  We measure the clustering of a sample of photometrically selected luminous
red galaxies around a low redshift (0.2<z<0.6) sample of quasars selected from
the Sloan Digital Sky Survey Data Release 5. We make use of a new statistical
estimator to obtain precise measurements of the LRG auto-correlations and
constrain halo occupation distributions for them. These are used to generate
mock catalogs which aid in interpreting our quasar-LRG cross correlation
measurements. The cross correlation is well described by a power law with slope
1.8\pm0.1 and r_0=6\pm0.5 h^{-1} Mpc, consistent with observed galaxy
correlation functions. We find no evidence for `excess' clustering on 0.1 Mpc
scales and demonstrate that this is consistent with the results of Serber et al
(2006) and Strand et al (2007), when one accounts for several subtleties in the
interpretation of their measurements. Combining the quasar-LRG cross
correlation with the LRG auto-correlations, we determine a large-scale quasar
bias b_QSO = 1.09\pm0.15 at a median redshift of 0.43, with no observed
redshift or luminosity evolution. This corresponds to a mean halo mass <M>~
10^{12} h^{-1} M_sun, Eddington ratios from 0.01 to 1 and lifetimes less than
10^{7} yr. Using simple models of halo occupation, these correspond to a number
density of quasar hosts greater than 10^{-3} h^{3} Mpc^{-3} and stellar masses
less than 10^{11} h^{-1} M_sun. The small-scale clustering signal can be
interpreted with the aid of our mock LRG catalogs, and depends on the manner in
which quasars inhabit halos. We find that our small scale measurements are
inconsistent with quasar positions being randomly subsampled from halo centers
above a mass threshold, requiring a satellite fraction > 25 per cent.
