Quantum Teleportation over Thermal Microwave Network.

Area of Science:

• Quantum Information Science
• Superconducting Quantum Circuits
• Quantum Networks

Background:

• Microwave quantum communication is crucial for distributed quantum computing and hybrid quantum networks.
• Superconducting quantum circuits typically require millikelvin temperatures, hindering large-scale network development.

Purpose of the Study:

• To demonstrate quantum teleportation of microwave coherent states over a noisy thermal channel at elevated temperatures (up to 4 K).
• To address the challenge of operating quantum circuits at higher temperatures for scalable quantum networks.

Main Methods:

• Utilized two spatially separated dilution refrigerators.
• Distributed two-mode squeezed states over a thermal microwave channel.
• Employed quantum entanglement for teleportation of coherent states.
• Modeled the protocol using Gaussian operator formalism, including losses and noise.

Main Results:

• Achieved quantum teleportation of coherent states with fidelities of 72.3±0.5% at 1 K and 59.9±2.5% at 4 K.
• Exceeded the no-cloning and classical communication thresholds.
• Identified parasitic heating of quantum nodes as the primary source of infidelity.

Conclusions:

• Demonstrated the experimental feasibility of distributed superconducting architectures operating at higher temperatures.
• Motivated further research into noisy quantum networks across various frequency regimes.
• Showcased a viable solution for scalable microwave quantum networks.