# Finite-time quantum entanglement in propagating squeezed microwaves

## TL;DR

This paper demonstrates the generation and analysis of propagating microwave two-mode squeezed states, revealing finite-time entanglement limits and supporting high-fidelity quantum communication protocols.

## Contribution

It introduces a method to generate propagating microwave TMS states using Josephson parametric amplifiers and models their dephasing process.

## Key findings

- Finite-time entanglement limits are characterized.
- Theoretical model accurately describes dephasing.
- High fidelities predicted for quantum communication protocols.

## Abstract

Two-mode squeezing is a fascinating example of quantum entanglement manifested in cross-correlations of incompatible observables between two subsystems. At the same time, these subsystems themselves may contain no quantum signatures in their self-correlations. These properties make two-mode squeezed (TMS) states an ideal resource for applications in quantum communication. Here, we generate propagating microwave TMS states by a beam splitter distributing single mode squeezing emitted from distinct Josephson parametric amplifiers along two output paths. We experimentally study the fundamental dephasing process of quantum cross-correlations in continuous-variable propagating TMS microwave states and accurately describe it with a theory model. In this way, we gain the insight into finite-time entanglement limits and predict high fidelities for benchmark quantum communication protocols such as remote state preparation and quantum teleportation.