Quantification of bipartite and multipartite entangled states in Mach-Zehnder interferometer

In the present study, the amount of entanglement of the quantum states capable of being used in an optical interferometer such as the Mach-Zehnder one was characterized and determined, and their relationship to the phase sensitivity was also examined. In other words, the multipartite entanglement of single-input, twin-input and N00N states were investigated in terms of the number of photon states entering Mach-Zehnder interferometer. In addition, the spatial modes of entanglement produced by Mach-Zehnder interferometer-as bipartite entangled states for Fock and squeezed states-was also determined. The amount of spatial modes of entanglement showed the interference of the quantum states. It was found that the more amount of the photon entanglement in twin-input and N00N states leads to the improvement of the phase sensitivity of the interferometer. In the squeezed state, by increasing the squeezed parameter of the two modes, their entanglement as well as their phase sensitivity was enhanced.