graphix.states module

Quantum states and operators.

class State

Bases: ABC

Abstract base class for single qubit states objects.

Only requirement for concrete classes is to have a to_statevector_numpy() method that returns the statevector representation of the state

abstractmethod to_statevector_numpy() → NDArray[complex128]

Return the state vector.

to_densitymatrix_numpy() → NDArray[complex128]

Return the density matrix.

class PlanarState(plane: Plane, angle: float)

Bases: State

Light object used to instantiate backends.

doesn’t cover all possible states but this is covered in graphix.sim.statevec.Statevector and graphix.sim.densitymatrix.DensityMatrix constructors.

Parameters:

• plane (graphix.pauli.Plane) – One of the three planes (XY, XZ, YZ)

• angle (float) – Angle (in units of π)

Returns:

State

Return type:

graphix.states.State object

plane: Plane

angle: float

to_statevector_numpy() → NDArray[complex128]

Return the state vector.

__init__(plane: Plane, angle: float) → None

class BasicStates

Bases: object

Basic states.

ZERO: ClassVar[PlanarState] = graphix.states.PlanarState(Plane.XZ, 0)

ONE: ClassVar[PlanarState] = graphix.states.PlanarState(Plane.XZ, 1)

PLUS: ClassVar[PlanarState] = graphix.states.PlanarState(Plane.XY, 0)

MINUS: ClassVar[PlanarState] = graphix.states.PlanarState(Plane.XY, 1)

PLUS_I: ClassVar[PlanarState] = graphix.states.PlanarState(Plane.XY, 0.5)

MINUS_I: ClassVar[PlanarState] = graphix.states.PlanarState(Plane.XY, -0.5)

VEC: ClassVar[list[PlanarState]] = [graphix.states.PlanarState(Plane.XY, 0), graphix.states.PlanarState(Plane.XY, 1), graphix.states.PlanarState(Plane.XZ, 0), graphix.states.PlanarState(Plane.XZ, 1), graphix.states.PlanarState(Plane.XY, 0.5), graphix.states.PlanarState(Plane.XY, -0.5)]