Circuit¶

A quantum optical circuit.

class mrmustard.lab.circuit.Circuit(components)[source]¶

A quantum optical circuit.

A circuit is defined by a collection of CircuitComponents. Each mode is expected to begin with a State followed by a series of Transformations.

Parameters:: components (list[CircuitComponent]) – A list of components in the circuit.

draw(draw_params=True)[source]¶

A string-based representation of this circuit.

Parameters:: draw_params (bool) – Whether to draw the parameters of the components.
Returns:: A string-based representation of the circuit.
Return type:: str

expectation(operator)[source]¶

Compute the expectation value of an operator with respect to the circuit.

Parameters:: operator (CircuitComponent) – The operator to compute the expectation value of. Expected to be a unitary-like component (input and output ket wires on each of its modes).
Returns:: The expectation value of the operator with respect to the circuit.
Raises:: ValueError – If the operator acts on a mode that is no longer open in the circuit (e.g. already measured out).
Return type:: Scalar

run(output_shape=None, representation=None)[source]¶

Runs the circuit.

The return type depends on whether the underlying computational graph is fully specified or not.

Parameters:

output_shape (tuple[int, ...] | None) – If the circuit returns a State, the shape of the output in the Fock basis.
representation (Literal[ReprEnum.BARGMANN, ReprEnum.FOCK] | None) – If the circuit returns a State, the representation of the output.

Returns:

The result of the circuit.

Return type:

State | Scalar

to_comp_graph()[source]¶

Compiles this circuit into a ComputationalGraph.

trace_out(modes)[source]¶

Trace out the specified modes.

Parameters:: modes (int | tuple[int, ...]) – The modes to trace out.
Returns:: A new Circuit with modes traced out.
Return type:: Circuit

code/lab/circuit

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