  We present a clustering analysis of QSOs over the redshift range z=0.3-2.9.
We use a sample of 10558 QSOs taken from the preliminary catalogue of the 2dF
QSO Redshift Survey (2QZ). The two-point redshift-space correlation function of
QSOs is shown to follow a power law on scales s~1-35h-1Mpc. Fitting a power law
to QSO clustering averaged over the redshift interval 0.3<z<2.9 we find
s_0=3.99+0.28-0.34h-1Mpc and gamma=1.58+0.10-0.09 for an Einstein-de Sitter
cosmology (EdS). With Omega_0=0.3 and lambda_0=0.7 the power law extends to
s~60h-1Mpc with a best fit of s_0=5.69+0.42-0.50h-1Mpc and
gamma=1.56+0.10-0.09. These values, measured at a mean redshift of z=1.49, are
comparable to the clustering of local optically selected galaxies. We measure
the evolution of QSO clustering as a function of redshift. For an EdS cosmology
there is no evolution in comoving coordinates over the redshift range of the
2QZ. For Omega_0=0.3 and lambda_0=0.7 QSO clustering shows a marginal increase
at high redshift. Although the clustering of QSOs is measured on large scales
where linear theory should apply, the evolution of QSO clustering does not
follow the linear theory predictions for growth via gravitational instability
(rejected at the >99 per cent confidence level). A redshift dependent bias is
required to reconcile QSO clustering observations with theory. A simple biasing
model, in which QSOs have cosmologically long lifetimes (or alternatively form
in peaks above a constant threshold in the density field) is acceptable in an
EdS cosmology, but is only marginally acceptable if Omega_0=0.3 and
lambda_0=0.7. Biasing models which assume QSOs form over a range in redshift,
based on the Press-Schechter formalism are approximately consistent with QSO
clustering evolution (abridged).
