def dispersive_chi_01(sweep, param_index, qubit_subsys=None, osc_subsys=None):
"""
For a given HilbertSpaceSweep, calculate the dispersive shift difference chi_01 for one value of the
external parameter.
Parameters
----------
sweep: ParameterSweep
param_index: int
qubit_subsys: QuantumSystem
osc_subsys: Oscillator
Returns
-------
float
dispersive shift chi_01
"""
qubitsys_index = sweep.hilbertspace.get_subsys_index(qubit_subsys)
oscsys_index = sweep.hilbertspace.get_subsys_index(osc_subsys)
omega = osc_subsys.omega
chi_values = np.empty(2, dtype=np.float_)
# chi_j = E_1j - E_0j - omega
for j in range(2):
bare_0j = make_bare_labels(sweep.hilbertspace, qubitsys_index, j, oscsys_index, 0)
bare_1j = make_bare_labels(sweep.hilbertspace, qubitsys_index, j, oscsys_index, 1)
energy_0j = sweep.lookup_energy_bare_index(bare_0j, param_index)
energy_1j = sweep.lookup_energy_bare_index(bare_1j, param_index)
if energy_0j and energy_1j:
chi_values[j] = energy_1j - energy_0j - omega
else:
chi_values[j] = np.NaN
return chi_values[1] - chi_values[0]
def dispersive_chis(sweep, param_index, qubit_subsys=None, osc_subsys=None):
"""
For a given HilbertSpaceSweep, calculate dispersive shift data for one value of the external parameter.
Parameters
----------
sweep: ParameterSweep
param_index: int
qubit_subsys: QuantumSystem
osc_subsys: Oscillator
Returns
-------
ndarray
dispersive shifts chi_0, chi_1, ...
"""
qubitsys_index = sweep.hilbertspace.get_subsys_index(qubit_subsys)
oscsys_index = sweep.hilbertspace.get_subsys_index(osc_subsys)
qubit_dim = qubit_subsys.truncated_dim
omega = osc_subsys.omega
chi_values = np.empty(qubit_dim, dtype=np.float_)
# chi_j = E_1j - E_0j - omega
for j in range(qubit_dim):
bare_0j = make_bare_labels(sweep.hilbertspace, qubitsys_index, j, oscsys_index, 0)
bare_1j = make_bare_labels(sweep.hilbertspace, qubitsys_index, j, oscsys_index, 1)
energy_0j = sweep.lookup_energy_bare_index(bare_0j, param_index)
energy_1j = sweep.lookup_energy_bare_index(bare_1j, param_index)
if energy_0j and energy_1j:
chi_values[j] = energy_1j - energy_0j - omega
else:
chi_values[j] = np.NaN
return chi_values
def dispersive_chi(
sweep: "ParameterSweep",
param_index: int,
qubit_subsys: "QubitBaseClass",
osc_subsys: "Oscillator",
chi_indices: Tuple[int, int] = None,
) -> Union[float, ndarray]:
r"""For a given ParameterSweep, calculate dispersive shift data for a single value of the external parameter. The
dispersive shift relates to a qubit subsystem coupled to an oscillator subsystem. :math:`\chi_j` is the shift of
qubit level :math:`j` due to the addition of a photon in the oscillator. It is calculated here from the exact
spectrum by means of :math:`\chi_j = E_{n=1,j} - E_{n=0,j} - \hbar\omega_\text{osc}`.
Parameters
----------
sweep: ParameterSweep
param_index:
index of the parameter value for which chis should be calculated
qubit_subsys:
osc_subsys:
chi_indices:
If specified, calculate chi_i - chi_j; otherwise return table of all chis in subspace of qubit_subsys
Returns
-------
chi_i - chi_j or chi_0, chi_1, ...
"""
qubitsys_index = sweep.get_subsys_index(qubit_subsys)
oscsys_index = sweep.get_subsys_index(osc_subsys)
if isinstance(chi_indices, tuple):
chi_count = 2
chi_range: Union[Tuple[int, int], List[int]] = chi_indices
else:
chi_count = qubit_subsys.truncated_dim
chi_range = list(range(chi_count))
chi_values = np.empty(chi_count, dtype=np.float_)
omega = osc_subsys.E_osc
# chi_j = E_1j - E_0j - omega
for j in chi_range:
bare_0j = utils.make_bare_labels(
sweep.subsystem_count, (qubitsys_index, j), (oscsys_index, 0)
)
bare_1j = utils.make_bare_labels(
sweep.subsystem_count, (qubitsys_index, j), (oscsys_index, 1)
)
energy_0j = sweep.lookup.energy_bare_index(bare_0j, param_index)
energy_1j = sweep.lookup.energy_bare_index(bare_1j, param_index)
if energy_0j and energy_1j:
chi_values[j] = energy_1j - energy_0j - omega
else:
chi_values[j] = np.NaN
if chi_indices is not None:
return chi_values[1] - chi_values[0]
return chi_values
def dispersive_chi(sweep,
param_index,
qubit_subsys,
osc_subsys,
chi_indices=None):
r"""For a given ParameterSweep, calculate dispersive shift data for a single value of the external parameter. The
dispersive shift relates to a qubit subsystem coupled to an oscillator subsystem. :math:`\chi_j` is the shift of
qubit level :math:`j` due to the addition of a photon in the oscillator. It is calculated here from the exact
spectrum by means of :math:`\chi_j = E_{n=1,j} - E_{n=0,j} - \hbar\omega_\text{osc}`.
Parameters
----------
sweep: ParameterSweep
param_index: int
index of the parameter value for which chis should be calculated
qubit_subsys: QuantumSystem
osc_subsys: Oscillator
chi_indices: tuple(int, int), optional
If specified, calculate chi_i - chi_j; otherwise return table of all chis in subspace of qubit_subsys
Returns
-------
float or ndarray
chi_i - chi_j or chi_0, chi_1, ...
"""
qubitsys_index = sweep.hilbertspace.get_subsys_index(qubit_subsys)
oscsys_index = sweep.hilbertspace.get_subsys_index(osc_subsys)
if chi_indices is not None:
chi_count = 2
chi_range = chi_indices
else:
chi_count = qubit_subsys.truncated_dim
chi_range = range(chi_count)
chi_values = np.empty(chi_count, dtype=np.float_)
omega = osc_subsys.E_osc
# chi_j = E_1j - E_0j - omega
for j in chi_range:
bare_0j = make_bare_labels(sweep.hilbertspace, (qubitsys_index, j),
(oscsys_index, 0))
bare_1j = make_bare_labels(sweep.hilbertspace, (qubitsys_index, j),
(oscsys_index, 1))
energy_0j = sweep.lookup.energy_bare_index(bare_0j, param_index)
energy_1j = sweep.lookup.energy_bare_index(bare_1j, param_index)
if energy_0j and energy_1j:
chi_values[j] = energy_1j - energy_0j - omega
else:
chi_values[j] = np.NaN
if chi_indices is not None:
return chi_values[1] - chi_values[0]
return chi_values