Open-Air Microwave Entanglement Distribution for Quantum Teleportation*

Experiments about entanglement distribution, key ingredient in quantum communication, have focused on optical regime. However, microwaves show advantages regarding low absorption rates and low energy consumption, and it is the working frequency in superconducting circuits. Here, we propose a feasibility analysis of an open-air entanglement distribution scheme in the microwave regime with two-mode squeezed states, which are accurately preparable entangled states in continuous-variable settings. Firstly, we adapt to the microwave technology both entanglement distillation and entanglement swapping, two techniques to reduce environmental entanglement degradation. Secondly, we compute the fidelity of a quantum teleportation protocol employing these states as resources, observing that entanglement is completely degraded after a distance around 300 m. While entanglement distillation can increase quantum correlations in the short-distance low-squeezing regime, entanglement swapping can extend their reach. Finally, we explore applications in satellite communication, where the thermal noise substantially reduces. This work can also find relevant applications in distributed quantum computing and quantum internet.