi))
print('\n END Plot: {}'.format(lab1))
# Get data for N=2
ms.set_num_molecules(2)
# Second plot: N=2, coherent
spec = qt.spectrum(H=hamiltonian.H(),
wlist=-xdat,
c_ops=hamiltonian.collapse_ops(),
a_op=ms.create_all_elec(),
b_op=ms.destroy_all_elec())
ydat2 = .5 * spec
# Print
lab2 = ' N=2, coherent'
print('\n BEGIN Plot: {}'.format(lab2))
for xi, yi in zip(xdat, ydat2):
print(' {:16.8f} {:16.8E}'.format(xi, yi))
print('\n END Plot: {}'.format(lab2))
# Third plot: N=2, incoherent
ydats3 = []
for i in range(ms.n):
ydats3.append(
qt.spectrum(H=hamiltonian.H(),
wlist=-xdat,
c_ops=hamiltonian.collapse_ops(),
a_op=ms.create_elec(i),
b_op=ms.destroy_elec(i)))
ydat3 = .5 * sum(ydats3, np.zeros_like(xdat))
# Print
lab3 = ' N=2, incoherent'
print('\n BEGIN Plot: {}'.format(lab3))
for xi, yi in zip(xdat, ydat3):
print(' {:16.8f} {:16.8E}'.format(xi, yi))
print('\n END Plot: {}'.format(lab3))
# Reset original num molecules
ms.set_num_molecules(num_molecules_original)
# Make and show plots
print('Displaying plot figure')
fig, ax = plt.subplots(1, 1)
ax.set_xlabel('omega_L - omega')
ax.set_ylabel('S(omega)/N')
ax.set_title(title)
ax.plot(xdat, ydat1, '--', label=lab1)
ax.plot(xdat, ydat2, '-', label=lab2)
ax.plot(xdat, ydat3, '-', label=lab3)
ax.legend()
plt.show()
return xdat, ydat1, ydat2, ydat3
np.sqrt(kappa * n_th) * a.dag(),
np.sqrt(gamma) * sm
]
"""
calculate the correlation function using the mesolve solver, and then fft to
obtain the spectrum. Here we need to make sure to evaluate the correlation
function for a sufficient long time and sufficiently high sampling rate so
that the discrete Fourier transform (FFT) captures all the features in the
"""
# resulting spectrum
tlist = np.linspace(0, 100, 5000)
corr = correlation_ss(H, tlist, c_ops, a.dag(), a)
wlist1, spec1 = qt.spectrum_correlation_fft(tlist, corr)
# calculate the power spectrum using spectrum, which internally uses essolve
# to solve for the dynamics (by default)
wlist2 = np.linspace(0.25, 1.75, 200) * 2 * np.pi
spec2 = qt.spectrum(H, wlist2, c_ops, a.dag(), a)
# plot the spectra
fig, ax = plt.subplots(1, 1)
ax.plot(wlist1 / (2 * np.pi), spec1, "b", lw=2, label="eseries method")
ax.plot(wlist2 / (2 * np.pi), spec2, "r--", lw=2, label="me+fft method")
ax.legend()
ax.set_xlabel("Frequency")
ax.set_ylabel("Power spectrum")
ax.set_title("Vacuum Rabi splitting")
ax.set_xlim(wlist2[0] / (2 * np.pi), wlist2[-1] / (2 * np.pi))
plt.show()
