  The quantum wave function of multiple particles provides additional
information which is inaccessible to detectors working alone. Here, we
introduce the coincidence wavefront sensing (CWS) method to reconstruct the
phase of the multiphoton transverse spatial wave function. The spatially
resolved coincidence photon counting is involved. Numerical simulations of
two-photon cases using the weak measurement wavefront sensor are performed to
test its correctness, and the phase information hidden in the correlation are
revealed. Our work provides a direct spatial way to characterize multipartite
quantum systems, and leads to fundamental studies like experimental Bohmian
mechanics and applications in quantum optical technologies.
