Converting beam polarizations into entanglement and classical correlation

Abstract

The nonclassicality of a macroscopic single-mode optical superposition state is potentially convertible into entanglement, when the state is mixed with the vacuum on a beam splitter. Considering light beams with polarization degree of freedom in Euclidean space as coherent product states in a bipartite Hilbert space, we propose a method to convert the polarization amplitudes into entanglement and classical correlation through generating nonclassicality in the superpositions of coherent and displaced Fock states. Equivalent Bell state emerges from the resulted superpositions and the proportion of mixed entanglement and correlation, quantified by the metric pair of negativity and Schmidt number, is determined by the two displacements along the polarization directions. We further characterize the constructed states with Wigner functions and propose an experimental method for generating these states and measuring them via homodyne tomography