  We study the quantum probability to survive in an open chaotic system in the
framework of the van Vleck-Gutzwiller propagator and present the first such
calculation that accounts for quantum interference effects. Specifically we
calculate quantum deviations from the classical decay after the break time for
both broken and preserved time-reversal symmetry. The source of these
corrections is identified in interfering pairs of correlated classical
trajectories. In our approach the quantized chaotic system is modelled by a
quatum graph.
