Consider two copies of a general pure two-mode Fock state with a definite number of photons N as follows.
|ψ⟩TMFS=∑Nn=0cn|n⟩a|N−n⟩b where cn are generic coefficients and a, b are the two modes. Some specific states that fall under this class of states are the Holland-Burnett states and the N00N states (with both mode and particle entanglement).
In analogy to the Bell measurement on two qubits, how to think of a corresponding entangling measurement that could create entanglement between the two copies of |ψ⟩TMFS. What would be the entangled two-copy basis for this measurement similar to the Bell basis?
Further, I would also like to extend it to scenarios that include more than two copies of |ψ⟩TMFS.
Are there any good references I can go through to think of this problem in a solid way? Thanks.