ElectronSpin

class ElectronSpin(dimension, name, qubit_subspace, gyromagnetic_ratio, zero_field_splitting=0.0, transverse_splitting=0.0, anisotropy_axis=None, local_quasistatic_noise=None, quantization_axis='global_z')

Spin representation tailored for electron spins.

Parameters:

• dimension (int) – Dimension, must be 2 for spin-1/2, 3 for spin-1, etc.

• name (str) – Name of the spin.

• qubit_subspace (Tuple[float, float]) – The quantum numbers that define the qubit subspace.

• gyromagnetic_ratio (float) – Gyromagnetic ratio (in \(\text{MHz}/\text{T}\)).

• zero_field_splitting (float) – Zero-field splitting parameter (in \(\text{MHz}\)).

• transverse_splitting (float) – Transverse splitting parameter (in \(\text{MHz}\)).

• anisotropy_axis (List[float] | None) – Local anisotropy axis of the spin, given in the global coordinate system.

• local_quasistatic_noise (List[float] | None) – Local-quasistatic noise components of the spin (in \(\text{MHz}\)).

• quantization_axis (str | Sequence[float]) – Quantization axis of the spin, given by the keyword 'global_z', 'local_static_field', or 'anisotropy_axis', or by an explicit vector in the global coordinate system. It determines which direction is treated as the spin’s local z-axis when building operators and states for that spin.

Raises:

SimphonyError – If an invalid dimension or qubit subspace is provided.

Note

Hamiltonian of the electron reads

\[H_e = \gamma_e \mathbf{B} \cdot \mathbf{S} + D \left( S_{z'}^2-\frac{S(S+1)}{3} \right) + E (S_{x'}^2 - S_{y'}^2),\]

where \(\gamma_e\) is the gyromagnetic_ratio, \(D\) is zero_field_splitting, \(E\) is the transverse_splitting. The zero-field terms are written in the principal axis frame \((x',y',z'),\) that is defined by the anisotropy_axis.

Attributes

anisotropy_axis	Local anisotropy axis of the spin, given in the global coordinate system.
anisotropy_tensor	Anisotropy tensor in the global coordinate system (in \(\text{MHz}\)).
dimension	Dimension, it is 2 for spin-1/2, 3 for spin-1, etc.
gyromagnetic_ratio	Gyromagnetic ratio (in \(\text{MHz}/\text{T}\)).
local_quasistatic_noise	Local quasistatic noise components.
name	Name of the spin.
operator	Spin operator.
operator_qubit_subspace	Pauli operators defined on the qubit subspace.
quantization_axis	Quantization axis of the spin.
quantum_nums	Quantum numbers corresponding to spin operator.
qubit_subspace	Qubit subspace that is defined by a two-length subset of the quantum_nums.
rotating_frame_frequency	Rotating frame frequency (in \(\text{MHz}\)).
transverse_splitting	Transverse splitting parameter (in \(\text{MHz}\)).
virtual_phase	Virtual z-phase of the spin.
ZEEMAN_SIGN	Sign of the Zeeman term.
zero_field_splitting	Zero-field splitting parameter (in \(\text{MHz}\)).