Quantum teleportation over thermal microwave network

TL;DR

This paper demonstrates microwave quantum teleportation over a thermal network at temperatures up to 4 K, showing feasibility for distributed superconducting quantum systems despite noise and loss.

Contribution

It presents the first successful microwave quantum teleportation over a thermal microwave channel at temperatures up to 4 K, modeling the process with a Gaussian formalism.

Findings

Achieved teleportation fidelities of 72.3% at 1 K and 59.9% at 4 K

Distributed two-mode squeezed states over a noisy thermal channel

Modeling shows infidelity mainly due to parasitic heating of quantum nodes

Abstract

Quantum communication in the microwave regime is set to play an important role in distributed quantum computing and hybrid quantum networks. However, typical superconducting quantum circuits require millikelvin temperatures for operation, which poses a significant challenge for largescale microwave quantum networks. Here, we present a solution to this challenge by demonstrating the successful quantum teleportation of microwave coherent states between two spatially-separated dilution refrigerators over a thermal microwave channel in the temperature range up to $4$ K. We distribute two-mode squeezed states over this noisy channel and employ the resulting quantum entanglement for quantum teleportation of coherent states with fidelities of $72.3 \pm 0.5 ~\%$ at $1$ K and $59.9 \pm 2.5 \%$ at $4$ K, exceeding the no-cloning and classical communication thresholds, respectively. We successfully model the teleportation protocol using a Gaussian operator formalism that includes losses and noise. Our analysis shows that the teleportation infidelity mainly stems from a parasitic heating of the cold quantum nodes due to the hot network connection. These results demonstrate the experimental feasibility of distributed superconducting architectures and motivate further investigations of noisy quantum networks in various frequency regimes.