qit.hamiltonian.magnetic_dipole

qit.hamiltonian.magnetic_dipole(dim, B=(0, 0, 1))

Local magnetic dipole Hamiltonian.

\[H = \sum_i \vec{B}(i) \cdot \vec{S}^{(i)},\]

where \(S_k^{(i)}\) is the k-component of the angular momentum operator of spin i.

Parameters

• dim (tuple[int]) – dimensions of the spins, i.e. dim == (2, 2, 2) would be a system of three spin-1/2’s.

• B (callable[[int], tuple[float]]) – The effective magnetic field the spins locally couple to. Either a 3-tuple (homogeneous field) or a function B(i) that returns a 3-tuple for a site-dependent field.

Returns

Hamiltonian operator

Return type

array[complex]