Entanglement by a beam splitter: Nonclassicality as a prerequisite for entanglement

Abstract

The entangling properties of a beam splitter for various pure inputs states including Fock states and squeezed states were studied. A simple formula was found to determine the entanglement of the output fields for squeezed input fields. The entanglement of the output fields when the input fields are in a Gaussian mixed state was examined. A sufficient condition for input fields was provided to have no entanglement in the output state. It was found that the entanglement of the output state is strongly related to the nonclassicality of the input fields.