Broadband continuous variable entanglement generation using Kerr-free Josephson metamaterial

TL;DR

This paper demonstrates a Josephson metamaterial device that generates broadband entangled microwave photons and achieves single-mode squeezing, advancing quantum information processing capabilities.

Contribution

It introduces a Kerr-free Josephson metamaterial for high-rate entangled photon generation and reports the first single-mode squeezing in such devices.

Findings

2 Gbps entangled photon generation rate

Over 4 GHz bandwidth of entanglement

First demonstration of single-mode squeezing in Josephson devices

Abstract

Entangled microwave photons form a fundamental resource for quantum information processing and sensing with continuous variables. We use a low-loss Josephson metamaterial comprising superconducting, non-linear, asymmetric inductive elements to generate frequency-entangled photons from vacuum fluctuations at a rate of 2 giga entangled bits per second spanning over 4 GHz bandwidth. The device is operated as a traveling wave parametric amplifier under Kerr-relieving biasing conditions. Furthermore, we realize the first successfully demonstration of single-mode squeezing in such devices -- $3.1\pm0.7$\,dB below the zero-point level at half of modulation frequency.