Extraction of displaced number states

摘要

We focus on implementation and optimization of an irreversible analog of the Hadamard gate. Three optical schemes are considered for the purpose. Two of them are probabilistic. Another is deterministic provided that a special auxiliary state is prepared beforehand. One of the optical schemes is based on photon subtraction. Number and displaced number states of the quantum oscillator are connected with each other through unitary transformation matrix. Extraction of displaced photons from initial optical beams makes it possible to improve characteristics of the analog of the Hadamard gate. We also present detailed analysis of one of the studied schemes in a realistic scenario. Results stemming from a realistic model coincide with those following from a simplified model.