  We investigate the resolution for imaging two pointlike entangled sources by
using the method of the moments and the spatial-mode demultiplexing (SPADE),
where the pointlike entangled sources can be generated by injecting single-mode
sources with arbitrary quantum statistics distribution into an optical
parametric amplifier (OPA). We demonstrate that the separation estimation
sensitivity is mainly determined by the photon distribution in each detected
modes and it can be enhanced by either increasing the squeezed parameter of the
OPA or eliminating the relative phase difference of the entangle sources.
Furthermore, in the limiting case of infinitely small source separation, the
usage of entangled sources can have better resolution than those using
incoherent and coherent sources. The results here can find important
applications for the quantum super-resolution imaging and quantum metrology.
