  We study Reeb dynamics on prequantization circle bundles and the filtered
(equivariant) symplectic homology of prequantization line bundles, aka negative
line bundles, with symplectically aspherical base. We define (equivariant)
symplectic capacities, obtain an upper bound on their growth, prove uniform
instability of the filtered symplectic homology and touch upon the question of
stable displacement. We also introduce a new algebraic structure on the
positive (equivariant) symplectic homology capturing the free homotopy class of
a closed Reeb orbit -- the linking number filtration -- and use it to give a
new proof of the non-degenerate case of the contact Conley conjecture (i.e.,
the existence of infinitely many simple closed Reeb orbits), not relying on
contact homology.
