  We present a thorough numerical study of the Richardson model with quenched
disorder (a fully-connected XX-model with longitudinal random fields). We study
the onset of delocalization in typical states (many-body delocalization) and
the delocalized phase which extends over the whole range of coupling strength
in the thermodynamic limit. We find a relation between the inverse
participation ratio, the Edwards-Anderson order parameter and the average
Hamming distance between spin configurations covered by a typical eigenstate
for which we conjecture a remarkably simple form for the thermodynamic limit.
We also studied the random process defined by the spread of a typical
eigenstate on configuration space, highlighting several similarities with
hopping on percolated hypercube, a process used to mimic the slow relaxation of
spin glasses.
