Entangled coherent states by mixing squeezed vacuum and coherent light

TL;DR

This paper demonstrates a method to generate high-fidelity entangled coherent states by mixing squeezed vacuum and coherent light on a beam-splitter, with potential applications in quantum communication.

Contribution

It introduces a deterministic scheme for creating entangled coherent states with small amplitudes using readily available optical states.

Findings

High fidelity entangled states achieved experimentally.

Nearly perfect similarity with ideal entangled coherent states.

Potential for deterministic entanglement distribution over long distances.

Abstract

Entangled coherent states are shown to emerge, with high fidelity, when mixing coherent and squeezed vacuum states of light on a beam-splitter. These maximally entangled states, where photons bunch at the exit of a beamsplitter, are measured experimentally by Fock-state projections. Entanglement is examined theoretically using a Bell-type nonlocality test and compared with ideal entangled coherent states. We experimentally show nearly perfect similarity with entangled coherent states for an optimal ratio of coherent and squeezed vacuum light. In our scheme, entangled coherent states are generated deterministically with small amplitudes, which could be beneficial, for example, in deterministic distribution of entanglement over long distances.