  Motivated by the notorious difficulties in determining the first quantum
corrections to the spectrum of short strings in AdS_5xS^5 from first
principles, we study closed bosonic strings in this background employing a
static gauge. In this gauge the world-sheet Hamiltonian density is constant
along the extension of the string and directly proportional to the square of
the spacetime energy. We quantize this system in a minisuperspace approach, in
which we consider only a single AdS_5 string mode excitation next to an
arbitrary particle like zero-mode contribution in the full AdS_5xS^5
background. We determine the quantum spectrum using this method to the
next-to-next-to-leading order in the large 't Hooft coupling expansion. We
argue for an ordering prescription which should arise from supersymmetrization
and indeed recover the integrability based predictions for the spectrum of the
lightest excitation, dual to the Konishi field scaling dimensions. The higher
excitations fail to agree, but this is shown to be a consequence of the string
mode truncation employed. Despite this simple setup, our system reveals
intriguing features, such as a close connection to particles in AdS_6,
classical integrability and preservation of the isometries of AdS_5xS^5 at the
quantum level.
