Observation of two-mode squeezing in a traveling wave parametric amplifier

TL;DR

This paper demonstrates that a traveling wave parametric amplifier can generate broadband two-mode squeezed microwave states, advancing quantum microwave photonics with potential applications in sensing and quantum computing.

Contribution

First experimental demonstration of two-mode squeezing in a traveling wave parametric amplifier for microwave quantum states.

Findings

Broadband entanglement generated between modes separated by up to 400 MHz

Logarithmic negativity between 0.27 and 0.51

Quadrature squeezing below vacuum limit between 1.5 and 2.1 dB

Abstract

Traveling wave parametric amplifiers (TWPAs) have recently emerged as essential tools for broadband near quantum-limited amplification. However, their use to generate microwave quantum states still misses an experimental demonstration. In this letter, we report operation of a TWPA as a source of two-mode squeezed microwave radiation. We demonstrate broadband entanglement generation between two modes separated by up to 400 MHz by measuring logarithmic negativity between 0.27 and 0.51 and collective quadrature squeezing below the vacuum limit between 1.5 and 2.1 dB. This work opens interesting perspectives for the exploration of novel microwave photonics experiments with possible applications in quantum sensing and continuous variable quantum computing.