  The complete theoretical description of experimentally observed
magnetoexcitons in cuprous oxide has been achieved by F. Schweiner et al [Phys.
Rev. B 95, 035202 (2017)], using a complete basis set and taking into account
the valence band structure and the cubic symmetry of the solid. Here, we extend
these calculations by investigating numerically the autoionising resonances of
cuprous oxide in electric fields and in parallel electric and magnetic fields
oriented in [001] direction. To this aim we apply the
complex-coordinate-rotation method. Complex resonance energies are computed by
solving a non-Hermitian generalised eigenvalue problem, and absorption spectra
are simulated by using relative oscillator strengths. The method allows us to
investigate the influence of different electric and magnetic field strengths on
the position, the lifetime, and the shape of resonances.
