QuantumSystemModel

class QuantumSystemModel(static_hamiltonian=None, drive_hamiltonian_coefficients=None, drive_hamiltonians=None, static_dissipators=None, drive_dissipator_coefficients=None, drive_dissipators=None)

Bases: object

Quantum system model class.

This class represents an abstract quantum system model containing Hamiltonian and/or Lindblad terms, specified in terms of the abstract operator instances provided in this module. Once constructed, the get_Solver() method can be used to convert the model into a Solver instance with a concrete array representation to solve the system for a given initial state. Alternatively, the solve() method can be called to solve the system for an initial state without needing to work with the Solver directly. See the models module for a concrete description of the Schrodinger and Lindblad master equations.

Models can be summed together to build more complex models, e.g. for a system with multiple subsystems. See the Systems Modelling Tutorial for an example of intended usage.

Initialize.

Parameters:

• static_hamiltonian (Optional[AbstractSubsystemOperator]) – The static Hamiltonian.

• drive_hamiltonian_coefficients (Optional[List[str]]) – A list of string labels for the drive Hamiltonian terms.

• drive_hamiltonians (Optional[List[AbstractSubsystemOperator]]) – The Hamiltonian terms with time-dependent coefficients. This is mapped to hamiltonian_operators in Solver.

• static_dissipators (Optional[List[AbstractSubsystemOperator]]) – The static dissipator terms.

• drive_dissipator_coefficients (Optional[List[str]]) – A list of string labels for the drive dissipator terms.

• drive_dissipators (Optional[List[AbstractSubsystemOperator]]) – Dissipator terms with time-dependent rates. This is mapped to dissipator_operators in Solver.

Methods

dressed_basis(ordered_subsystems=None, ordering='default')

Get the DressedBasis object for the system.

Parameters:

• ordered_subsystems (Optional[List]) – Subsystems in the desired order.

• ordering (str) – Ordering convention for the eigenvectors.

get_Solver(rotating_frame=None, array_library=None, vectorized=False, validate=False, ordered_subsystems=None)

Build concrete operators and instantiate solver.

Note that the map_signal_dictionary() method can be used to map signals given in a dictionary format {drive_coefficient: s}, where drive_coefficient is a string in drive_hamiltonian_coefficients + drive_dissipator_coefficients and s is a signal, to the required formatting of the signals argument in Solver.solve().

Parameters:

• rotating_frame (Union[ndarray, AbstractSubsystemOperator, None]) – Rotating frame to define the solver in.

• array_library (Optional[str]) – array library to use (e.g. “numpy”, “jax”, “jax_sparse”, “scipy_sparse”)

• vectorized (bool) – If doing lindblad simulation, whether or not to vectorize.

• validate (bool) – Whether or not to validate the operators.

• ordered_subsystems (Optional[List[Subsystem]]) – Chosen non-standard ordering for building the solver.

map_signal_dictionary(signals)

Map labelled signal dictionary to the required format for for the signals argument of a Solver generated from the get_Solver() method.

Parameters:

signals (List[Union[ndarray, number, int, float, complex, Tracer, Array, spmatrix, BCOO, list, Signal]]) – Signals in dictionary format {label: s}, for label a string in drive_hamiltonian_coefficients + drive_dissipator_coefficients and s a signal.

Returns:

A container of signals formatted for the signals argument of the Solver method Solver.solve().

solve(signals, t_span, y0, rotating_frame=None, array_library=None, vectorized=False, ordered_subsystems=None, **kwargs)

Solve the model.

This method internally constructs a Solver instance with fully-formed arrays according to the abstract model specified in this instance, and then solves. Note that the signals argument for this method expects a dictionary format mapping the coefficient labels for the drive terms specified at instantiation to the desired coefficient.

Parameters:

• signals (dict) – Signals in dictionary format {label: s}, where label is a string in drive_hamiltonian_coefficients + drive_dissipator_coefficients, and s is the corresponding singal.

• t_span (Union[ndarray, number, int, float, complex, Tracer, Array, spmatrix, BCOO, list]) – Time interval to integrate over.

• y0 (Union[ndarray, number, int, float, complex, Tracer, Array, spmatrix, BCOO, list, QuantumState, BaseOperator]) – Initial state.

• rotating_frame (Union[ndarray, AbstractSubsystemOperator, None]) – Rotating frame to transform the model into. Rotating frames which are diagonal can be supplied as a 1d array of the diagonal elements, to explicitly indicate that they are diagonal.

• array_library (Optional[str]) – Array library to use for storing operators of underlying model. See the model evaluation section of the Models API documentation for a more detailed description of this argument.

• vectorized (Optional[bool]) – If including dissipator terms, whether or not to construct the LindbladModel in vectorized form. See the model evaluation section of the Models API documentation for a more detailed description of this argument.

• ordered_subsystems (Optional[List[Subsystem]]) – List of Subsystem instances explicitly specifying the ordering of the subsystems desired when building the concrete model.

• kwargs – Keyword arguments to pass through to Solver.solve.

Attributes

drive_dissipator_coefficients

The drive dissipator coefficients.

drive_dissipators

The model drive dissipators.

drive_hamiltonian_coefficients

The drive Hamiltonian coefficients.

drive_hamiltonians

The model drive Hamiltonians.

static_dissipators

The model static dissipators.

static_hamiltonian

The model static Hamiltonian.

subsystems

The model subsystems.