  Quantum interference is investigated within the complex quantum
Hamilton-Jacobi formalism. As shown in a previous work [Phys. Rev. Lett. 102,
250401 (2009)], complex quantum trajectories display helical wrapping around
stagnation tubes and hyperbolic deflection near vortical tubes, these
structures being prominent features of quantum caves in space-time Argand
plots. Here, we further analyze the divergence and vorticity of the quantum
momentum function along streamlines near poles, showing the intricacy of the
complex dynamics. Nevertheless, despite this behavior, we show that the
appearance of the well-known interference features (on the real axis) can be
easily understood in terms of the rotation of the nodal line in the complex
plane. This offers a unified description of interference as well as an elegant
and practical method to compute the lifetime for interference features, defined
in terms of the average wrapping time, i.e., considering such features as a
resonant process.
