  We studied the effect of delocalized single-photon addition (DPA) on two
input modes containing four cases: two independent coherent states (CSs), two
independent thermal states (TSs), two independent single-mode squeezed vacuums
(SVs), and an entangled two-mode squeezed vacuum (TMSV). In essence, four types
of new non-Gaussian entangled light states are generated. We studied three
different resources (including entanglement, discorrelation and Wigner
negativity) for each two-mode light state. The output states after DPA are
entangled, with more parameters and complex structures, characterizing more
Wigner negativity or even discorrelation. In contrast, the CSs case is the most
tunable protocol, because its negativity under partial transposition,
discorrelation, and Wigner logarithmic negativity are more sensitive to
superposition phase than those in TSs, SVs and TMSV cases.
