ИСТИНА

Quantum photonics often demands new better ways of creating special quantum states of light [1,2] to implement quantum information processing algorithms. We consider linear-optical scheme for generation of the parametrized state in the dual-rail qubit encoding: ψ(α)=cosα|1010>+sinα|1010>, where is a variable parameter that define specific state with corresponding to the well-known Bell state. We analyze possible heralding scenarios that differ by the measurement pattern of the auxiliary modes necessary for successful generation of the parametrized state. Namely, the patterns were: 1) a two-photon event in a single auxiliary mode and 2) two single-photon events in two auxiliary modes. Using a custom numerical method of global optimization with a judiciously chosen objective function [3], optimal multiport scheme containing minimal possible functional elements have been found. In Fig. 1 the optimal scheme generating Bell state ψ(π/4) is depicted. In addition, the dependence of the probability of successful generation of the parametrized states is found using the optimization method.