  We report the first experimental study of the quantum interference correction
to the conductivity of bilayer graphene. Low-field, positive
magnetoconductivity due to the weak localisation effect is investigated at
different carrier densities, including those around the electroneutrality
region. Unlike conventional 2D systems, weak localisation in bilayer graphene
is affected by elastic scattering processes such as intervalley scattering.
Analysis of the dephasing determined from the magnetoconductivity is
complemented by a study of the field- and density-dependent fluctuations of the
conductance. Good agreement in the value of the coherence length is found
between these two studies.
