  This work studies the quantum cosmology of a closed, spatially homogeneous,
and isotropic FLRW minisuperspace model with electromagnetic radiation as a
matter content. We solve the associated Wheeler-DeWitt (WDW) equation using the
holographic regularization method and show that the electromagnetic zero-point
energy forms the vacuum energy and provides a unified resolution to the
horizon, flatness, singularity, and cosmic coincidence problems. This quantum
cosmology approach composes an alternative to the usual inflationary paradigm
and can be extended to more general matter contents and emergent gravity
schemes.
