magnopy.LSWT.O

method

LSWT.O(units='meV')

Computes coefficient of the one-operator terms.

Parameters:

unitsstr, default "meV"

Added in version 0.3.0.

Units of energy. See Units of energy for the full list of supported units.

Returns:

O(M, ) numpy.ndarray

Elements are complex numbers.

Notes

Before the diagonalization, the magnon Hamiltonian has the form

\[\mathcal{H} = \dots + \sqrt{N} \sum_{\alpha} \Bigl( O_{\alpha} a_{\alpha}(\boldsymbol{0}) + \overline{O_{\alpha}} a^{\dagger}_{\alpha}(\boldsymbol{0}) \Bigr) + \dots\]

where overline denotes complex conjugation. This function computes the coefficients \(O_{\alpha}\).

Examples

>>> import magnopy
>>> spinham = magnopy.examples.cubic_ferro_nn()
>>> lswt = magnopy.LSWT(spinham=spinham, spin_directions=[[0, 0, 1]])
>>> lswt.O()
array([0.+0.j])