Non-gaussian Entanglement Swapping between Three-Mode Spontaneous Parametric Down Conversion and Three Qubits

TL;DR

This paper demonstrates the generation and swapping of non-Gaussian tripartite entanglement between photons and qubits in a parametric amplification setup, highlighting potential applications in quantum metrology and computing.

Contribution

It introduces witnesses for genuine tripartite non-Gaussian entanglement and shows entanglement swapping from photons to qubits in a novel setup.

Findings

Entanglement is of non-Gaussian nature.

Entanglement can be swapped from photons to qubits.

Qubits exhibit genuine tripartite non-Gaussian entanglement over a wide parameter range.

Abstract

In this work we study the production and swapping of non-gaussian multipartite entanglement in a setup containing a parametric amplifier which generates three photons in different modes coupled to three qubits. We prove that the entanglement generated in this setup is of nongaussian nature. We introduce witnesses of genuine tripartite nongaussian entanglement, valid both for mode and qubit entanglement. Moreover, those witnesses show that the entanglement generated among the photons can be swapped to the qubits, and indeed the qubits display nongaussian genuine tripartite entanglement over a wider parameter regime, suggesting that our setup could be a useful tool to extract entanglement generated in higher-order parametric amplification for quantum metrology or quantum computing applications.