Heralded hybrid CV-DV entanglement generation by quantum interference between CV state and DV delocalized photon

TL;DR

This paper proposes a resource-efficient method to generate hybrid continuous-variable and discrete-variable entangled states using quantum interference, applicable under various experimental conditions and input states.

Contribution

A novel, resource-efficient scheme for heralded hybrid CV-DV entanglement generation using quantum interference with broad applicability.

Findings

The method reliably produces hybrid entanglement regardless of beam-splitter parameters.

Generated states exhibit nonclassical properties and measurable entanglement.

The approach works with truncated CV states and includes a simple method for producing specific CV states.

Abstract

Hybrid entangled states prove to be necessary for quantum information processing within heterogeneous quantum networks. A method with irreducible number of consumed resources that firmly provides hybrid CV-DV entanglement for any input conditions of the experimental setup is proposed. Namely, a family of CV states is introduced. Each of such CV states is first superimposed on a beam-splitter with a delocalized photon and then detected by a photo-detector behind the beam-splitter. Detection of any photon number heralds generation of a hybrid CV-DV entangled state in the outputs, independent of transmission/reflection coefficients of the beam-splitter and size of the input CV state. Nonclassical properties of the generated state are studied and their entanglement degree in terms of negativity is calculated. There are wide domains of values of input parameters of the experimental setup that can be chosen to make the generated state maximally entangled. The proposed method is also applicable to truncated versions of the input CV states. We also propose a simple method to produce even/odd CV states.